Memcached

1. OpenStack 使用 Memcached 做 cache tokens 暫存令牌，來進行服務的身份認證。memcached 服務通常運作在控制器節點上，安裝 memcached 服務。

   [root@ip112 ~]# yum install memcached python-memcached
   

2. 編輯 /etc/sysconfig/memcached，修改 OPTIONS="-l 127.0.0.1,::1" 中 IP 為控制節點的 IP，讓其他節點可以存取。

   [root@ip112 ~]# vim /etc/sysconfig/memcached 
   [root@ip112 ~]# cat /etc/sysconfig/memcached 
   PORT="11211"
   USER="memcached"
   MAXCONN="1024"
   CACHESIZE="64"
   OPTIONS="-l 127.0.0.1,::1"
   

3. 啟動 memcached，並設定開機啟動。

   [root@ip112 ~]# systemctl enable memcached.service 
   Created symlink from /etc/systemd/system/multi-user.target.wants/memcached.service 
   to /usr/lib/systemd/system/memcached.service.
   
   [root@ip112 ~]# systemctl start memcached.service 
   [root@ip112 ~]# systemctl status memcached.service 
   ● memcached.service - memcached daemon
      Loaded: loaded (/usr/lib/systemd/system/memcached.service; enabled; vendor preset: disabled)
      Active: active (running) since Wed 2018-05-23 17:15:58 CST; 6s ago
    Main PID: 13794 (memcached)
      CGroup: /system.slice/memcached.service
              └─13794 /usr/bin/memcached -p 11211 -u memcached -m 64 -c 1024 -l...
   
   May 23 17:15:58 ip112.csie.cyut.edu.tw systemd[1]: Started memcached daemon.
   May 23 17:15:58 ip112.csie.cyut.edu.tw systemd[1]: Starting memcached daemon...
   Hint: Some lines were ellipsized, use -l to show in full.