kubernetes: change the current/default context via kubectl command - kubernetes

Question

I am doing an exercise from KodeKoud which provide the CKAD certification training.
The exercise has a my-kube-config.yml file located under root/. The file content is below:
(I ommited some unrelated parts)
apiVersion: v1
kind: Config
clusters:
- name: production
cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: https://controlplane:6443
- name: development
cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: https://controlplane:6443
- name: test-cluster-1
cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: https://controlplane:6443
contexts:
- name: test-user#production
context:
cluster: production
user: test-user
- name: research
context:
cluster: test-cluster-1
user: dev-user
users:
- name: test-user
user:
client-certificate: /etc/kubernetes/pki/users/test-user/test-user.crt
client-key: /etc/kubernetes/pki/users/test-user/test-user.key
- name: dev-user
user:
client-certificate: /etc/kubernetes/pki/users/dev-user/developer-user.crt
client-key: /etc/kubernetes/pki/users/dev-user/dev-user.key
current-context: test-user#development
The exercise asking me to:
use the dev-user to access test-cluster-1. Set the current context
to the right one so I can do that.
Since I see in the config file, there is a context named research which meets the requirement, so I run the following command to change the current context to the required one:
kubectl config use-context research
but the console gives me error: error: no context exists with the name: "research".
Ok, I guessed maybe the name with value research is not acceptable, maybe I have to follow the convention of <user-name>#<cluster-name>? I am not sure , but I then tried the following:
I modified the name from research to dev-user#test-cluster-1, so that context part becomes:
- name: dev-user#test-cluster-1
context:
cluster: test-cluster-1
user: dev-user
after that I run command: kubectl config use-context dev-user#test-cluster-1, but I get error:
error: no context exists with the name: "dev-user#test-cluster-1"
Why? Based on the course material that is the way to chagne the default/current context. Is the course out-dated that I am using a deprecated one? What is the problem?

Answer 1

Your initial idea was correct. You would need to change the context to research which can be done using
kubectl config use-context research
But the command would not be applied to the correct config in this instance. You can see the difference by checking the current-context with and without a kubeconfig directed to the my-kube-config file.
kubectl config current-context
kubernetes-admin#kubernetes
kubectl config --kubeconfig=/root/my-kube-config current-context
test-user#development
So run the use-context command with the correct kubeconfig
kubectl config --kubeconfig=/root/my-kube-config use-context research

Answer 2

To able to change context, you have to edit $HOME/.kube/config file with your config data and merge with default one. I've tried to replicate your config file and it was possible to change the context, however your config file looks very strange.
See the lines from my console for your reference:
bazhikov#cloudshell:~ (nb-project-326714)$ kubectl config view
apiVersion: v1
clusters:
- cluster:
certificate-authority: /etc/kubernetes/pki/ca.crt
server: https://controlplane:6443
name: development
- cluster:
certificate-authority-data: DATA+OMITTED
server: https://35.246.22.167
name: gke_nb-project-326714_europe-west2_cluster-west2
...
...
...
- name: test-user
user:
client-certificate: /etc/kubernetes/pki/users/test-user/test-user.crt
client-key: /etc/kubernetes/pki/users/test-user/test-user.key
bazhikov#cloudshell:~ (nb-project-326714)$ kubectl config use-context research
Switched to context "research".
Copy your default config file prior editing if you don't want to ruin your cluster config :)