memcached+magent組成高可用

 

簡介：

     使用magent架設memcached高可用，當主的掛掉之後，備機能夠繼續使用。

 

                 magent

                   |

----------------------------------------

|                   |                  |

memcached1     memcached2           memcached3

 （master)       (master)             (backup)

 

 

 

一 安裝memcached

   下載下面安裝包

libevent-2.0.21-stable.tar.gz

memcached-1.4.32.tar.gz

magent-0.5.tar.gz

 

 

 

• 安裝libevent

 

tar –xzvf libevent-2.0.21-stable.tar.gz cd   libevent-2.0.21-stable ./configure –prefix=/usr/local/libevent make make   install

 

• 安裝memcached

 

tar –xzvf memcached-1.4.32 cd   memcached-1.4.32 ./configure   --prefix=/opt/memcached --with-libevent=/usr/local/libevent/ make make   install

 

 

 

 

• magent安裝

下載安裝包文件magent-0.5.tar.gz

解壓tar –xzvf magent-0.5.tar.gz

 

make   #執行編譯安裝

 

把編譯好的magent拷貝到/opt/memcached/bin/ 目錄下

 

  

 

• 安裝報錯解決方案

 

[root@i-0boypofz   magent]# make gcc   -Wall -g -O2 -I/usr/local/include -m64 -c -o magent.o magent.c magent.c:71:19:   error: event.h: No such file or directory magent.c:130: error: field ‘ev’ has incomplete type magent.c:161: error: field ‘ev’ has incomplete type magent.c: In function ‘server_free’: magent.c:494:   warning: implicit declaration of function ‘event_del’ magent.c:   In function ‘pool_server_handler’: magent.c:514: error: ‘EV_READ’ undeclared (first use in this function) magent.c:514:   error: (Each undeclared identifier is reported only once   # 解決辦法，檢查下libevent安裝路徑，若是自定義安裝了，拷貝下路徑庫。 ln -s /usr/lib/libevent*  /usr/lib64/   [root@i-0boypofz   magent]# make gcc   -Wall -g -O2 -I/usr/local/include -m64 -c -o magent.o magent.c magent.c: In function ‘writev_list’: magent.c:729: error: ‘SSIZE_MAX’ undeclared (first use in this function) magent.c:729:   error: (Each undeclared identifier is reported only once magent.c:729:   error: for each function it appears in.) make:   *** [magent.o] Error 1   解決方法： vi ./ketama.h   #在開頭加入    #ifndef SSIZE_MAX  #define SSIZE_MAX        32767  #endif   #libm.a不存在的時候，須要拷貝下面so，若是沒有，須要安裝glibc glibc-devel cp   /usr/lib64/libm.so /usr/lib64/libm.a   gcc   -Wall -g -O2 -I/usr/local/include -m64 -o magent magent.o ketama.o   /usr/lib64/libevent.a /usr/lib64/libm.a /usr/lib64/libevent.a(event.o):   In function `gettime': /root/libevent-2.0.21-stable/event.c:370:   undefined reference to `clock_gettime' /usr/lib64/libevent.a(event.o):   In function `detect_monotonic': /root/libevent-2.0.21-stable/event.c:340:   undefined reference to `clock_gettime' collect2:   ld returned 1 exit status make:   *** [magent] Error 1   解決方法：   vi   Makefile CFLAGS   = -Wall -g -O2 -I/usr/local/include $(M64) 改成：    CFLAGS   = -lrt -Wall -g -O2 -I/usr/local/include $(M64)       [root@i-0boypofz   magent5]# make        gcc   -lrt -Wall -g -O2 -I/usr/local/include    -o magent magent.o ketama.o -levent ketama.o:   In function `create_ketama': /root/magent5/ketama.c:399:   undefined reference to `floorf' collect2:   ld returned 1 exit status make:   *** [magent] Error 1   解決辦法： vi   Makefile   LIBS =   -levent –lm

 

 

 

三 啓動 

 

• 啓動memcached

 

/opt/memcached/bin/memcached   -d -u root -c 10000 -m 8192 192.168.100.22 -p 11211

 

• 啓動magent

 

/opt/memcached/bin/magent   -u root -n 102400 -l 192.168.100.24 -p 12001 -s   192.168.100.22:192.168.100.23:11211 -b 192.168.100.24:11211

 

 

 

四 測試

 

4.1 模擬一臺主的壞掉

 

設置數據：

 

 

kill掉一臺主

 

驗證數據正常：

 

 

4.2 模擬第二臺主機也down

 

 

驗證數據，讀寫都正常。

 

4.3 模擬三臺都宕機

 

magent沒法讀取數據

 

4.4 模擬主機down掉一臺，啓動主機，查看數據是否丟失

測試檢查丟失了一條數據。

因此當主down之後，不要當即啓動主，須要非工做時間處理。