Offline Jenkins Plugin Installation.

Step 1: Search Plugin ( example: blueocean )
https://plugins.jenkins.io/

Step 2: Click > How to install > Copy the CLI command

Step 3 : Download jenkins-plugin-manager. (https://github.com/jenkinsci/plugin-installation-manager-tool/blob/master/README.md)

Step 4 : Download the plugin with dependencies.

java -jar jenkins-plugin-manager-2.12.14.jar -d ./local_plugin --plugins blueocean:1.27.10

Step 5 : copy .jpi files to %JENKINS_HOME%/plugins folder.

## For Kubernetes Helm 
kubectl cp ./local_plugin jenkins-0:/var/jenkins_home/plugins

4. reboot Jenkins.