include arch label

[Despire]

closes #665

The API for retrieving the architecture isn't uniform across all cloud SDKs,

For GCP, Azure The architecture is retrieved via the Image client and then the Architecture is set to all the cached types. For OCI a regex match is done for the ARM machine type, but since the ARM type on OCI is a Flex instance, which claudie doesn't surpport, I couldn't test it

[bernardhalas]

Just curious, grepping the architecture from /proc/cpuinfo was not an option or uname -i? (It would also work on on-prem nodepools).

[Despire]

Afaik, this is for a template (kind: Node) that the autoscaler requests, and for retrieving it from /proc/cpuinfo I would need to ssh into an existing node of the cluster which would be more work that wouldn't be worth it. cc @MiroslavRepka

[bernardhalas]

One more question then - does this label appear on the nodes?

(If so, we'll need to figure out how to set it for the on-prem nodes.)

[MiroslavRepka]

Just to clarify/reiterate from the daily meeting. The label kubernetes.io/arch is automatically added to the node by kubelet. ref This means all of the nodes, on-prem or cloud, have this label set.

However, as Cluster Autoscaler needs the template of the node, to simulate scheduling, we need to populate this label without creating a new node. Imagine the case where you have some pending pods, with the node selector set to kubernetes.io/arch: arm64. Before this PR, Cluster Autoscaler would not know if the potential new node has an appropriate value for this pod.

[MiroslavRepka]

LGTM

[cloudziu]

LGTM 👍