[RFE] Check for metro capacity before deploying

[tormath1]

Current situation

CI takes ages on Equinix Metal platform because of not enough capacity on the metro.

Impact

It delays a lot the release as we require Equinix Metal tests to be 🟢

Ideal future situation

Iterate over metros to find one with enough capacity.

Implementation options

We could provide a list of candidates metro (instead of one) - and before each deployment, we check if the metro has enough capacity for the deployment if not: try the next one.

Additional information

• https://deploy.equinix.com/developers/api/metal#tag/Capacity/operation/checkCapacityForMetro
• https://deploy.equinix.com/developers/api/metal#tag/Capacity/operation/findCapacityForMetro

[pothos]

We can also use a Jenkins resource lock to limit parallel runs (or resource labels for partitioned parallel use but with the idea to check the capacity live this would mean to somehow generate the labels live through code instead of statically configure them). Otherwise we would still the problem that parallel tests compete for a metro.

[vielmetti]

There is an "any" metro option that allows you to deploy to any available metro.

Set metro: "any" and we will pick one for you that has availability.

(If you are using Terraform there are a few complications, described at equinix/terraform-provider-equinix#624 )