Comment 1 for bug 1882149

We recommend using juju scale-application

The remove-unit CLI is a shim to scale-application and was retained in k8s models for familiarity.

The error messages above do reflect the correct status of things. Maybe they are confusing and need rewording?

--
[agnew(charm-k8s-mattermost)] juju remove-unit mattermost/6
ERROR k8s models do not support removing named units.
Instead specify an application with --num-units (defaults to 1).

This is saying that you cannot remove a specific unit by name - you can only ask for the number of units to juju will ask k8s to set the replicaset scale and k8s will decide which pods get removed.

--
[agnew(charm-k8s-mattermost)] juju remove-unit mattermost
ERROR removing 0 units not valid

You need to tell juju how many units to remove from the specified application