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Introduction

Redis is an in-memory data storage that is used by the CoreOne Suite. This how-to gives you a brief overview on how to install a redis cluster on Ubuntu.For supported versions see: Next-Gen Workflows - Redis

Step 1 - Check your prerequisits

• Redis has to be installed on a Linux OS (Ubuntu, Redhat, Centos, etc.).

• To install Redis, at least 3 instances are needed. The instances can be distributed across different servers, or concentrated on one (best practice will be shown in the examples below).

• If the servers for Redis are in different network-zones, the servers must be able to communicate with eachother.

• The following Firewall-Ports must be open:

  • 6379

  • 16384

  • 16379

  • 7001 (Cluster)

  • 7002 (Cluster)

  • 7003 (Cluster)

  • 7004 (Cluster)

  • 7006 (FClusterCluster)

Example

In our example we got 3 virtual Ubuntu-Servers.

Redis HA 1 (192.168.17.134)
Redis HA 2 (192.168.17.135)
Redis HA 3 (192.168.17.136)

On Redis HA1 is a Master Instance 7001 and a Slave Instance 7004
On Redis HA2 is a Master Instance 7002 and a Slave Instance 7005
On Redis HA3 is a Master Instance 7003 and a Slave Instance 7006

For the Master 7001 the Slave is 7006
For the Master 7002 the Slave is 7006
For the Master 7003 the Slave is 7004

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Step 2 - Installation

General installation for all 3 servers:

Switch to root user:

sudo su

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cd /etc/redis/redis-6.2.6/
sudo make test

Step 3 - Configuration VM 1

In our example we have multiple redis instanced on one server. This means we need multiple config-files on the server as well.

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port 7004
cluster-enabled yes
cluster-config-file cluster-node-4.conf
cluster-node-timeout 5000
appendonly yes
appendfilename node-4.aof
dbfilename dump-4.rdb

Step 4 - Configuration VM 2

In our example we have multiple redis instanced on one server. This means we need multiple config-files on the server as well.

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port 7005
cluster-enabled yes
cluster-config-file cluster-node-5.conf
cluster-node-timeout 5000
appendonly yes
appendfilename node-5.aof
dbfilename dump-5.rdb

Step 5 - Configuration VM 3

In our example we have multiple redis instanced on one server. This means we need multiple config-files on the server as well.

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port 7006
cluster-enabled yes
cluster-config-file cluster-node-6.conf
cluster-node-timeout 5000
appendonly yes
appendfilename node-6.aof
dbfilename dump-6.rdb

Step 6 - Start Redis

We can start Redis now on each VM through the config-files we created.

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./redis-6.2.6/src/redis-server node1.conf &

./redis-6.2.6/src/redis-server node4.conf &

./redis-6.2.6/src/redis-server node2.conf &

./redis-6.2.6/src/redis-server node5.conf &

./redis-6.2.6/src/redis-server node3.conf &

./redis-6.2.6/src/redis-server node6.conf &

Step 7 - Connect Redis

We can now connect on each instace with the Redis-CLI

./redis-6.2.6/src/redis-cli -p 7001
./redis-6.2.6/src/redis-cli -p 7004

./redis-6.2.6/src/redis-cli -p 7002
./redis-6.2.6/src/redis-cli -p 7005

./redis-6.2.6/src/redis-cli -p 7003
./redis-6.2.6/src/redis-cli -p 7006

Step 8 - Configure Redis Cluster

Since the instaces are local at the moment, we need to connect them to the cluster.

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Check the config and confirm with: Y

Step 9 - Redis-CLI

Open Redis-CLI:

./redis-6.2.6/src/redis-cli -c -p 7001

ping

ping

The different nodes can be pinged:

info

info

Shows all information on the cluster

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cluster nodes

cluster nodes

Shows all nodes and if they are master or slave.

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info replication

info replication

Shows if the server is master or slave. Shows the depending slaves.

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Step 10 - Failover

We will terminate Master 7003 for this example. This will prompt the Slave 7004 to become the new master:

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