Large cluster deployment with 8 GiB RAM fails

[jefflill]

This appears to be a cluster advice issue. In this case, the tempo-ingester pods are not able to be scheduled:

Name:                 tempo-ingester-0
Namespace:            neon-monitor
Priority:             900000000
Priority Class Name:  neon-min
Node:                 <none>
Labels:               app.kubernetes.io/component=ingester
                      app.kubernetes.io/instance=tempo
                      app.kubernetes.io/managed-by=Helm
                      app.kubernetes.io/name=tempo
                      app.kubernetes.io/version=1.3.2
                      controller-revision-hash=tempo-ingester-848cd8689
                      helm.sh/chart=tempo-distributed-0.16.9
                      statefulset.kubernetes.io/pod-name=tempo-ingester-0
                      tempo-gossip-member=true
Annotations:          checksum/config: c764e248482a115a73aaa4678cf3e9a5b9ead286adccfc738cfc4a2e3f314e1c
                      sidecar.istio.io/inject: false
                      traffic.sidecar.istio.io/excludeInboundPorts: 7946
                      traffic.sidecar.istio.io/excludeOutboundPorts: 7946
Status:               Pending
IP:                   
IPs:                  <none>
Controlled By:        StatefulSet/tempo-ingester
Containers:
  ingester:
    Image:       registry.neon.local/neonkube/grafana-tempo:2.0.0
    Ports:       9095/TCP, 7946/TCP, 3100/TCP
    Host Ports:  0/TCP, 0/TCP, 0/TCP
    Args:
      -target=ingester
      -config.file=/conf/tempo.yaml
      -mem-ballast-size-mbs=64
      -config.expand-env=true
    Limits:
      memory:  1Gi
    Requests:
      memory:   1Gi
    Readiness:  http-get http://:http/ready delay=30s timeout=1s period=10s #success=1 #failure=3
    Environment:
      ACCESS_KEY_ID:      <set to the key 'accesskey' in secret 'minio'>  Optional: false
      SECRET_ACCESS_KEY:  <set to the key 'secretkey' in secret 'minio'>  Optional: false
      GOGC:               10
    Mounts:
      /conf from tempo-conf (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-xknb7 (ro)
      /var/tempo from data (rw)
Conditions:
  Type           Status
  PodScheduled   False 
Volumes:
  data:
    Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
    ClaimName:  data-tempo-ingester-0
    ReadOnly:   false
  tempo-conf:
    Type:      ConfigMap (a volume populated by a ConfigMap)
    Name:      tempo
    Optional:  false
  kube-api-access-xknb7:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   Burstable
Node-Selectors:              node.neonkube.io/monitor.traces-internal=true
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 30s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 30s
Events:
  Type     Reason            Age                From               Message
  ----     ------            ----               ----               -------
  Warning  FailedScheduling  12m                default-scheduler  0/6 nodes are available: 1 node(s) didn't match pod anti-affinity rules, 3 Insufficient memory, 3 node(s) didn't match Pod's node affinity/selector, 3 node(s) had untolerated taint {node-role.kubernetes.io/master: }, 5 node(s) didn't find available persistent volumes to bind. preemption: 0/6 nodes are available: 1 Insufficient memory, 5 Preemption is not helpful for scheduling.
  Warning  FailedScheduling  11m (x4 over 12m)  default-scheduler  0/6 nodes are available: 1 node(s) didn't match pod anti-affinity rules, 3 Insufficient memory, 3 node(s) didn't match Pod's node affinity/selector, 3 node(s) had untolerated taint {node-role.kubernetes.io/master: }, 5 node(s) had volume node affinity conflict. preemption: 0/6 nodes are available: 1 Insufficient memory, 5 Preemption is not helpful for scheduling.
  Warning  FailedScheduling  4m (x5 over 11m)   default-scheduler  0/6 nodes are available: 3 Insufficient memory, 3 node(s) didn't match Pod's node affinity/selector, 3 node(s) had untolerated taint {node-role.kubernetes.io/master: }, 5 node(s) had volume node affinity conflict. preemption: 0/6 nodes are available: 1 Insufficient memory, 5 Preemption is not helpful for scheduling.```

  I've temporarily reset the node RAM for these test clusters: 8 GiB --> 16 GiB

[jefflill]

@marcusbooyah looked at this and it's a problem with cluster advice. He hacked around this for clusters with 10 nodes or less but we'll need to put some more effort into how cluster advice works.

[marcusbooyah]

For now we should just recommend 16GB minimum