Cluster Autoscaler
•
수요에 따라 k8s Node를 자동으로 추가하는 기능
◦
리소스 부족으로 pod의 Node할당이 pending 될때 (scale-out)
◦
미사용 Node가 있을때 (scale-in)
•
각 cloud provider 마다 각자의 cluster autoscaling 방법이 있음
AWS AutoScaling
•
cluster-autoscaler-policy.json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"autoscaling:DescribeAutoScalingGroups",
"autoscaling:DescribeAutoScalingInstances",
"autoscaling:DescribeLaunchConfigurations",
"autoscaling:DescribeScalingActivities",
"ec2:DescribeImages",
"ec2:DescribeInstanceTypes",
"ec2:DescribeLaunchTemplateVersions",
"ec2:GetInstanceTypesFromInstanceRequirements",
"eks:DescribeNodegroup"
],
"Resource": ["*"]
},
{
"Effect": "Allow",
"Action": [
"autoscaling:SetDesiredCapacity",
"autoscaling:TerminateInstanceInAutoScalingGroup"
],
"Resource": ["*"]
}
]
}
JSON
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aws iam create-policy \
--policy-name AmazonEKSClusterAutoscalerPolicy \
--policy-document file://cluster-autoscaler-policy.json
Shell
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eksctl create iamserviceaccount \
--cluster=skills-eks-cluster \
--namespace=kube-system \
--name=cluster-autoscaler \
--attach-policy-arn=arn:aws:iam::362708816803:policy/AmazonEKSClusterAutoscalerPolicy \
--override-existing-serviceaccounts \
--approve
Shell
복사
•
cluster-auto-scaler.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: ["events", "endpoints"]
verbs: ["create", "patch"]
- apiGroups: [""]
resources: ["pods/eviction"]
verbs: ["create"]
- apiGroups: [""]
resources: ["pods/status"]
verbs: ["update"]
- apiGroups: [""]
resources: ["endpoints"]
resourceNames: ["cluster-autoscaler"]
verbs: ["get", "update"]
- apiGroups: [""]
resources: ["nodes"]
verbs: ["watch", "list", "get", "update"]
- apiGroups: [""]
resources:
- "namespaces"
- "pods"
- "services"
- "replicationcontrollers"
- "persistentvolumeclaims"
- "persistentvolumes"
verbs: ["watch", "list", "get"]
- 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", "csidrivers", "csistoragecapacities"]
verbs: ["watch", "list", "get"]
- apiGroups: ["batch", "extensions"]
resources: ["jobs"]
verbs: ["get", "list", "watch", "patch"]
- apiGroups: ["coordination.k8s.io"]
resources: ["leases"]
verbs: ["create"]
- apiGroups: ["coordination.k8s.io"]
resourceNames: ["cluster-autoscaler"]
resources: ["leases"]
verbs: ["get", "update"]
---
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: [""]
resources: ["configmaps"]
verbs: ["create", "list", "watch"]
- apiGroups: [""]
resources: ["configmaps"]
resourceNames:
["cluster-autoscaler-status", "cluster-autoscaler-priority-expander"]
verbs: ["delete", "get", "update", "watch"]
---
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: RoleBinding
metadata:
name: cluster-autoscaler
namespace: kube-system
labels:
k8s-addon: cluster-autoscaler.addons.k8s.io
k8s-app: cluster-autoscaler
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: cluster-autoscaler
subjects:
- kind: ServiceAccount
name: cluster-autoscaler
namespace: kube-system
---
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:
priorityClassName: system-cluster-critical
securityContext:
runAsNonRoot: true
runAsUser: 65534
fsGroup: 65534
seccompProfile:
type: RuntimeDefault
serviceAccountName: cluster-autoscaler
containers:
- image: registry.k8s.io/autoscaling/cluster-autoscaler:v1.26.2
name: cluster-autoscaler
resources:
limits:
cpu: 100m
memory: 600Mi
requests:
cpu: 100m
memory: 600Mi
command:
- ./cluster-autoscaler
- --v=4
- --stderrthreshold=info
- --cloud-provider=aws
- --skip-nodes-with-local-storage=false
- --expander=least-waste
- --node-group-auto-discovery=asg:tag=k8s.io/cluster-autoscaler/enabled,k8s.io/cluster-autoscaler/skills-eks-cluster
- --balance-similar-node-groups
- --skip-nodes-with-system-pods=false
volumeMounts:
- name: ssl-certs
mountPath: /etc/ssl/certs/ca-certificates.crt # /etc/ssl/certs/ca-bundle.crt for Amazon Linux Worker Nodes
readOnly: true
imagePullPolicy: "Always"
securityContext:
allowPrivilegeEscalation: false
capabilities:
drop:
- ALL
readOnlyRootFilesystem: true
volumes:
- name: ssl-certs
hostPath:
path: "/etc/ssl/certs/ca-bundle.crt"
YAML
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kubectl apply -f cluster-auto-scaler.yaml
Shell
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kubectl patch deployment cluster-autoscaler \
-n kube-system \
-p '{"spec":{"template":{"metadata":{"annotations":{"cluster-autoscaler.kubernetes.io/safe-to-evict": "false"}}}}}'
Shell
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kubectl -n kube-system logs -f deployment.apps/cluster-autoscaler
kubectl get nodes
Shell
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