How to configure Kubectl client in Multi-K8s Cluster Handoff

This article mainly introduces how to configure the Kubectl client in multi-K8s cluster switching, which has a certain reference value. Interested friends can refer to it. I hope you can learn a lot after reading this article.

Profile location of kubectl

The main location of the kubectl configuration file is $HOME / .kube, and by default we have a configuration file called config:

[node1 ~] $cd $HOME/.kube [node1 .kube] $ls-lah total 4.0K drwxr-xr-x 1 root root 37 Mar 12 20:48. Dr-xr-x--- 1 root root 19 Nov 29 11:46.. Drwxr-x--- 3 root root 23 Mar 12 20:48 cache lrwxrwxrwx 1 root root 26 Nov 29 11:46 config-> / etc/kubernetes/admin.conf drwxr-x--- 3 root root 4.0K Mar 12 20:48 http-cache

Multiple profiles and KUBECONFIG variables

By setting the appropriate KUBECONFIG shell variable, we can have multiple configuration files.

For example:

Export KUBECONFIG=$KUBECONFIG:/root/.kube/additional_config

Check the configuration from kubectl

We can check the current configuration (since there is nothing in my Additional_config file, it will be empty-we'll add something later-this is just a file in my KUBECONFIG variable):

[node1 ~] $kubectl config view apiVersion: v1 clusters: [] contexts: [] current-context: "" kind: Config preferences: {} users: []

Or from a specific file-let's look at the default file:

[node1] $kubectl config-- kubeconfig=.kube/config view apiVersion: v1 clusters:

Cluster: certificate-authority-data: DATA+OMITTED server: https://192.168.0.38:6443 name: kubernetes contexts:

Context: cluster: kubernetes user: kubernetes-admin name: kubernetes-admin@kubernetes current-context: kubernetes-admin@kubernetes kind: Config preferences: {} users:

Name: kubernetes-admin user: client-certificate-data: REDACTED client-key-data: REDACTED

If you do not set the KUBECONFIG variable, all configurations will be obtained from $HOME / .kube / config

Objects in kubectl configuration

Kubectl has the following object types in its configuration file

Cluster-information about the K8s cluster-contains cluster name and connection parameters

Users- information about the users you want to connect to the K8s cluster

Context-three times the cluster / user / namespace

Modify configuration from kubectl

Add Cluster

[node1] $kubectl config-kubeconfig=.kube/additional_config set-cluster dev-server= https://192.168.1.100-certificate-authority=fake-ca Cluster "dev" set. [node1] $kubectl config-kubeconfig=.kube/additional_config set-cluster prod-server= https://10.1.1.100-certificate-authority=fake-ca Cluster "prod" set.

New users

[node1] $kubectl config-kubeconfig=.kube/additional_config set-credentials developer-client-certificate=fake-cert-file-client-key=fake-key-seefile User "developer" set. [node1] $kubectl config-kubeconfig=.kube/additional_config set-credentials prod_admin-client-certificate=fake-cert-file-client-key=fake-key-seefile User "prod_admin" set.

Add context

[node1] $kubectl config-kubeconfig=.kube/additional_config set-context simple_app_development-cluster=dev-namespace=simple_app_dev-user=developer Context "simple_app_development" created. [node1] $kubectl config-kubeconfig=.kube/additional_config set-context simple_app_production-cluster=prod-namespace=simple_app_prod-user=prod_admin Context "simple_app_production" created.

Remove cluster / user / context from configuration

Kubectl-- kubeconfig=.kube/additional_config config unset users. Kubectl-- kubeconfig=.kube/additional_config config unset clusters. Kubectl-- kubeconfig=.kube/additional_config config unset contexts.

Sample configuration

[node1] $kubectl config-- kubeconfig=.kube/additional_config view apiVersion: v1 clusters:

Cluster: certificate-authority: / root/fake-ca server: https://192.168.1.100 name: dev

Cluster: certificate-authority: / root/fake-ca server: https://10.1.1.100 name: prod contexts:

Context: cluster: dev namespace: simple_app_dev user: developer name: simple_app_development

Context: cluster: prod namespace: simple_app_prod user: prod_admin name: simple_app_production current-context: "" kind: Config preferences: {} users:

Name: developer user: client-certificate: / root/fake-cert-file client-key: / root/fake-key-seefile

Name: prod_admin user: client-certificate: / root/fake-cert-file client-key: / root/fake-key-seefile

Change the environment

To get a list of contexts (you don't need-- kubeconfig, because we have added extra_config to the KUBECONFIG variable):

[node1 ~] $kubectl config get-contexts CURRENT NAME CLUSTER AUTHINFO NAMESPACE simple_app_development dev developer simple_app_dev simple_app_production prod prod_admin simple_app_prod

Set the context:

[node1 ~] $kubectl config use-context simple_app_development Switched to context "simple_app_development".

Get the current context:

[node1 ~] $kubectl config current-context simple_app_development

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