How to properly access multiple kubernetes cluster using kubectl - kubernetes

Question

I have two clusters and the config files are stored in .kube. I am exporting KUBECONFIG as below
export KUBECONFIG=/home/vagrant/.kube/config-cluster1:/home/vagrant/.kube/config-cluster2
checking the contexts
kubectl config get-contexts
CURRENT NAME CLUSTER AUTHINFO NAMESPACE
* cluster-1 cluster-1 kubernetes-admin
cluster-2 cluster-2 kubernetes-admin
But when I choose cluster-2 as my current context I get an error
kubectl config get-contexts
CURRENT NAME CLUSTER AUTHINFO NAMESPACE
* cluster-1 cluster-1 kubernetes-admin
cluster-2 cluster-2 kubernetes-admin
kubectl config use-context cluster-2
Switched to context "cluster-2".
kubectl get pods -A
error: You must be logged in to the server (Unauthorized)
If I export only the config for cluster-2 and try running kubectl it works fine.
My question is whether I am exporting the config files properly or should I be doing something more.

Answer 1

You need to separate the AUTHINFO (context.user on config file) for each cluster with the respective credentials.
For example:
apiVersion: v1
clusters:
- cluster:
server: https://192.168.10.190:6443
name: cluster-1
- cluster:
server: https://192.168.99.101:8443
name: cluster-2
contexts:
- context:
cluster: cluster-1
user: kubernetes-admin-1
name: cluster-1
- context:
cluster: cluster-2
user: kubernetes-admin-2
name: cluster-2
kind: Config
preferences: {}
users:
- name: kubernetes-admin-1
user:
client-certificate: /home/user/.minikube/credential-for-cluster-1.crt
client-key: /home/user/.minikube/credential-for-cluster-1.key
- name: kubernetes-admin-2
user:
client-certificate: /home/user/.minikube/credential-for-cluster-2.crt
client-key: /home/user/.minikube/credential-for-cluster-2.key
You can find more useful tips in the following article:
Using different kubectl versions with multiple Kubernetes clusters:
When you are working with multiple Kubernetes clusters, it’s easy to
mess up with contexts and run kubectl in the wrong cluster. Beyond
that, Kubernetes has restrictions for versioning mismatch between the
client (kubectl) and server (kubernetes master), so running commands
in the right context does not mean running the right client version.
To overcome this:
Use asdf to manage multiple kubectl versions
Set the KUBECONFIG env var to change between multiple kubeconfig files
Use kube-ps1 to keep track of your current context/namespace
Use kubectx and kubens to change fast between clusters/namespaces
Use aliases to combine them all together
I also recommend the following reads:
Mastering the KUBECONFIG file by Ahmet Alp Balkan (Google Engineer)
How Zalando Manages 140+ Kubernetes Clusters by Henning Jacobs (Zalando Tech)

Answer 2

I wrote a script to switch kubeconfig and namespace easily. Hope it can help you.
. k-use -k <kubeconfig> -n <namespace>
https://github.com/kingonion/k-use