Tag Archives: apache

Cassandra – Getting Started – (deployment Part 2 – Installing Ops Center)

26 March 2012 David 1 Comment

<< Previous: Cassandra – Going into Production – Part 2.

With an empty cluster running, the next step I’m going to take is to install and configure OpsCenter from DataStax. This is a fantastic tool for monitoring the health and performance of your cluster.

Installing Ops Center

The first order of business is to create a directory to store the Ops Center code on the server. I opted to do this within the user account used for Cassandra, as the directory datastax


:~$ mkdir datastax
:~$

Next, download and extract the OpsCenter package:


:~/datastax$ wget http://downloads.datastax.com/community/opscenter-1.4-free.tar.gz
--2012-03-26 08:25:30--  http://downloads.datastax.com/community/opscenter-1.4-free.tar.gz
Resolving downloads.datastax.com... 173.203.57.192
Connecting to downloads.datastax.com|173.203.57.192|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 21539843 (21M) [application/octet-stream]
Saving to: `opscenter-1.4-free.tar.gz'

100%[=======================================================================>] 21,539,843  3.72M/s   in 7.5s    

2012-03-26 08:25:38 (2.74 MB/s) - `opscenter-1.4-free.tar.gz' saved [21539843/21539843]

:~/datastax$ tar -xvzf opscenter-1.4-free.tar.gz
opscenter-1.4/
opscenter-1.4/log/
opscenter-1.4/bin/
opscenter-1.4/bin/create-keystore.bat
opscenter-1.4/bin/create-key-pair.bat
[...]
opscenter-1.4/conf/event-plugins/email.conf
opscenter-1.4/conf/ssl.conf
opscenter-1.4/conf/opscenterd.conf

:~/datastax$

Next is the setup for OpsCenter. Setup is done via a Python script, located in the BIN directory. Have your listening IP ready and know which port you want to use for the Ops Center web portal. I’m going to use the default of port 8888. Make sure you have the port open on your machine. (click here to jump to the my section on ports).


:~/datastax$ ls
opscenter-1.4  opscenter-1.4-free.tar.gz
:~/datastax$ cd opscenter-1.4
:~/datastax/opscenter-1.4$ bin/setup.py
Generating a 1024 bit RSA private key
.........++++++
...++++++
writing new private key to 'ssl/opscenter.key'
-----
MAC verified OK
Certificate was added to keystore

:~/datastax/opscenter-1.4$

Configure the Ops Center deamon. Set the listening IP to an IP available on the system. I’m going to node’s interal IP address (10.1.0.23). The values I’ve changed are in bold.


:~/datastax/opscenter-1.4$ vi conf/opscenterd.conf
[...]
[jmx]
# The default jmx port for Cassandra >= 0.8.0 is 7199.  If you are using
# Cassandra 0.7.*, the default is 8080, and you should change this to
# reflect that.
port = 8001
[...] 
[webserver]
port = 8888
interface = 10.1.0.23
staticdir = ./content
log_path = ./log/http.log
[...]
[cassandra]
# a comma-separated list of places to try for a connection to your Cassandra
# cluster:
seed_hosts = 10.1.0.23,10.1.0.26
[...]

Installing the Ops Center Agents

Each node in the cluster must have a running Ops Center agent. The installation package for this was generated by the Ops Center setup process, and saves a compressed file. This file then needs to be copied and extracted on each node you plan to monitor with the Ops Center.


:~/datastax$ mkdir opscenter-agent
:~/datastax$ cp opscenter-1.4/agent.tar.gz opscenter-agent/
:~/datastax$ cd opscenter-agent/
:~/datastax/opscenter-agent$ tar -xvzf agent.tar.gz
agent/opscenter-agent-2.5-standalone.jar
agent/conf/log4j.properties
agent/bin/setup.bat
[...]
agent/bin/ssl/agentKeyStore.p12
agent/bin/ssl/opscenter.key
agent/doc/LICENSE

:~/datastax/opscenter-agent$

Now run the agent’s setup, assigning it’s IP and the Ops Center’s IP. 10.1.0.26 is this node’s IP address. 10.1.0.23 is the location of the Ops Center install (this may or may not be on the same system or even the same IP address):


:~/datastax/opscenter-agent$ agent/bin/setup 10.1.0.26 10.1.0.23

Make sure you copy the agent file to ALL your other nodes and follow the same setup procedure (this is an example of how I copied the file, your system, ports etc. may be different), and repeat the steps above, with the appropriate IPs.


:~/datastax/opscenter-agent$ scp -P41718 agent.tar.gz bigdata@10.1.0.26:.
RSA key fingerprint is 2b:5b:26:03:87:a4:b1:ea:90:b5:4e:42:60:88:cd:d1.
bigdata@10.1.0.26's password: 
agent.tar.gz                                                                   100%   10MB  10.3MB/s   00:01    
:~/datastax/opscenter-agent$

Start up Ops Center

On the Ops Center machine, move back to it’s installed directory and start the process.


:~/datastax$ cd opscenter-1.4
~/datastax/opscenter-1.4$ bin/opscenter &

Now connect to the IP address and port and you should see a base Ops Center instance. This is what you would typically see before starting up your agents:

OpsCenter 2012-03-26 at 9.05.18 AM — DataStax Ops Center 1.4

Start up the Node Agents

The last step is to start up the Agent deamons so that the OpsCenter knows the status of each node.


:~/datastax/opscenter-1.4$ cd ../opscenter-agent/
:~/datastax/opscenter-agent$ agent/bin/opscenter-agent &
:~/datastax/opscenter-agent$  INFO [main] 2012-03-26 09:12:40,465 Loading conf files: conf/address.yaml
 INFO [main] 2012-03-26 09:12:40,505 Java vendor/version: Java HotSpot(TM) 64-Bit Server VM/1.7.0_03
 INFO [main] 2012-03-26 09:12:40,505 Waiting for the config from OpsCenter
 INFO [main] 2012-03-26 09:12:40,637 SSL communication is enabled
 INFO [main] 2012-03-26 09:12:40,637 Creating stomp connection to 10.1.0.23:61620

With the Agents fired up, you will see a nice dashboard, showing the current status of the cluster, and some metrics on performance.

OpsCenter 2012-03-26 at 9.22.47 AM — Ops Center up and running.

Conclusion

This basically concludes the fast deployment steps required to download, install, configure and start up Cassandra, along with the DataStax Ops Center.

Total time required to deploy was under 4 hours.

Software Development, Technology

Cassandra – Getting Started – (deployment Part 1 – Installing Cassandra)

26 March 2012 David 2 Comments

It’s been almost a month since I started the Apache Cassandra investigation, and now it’s time to move into a production stance. Some of these steps will differ from the original steps documented here in my blog. Later this week I will go back and amend those posts to point at this post as the more recent information. Those old links are already being referenced by multiple sites, so deleting them would not be a kind thing to do. Thus.. onward we move!

Getting the right JVM/JDK/JRE

Originally, the OpenJDK was being used for this introduction and research into Cassandra. Being a proponent of Open Source, I was going to avoid the use of Oracle’s potentially proprietary JDK/JRE in this environment. I have since seen first had, that the JDK DOES IN FACT MATTER, and the one that supports the latest tools is the one from Oracle.

That is located here:

Java SE Development Kit 7 Downloads – download this if you plan to do any Java development.
Java SE Runtime Environment 7 Downloads – Download this if you just want to run Java programs, and do not plan to write your own.

Downloading the JRE/JDK from Oracle has enabled the reliable use of DataStax’s OpsCenter management tool (more on that later).

These are the recommended minimums for Cassandra and OpsCenter from DataStax, a respected partner of the Apache Cassandra project.

Sun Java Runtime Environment 1.6.0_19 or later
Python 2.5, 2.6, or 2.7
OpenSSL version listed in Configuring SSL unless you disable SSL

I ended up selecting the JDK (linked here) and deposited it in the following location on my system as user root (create the directory path if you don’t already have it):


/opt/java/64/jdk-7u3-linux-x64.tar.gz

Extract the file:


:/opt/java/64# tar -xvzf jdk-7u3-linux-x64.tar.gz
jdk1.7.0_03/
jdk1.7.0_03/include/
jdk1.7.0_03/include/jvmti.h
jdk1.7.0_03/include/jawt.h
[...]
jdk1.7.0_03/jre/plugin/desktop/sun_java.desktop
jdk1.7.0_03/jre/COPYRIGHT
jdk1.7.0_03/LICENSE
jdk1.7.0_03/COPYRIGHT
:/opt/java/64#

The Cassandra Build I decided to use is this one: apache-cassandra-1.1.0-beta1. I downloaded the file to the user I created for this using wget:


:~$ wget http://apache.deathculture.net/cassandra/1.1.0/apache-cassandra-1.1.0-beta1-bin.tar.gz
--2012-03-25 22:52:27--  http://apache.deathculture.net/cassandra/1.1.0/apache-cassandra-1.1.0-beta1-bin.tar.gz
Resolving apache.deathculture.net... 173.236.158.254
Connecting to apache.deathculture.net|173.236.158.254|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 12505037 (12M) [application/x-gzip]
Saving to: `apache-cassandra-1.1.0-beta1-bin.tar.gz'

100%[=======================================================================>] 12,505,037  8.84M/s   in 1.3s    

2012-03-25 22:52:29 (8.84 MB/s) - `apache-cassandra-1.1.0-beta1-bin.tar.gz' saved [12505037/12505037]

Next the file is extracted, moved to a shorter directory name:


:~$ tar -xvzf apache-cassandra-1.1.0-beta1-bin.tar.gz
:~$ mv apache-cassandra-1.1.0-beta1 cass-beta1

Configuring a Node

Now the configuration is edited to define the node ring. The first file to edit is the cassandra.yaml file.

This initially will be only a 2 node cluster, but the tokens must still be calculated. Here are the node tokens I generated using a PERL script I wrote (see: Cassandra and Big Data – building a single-node “cluster” – Extra Credit for the code):


:~/cass-beta1$ ./token.pl 2
Calculate tokens for 2 nodes
factor = 170141183460469231731687303715884105728
node 0	token: 0
node 1	token: 85070591730234615865843651857942052864
:~/cass-beta1$

Edit the cluster name. I’m not testing, so I changed the name to one descriptive of the data I was storing. ‘ip’. In the example below, I’m showing configs for the 2nd of the two nodes. Note: The first node would have a different IP address and also a different initial token, in this case ‘0’, as calculated by the tool.


:~$ cd cass-beta1/
:~/cass-beta1$ vi conf/cassandra.yaml

[...]

# The name of the cluster. This is mainly used to prevent machines in
# one logical cluster from joining another.
cluster_name: 'ip'

[...]

 If blank, Cassandra will request a token bisecting the range of
# the heaviest-loaded existing node.  If there is no load information
# available, such as is the case with a new cluster, it will pick
# a random token, which will lead to hot spots.
initial_token: 85070591730234615865843651857942052864

[...]

# directories where Cassandra should store data on disk.
data_file_directories:
    - /home/bigdata/data/

[...]

# commit log
commitlog_directory: /home/bigdata/commitlog/

[...]

# saved caches
saved_caches_directory: /home/bigdata/saved_caches/

[...]

          # seeds is actually a comma-delimited list of addresses.
          # Ex: ",,"
          - seeds: "10.1.100.101,10.1.100.102"
[...]

# Setting this to 0.0.0.0 is always wrong.
listen_address: 10.1.1.101

[...]

rpc_address: 10.1.1.101

[...]

# Time to wait for a reply from other nodes before failing the command (this was done to increase timeout to 30 seconds, sometimes the search I need to run is pretty nasty)
rpc_timeout_in_ms: 30000

Following that, the shell file needs to be modified to designate the JMX listening port:


:~/cass-beta1$ vi conf/cassandra-env.sh

[...]

# Specifies the default port over which Cassandra will be available for
# JMX connections.
JMX_PORT="8001"

[...]

Make sure your logfile is in the desired location. I decided to keep it within the account itself for now:


vi cassA-1.0.8/conf/log4j-server.properties
[...]

log4j.appender.R.File=/home/bigdata/log/cassA.log

[...]

Next I set the paths in the .bash configuration file for the account, using the following 3 environment variables (ANT_HOME is used by the ANT compiler, if you are not writing code, your JAVA_HOME will point at the JRE, not the JDK, and you won’t need the ANT_HOME path at all):


vi ~/.bash_profile
export JAVA_HOME=/opt/java/64/jdk1.7.0_03
export ANT_HOME=/usr/lib/ant/
export CASS_BIN=$HOME/cass-beta1/bin
export PATH=$PATH:$ANT_HOME/bin:$CASS_BIN

Systems Administration

Make sure there is a location for the cassandra server to write it’s log files. You’ll need your SysAdmin, or root privs, to do this. I set the ownership to root and the user under which I’m currently running cassandra (bigdata):


root:/data/feed/indata# cd /var/log
root:/var/log# mkdir cassandra
root:/var/log# chown root:bigdata cassandra
root:/var/log# chmod 775 cassandra

The following ports need to be opened up, if you are running a firewall on each system (you ARE, right!?!), to allow Cassandra nodes to communicate with each other. This is a snippet from my rules-based firewall control file.

Port Usage:

9160 – Thrift port, where the API is serviced for Reads/Writes to Cassandra
8001 – Individual node listening port. This is used for the command line (cli)
7000 – Commands and Data TCP port, used nodes for communications
7001 – SSL port used for storage communications
8888 – Only used on systems that will host an Ops Center installation
61620 – Required for Ops Center Agent Communications


## Cassandra
ACCEPT          loc             $FW             tcp     9160,8001,7000,7001
## OpsCenter
ACCEPT          loc             $FW             tcp     8888,61620

Starting up the Cluster

This is where the truth is told. The rubber meets the road. The money is placed where your mouth is. Light ’em up!


:~$ cassandra
:~$  INFO 23:52:54,232 Logging initialized
 INFO 23:52:54,236 JVM vendor/version: Java HotSpot(TM) 64-Bit Server VM/1.7.0_03
 INFO 23:52:54,237 Heap size: 6291456000/6291456000
[...]
INFO 23:52:55,162 Node /10.1.0.23 state jump to normal
 INFO 23:52:55,163 Bootstrap/Replace/Move completed! Now serving reads.

IT LIVES!! Now start your other node(s), and check to verify you have a complete ring, properly configured. You should see something like this in subsequent nodes, I’ve highlighted the references to the other member node:


[...]
INFO 23:54:16,042 Node /10.1.0.23 has restarted, now UP
 INFO 23:54:16,043 InetAddress /10.1.0.23 is now UP
 INFO 23:54:16,043 Node /10.1.0.23 state jump to normal
 INFO 23:54:16,088 Compacted to [/home/bigdata/data/system/LocationInfo/system-LocationInfo-hc-6-Data.db,].  544 to 413 (~75% of original) bytes for 4 keys at 0.003425MB/s.  Time: 115ms.
 INFO 23:54:16,109 Completed flushing /home/bigdata/data/system/LocationInfo/system-LocationInfo-hc-5-Data.db (163 bytes)
 INFO 23:54:16,110 Node /10.1.0.26 state jump to normal
 INFO 23:54:16,111 Bootstrap/Replace/Move completed! Now serving reads.

Run nodetool:


:~$ nodetool -h10.1.0.23 -p 8001 ring
Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               85070591730234615865843651857942052864      
10.1.0.23      datacenter1 rack1       Up     Normal  17.77 KB        50.00%  0                                           
10.1.0.26      datacenter1 rack1       Up     Normal  17.66 KB        50.00%  85070591730234615865843651857942052864

WE HAVE A RING!

NEXT: SETTING UP OPS CENTER

Software Development, Technology

Inserting and Reading data from a Cassandra Cluster

19 March 2012 David Leave a comment

Rubber meeting the road. Time to insert some column families, then some data and finally pull it back off the stack.

First off, the keyspace was already defined, so I’m going to simply list it’s structure:


[default@unknown] describe ip_store;

Keyspace: ip_store:
  Replication Strategy: org.apache.cassandra.locator.SimpleStrategy
  Durable Writes: true
    Options: [replication_factor:2]

With a keyspace ready for some column families, those are created next. Here I’m establishing that there will be 4 families in this single keyspace. This is contrary to suggestions in the High Performance Cassandra Handbook, but follows all other documentation I’ve seen. Considering that this is NOT a production implementation, I’m going to go with a more conventional strategy of organizing related data in the same keyspace.

The first action is to assume the desired keyspace, then add the desired column families:


[default@unknown] use ip_store;
Authenticated to keyspace: ip_store

[default@ip_store] create column family warehouse with comparator = UTF8Type;
595945d0-71ce-11e1-0000-13393ec611bf
Waiting for schema agreement...
... schemas agree across the cluster

[default@ip_store] create column family hourly with comparator = UTF8Type;
65ea2170-71ce-11e1-0000-13393ec611bf
Waiting for schema agreement...
... schemas agree across the cluster

[default@ip_store] create column family daily with comparator = UTF8Type; 
6aaeae60-71ce-11e1-0000-13393ec611bf
Waiting for schema agreement...
... schemas agree across the cluster

[default@ip_store] create column family 30day with comparator = UTF8Type;
7b85bf30-71ce-11e1-0000-13393ec611bf
Waiting for schema agreement...
... schemas agree across the cluster

OK, a basic schema has been established. Now.. to load the data. I’ll post the relevant sections of the loader code at a later date. At this point you only need to consider that the loader DOES work and it’s loading data. We’ll look at the extraction of the data following loading a very small set.


time host=10.1.0.23 port=9160 ks=ip_store cf=warehouse ttl=0 datafile=5.ips ant -DclassToRun=loader.bulkIpLoader run
Buildfile: cBuild/build.xml

init:

compile:
    [javac] Compiling 1 source file to cBuild/build/classes

dist:
      [jar] Building jar: cBuild/dist/lib/cass.jar

run:
     [java] ks       ip_store
     [java] cf       warehouse
     [java] ttl      0
     [java] datafile 5.ips

BUILD SUCCESSFUL
Total time: 1 second

Of the set, there are three unique IPs and 2 are duplicates of other data (IMPORTANT NOTE: The IP’s have been changed to protect the innocent and clueless):


2016468288	1011	suspicious	2012-03-13 18:40:01
2016468288	1011	suspicious	2012-03-13 18:40:02
3149138705	1011	suspicious	2012-03-13 18:40:00
3149138705	1011	suspicious	2012-03-13 18:40:01
2179293112	1011	suspicious	2012-03-13 18:39:59

Having loaded these, I re-launch the command line interface, authenticate to the desired keyspace, and then a VERY important command to set an assumption about how we’re going to reference the keys. If you get a strange error like this “cannot parse ‘187.180.11.17’ as hex bytes“, that means you likely forgot to issue the assumes command. Commands I issued are in bold.


cass
Connected to: "ak-ip" on 10.1.0.23/9160
Welcome to Cassandra CLI version 1.0.8

[default@unknown] use ip_store

[default@ip_store] assume warehouse keys as utf8;   
Assumption for column family 'warehouse' added successfully.

[default@ip_store]  get warehouse['3149138705'];

=> (column=2012-03-13 18:40:00, value=7b227265706f72746564223a22323031322d30332d31332031383a34383a3031222c22617474726962757465223a22737573706963696f7573222c2270726f705f6964223a2231303131222c2270726f7065727479223a22426f74204375747761696c222c226465746563746564223a22323031322d30332d31332031383a34303a3030222c226d65746164617461223a22222c226970223a223139302e3137342e3235312e313435227d, timestamp=1332168862658)
=> (column=2012-03-13 18:40:01, value=7b227265706f72746564223a22323031322d30332d31332031383a34383a3031222c22617474726962757465223a22737573706963696f7573222c2270726f705f6964223a2231303131222c2270726f7065727479223a22426f74204375747761696c222c226465746563746564223a22323031322d30332d31332031383a34303a3031222c226d65746164617461223a22222c226970223a223139302e3137342e3235312e313435227d, timestamp=1331689681)
Returned 2 results.
Elapsed time: 39 msec(s).

There we go. A single key row ip_store[‘warehouse’][‘3149138705’] containing to column records, each with a JSON blob within it. Now.. the next step, to set the assumption of utf8 when recalling the records and get output mere mortals such as yourselves can understand.


[default@ip_store] assume warehouse validator as ascii; 
Assumption for column family 'warehouse' added successfully.

[default@ip_store]  t warehouse['3149138705'];  
     
=> (column=2012-03-13 18:40:00, 
  value={
   "reported":"2012-03-13 18:48:01",
   "attribute":"suspicious",
   "prop_id":"1011",
   "detected":"2012-03-13 18:40:00",
   "ip":"187.180.11.17"
  }, timestamp=1331689680)

=> (column=2012-03-13 18:40:01, 
  value={
    "reported":"2012-03-13 18:48:01",
    "attribute":"suspicious",
    "prop_id":"1011",
    "detected":"2012-03-13 18:40:01",
     "ip":"187.180.11.17"
  }, timestamp=1331689681)

Returned 2 results.
Elapsed time: 2 msec(s).

There is it! Data written, data read. Now, it’s up to you to think about how you might use this simple, flexible and powerful storage engine to solve your business needs.

Software Development, Technology

Drop keyspace using Cassandra Cli

18 March 2012 David Leave a comment

Dropping a an entire keyspace using the cassandra-cli is exceptionally simple.

First, access your cluster using the cli. I have an alias in my .bash_profile so I only need to type ‘cass’ to access the clid. In an attempt to be helpful though, I shall show the full command syntax for my environment. Your host and port may vary.


  alias cass='cassandra-cli -h 10.1.0.26'

In this example, I am going to drop the keyspace I was loading with test data in previous posts, ks33.


hpcass: ~$ cass
Connected to: "Test1" on 10.1.0.23/9160
Welcome to Cassandra CLI version 1.0.8

Type 'help;' or '?' for help.
Type 'quit;' or 'exit;' to quit.

DROP keyspace ks33;

07ad5e00-7120-11e1-0000-13393ec611bd
Waiting for schema agreement...
... schemas agree across the cluster
[default@unknown]

That’s all there was to it. Keyspace destroyed.

Previous Cassandra related articles

Apache Cassandra Project – processing “Big Data” – blog
Cassandra and Big Data – building a single-node “cluster” – blog
Cassandra – Getting a 3 node cluster built – apps
Java build env to prepare for Cassandra development – apps
Re-Configuring an Empty Cassandra Cluster – blog
Cassandra – Running some simple tests, including a multi-get strategy. – blog
Creating a simple Utils class – apps
Cassandra DB Connetor in Java, using Thrift API – apps
Java multi-get demonstrator for Cassandra NoSQL db – apps

Software Development, Technology

Cassandra – Running some simple tests, including a multi-get strategy.

14 March 2012 David 5 Comments

PREV: Re-Configuring an Empty Cassandra Cluster

Time for the rubber to meet the road. Get some data loaded and validate the theoretical concepts garnered from the documentation consumed.

This is an record example (IP’s have been changed to protect the clueless):

      ip_key: 1598595809
          ip: 10.2.162.225
     prop_id: 1033
    property: Bad Stuff
      threat: 1
   attribute: suspicious
        meta: 10.25.112.7
    detected: 2012-01-05 15:17:14
detected_sec: 1325805434
    reported: 2012-01-06 01:44:02
reported_sec: 1325843042

Preliminary model concept centers around the IP, however with over 60,000,000 records there are overlaps, so a single IP is not going to survive as the primary key. Trying to get a distribution out of MySQL takes some time. Here are some distributions by key. Thousands of of events per IP, and this is just a short 1 month window:

+------------+--------+
| ip_dec     | events |
+------------+--------+
| 3158358206 |   2705 |
|  652542280 |   2506 |
| 3495573656 |   2089 |
| 3232235778 |   2015 |
| 1072721396 |   1528 |
|  652542281 |   1432 |
| 3232235876 |   1427 |
| 3448822506 |   1232 |
| 1280052209 |   1106 |
| 3232235779 |   1086 |
+------------+--------+

Now, Cassandra will support MILLIONS of column items on a single row, thus, this actually might work, and scale without using Super Column Families (SCFs). Using the detected time seconds as the column name with an attribute suffix, then enclosing the data in a JSON blob could provide the required results. Using the datekey as a secondary index across the columns, or using them as a time progression. Concepts that need to be tested, which precisely the task at hand.

Considering that a good detected time is not always available, and the data is processed in batches, there could be a heavy grouping of timestamps. If there are a variety of issues detected on a specific IP, at the same obfuscated time, loss of data will occur. This is certainly NOT the desired result. Given this, the datastamp is not unique enough for a hash structure datastore such as Cassandra, without using SCFs.

A structure such as this could deliver the required granularity:


ipstore[$ipkey][$timekey][$propkey] = JSON:{}, JSON:{}, JSON{}...  ;

To get started with loading data, wrote a quick test program in Java, compliled it and ran it:

test1.java – source code


public class test1 {
  public static void main (String [] args) {
    System.out.println("Cassandra Calling!");
  }
}

compiling….


java/src/loader1$ javac test1.java -d ../../class/.

executing…


/java/class$ java test1
Cassandra Calling!

Environment confirmed for compiling loader code. With a model in mind…


ipstore[$ipkey][$popkey][$timestamp] = JSON:{}

..and IP data to load,

ipp < get_a_million.sql > a_million_ips.dta
cass:~$ ls -l
126180075 2012-03-13 13:06 a_million_ips.dta

cass:~$ wc -l a_million_ips.dta
1000001 a_million_ips.dta

...next it's designing the schema builder and loader.

REFERENCE: Setting up a Java build env to prepare for Cassandra development

With the environment confirmed, and a test file (test1.java) written, execute and verify function:


cass:~$ ant -DclassToRun=test1 run
Buildfile: ./build.xml

[...]

run:
     [java] This is Java.... drink up!

VERIFIED.

To get moving forward, I created a Utilities class and a DB connector Class. You can look at the source code for those at these two links:

Util Source Code

Cassandra DB Connector Source Code

With the code done, need to perform a couple of house keeping tasks to get it prepared for loading.

Adding the ks33 keyspace


[default@unknown] create keyspace ks33:
c7944700-6e2e-11e1-0000-13393ec611bd
Waiting for schema agreement...
... schemas agree across the cluster

[default@unknown] use ks33;
Authenticated to keyspace: ks33

Adding the cf33 ColumnFamily to ks33 Keyspace:


[default@ks33] create column family cf33 with comparator = UTF8Type; 
2501f8b0-6e2f-11e1-0000-13393ec611bd
Waiting for schema agreement...
... schemas agree across the cluster

Next, to load 100 trial rows. Here is a link to the source code:

Source for useMultiGet (tba)


hpcass@feed0:~/cassIP/java/cBuild$ host=10.1.0.123 port=9160 inserts=100 ks=ks33 cf=cf33 ant -DclassToRun=c01.useMultiGet run
Buildfile: /home/hpcass/cassIP/java/cBuild/build.xml

init:

compile:
    [javac] Compiling 1 source file to /home/hpcass/cassIP/java/cBuild/build/classes

dist:
      [jar] Building jar: /home/hpcass/cassIP/java/cBuild/dist/lib/cassIP.jar

run:
     [java] get time   89062577
     [java] mget time 494039096

BUILD SUCCESSFUL

Here are some results from multi-get tests. It's actually the inverse of my hope, the multi-get seems to rapidly lose it's benefit.

5 Item Slices  (1000 item dataset)
=========================================================
run:                    RUN 1      RUN 2      RUN 3   
     [java] get time  339041199  436440551  358115310
     [java] mget time 172484370  174690508  182833140

10 Item Slices  (1000 item dataset)
=========================================================
run:                    RUN 1      RUN 2      RUN 3   
     [java] get time  346512511  332820479  314136351
     [java] mget time 394049160  251152592  234719383

25 Item Slices  (1000 item dataset)
=========================================================
run:                    RUN 1      RUN 2      RUN 3   
     [java] get time  335286775  293802010  295948562
     [java] mget time 464933443  324505741  312226035

What I didn't expect to see, based on the information in the 'High Performance
Cookbook, was rapid fall-off in performance, and in face in all cases in the
slices of size 25 inverted the performance, showing that it became worse.

2 Item Slices  (1000 item dataset)
=========================================================
run:                    RUN 1      RUN 2      RUN 3   
     [java] get time  285509637  331970814  317512021
     [java] mget time 104567639   96477512  124040195

One thing I didn't think of testing was doing a slice of size 1, and see if maybe part of the perceived performance in the lower slices is really cache hits. AH! Look at this, it looks like the *test* is highly suspect at best. I think this shows some evidence the performance 'benefit' of the multi-get is really a cache hit artifact from extracting the exact same data a second time:

host=10.1.0.123 port=9160 inserts=1000 ks=ks33 cf=cf33 slice=1 ant -DclassToRun=c01.useMultiGet run
Buildfile: /home/hpcass/cassIP/java/cBuild/build.xml

1 Item Slices  (1000 item dataset)
=========================================================
run:                    RUN 1      RUN 2      RUN 3   
     [java] get time  295158535  298466321  283438099
     [java] mget time 109982545  103658894   98260286

This demonstrator failure to perform, is not a failure in and of itself. It's provided useful information regarding some concepts recommended in some documentation, but may not really be a true best practice. I long ago developed a healthy skepticism of expert advice in lieu of verification.

Software Development, Technology

Re-Configuring an Empty Cassandra Cluster

12 March 2012 David 1 Comment

PREV: Setting up a Java build env to prepare for Cassandra development

After doing more research, I decided the Ordered Partitioning was not going to buy me anything but a lop-sided distribution. Looking at this (it’s a case of IP distributions, not hostnames as originally envisioned, that will be a later evaluation).

I’d have 3 very heavy nodes and 3 very light nodes. This is a distribution of real world data.

Node:  Range:                             Dist:    
====== ================================== ======  
node00         0.0.0.0 to 42.170.170.171     6 %  
node01  42.170.170.172 to 85.85.85.87       32 %  
node02     85.85.85.88 to 128.0.0.3         34 %  
node03       128.0.0.4 to 170.170.170.175    2 %  
node04 170.170.170.176 to 213.85.85.91      21 %  
node05    213.85.85.92 to 255.255.255.255    3 %

Goofing around with pseudo random key naming to get a better balance only does one thing, make the keys I wanted to use (IPs) basically worthless, so the ordering is wrecked regardless. Random partitioning is the default configuration for Cassandra, so, that’s what I plan to use. Problem is, I’d built out this specific node set with this setting first:

– ByteOrderedPartitioner orders rows lexically by key bytes. BOP allows scanning rows in key order, but the ordering can generate hot spots for sequential insertion workloads.

I re-set the configurations to use the default instead:

– RandomPartitioner distributes rows across the cluster evenly by md5. When in doubt, this is the best option.

After changing the configuration from ByteOrderedPartitioner to RandomPartitioner and restarting the first node.. I am greeted with this happy message:

ERROR 13:03:36,113 Fatal exception in thread Thread[SSTableBatchOpen:3,5,main]
java.lang.RuntimeException: Cannot open /home/hpcass/data/node00/system/Versions-hc-3 because partitioner does not match org.apache.cassandra.dht.RandomPartitioner

In fact I’m greeted with a lot of them. This is then followed by what looks like possibly.. normal startup messaging?

 INFO 13:03:36,166 Creating new commitlog segment /home/hpcass/commitlog/node00/CommitLog-1331586216166.log
 INFO 13:03:36,175 Couldn't detect any schema definitions in local storage.
 INFO 13:03:36,175 Found table data in data directories. Consider using the CLI to define your schema.
 INFO 13:03:36,197 Replaying /home/hpcass/commitlog/node00/CommitLog-1331328557751.log
 INFO 13:03:36,222 Finished reading /home/hpcass/commitlog/node00/CommitLog-1331328557751.log
 INFO 13:03:36,227 Enqueuing flush of Memtable-LocationInfo@1762056890(213/266 serialized/live bytes, 7 ops)
 INFO 13:03:36,228 Writing Memtable-LocationInfo@1762056890(213/266 serialized/live bytes, 7 ops)
 INFO 13:03:36,228 Enqueuing flush of Memtable-Versions@202783062(83/103 serialized/live bytes, 3 ops)
 INFO 13:03:36,277 Completed flushing /home/hpcass/data/node00/system/LocationInfo-hc-16-Data.db (377 bytes)
 INFO 13:03:36,285 Writing Memtable-Versions@202783062(83/103 serialized/live bytes, 3 ops)
 INFO 13:03:36,357 Completed flushing /home/hpcass/data/node00/system/Versions-hc-4-Data.db (247 bytes)
 INFO 13:03:36,358 Log replay complete, 9 replayed mutations
 INFO 13:03:36,366 Cassandra version: 1.0.8
 INFO 13:03:36,366 Thrift API version: 19.20.0
 INFO 13:03:36,367 Loading persisted ring state
 INFO 13:03:36,384 Starting up server gossip
 INFO 13:03:36,386 Enqueuing flush of Memtable-LocationInfo@846275759(88/110 serialized/live bytes, 2 ops)
 INFO 13:03:36,386 Writing Memtable-LocationInfo@846275759(88/110 serialized/live bytes, 2 ops)
 INFO 13:03:36,440 Completed flushing /home/hpcass/data/node00/system/LocationInfo-hc-17-Data.db (196 bytes)
 INFO 13:03:36,446 Starting Messaging Service on port 7000
 INFO 13:03:36,452 Using saved token 0
 INFO 13:03:36,453 Enqueuing flush of Memtable-LocationInfo@59584763(38/47 serialized/live bytes, 2 ops)
 INFO 13:03:36,454 Writing Memtable-LocationInfo@59584763(38/47 serialized/live bytes, 2 ops)
 INFO 13:03:36,556 Completed flushing /home/hpcass/data/node00/system/LocationInfo-hc-18-Data.db (148 bytes)
 INFO 13:03:36,558 Node /10.1.0.23 state jump to normal
 INFO 13:03:36,558 Bootstrap/Replace/Move completed! Now serving reads.
 INFO 13:03:36,559 Will not load MX4J, mx4j-tools.jar is not in the classpath
 INFO 13:03:36,587 Binding thrift service to /10.1.0.23:9160
 INFO 13:03:36,590 Using TFastFramedTransport with a max frame size of 15728640 bytes.
 INFO 13:03:36,593 Using synchronous/threadpool thrift server on /10.1.0.23 : 9160
 INFO 13:03:36,593 Listening for thrift clients...

Despite the fatal errors, it does seem to have restarted the cluster with the new Partition engine:

Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               7169015515630842424558524306038950250903273734
10.1.0.27      datacenter1 rack1       Down   Normal  ?               93.84%  -2742379978670691477635174047251157095949195165
10.1.0.23      datacenter1 rack1       Up     Normal  15.79 KB        86.37%  0                                           
10.1.0.26      datacenter1 rack1       Down   Normal  ?               77.79%  896682280808232140910919391534960240163386913
10.1.0.24      datacenter1 rack1       Up     Normal  15.79 KB        53.08%  1927726543429020693034590137790785169819652674
10.1.0.25      datacenter1 rack1       Up     Normal  15.79 KB        35.85%  6138493926725652010223830601932265434881918085
10.1.0.28      datacenter1 rack1       Down   Normal  ?               53.08%  716901551563084242455852430603895025090327373

Starting up the other three nodes (example:)

 INFO 14:10:06,663 Node /10.1.0.25 has restarted, now UP
 INFO 14:10:06,663 InetAddress /10.1.0.25 is now UP
 INFO 14:10:06,664 Node /10.1.0.25 state jump to normal
 INFO 14:10:06,664 Node /10.1.0.24 has restarted, now UP
 INFO 14:10:06,665 InetAddress /10.1.0.24 is now UP
 INFO 14:10:06,665 Node /10.1.0.24 state jump to normal
 INFO 14:10:06,666 Node /10.1.0.23 has restarted, now UP
 INFO 14:10:06,667 InetAddress /10.1.0.23 is now UP
 INFO 14:10:06,668 Node /10.1.0.23 state jump to normal
 INFO 14:10:06,760 Completed flushing /home/hpcass/data/node01/system/LocationInfo-hc-18-Data.db (166 bytes)
 INFO 14:10:06,762 Node /10.1.0.26 state jump to normal
 INFO 14:10:06,763 Bootstrap/Replace/Move completed! Now serving reads.
 INFO 14:10:06,764 Will not load MX4J, mx4j-tools.jar is not in the classpath
 INFO 14:10:06,862 Binding thrift service to /10.1.0.26:9160

Re-checking the ring displays:

Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               7169015515630842424558524306038950250903273734
10.1.0.27      datacenter1 rack1       Up     Normal  11.37 KB        93.84%  -2742379978670691477635174047251157095949195165
10.1.0.23      datacenter1 rack1       Up     Normal  15.79 KB        86.37%  0                                           
10.1.0.26      datacenter1 rack1       Up     Normal  18.38 KB        77.79%  896682280808232140910919391534960240163386913
10.1.0.24      datacenter1 rack1       Up     Normal  15.79 KB        53.08%  1927726543429020693034590137790785169819652674
10.1.0.25      datacenter1 rack1       Up     Normal  15.79 KB        35.85%  6138493926725652010223830601932265434881918085
10.1.0.28      datacenter1 rack1       Up     Normal  15.79 KB        53.08%  7169015515630842424558524306038950250903273734

Switching partition engine appears to be easy enough. What I suspect however (and I’ve not confirmed this, is that the data would have been compromised or likely destroyed in this process. The documentation I’ve read so far indicated that you could not do this. Once setup with a specific partitioning engine that cluster was bound to it.

My conclusion is that if you have not yet started to saturate your cluster with data, and you wish to change the partitioning engine, it would appear that the right time to do it is now.. before you start to load data.

I plan to test this theory later after the first trial data load to see if in fact it mangles the information. More to follow!

UPDATE!

Despite the information that I thought nodetool was telling me, my cluster was unusable because of the partitioner change. What is the last step required to change partition? NUKE THE DATA. Unfun.. but that is what I need to do.

Having 6 nodes means 6 times the fun. Here is the kicker though, I’ll just move the data aside and re-construct, and that will let me swap it back in if I decided to go back and forth testing the impacts of Random vs. Ordered for my needs. Will I get away with this? I don’t know. That won’t stop me from trying!

The data was stored in ~/data/node00 (node## etc.). This is all I did:


mv data/node00 data/node00-bop       # bop = btye order partition.

Restarted node00:


hpcass:~/nodes$ node00/bin/cassandra -f
 INFO 16:38:46,525 Logging initialized
 INFO 16:38:46,529 JVM vendor/version: OpenJDK 64-Bit Server VM/1.6.0_0
 INFO 16:38:46,529 Heap size: 6291456000/6291456000
 INFO 16:38:46,529 Classpath: node00/bin/../conf:node00/bin/../build/classes/main:node00/bin/../build/classes/thrift:node00/bin/../lib/antlr-3.2.jar:node00/bin/../lib/apache-cassandra-1.0.8.jar:node00/bin/../lib/apache-cassandra-clientutil-1.0.8.jar:node00/bin/../lib/apache-cassandra-thrift-1.0.8.jar:node00/bin/../lib/avro-1.4.0-fixes.jar:node00/bin/../lib/avro-1.4.0-sources-fixes.jar:node00/bin/../lib/commons-cli-1.1.jar:node00/bin/../lib/commons-codec-1.2.jar:node00/bin/../lib/commons-lang-2.4.jar:node00/bin/../lib/compress-lzf-0.8.4.jar:node00/bin/../lib/concurrentlinkedhashmap-lru-1.2.jar:node00/bin/../lib/guava-r08.jar:node00/bin/../lib/high-scale-lib-1.1.2.jar:node00/bin/../lib/jackson-core-asl-1.4.0.jar:node00/bin/../lib/jackson-mapper-asl-1.4.0.jar:node00/bin/../lib/jamm-0.2.5.jar:node00/bin/../lib/jline-0.9.94.jar:node00/bin/../lib/json-simple-1.1.jar:node00/bin/../lib/libthrift-0.6.jar:node00/bin/../lib/log4j-1.2.16.jar:node00/bin/../lib/servlet-api-2.5-20081211.jar:node00/bin/../lib/slf4j-api-1.6.1.jar:node00/bin/../lib/slf4j-log4j12-1.6.1.jar:node00/bin/../lib/snakeyaml-1.6.jar:node00/bin/../lib/snappy-java-1.0.4.1.jar
 INFO 16:38:46,531 JNA not found. Native methods will be disabled.
 INFO 16:38:46,538 Loading settings from file:/home/hpcass/nodes/node00/conf/cassandra.yaml
 INFO 16:38:46,635 DiskAccessMode 'auto' determined to be mmap, indexAccessMode is mmap
 INFO 16:38:46,645 Global memtable threshold is enabled at 2000MB
 INFO 16:38:46,839 Creating new commitlog segment /home/hpcass/commitlog/node00/CommitLog-1331599126839.log
 INFO 16:38:46,848 Couldn't detect any schema definitions in local storage.
 INFO 16:38:46,849 Found table data in data directories. Consider using the CLI to define your schema.
 INFO 16:38:46,863 Replaying /home/hpcass/commitlog/node00/CommitLog-1331597615041.log
 INFO 16:38:46,887 Finished reading /home/hpcass/commitlog/node00/CommitLog-1331597615041.log
 INFO 16:38:46,892 Enqueuing flush of Memtable-LocationInfo@1834491520(98/122 serialized/live bytes, 4 ops)
 INFO 16:38:46,893 Enqueuing flush of Memtable-Versions@875509103(83/103 serialized/live bytes, 3 ops)
 INFO 16:38:46,894 Writing Memtable-LocationInfo@1834491520(98/122 serialized/live bytes, 4 ops)
 INFO 16:38:47,001 Completed flushing /home/hpcass/data/node00/system/LocationInfo-hc-1-Data.db (208 bytes)
 INFO 16:38:47,009 Writing Memtable-Versions@875509103(83/103 serialized/live bytes, 3 ops)
 INFO 16:38:47,057 Completed flushing /home/hpcass/data/node00/system/Versions-hc-1-Data.db (247 bytes)
 INFO 16:38:47,057 Log replay complete, 6 replayed mutations
 INFO 16:38:47,066 Cassandra version: 1.0.8
 INFO 16:38:47,066 Thrift API version: 19.20.0
 INFO 16:38:47,067 Loading persisted ring state
 INFO 16:38:47,070 Starting up server gossip
 INFO 16:38:47,091 Enqueuing flush of Memtable-LocationInfo@952443392(88/110 serialized/live bytes, 2 ops)
 INFO 16:38:47,092 Writing Memtable-LocationInfo@952443392(88/110 serialized/live bytes, 2 ops)
 INFO 16:38:47,141 Completed flushing /home/hpcass/data/node00/system/LocationInfo-hc-2-Data.db (196 bytes)
 INFO 16:38:47,149 Starting Messaging Service on port 7000
 INFO 16:38:47,155 Using saved token 0
 INFO 16:38:47,157 Enqueuing flush of Memtable-LocationInfo@1623810826(38/47 serialized/live bytes, 2 ops)
 INFO 16:38:47,157 Writing Memtable-LocationInfo@1623810826(38/47 serialized/live bytes, 2 ops)
 INFO 16:38:47,237 Completed flushing /home/hpcass/data/node00/system/LocationInfo-hc-3-Data.db (148 bytes)
 INFO 16:38:47,239 Node /10.1.0.23 state jump to normal
 INFO 16:38:47,240 Bootstrap/Replace/Move completed! Now serving reads.
 INFO 16:38:47,241 Will not load MX4J, mx4j-tools.jar is not in the classpath
 INFO 16:38:47,269 Binding thrift service to /10.1.0.23:9160
 INFO 16:38:47,272 Using TFastFramedTransport with a max frame size of 15728640 bytes.
 INFO 16:38:47,274 Using synchronous/threadpool thrift server on /10.1.0.23 : 9160
 INFO 16:38:47,275 Listening for thrift clients...

^Z
[1]+  Stopped                 node00/bin/cassandra -f
hpcass:~/nodes$ bg
[1]+ node00/bin/cassandra -f &

With the process backgrounded, checked the files in the new data directory for my node:


hpcass:~/data/node00$ ls -1 system
LocationInfo-hc-1-Data.db
LocationInfo-hc-1-Digest.sha1
LocationInfo-hc-1-Filter.db
LocationInfo-hc-1-Index.db
LocationInfo-hc-1-Statistics.db
LocationInfo-hc-2-Data.db
LocationInfo-hc-2-Digest.sha1
LocationInfo-hc-2-Filter.db
LocationInfo-hc-2-Index.db
LocationInfo-hc-2-Statistics.db
LocationInfo-hc-3-Data.db
LocationInfo-hc-3-Digest.sha1
LocationInfo-hc-3-Filter.db
LocationInfo-hc-3-Index.db
LocationInfo-hc-3-Statistics.db
Versions-hc-1-Data.db
Versions-hc-1-Digest.sha1
Versions-hc-1-Filter.db
Versions-hc-1-Index.db
Versions-hc-1-Statistics.db

Following that clearing and rebuild, I see the node tool results look a lot better:

hpcass@feed0:~/nodes$ cass00/bin/nodetool -h localhost ring
Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               6138493926725652010223830601932265434881918085
10.1.0.23      datacenter1 rack1       Up     Normal  15.68 KB        33.29%  0                                           
10.1.0.24      datacenter1 rack1       Up     Normal  18.34 KB        30.87%  1927726543429020693034590137790785169819652674
10.1.0.25      datacenter1 rack1       Up     Normal  18.34 KB        35.85%  6138493926725652010223830601932265434881918085

After resetting the old numerated nodes, I had a complete disaster! Negative node tokens? How did that happen? Restarts did nothing to fix this either.

Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               7169015515630842424558524306038950250903273734
10.1.0.27      datacenter1 rack1       Up     Normal  15.79 KB        93.84%  -2742379978670691477635174047251157095949195165
10.1.0.23      datacenter1 rack1       Up     Normal  15.79 KB        86.37%  0                                           
10.1.0.26      datacenter1 rack1       Up     Normal  15.79 KB        77.79%  896682280808232140910919391534960240163386913
10.1.0.24      datacenter1 rack1       Up     Normal  15.79 KB        53.08%  1927726543429020693034590137790785169819652674
10.1.0.25      datacenter1 rack1       Up     Normal  15.79 KB        35.85%  6138493926725652010223830601932265434881918085
10.1.0.28      datacenter1 rack1       Up     Normal  15.79 KB        53.08%  7169015515630842424558524306038950250903273734

To resolve this, I simply re-ran my token generator to get a new set of tokens:

node00	10.1.0.23  token: 0
node01	10.1.0.26  token: 28356863910078205288614550619314017621
node02	10.1.0.24  token: 56713727820156410577229101238628035242
node03	10.1.0.27  token: 85070591730234615865843651857942052863
node04	10.1.0.25  token: 113427455640312821154458202477256070485
node05	10.1.0.28  token: 141784319550391026443072753096570088106

Followed by manually setting the tokens in the ring:

bin/nodetool -h 10.1.0.24 move 56713727820156410577229101238628035242
bin/nodetool -h 10.1.0.25 move 113427455640312821154458202477256070485

bin/nodetool -h 10.1.0.26 move 28356863910078205288614550619314017621
bin/nodetool -h 10.1.0.27 move 85070591730234615865843651857942052863
bin/nodetool -h 10.1.0.28 move 141784319550391026443072753096570088106

This.. gave me the results I was expecting!

Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               141784319550391026443072753096570088106     
10.1.0.23      datacenter1 rack1       Up     Normal  24.95 KB        16.67%  0                                           
10.1.0.26      datacenter1 rack1       Up     Normal  20.72 KB        16.67%  28356863910078205288614550619314017621      
10.1.0.24      datacenter1 rack1       Up     Normal  25.1 KB         16.67%  56713727820156410577229101238628035242      
10.1.0.27      datacenter1 rack1       Up     Normal  13.38 KB        16.67%  85070591730234615865843651857942052863      
10.1.0.25      datacenter1 rack1       Up     Normal  25.1 KB         16.67%  113427455640312821154458202477256070485     
10.1.0.28      datacenter1 rack1       Up     Normal  25.14 KB        16.67%  141784319550391026443072753096570088106

Now, the question of actually connecting to the cluster can be answered. Pick one of the nodes and ports to connect too. I picked node00 on .23 (cli defaulted to port 9160 so I didn’t have to specify that):

node00/bin/cassandra-cli -h 10.1.0.23 
Connected to: "test-ip" on 10.1.0.23/9160
Welcome to Cassandra CLI version 1.0.8

Type 'help;' or '?' for help.
Type 'quit;' or 'exit;' to quit.

The big problem I had, was that the cli never did seem to respond. The trick is to end your command with a semi-colon. That might seem obvious to you, and generally obvious to me.. but I’d not seen the docs actually call out that little FACT.

[default@unknown] show cluster name;
test-ip

Created a test column family from the helpful Cassandra Wiki.

create keyspace Twissandra;
Keyspace names must be case-insensitively unique ("Twissandra" conflicts with "Twissandra")
[default@unknown] 
[default@unknown] 
[default@unknown] create column family User with comparator = UTF8Type;
Not authenticated to a working keyspace.
[default@unknown] use Twissandra;
Authenticated to keyspace: Twissandra
[default@Twissandra] create column family User with comparator = UTF8Type;
adf453a0-6cb0-11e1-0000-13393ec611bd
Waiting for schema agreement...
... schemas agree across the cluster
[default@Twissandra]

AND WE’RE OFF!! Next article will cover actually finishing up this last test and then adding real data. MORE TO COME!!

NEXT: Cassandra – A Use case examined (IP data)

Entrepreneurship, Software Development, Technology

Cassandra and Big Data – building a single-node “cluster”

2 March 2012 David 5 Comments

Cassandra – Getting off the ground.
Continuation of post: Apache Cassandra Project – processing “Big Data”

While researching a project on Big Data services, I knew that I’d need a multi-node cluster to experiment with, but a pile of hardware was not immediately available.

Using the VERY helpful book Cassandra High Performance Cookbook I was able to build a 3 node cluster on a single machine. This is how I did it:

For this cluster test example, I am using Ubunto 10, with following JVM


      JVM vendor/version: OpenJDK 64-Bit Server VM/1.6.0_22

Downloaded Cassandra 1.0.8 package from here:
http://apache.mirrors.tds.net//cassandra/1.0.8/apache-cassandra-1.0.8-bin.tar.gz

Created new user on system: bigdata

Create the required base data directories


  $ mkdir commitlog,log,data,saved_caches

Moved that package there and started the build


$ cp /tmp/apache-cassandra-1.0.8-bin.tar.gz .

Unzipped and extracted the contents


$ gunzip apache-cassandra-1.0.8-bin.tar.gz
$ tar xvf apache-cassandra-1.0.8-bin.tar

Moved the long directory name to first instance cassA-1.0.8


$ mv apache-cassandra-1.0.8 cassA-1.0.8

Extracted again and renamed this to the other two planned instances:


$ tar xfv apache-cassandra-1.0.8-bin.tar
$ mv apache-cassandra-1.0.8 cassB-1.0.8  

$ tar xfv apache-cassandra-1.0.8-bin.tar
$ mv apache-cassandra-1.0.8 cassC-1.0.8

This gave me three packages to build, and each with a unique IP


  cassA-1.0.8   10.1.1.101
  cassB-1.0.8   10.1.1.102
  cassC-1.0.8   10.1.1.103

Edit configuration files in each instance (casaA-1.0.8 used as example:)


$ vi cassA-1.0.8/conf/cassandra.yaml 

[...]

# directories where Cassandra should store data on disk.
data_file_directories: 
    - /home/bigdata/data/cassA

# commit log
commitlog_directory: /home/bigdata/commitlog/cassA

# saved caches
saved_caches_directory: /home/bigdata/saved_caches/cassA

[...]

# If blank, Cassandra will request a token bisecting the range of
# the heaviest-loaded existing node.  If there is no load information
# available, such as is the case with a new cluster, it will pick
# a random token, which will lead to hot spots.
initial_token: 0

[...]

# Setting this to 0.0.0.0 is always wrong.
listen_address: 10.1.1.101

[...]

rpc_address: 10.1.1.101

[...]

          # seeds is actually a comma-delimited list of addresses.
          # Ex: ",,"
          - seeds: "10.1.100.101,10.1.100.102,10.1.100.103"
[...]

Setting a separate logfile is recommended. Edit config to set separate log


vi cassA-1.0.8/conf/log4j-server.properties

[...]
log4j.appender.R.File=/home/bigdata/log/cassA.log
[...]

Repeat for instances cassB and cassC, setting the token value for B and C to appropriate values (see Extra Credit below if you need to know how to do *that* part):


#cassB
initial_token: 56713727820156410577229101238628035242

#cassC
initial_token: 113427455640312821154458202477256070485

To enable the JMX management console, each instance will require it’s own port. Edit the env file to set that up.


vi cassA-1.0.8/conf/cassandra-env.sh

[...]
# Specifies the default port over which Cassandra will be available for
# JMX connections.
JMX_PORT="8001"
[...]

Repeated for the other two instances, defining 8002 and 8003 respectively.

Now, for the final trick, start up the instances:


  cassA-1.0.8/bin/cassandra
  cassB-1.0.8/bin/cassandra
  cassC-1.0.8/bin/cassandra

Cluster elements started up, and they can be seen active in the process table here:


$ ps -lf
F S UID        PID  PPID  C PRI  NI ADDR SZ WCHAN  STIME TTY          TIME CMD
0 S bigdata   4554     1  2  80   0 - 226846 futex_ 12:13 pts/0   00:00:05 java -ea -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=
0 S bigdata   4593     1  2  80   0 - 210824 futex_ 12:13 pts/0   00:00:05 java -ea -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=
0 S bigdata   4632     1  2  80   0 - 226830 futex_ 12:13 pts/0   00:00:05 java -ea -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=
0 R bigdata   5047  3054  0  80   0 -  5483 -      12:16 pts/0    00:00:00 ps -lf

Finally, to check the status, connect to of the JMX node ports and check the ring. You only need to connect to one of the cluster’s nodes to check the complete cluster’s status:


$ bin/nodetool -h 10.1.100.101 -port 8001 ring
Address         DC          Rack        Status State   Load            Owns    Token                                       
                                                                               113427455640312821154458202477256070485     
10.1.100.101    datacenter1 rack1       Up     Normal  21.86 KB        33.33%  0                                           
10.1.100.102    datacenter1 rack1       Up     Normal  20.28 KB        33.33%  56713727820156410577229101238628035242      
10.1.100.103    datacenter1 rack1       Up     Normal  29.1 KB         33.33%  113427455640312821154458202477256070485

Now, that’s a functional 3 instance cluster running on a single node. These are not in separate VMs, and if you wanted to experiment with this on a larger cluster, running multiple instances on multiple VM’s on a single hypervisor.. I don’t really see why you cannot!

In the next article, I’m going to start feeding data into the cluster. Stay tuned for that!

Extra Credit:

To create the token value I needed for this three ring cluster, I used the following PERL script. BTW, bignum is required unless you want PERL printing these big numbers in scientific notation:


#!/usr/bin/perl
use bignum;
my $nodes = shift;
print "Calculate tokens for $nodes nodes\n";
print "node 0\ttoken: 0\n" unless $nodes;
exit unless $nodes;
my $factor = 2**127;
print "factor = $factor\n";
for (my $i=0;$i<$nodes;$i++) {
	my $token = $i * ( $factor / $nodes);
	print "node $i\ttoken: $token\n";
}

Running the script for three nodes gave me the following results:


$ ./maketokens.pl  3

Calculate tokens for 3 nodes
factor = 170141183460469231731687303715884105728
node 0	token: 0
node 1	token: 56713727820156410577229101238628035242.67
node 2	token: 113427455640312821154458202477256070485.34

Additional Comments:

If you are setting up a standard mutli-box cluster, make sure you have the following ports opened up on any firewalls. If not, the cluster members wont' find each other:


# TCP port, for commands and data
storage_port: 7000

# SSL port, for encrypted communication.  Unused unless enabled in
# encryption_options
ssl_storage_port: 7001

NEXT: Setting up a Java build env to prepare for Cassandra development

Software Development, Technology

Apache Cassandra Project – processing “Big Data”

17 February 2012 David 3 Comments

Being an old-school OSS’er, MySql has been my go-to DB for data storage since the turn of the century. It’s great, I love it (mostly) but it does have it’s drawbacks. Largest of which is it’s now owned by Oracle which does a HORRIBLE JOB of supporting it. I have personal experience with this, as the results of a recent issue with InnoDB and MySQL.

In the mean time, some of the hot-shot up-and-commers in another department have been facing their own data processing challenges (with MySql and other DB’s), and have started to look at some highly scalable alternatives. One of the front-runners right now is Apache’s Cassandra database project.

The synopsis from the page is (as would be most marketing verbiage) very encouraging!

The Apache Cassandra database is the right choice when you need scalability and high availability without compromising performance. Linear scalability and proven fault-tolerance on commodity hardware or cloud infrastructure make it the perfect platform for mission-critical data. Cassandra’s support for replicating across multiple datacenters is best-in-class, providing lower latency for your users and the peace of mind of knowing that you can survive regional outages.

This sounds too good to be true. Finally a solution that we might be able to implement and grow, and one that doe not have the incredibly frustrating drawback of InnoDB and MySql’s fragile replication architecture. I’ve found out exactly how fragile it is, despite have a cluster of high-speed specially designed DB servers, the amount of down time we had was NOT ACCEPTABLE!).

With a charter to handle ever growing amounts of data and the need for ultimate availability and reliability, an alternative to MySQL is almost certainly required.

Of the items discussed on the main page, this one really hits home and stands out to me:

Fault Tolerant

Data is automatically replicated to multiple nodes for fault-tolerance. Replication across multiple data centers is supported. Failed nodes can be replaced with no downtime.

I recently watched a video from the 2011 Cassandra Conference in San Francisco. A lot of good information shared. This video is available on the Cassandra home page. I recommend muscling through the marketing BS as the beginning and take in what they cover.

Job graph for ‘Big Data’ is skyrocketing.

Demand for Cassandra experts is also skyrocketing.

Big data players are using Cassandra.

It’s a known issue that RDBM’s (ex. MySql) have serious limitations (no kidding).

RDBM’s generally have an 8GB cache limit (this is interesting, and would explain some issues we’ve had with scalability in our DB severs, which have 64GB of memory).

The notion that Cassandra does not have good read speed, is a fallacy. Version 0.8 read speed is at parity of the already considered fast 0.6 write speed. Fast!?

No global or even low-level write locks. The column swap architecture alleviates the need for these locks, this allows high-speed writes.

Quorum reads and writes are consistent across the distribution.

New feature of local LOCAL_QUORUM allows quorums to be established from only the local nodes, alleviating latency waiting for a quorum including remote nodes in other geographic locations.

Cassandra uses XML files for schema modifications. In version 0.7 provides new features to allow on-line schema updates.

CLI for Cassandra is now very powerful.

Has a SQL language capability (yes!).

Latest version provides much easier to implement secondary indexing (indexes other than the primary).

Version 0.8 supports bulk loading. This is very interesting for my current project

There is wide support for Cassandra in both interpreted and compiled OSS languages, including the ones I most frequently use.

CQL Cassandra Query Language.

Replication architecture is vastly superior to MySQLs transaction and log replay strategy. Cassandra uses an rsync style replication where hash comparisons are exchanged to find which parts of the data tree a given replication node (that is responsible for that tree of data) might need updating, then then transferring just that data. Not only does this reduce bandwidth, but this implies asynchronous replication! Finally! Now this makes sense to me!!

Hadoop support exists for Cassandra, BUT, it’s not a great fit for Cassandra. Look into Brisk if Hadoop implementation is desired or required.

Division of Real-Time and Analytics nodes.

Nodes can be configured to communicate with each other in an encrypted fashion, but in general inter-node communication across public-private networks should be established using VPN tunnels.

This needs further research, but it’s very, VERY promising!

NEXT: “Cassandra and Big Data – building a single-node ‘cluster’“

Software Development, Technology

Help for Geeks – My Development Bookmarks

7 April 2010 David 2 Comments

I’ve thought about this many times. What info do I find useful, and would other geeks find it useful too? Perhaps. In that spirit here is my current list of Development related bookmarks. Slightly organized. You might find some nuggets of info in here that relates to a project you are working on. Or it might spark and idea to build something new, or re-design a process that is not as optimal is you’d like it to be.

I hope some of these help, as they have helped me over the years. One note though, I removed all my links to PHP development. I just can’t stand using it any more, it’s just too easy to PWN.

Apache

libapreq2-2.08: libapreq2: Apache2::Request
Apache2::RequestRec – Perl API for Apache request record accessors – search.cpan.org
Apache2::AuthCookie – Perl Authentication and Authorization via cookies – search.cpan.org
Adventures in the Land of Apache and mod_perl: perl. Computational Chemistry List, perl, mod_perl, modperl2, cgi, Apache, cgi, forms
Combining Apache and Perl
Useful OpenSSL Commands
Creating Self-Signed Certs on Apache 2.2 | CB1, INC.: CB1, INC. is a Minneapolis based software and consulting company specializing in custom development and systems integration.
NSS and SSL Error Codes
Smart HTTP and HTTPS RewriteRule Redirects: Smarter SSL HTTPS to HTTP Redirections in .htaccess using RewriteRule to set an environment variable
Apache Week. Using User Authentication: The O’Reilly Network has teamed with Red Hat Apache Week, the leading commercial Apache site to offer comprehensive Apache information and resources. Apache Week offers news, feature articles, reviews, resources, and documentation.
htaccess rewrite tips using RewriteRule and RewriteCond for .htaccess mod_rewrite: mod_rewrite tips and tricks for .htaccess files using RewriteBase, RewriteCond, RewriteEngine, RewriteLock, RewriteLog, RewriteLogLevel, RewriteMap, RewriteOptions, and RewriteRule
mod_perl: mod_perl 2.0 Server Configuration: mod_perl documentation: This chapter provides an in-depth mod_perl 2.0 configuration details.
Dr. Dobb’s | A mod_perl 2 Primer | December 1, 2004: Though it’s technically not quite ready for prime time, it’s high time we all got a taste of the next version of mod_perl.
Apache2::Status 4.00
apache 2: “private key not found”

HTML / CSS

CSS2 Reference: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.
CSS Tutorial – Border: Place customized CSS borders around your HTML elements with the CSS Border attribute.
How can I make just one cell in an HTML table bordered, or just one side of a cell bordered?
CSS Positioning Properties: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.
Ajaxload – Ajax loading gif generator: Ajaxload – Ajax loading gif generator
workalike for top.location.watch(“href”,fn) in IE? – JavaScript: workalike for top.location.watch(“href”,fn) in IE?. Get answers to your questions in our JavaScript forum.
window.onbeforeunload [javascript] [form]
HTML FIELDSET TAG: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.
wg:Bubble Tooltips: web graphics is a compilation of hypertext design resources, links, and commentary.
lixlpixel CSS tooltips: pure CSS pop up tooltips with clean semantic code – valid XHTML – degrades nicely
Simple Round CSS Links ( Wii Buttons )
HTML URL-encoding Reference: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.
Custom error responses
CSS and round corners: Making accessible menu tabs: Find out how to lose the box layout of your CSS pages and make great menu tabs
A List Apart: Articles: Sliding Doors of CSS: Must CSS layouts be flat and boxy? Nope! Bowman shows how to create slick tabbed navigation using CSS and structured XHTML lists.
Light Weight Low Tech CSS Tabs: An example of light weight tabs by combining the Sliding Doors method with the Mountaintop corners idea.
A List Apart: Articles: Mountaintop Corners: Using CSS to create standards-compliant, mountain top corners
Setting a Minimum Body Height:Solving the ‘Height’ Mystery
W3C Markup Validator: W3C’s easy-to-use HTML validation service, based on an SGML parser.
Private RSS Feeds: Support for security in aggregators – silverorange labs: We’ve been experimenting with security options for RSS feeds for our intranet product. However, we found that there weren’t many resources or guidelines for how encryption or authentification should be handled (either in feeds or in readers/aggregators).
The W3C CSS Validation Service
The Art of Web ~ CSS: border-radius and -moz-border-radius: One of the most keenly-anticipated CSS properties is border-radius. It’s not yet available in Internet Explorer, but there is limited support in Firefox (-moz-border-radius) and Safari (WebKit). Discussion and examples.
removeChild: javascript document object javascript document object model sans serif font document object model removechild: Removing objects from a web page.
Adding elements to the DOM: Click here for an introductory tutorial on the DOM of IE 5/ NS 6, and how to program using it
JavaScript tutorial – DOM nodes and tree
HTTP State Management Mechanism [RFC-Ref]
phone number validation: phone number validation
Validating with XML Schema
HTML Color Names: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.
CSS Color Names: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.
CSS Image Opacity / Transparency: Free HTML XHTML CSS JavaScript DHTML XML DOM XSL XSLT RSS AJAX ASP ADO PHP SQL tutorials, references, examples for web building.

JavaScript

O’Reilly Network — Dynamic HTML Tables: Improving Performance: The widespread browser adoption of the W3C Document Object Model (DOM) and other de facto standards have given developers many ways to repopulate a table. So what’s the best approach? Danny Goodman, author of JavaScript & DHTML Cookbook, investigated…
Managing the Dynamic created HTML table thru javascript – SEO Chat: Managing the Dynamic created HTML table thru javascript- HTML Coding. Visit SEO Chat to discuss Managing the Dynamic created HTML table thru javascript
JavaScript Kit- Text Object: Click here for a complete JavaScript Reference, including array, string, document. window, and more.
How do you know what button was pressed in the submit? – JavaScript: How do you know what button was pressed in the submit?. Get answers to your questions in our JavaScript forum.
The JavaScript Source: Forms : Auto Email Link: Automatically creates a new e-mail utilizing the user’s default e-mail client. The script fills in the subject line and adds the URL of the current Web page to the body. Note: May not be compatible with all e-mail clients.
Javascript – Early event handlers
Javascript – The events
Javascript – Introduction to Events
The JavaScript Source: Forms: Form Focus: Places the focus on the first editable field in a form on any web page. Efficient!
JavaScript Help: How to access parent elements from a child window or frame
Popup Window Tutorials: This series of tutorials takes you step by step thrugh thedifferent ways that you can create and modify popup windows.
DevGuru JavaScript PROPERTY: document::forms: Award-winning web developers’ resource: over 3000 pages of quick reference guides, tutorials, knowledge base articles, Ask DevGuru, useful products.
ActiveWidgets • sorting • download data xls

JAVA

java integer to string – Google Search
Java Dynamic Management Kit 5.1 Release Notes
NetBeans IDE 6.0.1 Download: NetBeans IDE 6.0.1 Download
Welcome to JavaWorld.com: Solutions for Java developers
Your Source for Java Information – Developer.com’s Gamelan.com: Get the latest Java news, articles, whitepapers, analyst reports, and more. This is your one stop for information that will help you make decisions related to Java.
String (Java Platform SE 6)
Arrays (The Java™ Tutorials > Learning the Java Language > Language Basics)
StringBuffer (Java 2 Platform SE 5.0)
Throwable (Java 2 Platform SE v1.4.2)
NetBeans Forums – How to use Netbeans packages?
Javadoc Guide
System Properties (The Java™ Tutorials > Deployment > Doing More With Rich Internet Applications)
Adding Classes to the JAR File’s Classpath (The Java™ Tutorials > Deployment > Packaging Programs in JAR Files)
NetBeans Forums – Create manifest, jar and class file in netbeans
Packaging and Deploying Desktop Java Applications: Creating executable JAR files and deploying netbeans projects
Understanding the Manifest: JAR files can support a wide range of functionality, including electronic signing, version control, package sealing, extensions, and others. What gives JAR files the ability to be so versatile? The answer is embodied in the JAR file’s manifest.
http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html#JAR%20Manifest
JAVA Illegal Start of Expression Error – Java: JAVA Illegal Start of Expression Error Java
do-jar-with-main class ‘manifest.available+main.class’ not set. – Google Search
Formatted Printing for Java (sprintf): The C language utility sprintf is for formatting strings of characters and numbers. This article documents the use of a Java programming language class, PrintfFormat, whose behavior is based on the sprintf specification. Source code is provided.
Java Tips – How to align your components in horizontal or vertical layout: Java Tips — Java, Java, and more Java, How to align your components in horizontal or vertical layout
Java Tips – PointBase Embedded: Java Tips — Java, Java, and more Java, PointBase Embedded
Programming with Java in 24 Hours: Building a Complex User Interface: Questions, corrections and clarifications for hour 16 of the book Teach Yourself Java 6 in 24 Hours by Rogers Cadenhead. The book teaches Java 6 programming for non-programmers, new programmers who hated learning a language, and experienced programmers who want to quickly get up to speed.
Java look and feel Graphics Repository: Welcome to the Java Software Human Interface Group’s Java look and feel Graphics Repository pages.

MySQL

MySQL Stored Procedures / Functions
MySQL AB :: MySQL Forums :: Install :: Comments on my.cnf for high insert volume db
MySQL Configuration
MySQL Performance Blog » Should MySQL and Web Server share the same box ?
MySQL AB :: Index update with update statement
MySQL AB :: MySQL 5.0 Reference Manual :: 18 Stored Procedures and Functions
MySQL Stored Procedures
MySQL Server Tweaking Basics – Admin Zone Forums: This is a basic guide to understanding what the directives in your my.cnf mean, and what they do. We’ll also try to give some general
mySql — CHECK TABLE Syntax
Live Backups of MySQL Using Replication: Russell Dyer, author of MySQL in a Nutshell, walks through the process of using replication for data backups in MySQL.
MySQL AB :: MySQL 5.0 Reference Manual :: B.1.4.1 How to Reset the Root Password
MySQL – best methods for backups: Best way to backup, MySQL/VPS etc Linux
MySQL AB :: MySQL 5.0 Reference Manual :: 12.2.17.1 Troubleshooting InnoDB Data Dictionary Operations
ERROR: database: mysql_error: Can’t connect to MySQL server on ‘10.10.0.7 (110) – Snort Forums Archive: The open source Snort Intrusion Detection and Prevention system is the most flexible and widely deployed solution available.
How to fix error 134 from storage engine – MySQL: How to fix error 134 from storage engine. Get answers to your questions in our MySQL forum.
MySQL AB :: MySQL 5.0 Reference Manual :: 12.2.3 InnoDB Configuration
MySQL Stored Procedures: Part 2: Part 2 of MySQL Stored Procedures covers some more advanced concepts, including conditions and loops.
MySQL AB :: MySQL 5.0 Reference Manual :: 10.11.1 GROUP BY (Aggregate) Functions
Select INTO OUTFILE
MySQL :: stored procedure to list stored procedures
MySQL :: MySQL 5.1 Reference Manual :: 10.4.5 The SET Type
InnoDbEngineStatusAndTuning < Development < TWiki
MySQL :: MySQL 5.0 Reference Manual :: 13.2.11 InnoDB Performance Tuning Tips
Regular Expressions in MySQL: Regular Expressions in MySQL
Dan Winchester – MySQL date_format
MySQL :: MySQL 5.0 Reference Manual :: B.1.2.11 Communication Errors and Aborted Connections
MySQL Bugs: #36910: Mysql Server has gone away
Mysql_User_Add < Development < TWiki
mytop – a top clone for MySQL
Using ON DUPLICATE KEY UPDATE to improve MySQL Replication Performance « Kevin Burton’s NEW FeedBlog
MySQL :: MySQL 5.1 Reference Manual :: 13.11 The FEDERATED Storage Engine
MySQL :: MySQL 5.1 Reference Manual :: 11.4.2 Regular Expressions
MySQL :: MySQL 5.1 Reference Manual :: 18.2 Partition Types

PERL

Proc::ProcessTable – Perl extension to access the unix process table – search.cpan.org
Proc::ProcessTable::Process – Perl process objects – search.cpan.org
perlvar
Perl 5.8 Documentation – Signals: Perl 5.8 Documentation – Signals
khtml2png – Make screenshots from webpages
Sys::Load – Perl module for getting the current system load and uptime – search.cpan.org
The CPAN Search Site – search.cpan.org
Perl HTML::Form: Perl 5.8 Documentation – HTML::Form – Class that represents HTML forms
LWP Cookbook – URL explosion
Reaping Zombies
PERL ‘UTF-16LE’ – MarkMail
urlencode / urldecode in Perl | melecio.org
Regular Expression Examples
how check new URL of redirected page
Getopt::Long – perldoc.perl.org
perl.com: Beginners Intro to Perl – Part 6: Doug Sheppard shows us how to activate Perl’s built in security features.
How can I make one class extend another one?
XML::Generator – Perl extension for generating XML – search.cpan.org
Free Perl source library: unescape: subroutine name: unescape decode URL-encoded string
rami.info » URLEncode And URLDecode For Perl
File Tests in Perl: File Tests in Perl
Page 2 – Build a Perl RSS Aggregator with Templating Tools: Page 2 – Build a Perl RSS Aggregator with Templating Tools
perl.com: Preventing Cross-site Scripting Attacks: Paul Lindner, author of the mod_perl Cookbook, explains how to secure our sites against Cross-Site Scripting attacks using mod_perl and Apache::TaintRequest
libapreq2-2.08: libapreq2: Apache2::Upload
binary data handling – examine a .gif file – Perl example: binary data handling – examine a .gif file – Perl example
PERL — Conversion Functions
LWP::UserAgent: Web user agent class
Fastest XML Parser ?

mod_perl

Practical mod_perl: 6.3.3.6. A third solution: This solution makes use of package-name declaration in the …
mod_perl: HTTP Handlers: mod_perl documentation: This chapter explains how to implement the HTTP protocol handlers in mod_perl.
Installing mod_perl from RPM | O’Reilly Media: It’s easy to install mod_perl using the Red Hat package manager. Configuring it is trickier.
mod_perl: Apache2::RequestRec – Perl API for Apache request record accessors: mod_perl documentation: <code>Apache2::RequestRec</code> provides the Perl API for Apache request_rec object.
How to extract name/value pairs from the query string? | ModPerl | ModPerl: How to extract name/value pairs from the query string? ModPerl ModPerl
mod_perl: Code Snippets: mod_perl documentation: A collection of mod_perl code snippets which you can either adapt to your own use or integrate directly into your own code.

XML

Helpful XML related sites

Swish-e

Connecting Linux or UNIX system to Network attached storage device: Network attached storage (NAS) allows using TCP/IP network to backup files. This enables multiple servers in IDC to share the same storage for backup at once, which minimizes overhead by centrally managing hard disks. NAS …
How do I access NAS server using automount?: Network-attached storage commonly used to store backup and other shared files over TCP/IP network. For example: i) Corporate e-mail system with multiple, load-balanced webmail servers ii) Load-balanced web servers access the same contents from NAS …
SmallNetBuilder: SmallNetBuilder provides networking and IT news, reviews, help and information for professional and "prosumer" SOHO and SMB users.
IP Subnet Calculator: Online IP Subnet Calculator
10 Steps to Installing PostgreSQL
Remote Network Commands | Linux Journal
Cikul » How to change hostname in CentOS
Thecus User Group – NFS mount failed permission denied
Thecus 1U4500 – Enable root SSH
Wahoo’s Word » Using watch to monitor Javascript
Ascii control codes (control characters, C0 controls)
DOM Based Cross Site Scripting
document.body, doctype switching, and more | evolt.org: A world community for web developers, evolt.org promotes the mutual free exchange of ideas, skills and experiences.
DOM:window.open – MDC
Welcome to Hadoop!
Internationalized domain name – Wikipedia, the free encyclopedia
Code Charts – Scripts
ISO 8859-1 Latin 1 and Unicode characters in ampersand entities
Dig Demonstrations
Re: say if grep can find non-ascii
http://www.ietf.org/rfc/rfc2181.txt
MIL-STD-498,MIL STD 498,MIL-STD,MIL-SPEC,MIL SPEC,Military Standards: MIL-STD-498,MIL-STD,MIL-SPEC,MIL STD,MIL SPEC,Military Standards for ISA
J-STD-016 & MIL-STD-498 vs. DOD-STD-2167A & 7935A
DOD Standards Procedures Collection Document Listing – Page 2: IHS, DOD STANDARDS (MILITARY/FEDERAL SPECS) – General Collection
Fred Morris, project management/distributed systems/practices
Info: (dir) Top
VICNET Help: Online – Web Design – .htpasswd encoder
reminders about programming: Fedora firewall setup is simple using built-in tools
Sample Usability Test Plan
FavIcon from Pics — free favicon.ico for your website (animated, static and marquee icons): Free and easy to use online tool for creating favicons (.ico, animated, marquee and static) for browser address bars, favorites and tabs, from pictures, logos and other graphics.
How to Obscure Any URL
frames test page for harvesters
IP CIDR Subnet Calculator: Online IP CIDR / VLSM Supernet Calculator
DNS BIND named.conf Parameters
Copy files and directories recursively with tar – Tech-Recipes.com: Copying a directory tree and its contents to another filesystem using tar will preserve ownership, permissions, and timestamps. A neat trick allows using tar to perform a recursive copy without creating an intermediate tar file.
Scrum (development) – Wikipedia, the free encyclopedia
Searching your files with SWISH-E
Disk I/O
Installing and Configuring iptables
How to add an external USB hard drive to your Linux server (Redhat, CentOS, Ubuntu, Gentoo and SUSE) | my-whiteboard: Extenal USB hard disk is really useful (and inexpensive) for backing up your Linux server. Follow these steps to get it to work. 1, Buy a USB hard disk (I have
Which Web Browser is King? – Round 5: JavaScript Library and Framework Tests – OS, Software & Networking by ExtremeTech: Which browser is faster? IE7, Firefox 3, Google Chrome, Safari, or Opera? We run a bevy of tests to determine the king of the Web browser hill.
How to: Debug SSL certificate problems from the shell prompt: OpenSSL is a cryptography toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) network protocols and related cryptography standards required by them. It also includes the openssl command, which provides a rich variety of commands You can use the same command to debug problems with SSL certificates. To test the secure connections to a server, type the following command at a shell prompt: openssl s_client -connect ssl.servername.com:443 Where, s_client : This implements a generic SSL/TLS client which can establish a transparent connection to a remote server speaking SSL/TLS. It’s intended for testing …
Ascii Table – ASCII character codes and html, octal, hex and decimal chart conversion: Ascii character table – ascii ascii ascii ascii and ascii…conversions
How to Copy Files Across a Network/Internet in UNIX/LINUX (Redhat, Debian, FreeBSD, etc) – scp tar rsync
HOWTO: Installing DenyHosts – Page 2 – Ubuntu Forums: Page 2- HOWTO: Installing DenyHosts Tutorials & Tips
sendmail Configuration
history–Show status of files and users
using rsync to copy files from one server to another
CVS Commands
FC5 Repositories & Updates
Multiple Bugzilla databases with a single installation
IP Address Lookup (IPv4 & IPv6): Determines your IP address and shows information (host, location, whois…) about any IP address entered – Up to 10 IP addresses can be looked up at the same time
FC10 network setup repeatedly overwritten – FedoraForum.org: FC10 network setup repeatedly overwritten Installation Help
Interface Configuration Files
CVS revision numbers
CVS Branch and Merge example
CVS–Concurrent Versions System – Merging two revisions
Linux.com :: All about Linux swap space: When your computer needs to run programs that are bigger than your available physical memory, most modern operating systems use a technique called swapping, in which chunks of memory are temporarily stored on the hard disk while other data is moved into physical memory space. Here are some techniques that may help you better manage swapping on Linux systems and get the best performance from the Linux swapping subsystem.
Zone Files
HowTo Setup an NTP Daemon for Time Synchronization – SIPfoundry sipXecs IP PBX, The Open Source SIP PBX for Linux – Calivia
YAML Ain’t Markup Language (YAML) Version 1.1
Trouble editing whine.txt.tmpl – What variables can I use? – mozilla.support.bugzilla | Google Groups
The Cafes » Privacy Tip #3: Block Referer Headers in Firefox
Writing Software Requirements Specifications | A Technical Communication Community
DiG HOWTO: How to use dig to query DNS name servers.
Behavior Driven Development – Wikipedia, the free encyclopedia
Agile software development – Wikipedia, the free encyclopedia
Waterfall model – Wikipedia, the free encyclopedia

David DeMartini actual

Tag Archives: apache

Cassandra – Getting Started – (deployment Part 2 – Installing Ops Center)

Installing Ops Center

Installing the Ops Center Agents

Start up Ops Center

Start up the Node Agents

Conclusion

Cassandra – Getting Started – (deployment Part 1 – Installing Cassandra)

Getting the right JVM/JDK/JRE

Configuring a Node

Systems Administration

Starting up the Cluster

Inserting and Reading data from a Cassandra Cluster

Drop keyspace using Cassandra Cli

Previous Cassandra related articles

Cassandra – Running some simple tests, including a multi-get strategy.

Re-Configuring an Empty Cassandra Cluster

UPDATE!

Cassandra and Big Data – building a single-node “cluster”

Extra Credit:

Additional Comments:

Apache Cassandra Project – processing “Big Data”

Help for Geeks – My Development Bookmarks

Apache

HTML / CSS

JavaScript

JAVA

MySQL

PERL

mod_perl

XML

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