Docker installs 3 master and 3 slave redis clusters

1. Turn off firewall + start-up docker Background services

systemctl start docker

2. newly build 6 individual docker Containers redis example

docker run -d --name redis-node-1 --net host --privileged=true -v /data/redis/share/redis-node-1:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6381
 
docker run -d --name redis-node-2 --net host --privileged=true -v /data/redis/share/redis-node-2:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6382
 
docker run -d --name redis-node-3 --net host --privileged=true -v /data/redis/share/redis-node-3:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6383
 
docker run -d --name redis-node-4 --net host --privileged=true -v /data/redis/share/redis-node-4:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6384
 
docker run -d --name redis-node-5 --net host --privileged=true -v /data/redis/share/redis-node-5:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6385
 
docker run -d --name redis-node-6 --net host --privileged=true -v /data/redis/share/redis-node-6:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6386

The command is explained step by step ：

docker run：  Create and run docker Container instance 
--name redis-node-6 ：  Container name 
--net host ：  Using the host IP And port , Default 
--privileged=true ：  Get host root User permissions 
-v /data/redis/share/redis-node-6:/data ：  The container volume , Host address :docker Internal address 
redis:6.0.8 ： redis Image and version number 
--cluster-enabled yes ：  Turn on redis colony 
--appendonly yes ：  Turn on persistence 
--port 6386: redis Port number 

Into the container redis-node-1 And for 6 Build cluster relationships on machines :
Into the container :

docker exec -it redis-node-1 /bin/bash

Build a master-slave relationship :

# Be careful , Get into docker After the container, you can execute the command , And pay attention to your truth IP Address 
redis-cli --cluster create 192.168.111.147:6381 192.168.111.147:6382 192.168.111.147:6383 192.168.111.147:6384 192.168.111.147:6385 192.168.111.147:6386 --cluster-replicas 1
 
--cluster-replicas 1  For each master Create a slave node 

everything OK Words ,3 Lord 3 From here on out
Link to 6381 As an entry point , View the cluster status :
Link to 6381 As an entry point , View node status :

cluster info
cluster nodes

Master slave failover migration case :

Data read / write storage :
1. start-up 6 Cluster composed of machines and through exec Get into
2. Yes 6381 Add two key
3. Prevent route failure and add parameters -c And add two key

4. View cluster information :

redis-cli --cluster check 192.168.111.147:6381

Failover migration :

Lord 6381 And slave switching , Stop the host first 6381
6381 The main engine stopped , The corresponding real slave computer
6381 As 1 The slave assigned by host No. 1 shall be subject to the actual situation , Specifically, the number of machines is the number

View the cluster information again :

6381 It's down. ,6385 The superior has become a new master.
The slave attached under each case shall be subject to the actual situation , Specifically, the number of machines is the number

Restore the previous 3 Lord 3 from :

First start 6381:

docker start redis-node-1

Stop again 6385:

docker stop redis-node-5

To rev. 6385:

docker start redis-node-5

The distribution of master-slave machines shall be subject to the actual situation :

View the cluster status :

redis-cli --cluster check  own IP:6381

Master slave capacity expansion cases :

newly build 6387、6388 Two nodes + Start after creating a new one + See if 8 node

docker run -d --name redis-node-7 --net host --privileged=true -v /data/redis/share/redis-node-7:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6387
docker run -d --name redis-node-8 --net host --privileged=true -v /data/redis/share/redis-node-8:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6388
docker ps

Get into 6387 Inside the container instance :

docker exec -it redis-node-7 /bin/bash

Will add 6387 node ( Empty slot number ) As master The node joins the original cluster :

 Will add 6387 As master Nodes join the cluster 
redis-cli --cluster add-node  Actually IP Address :6387  Actually IP Address :6381
6387  Is going to be master New node 
6381  Is the leader in the original cluster node , amount to 6387 Bye-bye 6381 So as to find organizations to join the cluster 

Check the cluster condition 1 Time :

redis-cli --cluster check  real ip Address :6381

Reassign slot numbers :

 Reassign slot numbers 
 command :redis-cli --cluster reshard IP Address : Port number 
redis-cli --cluster reshard 192.168.111.147:6381

Check the cluster condition 2 Time :

redis-cli --cluster check  real ip Address :6381

Slot number assignment description :
Why? 6387 yes 3 A new interval , It used to be continuous ？
Reallocation costs are too high , So before 3 Each family sets aside a part , from 6381/6382/6383 Separate out the three old nodes 1364 A pit for the new node 6387

Master node 6387 Assign slave nodes 6388:

 command ：redis-cli --cluster add-node ip: new slave port  ip: new master port  --cluster-slave --cluster-master-id  New host node ID
 
redis-cli --cluster add-node 192.168.111.147:6388 192.168.111.147:6387 --cluster-slave --cluster-master-id e4781f644d4a4e4d4b4d107157b9ba8144631451------- This is 6387 The number of , According to your actual situation 

Check the cluster condition 3 Time :

redis-cli --cluster check 192.168.111.147:6382

Master-slave volume reduction case :

1. Purpose ：6387 and 6388 Offline
2. Check the cluster 1 get 6388 The node of ID

redis-cli --cluster check 192.168.111.147:6382

3. take 6388 Delete
From the cluster 4 No. slave node 6388 Delete

 command ：redis-cli --cluster del-node ip: Slave port   Slave 6388 node ID
 
redis-cli --cluster del-node 192.168.111.147:6388 5d149074b7e57b802287d1797a874ed7a1a284a8

redis-cli --cluster check 192.168.111.147:6382

4. take 6387 Empty the slot number , Redistribution , In this example, all the slot numbers cleared are given to 6381

redis-cli --cluster reshard 192.168.111.147:6381

5. Check the cluster for the second time

redis-cli --cluster check 192.168.111.147:6381
 
4096 All slots are pointed to 6381, It became 8192 Slots , It's equivalent to giving everything to 6381 了 , Otherwise, enter 3 Time , One pot 

6. take 6387 Delete

 command ：redis-cli --cluster del-node ip: port  6387 node ID
 
redis-cli --cluster del-node 192.168.111.147:6387 e4781f644d4a4e4d4b4d107157b9ba8144631451

7. Check the cluster for the third time

redis-cli --cluster check 192.168.111.147:6381