Multi-cluster with limited port availability


I’m trying to mirror services from an on-prem cluster to a GKE cluster. The on-prem cluster is a k3s installed with k3sup and has three ports open P1, P2, P3. One port is used up by the kube API endpoint, one is used up by a SSH server and one port is open. Let’s call it P3.

The multicluster gateway seems to require two ports: mc-gateway and mc-probe, and as a result the GKE cluster can’t connect to the on-prem gateway. Is there an easy way to resolve this without opening another port?

hi @ds-alpha

The multi-cluster implementation uses a couple of ports for external communication, by default those are 4143 and 4181.

Requests to 4181, are to the gatewayProbePort which is used for healthchecking and is handled by nginx.

Requests to 4131 are handled by the Linkerd proxy because that is the inbound port configured for the proxy.

The simplest way would be to open both ports. Otherwise you could look into solutions for remapping the ports based on the path, but that would definitely be more work.

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