CODEWITHSUNDEEP
redisnode-redis
Devarajan
Devarajan

Reputation: 21

Adding new redis node to the existing cluster

I have installed latest version ( 6.0.8) of redis in new centos D,E,F servers, now I want to add these new servers to the the existing cluster A,B,C which has old redis version, My plan is to after added new redis servers then decommission the old servers. Can anyone please guide me with the steps

Upvotes: 1

Views: 1353

Answers (1)

spike 王建
spike 王建

Reputation: 1714

1. Setup your new Redis instance as a slave for your current Redis instance. In order to do so you need a different server, or a server that has enough RAM to keep two instances of Redis running at the same time.
2. If you use a single server, make sure that the slave is started in a different port than the master instance, otherwise the slave will not be able to start at all.
3. Wait for the replication initial synchronization to complete (check the slave log file).
4. Make sure using INFO that there are the same number of keys in the master and in the slave. Check with redis-cli that the slave is working as you wish and is replying to your commands.
5. Allow writes to the slave using CONFIG SET slave-read-only no
6. Configure all your clients in order to use the new instance (that is, the 
  slave). Note that you may want to use the CLIENT PAUSE command in order to make sure that no client can write to the old master during the switch.
7. Once you are sure that the master is no longer receiving any query (you can check this with the MONITOR command), elect the slave to master using the SLAVEOF NO ONE command, and shut down your master.

You can follow this guide upgrading-or-restarting-a-redis-instance-without-downtime.

Upvotes: 1

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