Kubernetes: specify cluster context in apply command

There seems to be --context=... option.

kubectl optionsThe following options can be passed to any command:...      --context='': The name of the kubeconfig context to use

at least in version v1.18.6

kubectl takes a --context option:

kubectl --context cluster-1-context apply -f ./deploy-to-cluster-1.yml

There's no way to specify or enforce this in resource YAML files; it's still possible to have accidents.

If you have multiple .kube/config files, you can also set the $KUBECONFIG environment variable to point at one of those. This is understood by the standard Kubernetes SDKs, so almost all tools should support it.

export KUBECONFIG=./cluster-1-config.ymlkubectly apply -f ./deploy-to-cluster-1.yml

(Given the choice I would prefer this approach, because environment variables are shell-local but kubectl config current-context will affect all of my open terminal windows. Standard tooling that configures the .kube/config file tends to default to the single shared global file, though, and teasing it apart can be a little tricky.)

Is there a better way to do this?

You can use kubectx tool to switch between contexts back and forth in a much easier way than kubectl.

USAGE:  kubectx                   : list the contexts  kubectx <NAME>            : switch to context <NAME>  kubectx -                 : switch to the previous context  kubectx -c, --current     : show the current context name  kubectx <NEW_NAME>=<NAME> : rename context <NAME> to <NEW_NAME>  kubectx <NEW_NAME>=.      : rename current-context to <NEW_NAME>  kubectx -d <NAME>         : delete context <NAME> ('.' for current-context)                              (this command won't delete the user/cluster entry                              that is used by the context)  kubectx -u, --unset       : unset the current context$ kubectx minikubeSwitched to context "minikube".$ kubectx -Switched to context "oregon".$ kubectx -Switched to context "minikube".$ kubectx dublin=gke_ahmetb_europe-west1-b_dublinContext "dublin" set.Aliased "gke_ahmetb_europe-west1-b_dublin" as "dublin".

As it stands out today there is no way to specify context as part of deployment yaml. You can submit a feature request in kubernetes GitHub repo for this.