False positive: nrpe lacp_bonds/netlinks errors on LMA model

[Paul Goins]

False positives found on LMA model:

2023-08-23 11:54:51 [ERROR] [lma-bundle.yaml] [manual/manual] Application nrpe has incorrect setting for 'lacp_bonds': Should not be ''
2023-08-23 11:54:51 [ERROR] [lma-bundle.yaml] [manual/manual] Application nrpe has incorrect setting for 'netlinks': Should not be ''

Per https://bugs.launchpad.net/juju-lint/+bug/2011568, it seems that these can be avoided via deploying the nrpe app with an lxd or container suffix. Neither of those is accurate for the LMA model since those are typically VMs running on the infra nodes.

Should a new suffix be added to cover this case?

[Andrea Ieri (aieri)]

Yes, the suffixes logic was added in bug 1944406, and can be seen in lint.py, line 534 and later.
The idea is that rules would only apply to applications matching the base charm name or the base charm name + listed suffix.
This mechanism is very fragile, but it's supposed to work: if you deploy nrpe in tha LMA model with any suffix that is *not* -host or -physical, the lacp_bonds and netlinks configuration checks will be skipped.

Unfortunately making juju-lint able to dynamically determine the type of nrpe unit and act accordingly is at the moment likely to be very complex.

As an alternative, one could specify different rulesets for the LMA model, of course.

Would either of the workarounds above be sufficient for the time being?