Is consul client backward compatible with v1.0.0?

As per the documentation, the consul clients are not enabled by default from v1.0.0.

If we enable it, will the consul client be backwards compatible? Can the pods still use the client to communicate with the consul server?

I am looking at a scenario where existing pods are still using the envoy proxy sidecar during the upgrade and my understanding is consul dataplane sidecar will only be injected if the old pods are being restarted.

So once we make the upgrade do the existing pods fail to communicate with the consul server? or else it will work as usual if we the consul client enabled

Hi @MageshSrinivasulu,

This official documentation explains how to upgrade from a non-dataplane to a dataplane cluster.

ref: Upgrading Consul on Kubernetes Components | Consul | HashiCorp Developer

To answer your question, yes the old pods would be able to communicate, but it is recommended that the deployments are restarted (rollout restart), so that they get the new data plane component injected.

Please read through the instructions, as it has some additional steps compared to a normal upgrade.

I hope this helps.