Read-only active replicas

Hi everyone,

I want to use a single master with multiple read-only replicas. I notice that active-replication includes some fail-over mechanism so that running sentinel is not necessary. But is this only true in a multi-master scenario?

I would be setting the following configs:

“active-replica yes”
“replica-read-only yes”
“multi-master no”

Will these play nicely together?

I just tried this, replication is working but fail-over doesn’t occur when I kill the master.

When you say failover, did you mean

  1. A read-only replica is automatically promoted to a master when the master goes down.
  2. When a master goes down, incoming read/writes operations are sent to another node? If this is your goal, you will need a load balancer such as HA proxy.

I believe what you’re doing is you’re trying to run a single master with multiple attached read-only replicas. When the single master goes down, you want one of the attached read-only replicas to be promoted to the new single master when the original old master goes down. If that’s the case, I don’t believe active-replication / multi-master needs to be set.

Yes, I want a read-only replica to be promoted to master. I think the problem is that KeyDB’s active replication has fail-over mechanisms, so sentinel doesn’t need to be deployed. However this only works in mult-master mode and the docs aren’t entirely explicit about this.

It would be a nice feature for KeyDB to handle fail-over in this scenario also. I ended up deploying Sentinel so my problem is solved. Thanks!