Update on research

 Triviality
Nov 132009
 

I’ve deployed Cassandra to my development environment, running on 4 servers with replica 2. I picked the number 4 and 2 because it’s more like a real world thing, and it is the requirement from my friend. I can test fail-over etc later on.

I’ve also composed some scripts to do service stuffs – the script I composed can start/stop/restart Cassandra gracefully, it can also tell status of the node and the cluster, it’s a simple Shell script, I will make it a service under Fedora, and a init.d script under Ubuntu (I’m running only these two platform now). Cassandra was upgrade from 0.4.1 to 0.4.2 days ago, and I used that as a chance to test my deployment stuffs, seems pretty good. I think I just need to be careful with 0.4.x => 0.5.x upgrade since it may break compatibility on configuration and command line.

I’ve converted my PowerBook to a dedicated client machine running Fedora … it’s a pretty old machine and seems Apple does not want to roll out new software (such as JDK 1.6) for it, so I did some survey around and picked Fedora (Ubuntu is not ppc friendly – the support is community based).

And finally I have Thrift/PHP up and running. At the very beginning I was thinking I should use Java as the client but later one found that I have no idea how to develop Java based web application, and since Thrift mentioned it supports all C/C++, Java, Perl, PHP, Ruby, Python pretty well, I should just pick my favorite language to do the test and then let real clients pick what theyย  want to use (where is my client, BTW? ๐Ÿ™ ).

And yes, I confirmed the schema (though Cassandra is schema-less thing), I’m going to test the schema with PHP client today. After that I will have to find a place to hold all my codes/configuration, etc, in a subversion, and based on what I found so far, github.com is the best candidate.

Will update here today or tomorrow.

  2 Responses to “Update on research”

  1. Scott Mitchell says:
    2010-12-14 at 10:01

    Any chance that you can post the scripts that “start/stop/restart Cassandra gracefully”

    I am trying to do the same thing … but having difficulty.

    Thanks in advance for any help you can provide.

  2. Hang says:
    2010-12-14 at 18:36

    Here we go, it works with 0.6.4 at least, as I stopped playing with Cassandra after that. I cannot recall if I wrote the script all by myself or I actually changed an existing one from someone else, but anyway:

    #!/bin/sh
#
# cassandra     This shell script takes care of starting and stopping
#               the Cassandra service.
#
# chkconfig: - 30 60
# description: Cassandra is a highly scalable, eventually consistent,
#              distributed, structured key-value store.
# probe: true

### BEGIN INIT INFO
# Provides: cassandra
# Required-Start: network autofs syslog
# Should-Start: network autofs syslog
# Required-Stop: $autofs $network $syslog
# Should-Stop: $autofs $network $syslog
# Default-Start:  2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start up the Cassandra server sevice
# Description: Cassandra is a highly scalable, eventually consistent,
#              distributed, structured key-value store.
### END INIT INFO

CASSANDRA_HOME=/net/f5/shared/nosql/cassandra/current
HOSTNAME=$(hostname)
DATA_DIR=/var/lib/cassandra

export JVM_OPTS=" \
        -Xrunjdwp:transport=dt_socket,server=y,address=8888,suspend=n \
        -Xms256M \
        -Xmx384M \
        -XX:SurvivorRatio=8 \
        -XX:TargetSurvivorRatio=90 \
        -XX:+AggressiveOpts \
        -XX:+UseParNewGC \
        -XX:+UseConcMarkSweepGC \
        -XX:CMSInitiatingOccupancyFraction=1 \
        -XX:+CMSParallelRemarkEnabled \
        -XX:+HeapDumpOnOutOfMemoryError \
        -Dcom.sun.management.jmxremote.port=8080 \
        -Dcom.sun.management.jmxremote.ssl=false \
        -Dcom.sun.management.jmxremote.authenticate=false"

export CASSANDRA_CONF=/etc/cassandra
export CASSANDRA_INCLUDE=/dev/null
export CLASSPATH=$(find $CASSANDRA_HOME/lib -name \*.jar | tr "\n" ":")
if [ -d $CASSANDRA_HOME/build/ ] ; then
    export CLASSPATH=$CLASSPATH$(find $CASSANDRA_HOME/build/ -name \*.jar | tr "\n" ":")
fi

PATIENCE=30
start() {
    $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
    if [ $? -eq 0 ] ; then
        echo "There is already an instance running"
        return
    fi

    $CASSANDRA_HOME/bin/cassandra -p $DATA_DIR/cassandra.pid > $DATA_DIR/rc.log 2>&1
    if [ $? -ne 0 ] ; then
        echo "Unable to start Cassandra"
        return
    fi

    echo -n Waiting for Cassandra warm up .
    for RETRY in $(seq 1 $PATIENCE) ; do
        $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
        [ $? -eq 0 ] && break
        echo -n .
        sleep 1
    done

    echo
    $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
    if [ $? -eq 0 ] ; then
        echo "Cassandra started"
    else
        echo "Cassandra was not started"
    fi
}

stop() {
    $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
    if [ $? -ne 0 ] ; then
        echo "There is no instance running"
        return
    fi

    [ -f $DATA_DIR/cassandra.pid ] && kill $(cat $DATA_DIR/cassandra.pid) >/dev/null 2>&1
    rm -f $DATA_DIR/cassandra.pid
    lsof -P | grep TCP | grep :7000 | grep LISTEN | awk '{print $2}' | xargs -r kill
    echo -n Waiting for Cassandra terminate .
    for RETRY in $(seq 1 $PATIENCE) ; do
        $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
        [ $? -ne 0 ] && break
        echo -n .
        sleep 1
    done
    echo

    $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
    if [ $? -eq 0 ] ; then
       echo "Cannot stop Cassandra"
    else
       echo "Cassandra stopped"
    fi
}

status() {
    unset CASSANDRA_INCLUDE
    $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME info >/dev/null 2>&1
    if [ $? -eq 0 ] ; then
        $CASSANDRA_HOME/bin/nodetool -h $HOSTNAME $1
    else
        echo "Cassandra is not running"
    fi
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart)
        stop
        start
        ;;
    status)
        status info
        ;;
    ring)
        status ring
        ;;
    *)
        echo $"Usage: $(basename $0) {start|stop|restart|status|ring}"
        exit 2
esac

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