使用 kubeadm
创建一个集群,我有一个主节点和一个工作节点。
现在我想在工作节点共享一个persistentVolume
,它会绑定(bind)Postgres
pod。
预计代码会在工作节点的路径/postgres
中创建persistentVolume
,但似乎hostPath
不会在集群中工作, 我应该如何将此属性分配给特定节点?
kind: PersistentVolume
apiVersion: v1
metadata:
name: pv-postgres
labels:
type: local
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/postgres"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: pvc-postgres
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: postgres
spec:
selector:
matchLabels:
app: postgres
replicas: 1
strategy: {}
template:
metadata:
labels:
app: postgres
spec:
dnsPolicy: ClusterFirstWithHostNet
hostNetwork: true
volumes:
- name: vol-postgres
persistentVolumeClaim:
claimName: pvc-postgres
containers:
- name: postgres
image: postgres:12
imagePullPolicy: Always
env:
- name: DB_USER
value: postgres
- name: DB_PASS
value: postgres
- name: DB_NAME
value: postgres
ports:
- name: postgres
containerPort: 5432
volumeMounts:
- mountPath: "/postgres"
name: vol-postgres
livenessProbe:
exec:
command:
- pg_isready
- -h
- localhost
- -U
- postgres
initialDelaySeconds: 30
timeoutSeconds: 5
readinessProbe:
exec:
command:
- pg_isready
- -h
- localhost
- -U
- postgres
initialDelaySeconds: 5
timeoutSeconds: 1
---
apiVersion: v1
kind: Service
metadata:
name: postgres
spec:
ports:
- name: postgres
port: 5432
targetPort: postgres
selector:
app: postgres
最佳答案
根据 docs 。
A hostPath volume mounts a file or directory from the host node’s filesystem into your Pod. This is not something that most Pods will need, but it offers a powerful escape hatch for some applications.
简而言之,hostPath
类型是指节点(机器或VM)资源,您将在其中调度pod。这意味着您已经需要在此节点上拥有此文件夹。
要将资源分配给指定节点,您必须在 Deployment
、PV
中使用 nodeSelector。
根据具体情况,使用 hostPath
并不是最好的主意,但是我将在下面提供示例 YAML,这可能会向您展示概念。基于您的 YAML,但使用 nginx 图像
。
kind: PersistentVolume
apiVersion: v1
metadata:
name: pv-postgres
spec:
capacity:
storage: 2Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/tmp/postgres" ## this folder need exist on your node. Keep in minds also who have permissions to folder. Used tmp as it have 3x rwx
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- ubuntu18-kubeadm-worker1
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: pvc-postgres
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: postgres
spec:
selector:
matchLabels:
app: postgres
replicas: 1
strategy: {}
template:
metadata:
labels:
app: postgres
spec:
containers:
- image: nginx
name: nginx
volumeMounts:
- mountPath: /home ## path to folder inside container
name: vol-postgres
affinity: ## specified affinity to schedule all pods on this specific node with name ubuntu18-kubeadm-worker1
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- ubuntu18-kubeadm-worker1
dnsPolicy: ClusterFirstWithHostNet
hostNetwork: true
volumes:
- name: vol-postgres
persistentVolumeClaim:
claimName: pvc-postgres
persistentvolume/pv-postgres created
persistentvolumeclaim/pvc-postgres created
deployment.apps/postgres created
不幸的是,PV 以 1:1 的关系绑定(bind)到 PVC,因此每次都需要创建 PV 和 PVC。
但是,如果您使用的是 hostPath
,则在 中指定
没有nodeAffinity
、volumeMounts
和 volumes
就足够了部署PV
和PVC
的YAML。
apiVersion: apps/v1
kind: Deployment
metadata:
name: postgres
spec:
selector:
matchLabels:
app: postgres
replicas: 1
strategy: {}
template:
metadata:
labels:
app: postgres
spec:
containers:
- image: nginx:latest
name: nginx
volumeMounts:
- mountPath: /home
name: vol-postgres
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- ubuntu18-kubeadm-worker1
dnsPolicy: ClusterFirstWithHostNet
hostNetwork: true
volumes:
- name: vol-postgres
hostPath:
path: /tmp/postgres
deployment.apps/postgres created
user@ubuntu18-kubeadm-master:~$ kubectl get pods
NAME READY STATUS RESTARTS AGE
postgres-77bc9c4566-jgxqq 1/1 Running 0 9s
user@ubuntu18-kubeadm-master:~$ kk exec -ti postgres-77bc9c4566-jgxqq /bin/bash
root@ubuntu18-kubeadm-worker1:/# cd home
root@ubuntu18-kubeadm-worker1:/home# ls
test.txt txt.txt
关于kubernetes - HostPath 将 persistentVolume 分配给集群中的特定工作节点,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/60247100/