New 2.6 feature: Better removal support


#1

In Juju v.2.6.0, there is better support for the removal of Juju objects.

Juju object removal commands do not succeed when there are errors in the multiple steps that are required to remove the underlying object. For instance, a unit will not remove properly if it has a hook error or a model cannot be removed if application units are in an error state. This is a conservative approach to the deletion of things, which is good.

However, this policy can also be a source of frustration for users in certain situations (i.e. “I don’t care, I just want my model gone!”). Because of this, several commands have grown a --force option.

Secondly, even when utilising the --force option the process may take more time than an operator is willing to accept (i.e. Just go away as quickly as possible!). Because of this, several commands that support the --force option have, in addition, been given a --no-wait option.

Caution: The --force and --no-wait options should be regarded as tools to wield as a last resort. Using them introduces a chance of associated parts (e.g. relations) not being cleaned up, which can lead to future problems.

As of v.2.6.0, this is the state of affairs for those commands that support at least the --force option:

command --force --no-wait
destroy-model yes yes
detach-storage yes no
remove-application yes yes
remove-machine yes yes
remove-offer yes no
remove-relation yes no
remove-storage yes no
remove-unit yes yes

When a command has --force but not --no-wait it indicates that the combination of those options simply does not apply.