Giant Swarm OS Defaults within Cluster API

[puja108]

User Story: As a customer, I want to be able to keep relying on the sensible defaults (for security, reliability, and performance) that Giant Swarm currently provides.

The above user story is split into two issues:

1. Sensible defaults pertaining to Kubernetes and other user-space components Giant Swarm manages Implement Giant Swarm Kubernetes and Component Defaults within Cluster API #425
2. Sensible defaults pertaining to Operating System underlying the above-mentioned software (this issue)

The split is based on technical challenges upstream that are currently blocking this issue, but are not present for the other one.

Providers

Beta Give feedback

1. OS default settings for CAPA #1995
   area/kaas goal/capa-internal-ga kind/epic provider/cluster-api-aws team/phoenix topic/capi +6
   
2. Introduce hardened Flatcar Images for CAPZ #1659
   area/kaas team/clippy +2
   
3. https://github.com/giantswarm/giantswarm/issues/25295
4. CAPV
5. CAPVCD
6. use flatcar as base OS on capo clusters #778
   area/kaas epic/capo needs/refinement provider/openstack team/rocket +5

[teemow]

@puja108 do we need this issue still?

[puja108]

Yes, we are still using Ubuntu and need to move our existing OS hardening once we have moved to Flatcar with the CAPI providers.

[puja108]

just adding an aka and/or pre-req for this issue: Flatcar support in all providers.

cc @stone-z had some relevant comments on Slack about the priority of this, as all our hardening is done for Flatcar and Ubuntu as base OS for CAPI is creating a lot of overwork like in giantswarm/node-exporter-app#172

cc @alex-dabija @gawertm @Rotfuks

[gawertm]

checking for CAPVCD in: https://github.com/giantswarm/giantswarm/issues/25295
for CAPV its supported

[Rotfuks]

Flatcar support for CAPZ was merged this week, so it's also supported.
Ticket to track for the effort is here: #1659

[alex-dabija]

Separate epic for the work that needs to be done for CAPA.

[alex-dabija]

I removed CAPG from the list.

[Rotfuks]

The harmonisation of OS Images over all providers will be done in the scope of #2544
This story can therefore be closed