Long run of slo and slo versioning

[freeseacher]

From time to time we need to adjust queries or labels for slo.
as for now changing labels will break slo calculation for changed.

I propose to add label (?) slo_version to rules calculation and that label to the calculations of

• slo:current_burn_rate:ratio
• slo:period_burn_rate:ratio
• slo:period_error_budget_remaining:ratio
• alerts
  that would be enough to create different version of slo that can be tracked independently

[ervinb]

I worked around this limitation by simply having the revision in the SLO name.

For example

  slos:
    name: http-availability-rev-1 
    description: 99.5% of the requests should be successful for the user-facing API
    ...

becomes

  slos:
    name: http-availability-rev-2
    description: 99.5% of the requests should be successful for the user-facing API
    ...

which results in a new SLO, while being able to track the previous one - the same behavior you'd get with having the slo_version label.

[freeseacher]

at the end of the day we got the same idea but we've introduced Version filed in spec.
something like this.
a.txt

i believe this works should be done in different way with introduction of prometheus/v2 kind. and we are not sure if it must go to upstream because of this.