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Cluster Autoscaler

Introduction
Cluster Autoscaler is a component that automatically adjusts the size of a Kubernetes Cluster so that all pods have a place to run and there are no unneeded nodes.
The cluster autoscaler for Flow scales worker nodes within any specified Flow Kubernetes cluster.
Installation
As there is no concept of a node group within Flow Cloud's Kubernetes offering, the configuration required is quite simple. You need to set:
Your Flow Application Token
The Kubernetes Cluster's ID (not the name)
The minimum and maximum number of worker nodes you want (the master is excluded)
1.Please adjust the following bold values in the yaml file below:
Minimum & Maximum of worker nodes (for example minimum 3 and maximal nine): nodes=3:9:workers

Generate an application token in https://my.flow.swiss/#/organization/applications and convert it to a base64 string and replace the **api-token** value.

Retrieve the cluster ID from your Kubernetes Cluster, convert it to a base64 string and replace the **cluster-id** value.
cluster-autoscaler.yaml
 
---
apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
  name: cluster-autoscaler
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: cluster-autoscaler
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
rules:
  - apiGroups: [""]
    resources:
      [
        "pods",
        "services",
        "replicationcontrollers",
        "persistentvolumeclaims",
        "persistentvolumes",
        "nodes",
        "endpoints",
        "namespaces",
        "configmaps",
      ]
    verbs: ["watch", "list", "get", "update", "create", "delete"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["watch", "list", "get", "create", "update", "delete", "patch"]
  - apiGroups: ["extensions"]
    resources: ["replicasets", "daemonsets"]
    verbs: ["watch", "list", "get"]
  - apiGroups: ["policy"]
    resources: ["poddisruptionbudgets"]
    verbs: ["watch", "list"]
  - apiGroups: ["apps"]
    resources: ["statefulsets", "replicasets", "daemonsets"]
    verbs: ["watch", "list", "get"]
  - apiGroups: ["storage.k8s.io"]
    resources:
      ["storageclasses", "csinodes", "csistoragecapacities", "csidrivers"]
    verbs: ["watch", "list", "get"]
  - apiGroups: ["batch", "extensions"]
    resources: ["jobs"]
    verbs: ["get", "list", "watch", "patch"]
  - apiGroups: ["coordination.k8s.io"]
    resources: ["leases"]
    verbs: ["get", "create", "update"]
  - apiGroups: [""]
    resources: ["pods/eviction"]
    verbs: ["create"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: cluster-autoscaler
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-autoscaler
subjects:
  - kind: ServiceAccount
    name: cluster-autoscaler
    namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: cluster-autoscaler
  namespace: kube-system
  labels:
    k8s-addon: cluster-autoscaler.addons.k8s.io
    k8s-app: cluster-autoscaler
rules:
  - apiGroups: ["coordination.k8s.io"]
    resources: ["leases"]
    verbs: ["create", "get", "update"]
    resourceNames: ["cluster-autoscaler"]
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["create", "list", "watch", "update"]
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: cluster-autoscaler
  namespace: kube-system
  labels:
    app: cluster-autoscaler
spec:
  replicas: 1
  selector:
    matchLabels:
      app: cluster-autoscaler
  template:
    metadata:
      labels:
        app: cluster-autoscaler
      annotations:
        prometheus.io/scrape: "true"
        prometheus.io/port: "8085"
    spec:
      serviceAccountName: cluster-autoscaler
      containers:
        - image: flowswiss/cluster-autoscaler:v0.0.4 
          name: cluster-autoscaler
          imagePullPolicy: Always
          resources:
            limits:
              cpu: 100m
              memory: 300Mi
            requests:
              cpu: 100m
              memory: 300Mi
          command:
            - ./cluster-autoscaler
            - --v=4
            - --stderrthreshold=info
            - --cloud-provider=flow
            - --nodes=1:6:workers
            - --skip-nodes-with-local-storage=false
            - --skip-nodes-with-system-pods=false
          env:
            - name: FLOW_API_TOKEN
              valueFrom:
                secretKeyRef:
                  key: **api-token** #base64_encoded_api_token
                  name: cluster-autoscaler-secrets
            - name: FLOW_CLUSTER_ID
              valueFrom:
                secretKeyRef:
                  name: cluster-autoscaler-secrets
                  key: **cluster-id** #base64_encoded_cluster_id
            - name: FLOW_API_URL
              valueFrom:
                secretKeyRef:
                  name: cluster-autoscaler-secrets
                  key: aHR0cHM6Ly9hcGkuZmxvdy5zd2lzcy8= #base64_encoded_api_url
2.Apply the yaml file with kubectl in your desired Kubernetes Cluster.

3.Follow the official documentation to configure the behavior of the cluster autoscaler: https://github.com/kubernetes/autoscaler/tree/master/cluster-autoscaler
External Load Balancers
Traefik upgrade and tests
Last modified 3mo ago