Teach you how to build Redis cluster mode and sentinel mode with docker in 5 minutes

1. Preparation

Pull the redis image

2. Deploy redis sentinel master-slave mode

1. What is Docker Compose?
2. Write reids master-slave docker-compose.yml
3. Start the master-slave redis
4. Write Sentinel docker-compose.yml
5. Write sentinel.conf
6. Start Sentinel

3. Deploy redis cluster mode

1. Create directories and files
2. redis.conf configuration file
3. Docker-compose configuration file
4. Enter the container and create a cluster

Summarize:

If you are asked to set up a sentinel and cluster mode redis for the development environment and test environment respectively, how long will it take you at the fastest? Maybe you will need a day? 2 hours? The truth is it can be shorter. Yes, you have guessed it, it really only takes a dozen minutes to deploy with Docker.

1. Preparation

Pull the redis image

Run the following command:

docker pull redis

The image pulled by this command is the official image. Of course, you can search for other images. Here we will not go into detail about the image situation:

2. Deploy redis sentinel master-slave mode

What is Sentry Mode? --Please Baidu

1. What is Docker Compose?

Docker Compose can be understood as solidifying the way and configuration of running multiple containers!

Take the simplest example, if we want to prepare a MySQL container and a Redis container for our application container, then at each startup, we must first start the MySQL container and the Redis container, and then run the application container. Don’t forget to connect the container network to the MySQL container and the Redis container when creating the application container so that the application can connect to them and exchange data.

This is not enough. If we have made various configurations for the container, we'd better save the commands for creating and configuring the container so that we can use them directly next time.

In response to this situation, we have to introduce the most commonly used multi-container definition and running software in our development, that is, Docker Compose.

2. Write reids master-slave docker-compose.yml

version: '3.7'
services:
  master:
    image: redis
    container_name: redis-master
    restart: always
    command: redis-server --requirepass redispwd --appendonly yes
    ports:
      -6379:6379
    volumes:
      - ./data1:/data
  slave1:
    image: redis
    container_name: redis-slave-1
    restart: always
    command: redis-server --slaveof redis-master 6379 --requirepass redispwd --masterauth redispwd --appendonly yes
    ports:
      -6380:6379
    volumes:
      - ./data2:/data
  slave2:
    image: redis
    container_name: redis-slave-2
    restart: always
    command: redis-server --slaveof redis-master 6379 --requirepass redispwd --masterauth redispwd --appendonly yes
    ports:
      -6381:6379
    volumes:
      - ./data3:/data

Glossary:

3. Start the master-slave redis

Enter the directory of docker-compose.yml corresponding to redis and execute the command:

docker-compose up -d

-d means running in the background. Use the docker ps command to view the startup results:

The screenshot appears, indicating successful operation

4. Write Sentinel docker-compose.yml

version: '3.7'
services:
  sentinel1:
    image: redis
    container_name: redis-sentinel-1
    restart: always
    ports:
      -26379:26379
    command: redis-sentinel /usr/local/etc/redis/sentinel.conf
    volumes:
      - ./sentinel1.conf:/usr/local/etc/redis/sentinel.conf
  sentinel2:
    image: redis
    container_name: redis-sentinel-2
    restart: always
    ports:
    -26380:26379
    command: redis-sentinel /usr/local/etc/redis/sentinel.conf
    volumes:
      - ./sentinel2.conf:/usr/local/etc/redis/sentinel.conf
  sentinel3:
    image: redis
    container_name: redis-sentinel-3
    ports:
      -26381:26379
    command: redis-sentinel /usr/local/etc/redis/sentinel.conf
    volumes:
      - ./sentinel3.conf:/usr/local/etc/redis/sentinel.conf
networks:
  default:
    external:
      name: redis_default

5. Write sentinel.conf

# Customize the cluster name, where 172.19.0.3 is the IP address of redis-master, 6379 is the port number of redis-master, and 2 is the minimum number of votes (because there are 3 Sentinels, it can be set to 2)
port 26379
dir /tmp
sentinel monitor mymaster 172.19.0.3 6379 2
sentinel down-after-milliseconds mymaster 30000
sentinel parallel-syncs mymaster 1
sentinel auth-pass mymaster redispwd
sentinel failover-timeout mymaster 180000
sentinel deny-scripts-reconfig yes

Copy the above files into three copies and name them sentinel1.conf, sentinel2.conf, and sentinel3.conf to correspond to the configuration files in docker-compose.yml, and then place them in the same directory as Sentinel's docker-compose.yml

6. Start Sentinel

Enter the directory where the sentinel docker-compose.yml is located and execute the command:

docker-compose up -d

Check the container and you can see that the sentinel and the master-slave redis are up.

6.1 Sentinel startup log

As can be seen from the above log, Sentinel monitors the master and slave nodes

6.2 Shut down the master node

Stop the redis master node through the command

docker stop redis-master

From the above logs, we can see sdown, odown, what do they mean?
Sdown is a subjective downtime. If a sentinel thinks that a master is down, then it is a subjective downtime.
odown is an objective downtime. If a quorum of sentinels think that a master has crashed, then it is an objective downtime and the election begins. From the log, we can see that two sentinels have selected the same slave node. At this time, the minimum number of votes we configured is met, and this slave is selected as the new master.

6.3 Restart the master node

The above logs show that Sentinel detects that the original master has restarted and turns the original master node into a slave node of the new master.

3. Deploy redis cluster mode

1. Create directories and files

├── docker-compose.yml
├── redis-6371
│ ├── conf
│ │ └── redis.conf
│ └── data
├── redis-6372
│ ├── conf
│ │ └── redis.conf
│ └── data
├── redis-6373
│ ├── conf
│ │ └── redis.conf
│ └── data
├── redis-6374
│ ├── conf
│ │ └── redis.conf
│ └── data
├── redis-6375
│ ├── conf
│ │ └── redis.conf
│ └── data
└── redis-6376
    ├── conf
    │ └── redis.conf
    └── data

2. redis.conf configuration file

port 6371
cluster-enabled yes
cluster-config-file nodes-6371.conf
cluster-node-timeout 5000
appendonly yes
protected-mode no
requirepass 1234
masterauth 1234
cluster-announce-ip 10.12.12.10 # This is the host IP
cluster-announce-port 6371
cluster-announce-bus-port 16371

The configuration of each node only requires changing the port.

3. Docker-compose configuration file

version: "3"

# Define services, you can have multiple services:
  redis-6371: # Service nameimage: redis # Image required when creating a containercontainer_name: redis-6371 # Container namerestart: always # Container always restartsvolumes: # Data volume, directory mount- ./redis-6371/conf/redis.conf:/usr/local/etc/redis/redis.conf
      - ./redis-6371/data:/data
    ports:
      -6371:6371
      -16371:16371
    command:
      redis-server /usr/local/etc/redis/redis.conf

  redis-6372:
    image: redis
    container_name: redis-6372
    volumes:
      - ./redis-6372/conf/redis.conf:/usr/local/etc/redis/redis.conf
      - ./redis-6372/data:/data
    ports:
      -6372:6372
      - 16372:16372
    command:
      redis-server /usr/local/etc/redis/redis.conf

  redis-6373:
    image: redis
    container_name: redis-6373
    volumes:
      - ./redis-6373/conf/redis.conf:/usr/local/etc/redis/redis.conf
      - ./redis-6373/data:/data
    ports:
      -6373:6373
      -16373:16373
    command:
      redis-server /usr/local/etc/redis/redis.conf
      
  redis-6374:
    image: redis
    container_name: redis-6374
    restart: always
    volumes:
      - ./redis-6374/conf/redis.conf:/usr/local/etc/redis/redis.conf
      - ./redis-6374/data:/data
    ports:
      -6374:6374
      -16374:16374
    command:
      redis-server /usr/local/etc/redis/redis.conf

  redis-6375:
    image: redis
    container_name: redis-6375
    volumes:
      - ./redis-6375/conf/redis.conf:/usr/local/etc/redis/redis.conf
      - ./redis-6375/data:/data
    ports:
      -6375:6375
      -16375:16375
    command:
      redis-server /usr/local/etc/redis/redis.conf

  redis-6376:
    image: redis
    container_name: redis-6376
    volumes:
      - ./redis-6376/conf/redis.conf:/usr/local/etc/redis/redis.conf
      - ./redis-6376/data:/data
    ports:
      -6376:6376
      -16376:16376
    command:
      redis-server /usr/local/etc/redis/redis.conf

After writing, use docker-compose up -d to start the container. The host mode is not used here, but the NAT mode is used because the host mode may cause external clients to be unable to connect.

4. Enter the container and create a cluster

The above only starts 6 Redis instances, and does not build a Cluster.
Execute docker exec -it redis-6371 bash to enter a Redis node container, any one will do.
Continue to execute the following command to create a cluster:

# Cluster creation command redis-cli -a 1234 --cluster create 10.35.30.39:6371 10.35.30.39:6372 10.35.30.39:6373 10.35.30.39:6374 10.35.30.39:6375 10.35.30.39:6376 --cluster-replicas 1
# After execution, the following output will be displayed: Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica 10.35.30.39:6375 to 10.35.30.39:6371
Adding replica 10.35.30.39:6376 to 10.35.30.39:6372
Adding replica 10.35.30.39:6374 to 10.35.30.39:6373
>>> Trying to optimize slaves allocation for anti-affinity
[WARNING] Some slaves are in the same host as their master
M: e9a35d6a9d203830556de89f06a3be2e2ab4eee1 10.35.30.39:6371
   slots:[0-5460] (5461 slots) master
M: 0c8755144fe6a200a46716371495b04f8ab9d4c8 10.35.30.39:6372
   slots:[5461-10922] (5462 slots) master
M: fcb83b0097d2a0a87a76c0d782de12147bc86291 10.35.30.39:6373
   slots:[10923-16383] (5461 slots) master
S: b9819797e98fcd49f263cec1f77563537709bcb8 10.35.30.39:6374
   replicates fcb83b0097d2a0a87a76c0d782de12147bc86291
S: f4660f264f12786d81bcf0b18bc7287947ec8a1b 10.35.30.39:6375
   replicates e9a35d6a9d203830556de89f06a3be2e2ab4eee1
S: d2b9f265ef7dbb4a612275def57a9cc24eb2fd5d 10.35.30.39:6376
   replicates 0c8755144fe6a200a46716371495b04f8ab9d4c8
Can I set the above configuration? (type 'yes' to accept): yes # Enter yes here and press Enter to confirm the node master-slave identity and hash slot allocation >>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster
Waiting for the cluster to join
.
>>> Performing Cluster Check (using node 10.35.30.39:6371)
M: e9a35d6a9d203830556de89f06a3be2e2ab4eee1 10.35.30.39:6371
   slots:[0-5460] (5461 slots) master
   1 additional replica(s)
M: 0c8755144fe6a200a46716371495b04f8ab9d4c8 10.35.30.39:6372
   slots:[5461-10922] (5462 slots) master
   1 additional replica(s)
S: b9819797e98fcd49f263cec1f77563537709bcb8 10.35.30.39:6374
   slots: (0 slots) slave
   replicates fcb83b0097d2a0a87a76c0d782de12147bc86291
M: fcb83b0097d2a0a87a76c0d782de12147bc86291 10.35.30.39:6373
   slots:[10923-16383] (5461 slots) master
   1 additional replica(s)
S: f4660f264f12786d81bcf0b18bc7287947ec8a1b 10.35.30.39:6375
   slots: (0 slots) slave
   replicates e9a35d6a9d203830556de89f06a3be2e2ab4eee1
S: d2b9f265ef7dbb4a612275def57a9cc24eb2fd5d 10.35.30.39:6376
   slots: (0 slots) slave
   replicates 0c8755144fe6a200a46716371495b04f8ab9d4c8
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

When you see the above output, the Cluster configuration is complete. And there are 3 masters and 3 slaves.

Summarize:

The above is the whole process of deploying sentinel mode and cluster mode through docker compose. Redis is deployed in docker, which is suitable for local, development, testing and other environments. Please use it with caution in production environment unless you have a strong control over docker.

This is the end of this article about how to use docker to build Redis cluster mode and sentinel mode in 5 minutes. For more information about building Redis cluster mode and sentinel mode with docker, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope you will support 123WORDPRESS.COM in the future!

You may also be interested in:

Detailed explanation of the environment construction of docker to build redis cluster
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Use Docker to build a Redis master-slave replication cluster
Building a Redis cluster on Docker
Implementation of Redis master-slave cluster based on Docker
How to deploy Redis 6.x cluster through Docker
How to quickly build a redis cluster using Docker-swarm

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