redis5集羣擴容-增長主從節點

回顧上節redis cluster集羣入門已經搭建完成的集羣節點

b3363a81c3c59d57143cd3323481259c044e66d2 192.168.8.196:5006@15006 slave 1b7aa419065c5477c0def9d5e25106963fbdda76 0 1572917132045 6 connected
9dc870942555447543694e42e40061823ed91271 192.168.8.196:5004@15004 slave d1a4b1aa3e924a5917efc240cdb2e3ada39e01c2 0 1572917130038 4 connected
1b7aa419065c5477c0def9d5e25106963fbdda76 192.168.8.196:5003@15003 master - 0 1572917131041 3 connected 10923-16383
b1b67d4e554e29605bdbe40deab6670a42dd8836 192.168.8.196:5002@15002 master - 0 1572917130000 2 connected 5461-10922
fbf9f23ecf0fea399debf7db42c73fece04b98fd 192.168.8.196:5005@15005 slave b1b67d4e554e29605bdbe40deab6670a42dd8836 0 1572917131000 5 connected
d1a4b1aa3e924a5917efc240cdb2e3ada39e01c2 192.168.8.196:5001@15001 myself,master - 0 1572917127000 1 connected 0-5460

本章目標
上次存在6個節點，本次將要增長5007,5008一主從兩節點來演示redis5如何實現動態擴容。

1、添加兩個服務節點到集羣

redis-cli --cluster add-node 192.168.8.196:5007 192.168.8.196:5001
redis-cli --cluster add-node 192.168.8.196:5008 192.168.8.196:5001

此時查看集羣中的節點發現，5007,5008默認均爲master

2、爲master節點添加分片
這裏將192.168.8.196:5007做爲master節點，對其進行分片

redis-cli --cluster reshard 192.168.8.196:5007

這時，會出現如下選項：

How many slots do you want to move (from 1 to 16384)? 500
#這裏填寫分配多少個槽給5007

What is the receiving node ID? 63aa476d990dfa9f5f40eeeaa0315e7f9948554d
#這裏添加接收節點的ID，咱們填寫5007服務節點的ID
Please enter all the source node IDs.
Type 'all' to use all the nodes as source nodes for the hash slots.
Type 'done' once you entered all the source nodes IDs.
Source node #1: all
#這裏填寫槽的來源，all表示是全部服務節點

到這裏，分片工做完成

3、設置從節點
這裏咱們將5008服務節點做爲5007的從節點
先登陸5008服務節點

redis-cli -c -h 192.168.8.196 -p 5008

指定5008從節點的主節點ID,這裏咱們填寫5007服務節點ID

cluster replicate 63aa476d990dfa9f5f40eeeaa0315e7f9948554d

4、查看當前集羣節點

cluster nodes

大功告成。