memcached演练(1) 搭建memcached服务

memcached已经火了好多年了，现在网上关于memcached的资源相当多了，我就不浪费话语了。干脆写一个实战系列，坚持一切用实施说话。

环境介绍

Linux虚拟机

内核信息

[root@hadoop1 ~]# uname -a
Linux hadoop1 2.6.32-358.el6.i686

内存：1G

安装过程

1.准备编译环境，安装必须的gcc，make工具，如果没有安装yum，最好安装下。网上有很多共享的yum源。

2.下载最新版本的libevent

# wget https://github.com/libevent/libevent/releases/download/release-2.0.22-stable/libevent-2.0.22-stable.tar.gz

3.解压libevent对应压缩包

# tar zxvf libevent-2.0.22-stable.tar.gz

解压之后的文件路径：/u01/software/libevent-2.0.22-stable

3.编译libevent

$ cd /u01/software/libevent-2.0.22-stable$  ./configure -prefix=/usr/local/libevent$ make$ make install确认安装结果$ ls -al /usr/local/lib |grep libevent

4.下载最新版本的memcached

$ wget http://memcached.org/latest

5.解压memcached对应压缩包

$ tar zxvf memcached-1.4.29.tar.gz

解压之后的文件路径：/u01/software/memcached-1.4.29

6.编译memcached

$ cd /u01/software/memcached-1.4.29$ [root@hadoop1 memcached-1.4.29]# ./configure  -help`configure' configures memcached 1.4.29 to adapt to many kinds of systems.Usage: ./configure [OPTION]... [VAR=VALUE]...Configuration:  -h, --help              display this help and exit      --help=short        display options specific to this package      --help=recursive    display the short help of all the included packages  -V, --version           display version information and exit  -q, --quiet, --silent   do not print `checking ...' messages      --cache-file=FILE   cache test results in FILE [disabled]  -C, --config-cache      alias for `--cache-file=config.cache'  -n, --no-create         do not create output files      --srcdir=DIR        find the sources in DIR [configure dir or `..']Installation directories:  --prefix=PREFIX         install architecture-independent files in PREFIX                          [/usr/local]...Fine tuning of the installation directories:  --bindir=DIR            user executables [EPREFIX/bin]  --sbindir=DIR           system admin executables [EPREFIX/sbin]  --libexecdir=DIR        program executables [EPREFIX/libexec]  --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]  --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]  --localstatedir=DIR     modifiable single-machine data [PREFIX/var]  --libdir=DIR            object code libraries [EPREFIX/lib]  --includedir=DIR        C header files [PREFIX/include]  --oldincludedir=DIR     C header files for non-gcc [/usr/include]  --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]  --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]  --infodir=DIR           info documentation [DATAROOTDIR/info]  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]  --mandir=DIR            man documentation [DATAROOTDIR/man]  --docdir=DIR            documentation root [DATAROOTDIR/doc/memcached]  --htmldir=DIR           html documentation [DOCDIR]  --dvidir=DIR            dvi documentation [DOCDIR]  --pdfdir=DIR            pdf documentation [DOCDIR]  --psdir=DIR             ps documentation [DOCDIR]  Optional Packages:  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)  --with-libevent=PATH     Specify path to libevent installation     # ./configure --prefix=/usr/local/memcached  --with-libevent=/usr/local/lib/  # make    # make install

这时候memcached安装成功了

启动memcached

$ /usr/local/memcached/bin/memcached 报错

error while loading shared libraries: libevent-2.0.so.5: cannot open shared object file: No such file or directory

解决思路

##跟踪运行memcached所有加载库文件的路径

$ LD_DEBUG=libs LD_DEBUG=libs ./memcached -v     15862:     find library=libevent-2.0.so.5 [0]; searching     15862:      search cache=/etc/ld.so.cache     15862:      search path=/lib/tls/i686/sse2:/lib/tls/i686:/lib/tls/sse2:/lib/tls:/lib/i686/sse2:/lib/i686:/lib/sse2:/lib:/usr/lib/tls/i686/sse2:/usr/lib/tls/i686:/usr/lib/tls/sse2:/usr/lib/tls:/usr/lib/i686/sse2:/usr/lib/i686:/usr/lib/sse2:/usr/lib            (system search path)     15862:       trying file=/lib/tls/i686/sse2/libevent-2.0.so.5     15862:       trying file=/lib/tls/i686/libevent-2.0.so.5     15862:       trying file=/lib/tls/sse2/libevent-2.0.so.5     15862:       trying file=/lib/tls/libevent-2.0.so.5     15862:       trying file=/lib/i686/sse2/libevent-2.0.so.5     15862:       trying file=/lib/i686/libevent-2.0.so.5     15862:       trying file=/lib/sse2/libevent-2.0.so.5     15862:       trying file=/lib/libevent-2.0.so.5     ...

首先确认建立软连接

$ ls /usr/local/lib/libevent-2.0.so.5/usr/local/lib/libevent-2.0.so.5$ ln -s /usr/local/lib/libevent-2.0.so.5   /usr/lib/i686/libevent-2.0.so.5

如果以root用户登陆，必须指定-u参数

$ /usr/local/memcached/bin/memcached  -u hadoop

确认memcached是否启动成功

$ ps -ef |grep memcachedhadoop   15891  4034  0 22:45 pts/4    00:00:00 /usr/local/memcached/bin/memcached -u hadooproot     15899 15561  0 22:45 pts/5    00:00:00 grep memcached# netstat -tlnp |grep memcachedtcp        0      0 0.0.0.0:11211               0.0.0.0:*                   LISTEN      15891/memcached     tcp        0      0 :::11211                    :::*                        LISTEN      15891/memcached

最后telnet 确认下

$ telnet 127.0.0.1 11211Trying 127.0.0.1...Connected to 127.0.0.1.Escape character is '^]'.statsSTAT pid 15891STAT uptime 86STAT time 1470494793

OK。至此memcached1.4.9版本已经成功在机器上安装。个人感觉最麻烦的地方，就是处理libevent。

参考了很多资源，才把问题解决。

memcached设置自启动

为了方便，现将memcached执行变更下权限

1. 最简单的启动方式

   只需在/etc/rc.d/rc.local中加入一行
   /usr/local/memcached/bin/memcached -d -m 20 -p 11211 -u hadoop

注意

-d：设置为后台进程

-u：指向用户

-p:端口

-m:内存

1. 推荐的方式

2.1.拷贝memcached源码包的memcached.sysv拷贝到/etc/init.d，做为memcached的启动脚本

$ cp /u01/software/memcached-1.4.29/scripts/memcached.sysv  /etc/init.d/memcached

[root@hadoop1 bin]# vi /etc/init.d/memcached #! /bin/sh## chkconfig: - 55 45# description:  The memcached daemon is a network memory cache service.# processname: memcached# config: /etc/sysconfig/memcached# Source function library.. /etc/rc.d/init.d/functionsPORT=11211USER=nobodyMAXCONN=1024CACHESIZE=64OPTIONS=""if [ -f /etc/sysconfig/memcached ];then    . /etc/sysconfig/memcachedfi# Check that networking is up.if [ "$NETWORKING" = "no" ]then    exit 0fiRETVAL=0prog="memcached"start () {    echo -n $"Starting $prog: "    # insure that /var/run/memcached has proper permissions    chown $USER /var/run/memcached    daemon memcached -d -p $PORT -u $USER  -m $CACHESIZE -c $MAXCONN -P /var/run/memcached/memcached.pid $OPTIONS    RETVAL=$?    echo    [ $RETVAL -eq 0 ] && touch /var/lock/subsys/memcached}stop () {    echo -n $"Stopping $prog: "    killproc memcached    RETVAL=$?    echo    if [ $RETVAL -eq 0 ] ; then        rm -f /var/lock/subsys/memcached        rm -f /var/run/memcached/memcached.pid    fi}restart () {    stop    start}# See how we were called.case "$1" in    start)        start        ;;    stop)    stop    ;;    status)    status memcached    ;;    restart|reload)    restart    ;;    condrestart)    [ -f /var/lock/subsys/memcached ] && restart || :    ;;    *)    echo $"Usage: $0 {start|stop|status|restart|reload|condrestart}"    exit 1esacexit $?

修改下面这一句（其实就将memcached 命令指向咱们的全路径）

daemon memcached -d -p $PORT -u $USER -m $CACHESIZE -c $MAXCONN -P /var/run/memcached/memcached.pid $OPTIONS

daemon /usr/local/memcached/bin/memcached -d -p $PORT -u $USER -m $CACHESIZE -c $MAXCONN -P /var/run/memcached/memcached.pid $OPTIONS

配置自启动

[root@hadoop1 bin]$ chkconfig memcached on[root@hadoop1 bin]$ chkconfig |grep memcachedmemcached       0:off   1:off   2:on    3:on    4:on    5:on    6:off

安装nc

[root@hadoop1 yum.repos.d]$ yum install nc

memcached 自带的stats命令，对搜索不太友好。为了很好的搜索，借助nc工具。

比如，想查找connection相关的参数

[root@hadoop1 yum.repos.d]# echo stats | nc 127.0.0.1 11211 |grep connectionSTAT curr_connections 10STAT total_connections 13STAT connection_structures 11

配合nc使用形式，个人参考网上资源，简单罗列下

watch "echo stats | nc 127.0.0.1 11211"printf "stats\r\n" | nc 127.0.0.1 11211echo stats | nc 127.0.0.1 11211

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The End

接下来，演练的内容是通过telnet命令行和JAVA 客户端工具，访问memcachd.