ci-automation/azure: enable back Azure

[tormath1]

In this PR:

• we enable back garbage collection even if this one is quite useless in the new subscription as there is an automatic garbage collection on nightlies
• we drop the use of private IPs for kola spawned instances to use assigned public IP as the subscription is not locked-down

This has been partially tested here: https://jenkins.flatcar.org/job/container/job/test/48/console

17:01:44  --- PASS: cl.internet (104.59s)
17:01:44      --- PASS: cl.internet/NTPDate (7.12s)
17:01:44      --- PASS: cl.internet/UpdateEngine (0.25s)
17:01:44      --- PASS: cl.internet/DockerPing (9.89s)
17:01:44      --- PASS: cl.internet/DockerEcho (0.52s)
17:01:44  PASS, output in _kola_temp/azure-2026-04-08-1456-108

NOTE:

• test/azure: use public IP needs to be backported on maintainance channel but let's try on main a full run first

[chewi]

Wouldn't using a private IP be preferable security-wise?

[tormath1]

Wouldn't using a private IP be preferable security-wise?

With this flag, it means that we use a private IP to access the VM but the VM will still have a public IP. See: https://github.com/flatcar/mantle/blob/1147d638804f6c25e10c60bbbea8e25525849182/platform/api/azure/instance.go#L251-L319

We needed to use private IP on the previous subscription because firewall was blocking requests on external IPs.

[chewi]

Okay, but would it be better to have an option to not allocate a public IP in the first place? Feel free to say "maybe, but later."

[tormath1]

Okay, but would it be better to have an option to not allocate a public IP in the first place? Feel free to say "maybe, but later."

Sure, that seems to be a good idea but let's not forget that those created instances have a short time to live and don't have any associated credentials (e.g managed identities) - so to me the security risk is low but happy to get your input here (and even more happy to update the codebase!)

[tormath1]

Cherry-picked test/azure: use public IP to:

• flatcar-4628
• flatcar-4593
• flatcar-4459
• flatcar-4081