Handling Kubeconfigs

By default, k3d will update your default kubeconfig with your new cluster’s details and set the current-context to it (can be disabled).
To get a kubeconfig set up for you to connect to a k3d cluster without this automatism, you can go different ways.

What is the default kubeconfig?

We determine the path of the used or default kubeconfig in two ways:

1. Using the KUBECONFIG environment variable, if it specifies exactly one file
2. Using the default path (e.g. on Linux it’s `#!bash $HOME/.kube/config`)

Getting the kubeconfig for a newly created cluster

1. Create a new kubeconfig file after cluster creation

   • `#!bash k3d kubeconfig write mycluster`
     • Note: this will create (or update) the file $HOME/.k3d/kubeconfig-mycluster.yaml
     • Tip: Use it: `#!bash export KUBECONFIG=$(k3d kubeconfig write mycluster)`
     • Note 2: alternatively you can use `#!bash k3d kubeconfig get mycluster > some-file.yaml`

2. Update your default kubeconfig upon cluster creation (DEFAULT)

   • `#!bash k3d cluster create mycluster –kubeconfig-update-default`
     • Note: this won’t switch the current-context (append --kubeconfig-switch-context to do so)

3. Update your default kubeconfig after cluster creation

   • `#!bash k3d kubeconfig merge mycluster –kubeconfig-merge-default`
     • Note: this won’t switch the current-context (append --kubeconfig-switch-context to do so)

4. Update a different kubeconfig after cluster creation

   • `#!bash k3d kubeconfig merge mycluster –output some/other/file.yaml`
     • Note: this won’t switch the current-context
   • The file will be created if it doesn’t exist

Switching the current context

None of the above options switch the current-context by default.
This is intended to be least intrusive, since the current-context has a global effect.
You can switch the current-context directly with the kubeconfig merge command by adding the --kubeconfig-switch-context flag.

Removing cluster details from the kubeconfig

`#!bash k3d cluster delete mycluster` will always remove the details for mycluster from the default kubeconfig. It will also delete the respective kubeconfig file in $HOME/.k3d/ if it exists.

Handling multiple clusters

k3d kubeconfig merge let’s you specify one or more clusters via arguments or all via --all.
All kubeconfigs will then be merged into a single file if --kubeconfig-merge-default or --output is specified.
If none of those two flags was specified, a new file will be created per cluster and the merged path (e.g. $HOME/.k3d/kubeconfig-cluster1.yaml:$HOME/.k3d/cluster2.yaml) will be returned.
Note, that with multiple cluster specified, the --kubeconfig-switch-context flag will change the current context to the cluster which was last in the list.

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Last update: June 9, 2021