feat(cluster-autoscaler/cloudprovider/exoscale): Add caching capability

[thomasstxyz]

Which component are you using?:

cluster-autoscaler / cloudprovider / exoscale

Is your feature request designed to solve a problem? If so describe the problem this feature should solve.:

Currently with a cluster with 50+ nodes, the cluster-autoscaler controller needs a couple of minutes to do scale ups/downs, because it continuously is looking up the nodegroup belonging to a node.

Describe the solution you'd like.:

• node metadata is cached, so the main loop runs fast, and is done in a couple of seconds

Describe any alternative solutions you've considered.:

-

Additional context.:

In these logs you see how long the controller currently takes for each node:

I1109 23:12:08.429748       1 log.go:36] exoscale-provider: looking up node group for node ID 1c02381c-275a-42cc-b2ba-6247754992f4
I1109 23:12:08.698391       1 log.go:36] exoscale-provider: found node 1c02381c-275a-42cc-b2ba-6247754992f4 belonging to SKS Nodepool d83024e8-e362-4d54-b259-c3f25d249f51
I1109 23:12:09.222860       1 log.go:36] exoscale-provider: looking up node group for node ID 4f6e4a80-b7d3-4846-bdfe-40759caa208d
I1109 23:12:09.524159       1 log.go:36] exoscale-provider: found node 4f6e4a80-b7d3-4846-bdfe-40759caa208d belonging to SKS Nodepool d83024e8-e362-4d54-b259-c3f25d249f51
I1109 23:12:10.014878       1 log.go:36] exoscale-provider: looking up node group for node ID e6898ac6-d452-4451-9ab3-63a0963c2585
I1109 23:12:10.284943       1 log.go:36] exoscale-provider: found node e6898ac6-d452-4451-9ab3-63a0963c2585 belonging to SKS Nodepool d83024e8-e362-4d54-b259-c3f25d249f51
I1109 23:12:10.832619       1 log.go:36] exoscale-provider: looking up node group for node ID bbb6a12f-4bfa-4781-9bf5-2413fb31b5b0
I1109 23:12:11.117948       1 log.go:36] exoscale-provider: found node bbb6a12f-4bfa-4781-9bf5-2413fb31b5b0 belonging to SKS Nodepool d83024e8-e362-4d54-b259-c3f25d249f51
I1109 23:12:11.688147       1 log.go:36] exoscale-provider: looking up node group for node ID cc65c8a2-8938-44fc-81bc-59b07fef3e47
I1109 23:12:11.947046       1 log.go:36] exoscale-provider: found node cc65c8a2-8938-44fc-81bc-59b07fef3e47 belonging to SKS Nodepool d83024e8-e362-4d54-b259-c3f25d249f51
I1109 23:12:12.518103       1 log.go:36] exoscale-provider: looking up node group for node ID 0b4080da-67ec-4c18-9e35-f1e59de07aef
I1109 23:12:12.792736       1 log.go:36] exoscale-provider: found node 0b4080da-67ec-4c18-9e35-f1e59de07aef belonging to SKS Nodepool d83024e8-e362-4d54-b259-c3f25d249f51

[adrianmoisey]

/area cluster-autoscaler

[Sapd]

fyi @pierre-emmanuelJ @PhilippeChepy