How to switch namespace in kubernetes

Question

I like my answers short, to the point and with references to official documentation:

Answer:

kubectl config set-context --current --namespace=my-namespace

From:

https://kubernetes.io/docs/reference/kubectl/cheatsheet/

# permanently save the namespace for all subsequent kubectl commands in that context.
kubectl config set-context --current --namespace=ggckad-s2

There are a few options:

• Switch namespace only using the kubectl commands::

kubectl config set-context --current --namespace=<namespace>

• Or, Create a new context with namespace defined:

kubectl config set-context gce-dev --user=cluster-admin --namespace=dev
kubectl config use-context gce-dev

• Or, Use addons, like kubectx & kubens, the below command will switch the context to kube-system:

$ kubens kube-system 

• Or, Another easy alternative that I like without installing third party tools, is using bash alias(linux).

$ alias kubens='kubectl config set-context --current --namespace '
$ alias kubectx='kubectl config use-context '

// Usage
$ kubens kube-system    //Switch to a different namespace
$ kubectx docker        //Switch to separate context

I was able to switch namespace using the below steps

kubectl config set-context $(kubectl config current-context) --namespace=<namespace>
kubectl config view | grep namespace
kubectl get pods

This is how i have tested

# Create namespaces k8s-app1, k8s-app2 and k8s-app3
master $ kubectl create ns k8s-app1
namespace/k8s-app1 created
master $ kubectl create ns k8s-app2
namespace/k8s-app2 created
master $ kubectl create ns k8s-app3
namespace/k8s-app3 created

# Create Service Account app1-sa in k8s-app1
# Service Account app2-sa in k8s-app2
# Service Account app3-sa in k8s-app3
master $ kubectl create sa app1-sa -n k8s-app1
serviceaccount/app1-sa created
master $ kubectl create sa app2-sa -n k8s-app2
serviceaccount/app2-sa created
master $ kubectl create sa app3-sa -n k8s-app3
serviceaccount/app3-sa created

# Switch namespace
master $ kubectl config set-context $(kubectl config current-context) --namespace=k8s-app1
Context "kubernetes-admin@kubernetes" modified.
master $ kubectl config view | grep namespace
    namespace: k8s-app1
master $ kubectl get sa
NAME      SECRETS   AGE
app1-sa   1         1m
default   1         6m
master $
master $ kubectl config set-context $(kubectl config current-context) --namespace=k8s-app2
Context "kubernetes-admin@kubernetes" modified.
master $ kubectl get sa
NAME      SECRETS   AGE
app2-sa   1         2m
default   1         7m
master $
master $ kubectl config set-context $(kubectl config current-context) --namespace=k8s-app3
Context "kubernetes-admin@kubernetes" modified.
master $ kubectl get sa
NAME      SECRETS   AGE
app3-sa   1         2m
default   1         7m

I didn't like kubectx and kubens because they are adding one more letter for bash-complection to kubectl command.

So I just wrote tiny kubectl-use plugin:

# kubectl use prod
Switched to context "prod".

# kubectl use default
Switched to namespace "default".

# kubectl use stage kube-system
Switched to context "stage".
Switched to namespace "kube-system".

If you interesting to it, check https://github.com/kvaps/kubectl-use

You could use the following package called kubectx which make it very easy to switch between clusters using kubectx

and switching between namespaces using kubens

I created a function in .zshrc

ksns() { kubectl config set-context --current --namespace="$1" }

Then I call ksns default