warn/alert on non-default configuration

[Garrett Neugent]

To ensure that minimal changes are made for a given application (and that default configuration isn't set by the user), it would be great to add a check for this. The following command will show non-default configs for a given application:

juju config $app --format json | jq -c '.settings | to_entries[] | select(.value.source=="user") | [.key, .value.value]'

[Andrea Ieri (aieri)]

@Garrett are you suggesting we alert on any user-set config option or only on options that have a value set which is identical to the default?

I'm thinking that there are probably many instances of charm options that will almost always require a user config; we wouldn't want to perma-alert on those.

[Garrett Neugent (thogarre)]

I think as a first step it would be great to identify settings that already match the default.

In terms of non-default settings, i'm not sure how we'd go about this, but it would be good to make sure that these are still validated. maybe a warn instead of a crit? or we can add a known list of common changes, to ignore (e.g nagios host context, netlinks, certs, etc.)

[Eric Chen (eric-chen)]

Migrate to https://github.com/canonical/juju-lint/issues/147