Ensure appropriate scalability for all managed apps

[LolloneS]

User Story

• As a customer, I want Managed Apps to scale according to the most appropriate metrics so that they are always able to properly ensure performance and reliability without overcommitting resources, hence not overpaying for unused resources
• As a Giant Swarm engineer, I want Managed Apps to scale according to the most appropriate metric so that they lead to fewer pages and do not require manual tuning

Details, Background

Pod Autoscaling generally happens based on CPU/RAM usage. While this is generally a sensible default, some applications' scaling behaviour might be better related to other metrics. For instance, for nginx a metric such as requests per second could be more useful than just looking at CPU and RAM.

In the end, as part of the "Managed" experience we should be able to have all applications scale based on the most impactful metrics to ensure smooth operations, happier customers, and fewer pages. Scaling is intended as both Vertical and Horizontal pod autoscaling.

Finally, having PDBs defined as percentages would also go in this direction, especially as far as stability at all scales is concerned.

Team Atlas

Beta Give feedback

1. Implement best practices for datadog app #2285
   team/atlas +1
   
2. Implement best practices for efk-stack-app app #2286
   component/elasticsearch component/fluent-bit team/atlas +3
3. Implement best practices for fluent-logshipping-app app #2287
   component/fluent-bit component/fluent-logshipping-app team/atlas +3
4. Implement best practices for grafana app #2289
   component/grafana needs/refinement team/atlas +3
5. Implement best practices for loki app #2290
   team/atlas +1
6. Implement best practices for prometheus-agent app #2291
   Planning team/atlas +2
   
7. Implement best practices for prometheus-operator-app app #2292
   component/prometheus-operator needs/refinement team/atlas +3
8. Implement best practices for promtail app #2293
   Planning team/atlas +2
   
9. Implement best practices for vertical-pod-autoscaler-app app #2294
   component/vertical-pod-autoscaler team/atlas +2
10. Implement best practices for grafana-agent app #3341
    Planning component/grafana-agent team/atlas +3

Team Cabbage

Beta Give feedback

1. Implement best practices for cert-manager-app app #2310
   component/cert-manager epic/best-practices team/bigmac topic/managed-apps +4
   
2. Implement best practices for cloudflared app #2313
   area/managed-apps epic/best-practices team/cabbage +3
3. Implement best practices for coredns app #2311
   area/managed-apps epic/best-practices team/cabbage +3
   
4. Implement best practices for external-dns-app app #2314
   team/cabbage +1
   
5. Implement best practices for kong-app app #2315
   area/managed-apps epic/best-practices team/cabbage +3
   
6. Implement best practices for linkerd-bundle app #2316
   team/cabbage +1
   
7. Implement best practices for linkerd-control-plane app #2317
   component/linkerd team/cabbage +2
   
8. Implement best practices for linkerd-multicluster app #2318
   team/cabbage +1
   
9. Implement best practices for linkerd-multicluster-link app #2319
   team/cabbage +1
   
10. Implement best practices for linkerd-viz app #2320
    component/linkerd team/cabbage +2
    
11. Implement best practices for linkerd2-app app #2321
    team/cabbage +1
    
12. Implement best practices for linkerd2-cni app #2322
    team/cabbage +1
    
13. Implement best practices for linkerd2-cni-app app #2323
    team/cabbage +1
14. Implement best practices for linkerd2-multicluster-app app #2324
    team/cabbage +1
15. Implement best practices for linkerd2-multicluster-link-app app #2325
    team/cabbage +1
16. Implement best practices for nginx-ingress-controller-app app #2326
    team/cabbage +1
    
17. Implement best practices for oauth2-proxy app #2327
    team/cabbage +1

Team Honeybadger

Beta Give feedback

1. Implement best practices for external-secrets app #2307
   team/honeybadger +1
   
2. Implement best practices for flux-app app #2308
   team/honeybadger +1
   
3. Implement best practices for gitops-server app #2309
   team/honeybadger +1
   

Team Hydra

Beta Give feedback

1. Implement best practices for default-apps-aws app #2306
   team/hydra +1

Team Phoenix

Beta Give feedback

1. Implement best practices for aws-cloud-controller-manager-app app #2302
   team/phoenix +1
2. Implement best practices for aws-load-balancer-controller app #2303
   team/cabbage team/phoenix +2
   
3. Implement best practices for aws-node-termination-handler-app app #2304
   team/phoenix +1
4. Implement best practices for k8s-dns-node-cache-app app #2305
   team/cabbage +1

Team Rainbow

Beta Give feedback

1. Implement best practices for athena app #2298
   team/rainbow +1
   
2. Implement best practices for dex-app app #2299
   team/rainbow +1
   
3. Implement best practices for rbac-bootstrap app #2301
   team/rainbow +1

Team Shield

Beta Give feedback

1. Implement best practices for falco app #2273
   team/shield +1
2. Implement best practices for falco-app app #2274
   team/shield +1
3. Implement best practices for jiralert app #2281
   team/shield +1
4. Implement best practices for kyverno app #2276
   team/shield +1
5. Implement best practices for kyverno-policies app #2280
   team/shield +1
   
6. Implement best practices for starboard-app app #2278
   team/shield +1
7. Implement best practices for starboard-exporter app #2279
   team/shield +1
8. Implement best practices for trivy app #2282
   team/shield +1
9. Implement best practices for trivy-app app #2283
   team/shield +1
10. Implement best practices for trivy-operator app #2284
    team/shield +1

Team Turtle

Beta Give feedback

1. Implement best practices for goldilocks-app app #2288
   needs/refinement team/turtles +2

Blocked by / depends on

• https://github.com/giantswarm/prometheus-adapter-app would probably be needed for custom metrics

[QuentinBisson]

@Rotfuks should you be assigned here? It feels weird to have an issue in wip without any assignee?

[Rotfuks]

Done for Team Atlas.

[teemow]

ping to ping @JosephSalisbury

[JosephSalisbury]

pinged POs on outstanding issues, will check progress shortly

[JosephSalisbury]

nice, all linked issues closed, closing here