Make server's data-dir configurable for getting node token in join command

[alexellis]

Signed-off-by: Alex Ellis (OpenFaaS Ltd) [email protected]

Description

Make data-dir configurable for getting node token

Why do you need this?

Three users, none of them are sponsors requested this feature in #373

When using a different data-dir for K3s on a server, the hard-coded node-token path fails to match a valid token file.

So this change allows the join command to override the value for the path.

Closes: #373

How Has This Been Tested?

I created two multipass VMs, running sudo mkdir -p /mnt/ssd/k3s on both.

On the server:

./k3sup install --local --ip 127.0.0.1 --k3s-extra-args "--data-dir /mnt/ssd/k3s"

On the agent:

./k3sup join --ip 127.0.0.1 \
  --user ubuntu \
  --server-ip 10.143.143.215 \
  --server-user ubuntu  \
  --k3s-extra-args "--data-dir /mnt/ssd/k3s" \
  --server-data-dir /mnt/ssd/k3s/

Originally, the command above failed with the error seen in the user's report.

Afterwards, it connected and worked as expected.

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.

For future work, adding --data-dir as a first-class flag would mean less typing i.e. no need for --k3s-extra-args "--data-dir /mnt/ssd/k3s", instead it'd be --data-dir /mnt/ssd/k3s and then translated into the k3s extra args automatically, like other flags are today.