Why do you need this?

This PR adds the --merge flag to the plan command, in order to add said flag to the generated script. This way, when executing the script, it is possible to merge the new kubeconfig with an existing one, making it easier to fully automate the creation of clusters in CI/CD pipelines without manual intervention

• I have raised an issue to propose this change (required). Close Add --merge flag to k3sup plan command #438

If you have no approval from a maintainer, close this PR and raise an issue.

Description

Added the flag to the command, with a check that conditionally adds the --merge flag to the install command of the primary server. Indentation and blank lines remain the same as before.

How Has This Been Tested?

Compiled the program and run it with and without the new flag. Here's the outputs:

• ./bin/k3sup plan hosts.json --local-path ./kubeconfig:

  #!/bin/sh
  
  echo "Setting up primary server 1"
  k3sup install --host test-host-01 \
  --user root \
  --cluster \
  --local-path ./kubeconfig \
  --context default
  
  echo "Fetching the server's node-token into memory"
  
  export NODE_TOKEN=$(k3sup node-token --host test-host-01 --user root)
  
  ...

• ./bin/k3sup plan hosts.json --local-path ./kubeconfig --merge:

  #!/bin/sh
  
  echo "Setting up primary server 1"
  k3sup install --host test-host-01 \
  --user root \
  --cluster \
  --local-path ./kubeconfig \
  --context default \
  --merge
  
  echo "Fetching the server's node-token into memory"
  
  export NODE_TOKEN=$(k3sup node-token --host test-host-01 --user root)
  
  ...

I haven't added unit tests, as there are none for the plan command.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s
• I have added tests to cover my changes.
• All new and existing tests passed.