Cluster Replication and Failover in Garnet - Single Master Node Issue

[wessisaac]

I'm working on setting up Cluster Replication and Failover in Garnet. My question is whether it’s possible to use a single master node with all slots (0-16383) on a single node, or do I need at least three master nodes, similar to the Redis cluster setup?

Currently, when attempting to use a single master node on Windows, I encounter the following error:

(error) ERR I don't know about node

Has anyone encountered this issue, or does anyone know how to resolve this? Any insights would be greatly appreciated.

[shanipribadi]

it is possible,

the doc in https://microsoft.github.io/garnet/docs/cluster/overview only gives instruction of using redis-cli --cluster command, which does not work with only a single node (the cli has a validation for minimum 3 master nodes).

but you can achieve it by using the CLUSTER RESP commands manually.

start garnet using the --cluster flag (if both primary and replica is on single machine, then make sure to use different data dir, and either different --bind address (e.g. 127.0.0.2 and 127.0.0.3) or --port number for the two.

1. redis-cli -h [primary-ip] CLUSTER ADDSLOTSRANGE 0 16383
2. redis-cli -h [primary-ip] CLUSTER MYID # take note of the node-id
3. redis-cli -h [primary-ip] CLUSTER SET-CONFIG-EPOCH 1
4. redis-cli -h [replica-ip] CLUSTER SET-CONFIG-EPOCH 2
5. redis-cli -h [replica-ip] CLUSTER MEET [primary-ip] 6379
6. redis-cli -h [replica-ip] CLUSTER REPLICATE [primary-node-id]

EDIT, actually, I just realized it's documented here: https://microsoft.github.io/garnet/docs/cluster/replication

[vazois]

Adding to that, you don't have to use redis-cli. You can use your favorite redis compatible client and issue the same commands programmatically.
We have been using StackExchangeRedis.

[wessisaac]

The IP address (127.0.0.1) should be used during clustering instead of 'localhost'. It is working now.