kubernetes上部署Memcached高可用记录

摘要：部署实现高可用常用的两个工具连接多个，请求转发单单，互为主辅结构结构主要部署步骤使用启动个每个容器初始化脚本得到另一个节点的因为就两个节点，不是就是判断另一个节点的监听状态如果在监听说明是主节点需要复制它，否则反之复制节点

memcached实现高可用常用的两个工具：
1）magent：连接多个memcached，请求转发
2）repcached：单master单slave，互为主辅

md-5c107eeae9fb1-0                  1/1       Running     0          59s
md-5c107eeae9fb1-1                  1/1       Running     0          49s

#得到另一个节点的HOSTNAME(因为就两个节点，不是0就是1)
PARTNER=${HOSTNAME##*-}
if [ "${PARTNER}" = "0" ]; then
        PARTNER=${MY_POD_NAME}-1
fi
if [ "${PARTNER}" = "1" ]; then
        PARTNER=${MY_POD_NAME}-0
fi

#判断另一个节点的监听状态(如果在监听说明是主节点需要复制它，否则反之)

测试
主备切换
//启动主节点后状态为Listen，设置同步端口为22222
root@md-5c107eeae9fb1-0:/# memcached -p 11211 -X 22222 -v -d -u root -m 512
root@md-5c107eeae9fb1-0:/# replication: listen
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:11211           0.0.0.0:*               LISTEN      260/memcached
tcp        0      0 0.0.0.0:22222           0.0.0.0:*               LISTEN      260/memcached
tcp6       0      0 :::11211                :::*                    LISTEN      260/memcached

//启动复制节点，同样设置同步端口为22222
root@md-5c107eeae9fb1-1:/# memcached -p 11211 -X 22222 -x md-5c107eeae9fb1-0.md-5c107eeae9fb1.itfarm3.svc.cluster.local -v -d -u root -m 512
root@md-5c107eeae9fb1-1:/# replication: connect (peer=10.244.5.50:22222)
replication: marugoto copying
replication: start

//从节点加入后，主节点状态为accept并取消对22222的监听
root@md-5c107eeae9fb1-0:/# replication: listen
replication: accept
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:11211           0.0.0.0:*               LISTEN      263/memcached
tcp6       0      0 :::11211                :::*                    LISTEN      263/memcached

//kill掉主节点
root@md-5c107eeae9fb1-0:/# kill 263
replication: cleanup start
replication: close
root@md-5c107eeae9fb1-0:/# replication: cleanup complete

//此时从节点成Listen状态，监听复制端口22222，等待加入
root@md-5c107eeae9fb1-1:/# replication: connect (peer=10.244.5.50:22222)
replication: marugoto copying
replication: start
replication: close
replication: listen
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:11211           0.0.0.0:*               LISTEN      258/memcached
tcp        0      0 0.0.0.0:22222           0.0.0.0:*               LISTEN      258/memcached
tcp6       0      0 :::11211                :::*                    LISTEN      258/memcached
高可用
//启动2个节点（一主一备）
md-5c107eeae9fb1-0                  1/1       Running     0          59s
md-5c107eeae9fb1-1                  1/1       Running     0          49s

//在主节点中添加item
$ telnet md-5c107eeae9fb1-0.md-5c107eeae9fb1.itfarm3.svc.cluster.local 11211
Trying 10.244.4.162...
Connected to md-5c107eeae9fb1-0.md-5c107eeae9fb1.itfarm3.svc.cluster.local.
Escape character is "^]".
set name 0 0 8
zhangsan
STORED
quit
Connection closed by foreign host.

//从节点查看item
$ telnet md-5c107eeae9fb1-1.md-5c107eeae9fb1.itfarm3.svc.cluster.local 11211
Trying 10.244.3.176...
Connected to md-5c107eeae9fb1-1.md-5c107eeae9fb1.itfarm3.svc.cluster.local.
Escape character is "^]".
get name
VALUE name 0 8
zhangsan
END

//模拟故障
$ kubectl.exe delete po md-5c107eeae9fb1-0
pod "md-5c107eeae9fb1-0" deleted

//重启后数据恢复
$ telnet md-5c107eeae9fb1-0.md-5c107eeae9fb1.itfarm3.svc.cluster.local 11211
Trying 10.244.4.162...
Connected to md-5c107eeae9fb1-0.md-5c107eeae9fb1.itfarm3.svc.cluster.local.
Escape character is "^]".
get name
VALUE name 0 8
zhangsan
END
部署sasl安全认证的memcached

测试
//使用statefulset启动N个memcached
md-5c11b67a6ae9b-0                  1/1       Running            0          1h
md-5c11b67a6ae9b-1                  1/1       Running            0          1h
md-5c11b67a6ae9b-2                  1/1       Running            0          1h
使用python连接memcached
$ python3
Python 3.5.2 (default, Nov 23 2017, 16:37:01)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import bmemcached
>>> client = bmemcached.Client(("md-5c11b67a6ae9b-ha:11211"), "md-5c11b67a6ae9b", "ZcUu1AVGbB3PnDzhxfOjRLJhatugwZBe")
>>> client.set("name", "zhangsan")
True
>>> client.get("name")
"zhangsan"
>>>
分布式存储
使用无头服务来区分多个memcache
#!/usr/bin/env python3
import bmemcached
client = bmemcached.Client(("md-5c11b67a6ae9b-0.md-5c11b67a6ae9b.itfarm3.svc.cluster.local:11211",
    "md-5c11b67a6ae9b-1.md-5c11b67a6ae9b.itfarm3.svc.cluster.local:11211",
    "md-5c11b67a6ae9b-1.md-5c11b67a6ae9b.itfarm3.svc.cluster.local:11211"), "md-5c11b67a6ae9b", "ZcUu1AVGbB3PnDzhxfOjRLJhatugwZBe")
print(client.set("name", "zhangsan"))
print(client.get("name"))
运行
$ python3 test.py
True
zhangsan
各客户端连接开启了sasl安全认证的memcached方案