K8S实战 之 数据库部署

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本文以MySQL部署为例

目录

PV

什么是持久卷(PV)?

  • 持久卷(Persistent Volume)是集群中的一块存储

为什么需要持久卷(PV)?

  • 当Pod不再存在时 K8S会销毁临时卷 但不会销毁持久卷
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vim pv.yml
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apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"
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kubectl apply -f pv.yml

kubectl get pv
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NAME       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
mysql-pv   20Gi       RWO            Retain           Available           manual                  30s

PVC

什么是持久卷申领(PVC)?

  • 持久卷申领(Persistent Volume Claim)表达的是用户对存储的请求
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vim pvc.yml
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apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pvc
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
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kubectl apply -f pvc.yml

kubectl get pvc
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NAME        STATUS   VOLUME     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
mysql-pvc   Bound    mysql-pv   20Gi       RWO            manual         11s

Secret

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kubectl create secret generic mysql-secrets --from-literal=ROOT_PASSWORD=123456

kubectl get secret mysql-secrets -o yaml
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apiVersion: v1
data:
  ROOT_PASSWORD: MTIzNDU2
kind: Secret
metadata:
  creationTimestamp: "2021-09-24T03:41:55Z"
  name: mysql-secrets
  namespace: default
  resourceVersion: "106265"
  selfLink: /api/v1/namespaces/default/secrets/mysql-secrets
  uid: f2202426-45a9-4671-8181-61406d2b224e
type: Opaque

Deployment

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vim deploy.yml
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apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
        - image: mysql:5.7
          name: mysql
          ports:
            - containerPort: 3306
              name: mysql
          volumeMounts:
            - name: mysql-data
              mountPath: /var/lib/mysql
          env:
            - name: MYSQL_ROOT_PASSWORD
              valueFrom:
                secretKeyRef:
                  name: mysql-secrets
                  key: ROOT_PASSWORD
      volumes:
        - name: mysql-data
          persistentVolumeClaim:
            claimName: mysql-pvc
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kubectl apply -f deploy.yml

kubectl get pods
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NAME                    READY   STATUS    RESTARTS   AGE
mysql-78b5646c6-t6wgq   1/1     Running   0          115s

Service

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vim service.yml
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apiVersion: v1
kind: Service
metadata:
  name: mysql-service
spec:
  type: NodePort
  selector:
    app: mysql
  ports:
    - protocol: TCP
      port: 3306
      targetPort: 3306
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kubectl apply -f service.yml

kubectl get svc mysql-service
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NAME            TYPE       CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
mysql-service   NodePort   10.100.130.112   <none>        3306:30653/TCP   165m
  • 使用
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kubectl run -it --rm --image=mysql:5.7 --restart=Never mysql-client -- mysql -h 10.100.130.112 -p123456
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CREATE DATABASE IF NOT EXISTS test_db DEFAULT CHARSET utf8 COLLATE utf8_general_ci;

USE test_db;

CREATE TABLE IF NOT EXISTS `test_tb`(
    `id` INT UNSIGNED AUTO_INCREMENT,
    `data` VARCHAR(100) NOT NULL,
    PRIMARY KEY ( `id` )
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO test_tb ( data ) VALUES ('hello world');

SELECT * FROM test_tb;
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+----+-------------+
| id | data        |
+----+-------------+
|  1 | hello world |
+----+-------------+
1 row in set (0.00 sec)

清理

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kubectl delete -f service.yml

kubectl delete -f deploy.yml

kubectl delete secret mysql-secrets

kubectl delete -f pvc.yml

kubectl delete -f pv.yml

参考