How to setup a Memcached server on CentOS :: Article

Articles

How to setup a Memcached server on CentOS

Author: nathacof
Published: Monday 1st of June 2009

Requirements

The first thing to do is install the libevent libraries from your distributions repositories:

[root@dev ~]# yum list libevent*
Loaded plugins: fastestmirror, priorities
Loading mirror speeds from cached hostfile
 * base: ftp.lug.udel.edu
 * updates: centos.aol.com
 * addons: centos.mirror.nac.net
 * extras: centos.mirror.nac.net
Installed Packages
libevent.i386           1.1a-3.2.1      installed
libevent.x86_64         1.1a-3.2.1      installed
libevent-devel.i386     1.1a-3.2.1      installed
libevent-devel.x86_64   1.1a-3.2.1      installed

Compile Memcached

Next we need to install memcached! Grab the latest source from the memcached website.

[nathacof@dev src]$ wget http://memcached.googlecode.com/files/memcached-1.2.8.tar.gz
[nathacof@dev src]$ tar xzf memcached-1.2.8.tar.gz
[nathacof@dev src]$ cd memcached-1.2.8
[nathacof@dev memcached-1.2.8]$ ./configure --enable-64bit --enable-threads && make && sudo make install

Service Configuration

Next we need a startup script for memcached . Memcached comes with a number of startup scripts in the scripts/ directory but I opted to write my own based off the standard CentOS service control scripts. :P

#!/bin/bash
#
# memcached        This shell script takes care of starting and stopping
#               the MemcacheD service (memcached).
#
# chkconfig: - 60 30
# description:  MemcacheD server.
# processname: memcached
# pidfile: /var/run/memcached/memcached.pid

# Source function library.
. /etc/rc.d/init.d/functions

prog=/usr/local/bin/memcached
username=memcached # Avoid running as root
memory_max=128 # Default 64 MB
port=11211 # Change this, memcached has no security

# Values based on CentOS 5.x
PID=/var/run/memcached/memcached.pid
LOCK=/var/lock/subsys/memcached

start(){
        $prog -d -u $username -m $memory_max -P $PID  /dev/null 2&1 &
        ret=$?
        if [ $ret -eq 0 ] && touch $LOCK;
        then
                action $"Starting $prog: " /bin/true
        else
                ret=1
                action $"Startng $prog: " /bin/false
        fi
        return $ret
}


stop(){
        MEMCACHEDPID=$(cat "$PID"  2/dev/null)
        if [ -n "$MEMCACHEDPID" ]; then
            /bin/kill "$MEMCACHEDPID" /dev/null 2&1
            ret=$?
            if [ $ret -eq 0 ]; then
                STOPTIMEOUT=60
                while [ $STOPTIMEOUT -gt 0 ]; do
                    /bin/kill -0 "$MEMCACHEDPID" /dev/null 2&1 || break
                    sleep 1
                    let STOPTIMEOUT=${STOPTIMEOUT}-1
                done
                if [ $STOPTIMEOUT -eq 0 ]; then
                    echo "Timeout error occurred trying to stop MemcacheD Daemon."
                    ret=1
                    action $"Stopping $prog: " /bin/false
                else
                    rm -f $LOCK
                    action $"Stopping $prog: " /bin/true
                fi
            else
                action $"Stopping $prog: " /bin/false
            fi
        else
            ret=1
            action $"Stopping $prog: " /bin/false
        fi
        return $ret

}

restart(){
        start
        stop
}

# See how we were called.
case "$1" in
  start)
    start
    ;;
  stop)
    stop
    ;;
  status)
    status memcached 
    ;;
  restart)
    restart
    ;;
  *)
    echo $"Usage: $0 {start|stop|status|restart}"
    exit 1
esac

exit $?

We'll copy this to the /etc/init.d directory. We also need to create a user, and a directory.

[nathacof@dev src]$ sudo cp memcached.sh /etc/init.d/memcached
[nathacof@dev src]$ sudo /usr/sbin/adduser -M memcached -s /sbin/nologin -u 10000
[nathacof@dev src]$ sudo mkdir /var/run/memcached/ && sudo chown memcached:memcached /var/run/memcached/

Next we need to startup the service, and ensure that our server will start this service on the next reboot.

[nathacof@dev src]$ sudo /sbin/chkconfig --level 345 memcached on
[nathacof@dev src]$ sudo /sbin/service memcached start
Starting /usr/local/bin/memcached:                         [  OK  ]

Let's check that the server is running.

[nathacof@dev src]$ sudo /sbin/service memcached status
memcached (pid 9516) is running...
[nathacof@dev src]$ sudo /usr/sbin/lsof -ai 4 -p 9516
COMMAND    PID      USER   FD   TYPE DEVICE SIZE NODE NAME
memcached 9516 memcached    7u  IPv4 209971       TCP *:11211 (LISTEN)
memcached 9516 memcached    9u  IPv4 209976       UDP *:11211

Great! We've got all the confirmation we need to ensure that Memcached is running! That's all there is to it. See the Memcached wiki for more information.

Articles