[Fix] Removing non-existing cluster via configuration

[kuritka]

What

With k3d I can delete a cluster before it is created. Such a use case is very useful in case I want to restart my test environment.

reset:
     k3d cluster delete mycluster
     k3d cluster create mycluster
     <installing things....>

Even better is to use a configuration with the argument -c config.yaml. The k3d can delete a
cluster based on configuration, but it cannot handle the case that the cluster does not exist.

INFO[0000] Using config file ./local.yaml (k3d.io/v1alpha3#simple) 
FATA[0000] failed to delete cluster 'mycluster': No nodes found for given cluster 

This PR allows that if I use the configuration and delete a non-existing cluster, k3d will not end up fatal.

# k3d cluster delete -c ./local.yaml
INFO[0000] Using config file ./local.yaml (k3d.io/v1alpha3#simple) 
INFO[0000] No nodes found for cluster 'mucluster', nothing to delete. 
INFO[0000] No clusters found                            

Why

It is important for me that the cluster name is used in one single place - ideally the configuration.
Thanks to this PR I can do the following:

reset:
	k3d cluster delete -c cluster/local.yaml
	k3d cluster create -c cluster/local.yaml

Implications

The change concerns one scenario - deleting a non-existing cluster if the cluster name is in the configuration.

Signed-off-by: kuritka [email protected]

[iwilltry42]

Hi @kuritka , thanks for your contribution!
I just have a slightly different take on this 👍