redis集群3 2台机器迁移为3台机器
环境
系统：Centos6.6
软件：redis 3.0.3
背景
因为2个机器搭建的redis集群一旦1台机器损坏，集群依然不可用,为了解决该问题，决定添加一个机器，组成3台机器的高可用环境。
集群节点：
把原来的5.17 5.18 的7002端口去掉，新增5.16的7000 7001
迁移前主机 端口 迁移后主机 端口
10.112.5.17 7000 10.112.5.16 7000
10.112.5.17 7001 10.112.5.16 7001
10.112.5.17 7002 10.112.5.17 7000
10.112.5.18 7000 10.112.5.17 7001
10.112.5.18 7001 10.112.5.18 7000
10.112.5.18 7002 10.112.5.18 70012个机器的原始状态：
[worker@LFTz-Zkp02 ~]$ redis-cli -p 7000 -c cluster nodes|awk '{print $1,$2,$3,$4,$NF}'| sort -k2
231b544622793b0b69e88a286ac8b46d211c8172 10.112.5.17:7000 myself,master - 5461-10922
936482ede8b9e8b94eeb7d947e51ef635e5173df 10.112.5.17:7001 slave c3312b79d40e6b90eb856c3e52d0fae21ba217e7 connected
2304aalsdkjfalsjdflkajsfj23rklwj10932je9 10.112.5.17:7002 slave 231b544622793b0b69e88a286ac8b46d211c8172 connected
c3312b79d40e6b90eb856c3e52d0fae21ba217e7 10.112.5.18:7000 master - 0-5460
fb13b382748edee5e329db61af6ccbe5a426dade 10.112.5.18:7001 slave e442abf8ec244a697a203c67092fc184b45220bb connected
e442abf8ec244a697a203c67092fc184b45220bb 10.112.5.18:7002 master - 10923-16383因为需要摘除7002节点，所以找到7002节点
[worker@LFTz-Zkp02 ~]$ redis-cli -p 7000 -c cluster nodes|awk '{print $1,$2,$3,$4,$NF}'| sort -k2|grep :7002
2304aalsdkjfalsjdflkajsfj23rklwj10932je9 10.112.5.17:7002 slave 231b544622793b0b69e88a286ac8b46d211c8172 connected
e442abf8ec244a697a203c67092fc184b45220bb 10.112.5.18:7002 master - 10923-16383从上面的节点信息可以看到
10.112.5.17:7002是slave节点，可以直接摘除，
10.112.5.18:7002是master节点，需要先变成从节点，再进行摘除：
现在先把10.112.5.18:7002变成从节点
1 先kill掉10.112.5.18:7002的进程，让salve这个节点下线，让他的slave节点变成主
ps -ef|grep 7002 |awk '{print $2}'|kill
2.查看节点状态
redis-cli -c -p 7000 cluster nodes
发现10.112.5.18:7002 已经下线，并且10.112.5.18:7001 已经变成了主节点
3.启动10.112.5.18:7002 ,让他也变成从节点
redis-server 7002/7002.conf
redis-cli -c -p 7000 cluster nodes
查看节点状态后，10.112.5.18:7002已经变成从节点
此时2个节点已经变成从节点，可以直接执行摘除操作。
为了安全考虑，先把2个新的节点添加到集群，再执行节点摘除操作。
[worker@LFTz-Zkp02 ~]$ redis-cli -p 7000 -c cluster nodes|awk '{print $1,$2,$3,$4,$NF}'| sort -k2
231b544622793b0b69e88a286ac8b46d211c8172 10.112.5.17:7000 myself,master - 5461-10922
936482ede8b9e8b94eeb7d947e51ef635e5173df 10.112.5.17:7001 slave c3312b79d40e6b90eb856c3e52d0fae21ba217e7 connected
2304aalsdkjfalsjdflkajsfj23rklwj10932je9 10.112.5.17:7002 slave 231b544622793b0b69e88a286ac8b46d211c8172 connected
c3312b79d40e6b90eb856c3e52d0fae21ba217e7 10.112.5.18:7000 master - 0-5460
fb13b382748edee5e329db61af6ccbe5a426dade 10.112.5.18:7001 master - 10923-16383
e442abf8ec244a697a203c67092fc184b45220bb 10.112.5.18:7002 slave fb13b382748edee5e329db61af6ccbe5a426dade connected新的节点是为了替换2个7002端口的从节点，所以找到2个7002端口对应的2个主节点：
231b544622793b0b69e88a286ac8b46d211c8172 10.112.5.17:7000 myself,master - 5461-10922
fb13b382748edee5e329db61af6ccbe5a426dade 10.112.5.18:7001 master - 10923-16383
执行添加节点操作：
命令用法：redis-trib.rb add-node newip:newport IP:port
redis-trib.rb add-node --slave --master-id 231b544622793b0b69e88a286ac8b46d211c8172 10.112.5.16:7000 10.112.5.17:7000
redis-trib.rb add-node --slave --master-id fb13b382748edee5e329db61af6ccbe5a426dade 10.112.5.16:7001 10.112.5.17:7000
添加2个新的从节点后，查看状态,一共8个节点
[worker@LFTz-Zkp02 ~]$ redis-cli -p 7000 -c cluster nodes|awk '{print $1,$2,$3,$4,$NF}'| sort -k2
e442abf8ec244a697a203c67092fc184b45220bb 10.112.5.16:7001 slave fb13b382748edee5e329db61af6ccbe5a426dade connected
341a85b5ca42f8bb7baf707579025fa352c822b6 10.112.5.16:7000 slave 231b544622793b0b69e88a286ac8b46d211c8172 connected
231b544622793b0b69e88a286ac8b46d211c8172 10.112.5.17:7000 myself,master - 5461-10922
936482ede8b9e8b94eeb7d947e51ef635e5173df 10.112.5.17:7001 slave c3312b79d40e6b90eb856c3e52d0fae21ba217e7 connected
2304aalsdkjfalsjdflkajsfj23rklwj10932je9 10.112.5.17:7002 slave 231b544622793b0b69e88a286ac8b46d211c8172 connected
c3312b79d40e6b90eb856c3e52d0fae21ba217e7 10.112.5.18:7000 master - 0-5460
fb13b382748edee5e329db61af6ccbe5a426dade 10.112.5.18:7001 master - 10923-16383
e442abf8ec244a697a203c67092fc184b45220bb 10.112.5.18:7002 slave fb13b382748edee5e329db61af6ccbe5a426dade connected删除2个7002端口的几点：
redis-trib.rb del-node 10.112.5.17:7001 e442abf8ec244a697a203c67092fc184b45220bb
redis-trib.rb del-node 10.112.5.17:7001 fb13b382748edee5e329db61af6ccbe5a426dade
迁移后的节点状态：
[worker@LFTz-Zkp02 ~]$ redis-cli -p 7000 -c cluster nodes|awk '{print $1,$2,$3,$4,$NF}'
e442abf8ec244a697a203c67092fc184b45220bb 10.112.5.16:7001 slave fb13b382748edee5e329db61af6ccbe5a426dade connected
936482ede8b9e8b94eeb7d947e51ef635e5173df 10.112.5.17:7001 slave c3312b79d40e6b90eb856c3e52d0fae21ba217e7 connected
231b544622793b0b69e88a286ac8b46d211c8172 10.112.5.17:7000 myself,master - 5461-10922
341a85b5ca42f8bb7baf707579025fa352c822b6 10.112.5.16:7000 slave 231b544622793b0b69e88a286ac8b46d211c8172 connected
c3312b79d40e6b90eb856c3e52d0fae21ba217e7 10.112.5.18:7000 master - 0-5460
fb13b382748edee5e329db61af6ccbe5a426dade 10.112.5.18:7001 master - 10923-16383