# redis-master-slave-sentinel

Redis cluster with Docker Compose

There are following services in the cluster,

• master: Master Redis Server
• slave: Slave Redis Server
• sentinel: Sentinel Server

The sentinels are configured with a "mymaster" instance with the following properties -

sentinel monitor mymaster redis-master 6379 2
sentinel down-after-milliseconds mymaster 5000
sentinel parallel-syncs mymaster 1
sentinel failover-timeout mymaster 5000

The details could be found in sentinel/sentinel.conf

The default values of the environment variables for Sentinel are as following

• SENTINEL_QUORUM: 2
• SENTINEL_DOWN_AFTER: 5000
• SENTINEL_FAILOVER: 5000

Try it

Build and start services

docker-compose up --build

Check the status of redis cluster

docker-compose ps

The result is

               Name                              Command               State    Ports   
---------------------------------------------------------------------------------------
redisclusterwithsentinel_master_1     docker-entrypoint.sh redis ...   Up      6379/tcp 
redisclusterwithsentinel_sentinel_1   entrypoint.sh                    Up      6379/tcp 
redisclusterwithsentinel_slave_1      docker-entrypoint.sh redis ...   Up      6379/tcp 

Scale out the instance number of sentinel

docker-compose scale sentinel=3

Scale out the instance number of slaves

docker-compose scale slave=4

Check the status of redis cluster

docker-compose ps

The result is

               Name                              Command               State    Ports   
---------------------------------------------------------------------------------------
redisclusterwithsentinel_master_1     docker-entrypoint.sh redis ...   Up      6379/tcp 
redisclusterwithsentinel_sentinel_1   entrypoint.sh                    Up      6379/tcp 
redisclusterwithsentinel_sentinel_2   entrypoint.sh                    Up      6379/tcp 
redisclusterwithsentinel_sentinel_3   entrypoint.sh                    Up      6379/tcp 
redisclusterwithsentinel_slave_1      docker-entrypoint.sh redis ...   Up      6379/tcp 
redisclusterwithsentinel_slave_2      docker-entrypoint.sh redis ...   Up      6379/tcp 
redisclusterwithsentinel_slave_3      docker-entrypoint.sh redis ...   Up      6379/tcp 
redisclusterwithsentinel_slave_4      docker-entrypoint.sh redis ...   Up      6379/tcp 

For stop master redis server.

 docker-compose unpause master

And get the sentinel infomation with following commands

docker-compose exec sentinel redis-cli -p 26379 SENTINEL get-master-addr-by-name mymaster

Connect to the master node from local node

redis-cli -h localhost -p 6379
localhost:6379> SET test test2

Connect to the slave node from local node

redis-cli -h localhost -p 6380
localhost:6380> get test
"test2"

References

[https://github.com/AliyunContainerService/redis-cluster][1]

[https://registry.hub.docker.com/u/joshula/redis-sentinel/] [2]

[https://docs.docker.com/compose/] [3]

Contributors

• Rajdeep Bhattacharya (rajdeepbhattacharya@gmail.com)