Add support for custom ports when using ssh tunnel

[mikeblakeuk]

Add support for custom ports to bastion ssh.

The use case is that we want to connect to a Private AKS cluster. We have bastion setup and VM we connect to.

It would be nice to force the custom ports, and let az do the ssh key management.

az network bastion ssh --name "bastion" --resource-group "$group" --target-resource-id "$vmId" --resource-port 22 --auth-type AAD -- -L $customPort:our-cluster-abcde.dev-eus.privatelink.eastus.azmk8s.io:443

https://github.com/Azure/azure-cli-extensions/blob/a2dc8d7661670d56c92115092725214710f4a9ab/src/bastion/azext_bastion/custom.py

Instead we have to create the tunnel, the create ssh keys, then run ssh with port forwarding.

kubectl config set "clusters.$name.server" "https://localhost:$clusterPort"

az network bastion tunnel --name bastion --resource-group $group--target-resource-id '$vmId' --resource-port 22 --port $bastionPort

az ssh config --ip localhost --port $bastionPort --file $sshConfigPath --overwrite --yes-without-prompt #--debug

ssh -NTf -v $sshParams localhost -p $bastionPort -F $sshConfigPath -o ExitOnForwardFailure=yes -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null

[yonzhan]

Thank you for opening this issue, we will look into it.

[mikeblakeuk]

@yonzhan / @necusjz any more thoughts on this?