Simple Blog

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# Deployment 的 Pod 名称（随机）
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nginx-deployment-7d8b9f2c-x7k9m
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nginx-deployment-7d8b9f2c-p4q2n
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nginx-deployment-7d8b9f2c-m8w5t
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# StatefulSet 的 Pod 名称（固定编号）
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mysql-0  # 第一个 Pod，编号从 0 开始
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mysql-1  # 第二个 Pod
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mysql-2  # 第三个 Pod

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# Pod mysql-1 崩溃前的 IP
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mysql-1: 10.244.1.100
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# Pod mysql-1 重启后的 IP
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mysql-1: 10.244.2.200  # IP 变了
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# 但 DNS 名称不变，其他 Pod 仍然可以通过名称访问
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nslookup mysql-1.mysql-service
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# 自动解析到新 IP: 10.244.2.200

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cd /root/k8s-yaml
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cat > nginx-deployment.yaml <<EOF
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apiVersion: apps/v1
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kind: Deployment
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metadata:
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  name: nginx-deploy
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spec:
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  replicas: 3
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  selector:
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    matchLabels:
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      app: nginx-deploy
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  template:
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    metadata:
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      labels:
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        app: nginx-deploy
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    spec:
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      containers:
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      - name: nginx
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        image: nginx:1.20
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        ports:
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        - containerPort: 80
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EOF
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kubectl apply -f nginx-deployment.yaml
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# 查看 Pod 名称（随机后缀）
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kubectl get pods -l app=nginx-deploy

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# 先创建 Headless Service（必须的！）
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cat > nginx-headless.yaml <<EOF
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apiVersion: v1
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kind: Service
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metadata:
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  name: nginx-sts
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spec:
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  clusterIP: None  # Headless Service
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  selector:
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    app: nginx-sts
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  ports:
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  - port: 80
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EOF
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kubectl apply -f nginx-headless.yaml
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# 创建 StatefulSet
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cat > nginx-statefulset.yaml <<EOF
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apiVersion: apps/v1
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kind: StatefulSet
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metadata:
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  name: nginx-sts
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spec:
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  serviceName: nginx-sts  # 关联 Headless Service
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  replicas: 3
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  selector:
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    matchLabels:
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      app: nginx-sts
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  template:
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    metadata:
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      labels:
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        app: nginx-sts
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    spec:
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      containers:
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      - name: nginx
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        image: nginx:1.20
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        ports:
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        - containerPort: 80
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EOF
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kubectl apply -f nginx-statefulset.yaml
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# 观察 Pod 启动过程（会看到按顺序启动）
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watch kubectl get pods -l app=nginx-sts

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# 测试 StatefulSet 的 Pod（有固定 DNS）
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kubectl exec -it nginx-sts-0 -- nslookup nginx-sts-1.nginx-sts
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# 预期输出：
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# Server:    10.96.0.10
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# Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
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#
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# Name:      nginx-sts-1.nginx-sts
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# Address 1: 10.244.2.100 nginx-sts-1.nginx-sts.default.svc.cluster.local
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# 每个 StatefulSet Pod 都有固定 DNS
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kubectl exec -it nginx-sts-0 -- nslookup nginx-sts-0.nginx-sts
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kubectl exec -it nginx-sts-0 -- nslookup nginx-sts-2.nginx-sts

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# 删除 Deployment 的一个 Pod
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DEPLOY_POD=$(kubectl get pods -l app=nginx-deploy -o jsonpath='{.items[0].metadata.name}')
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kubectl delete pod $DEPLOY_POD
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kubectl get pods -l app=nginx-deploy
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# 输出：新 Pod 名称完全不同
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# 删除 StatefulSet 的一个 Pod
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kubectl delete pod nginx-sts-1
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kubectl get pods -l app=nginx-sts
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# 输出：新 Pod 名称完全相同
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# nginx-sts-1  ← 名称不变！

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kubectl delete deployment nginx-deploy
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kubectl delete statefulset nginx-sts
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kubectl delete svc nginx-sts

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# 命名规则：<pvc-name>-<statefulset-name>-<ordinal>
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data-mysql-0  # mysql-0 的 PVC
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data-mysql-1  # mysql-1 的 PVC
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data-mysql-2  # mysql-2 的 PVC

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kubectl set image statefulset/mysql mysql=mysql:8.0.35
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kubectl rollout status statefulset/mysql

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kubectl set image statefulset/mysql mysql=mysql:8.0.30

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kubectl scale statefulset mysql --replicas=5
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# 顺序创建：mysql-3 → mysql-4

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kubectl scale statefulset mysql --replicas=3
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# 反序删除：mysql-4 → mysql-3
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# PVC 不会被删除（数据保留）

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kubectl delete statefulset mysql
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kubectl get pvc  # PVC 仍然存在
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kubectl delete pvc -l app=mysql  # 手动删除

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cd /root/k8s-yaml
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cat > mysql-configmap.yaml <<EOF
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apiVersion: v1
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kind: ConfigMap
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metadata:
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  name: mysql-config
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data:
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  master.cnf: |
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    [mysqld]
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    log-bin=mysql-bin   # 开启 binlog
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    server-id=1         # 主库 ID
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  slave.cnf: |
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    [mysqld]
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    server-id=2         # 从库 ID（会被动态修改）
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    read_only=1         # 只读模式
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EOF
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kubectl apply -f mysql-configmap.yaml

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cat > mysql-service.yaml <<EOF
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apiVersion: v1
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kind: Service
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metadata:
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  name: mysql
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spec:
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  clusterIP: None       # Headless Service
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  selector:
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    app: mysql
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  ports:
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  - name: mysql
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    port: 3306
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---
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apiVersion: v1
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kind: Service
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metadata:
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  name: mysql-read     # 读请求负载均衡
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spec:
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  selector:
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    app: mysql
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  ports:
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  - name: mysql
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    port: 3306
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EOF
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kubectl apply -f mysql-service.yaml

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cat > mysql-statefulset.yaml <<'EOF'
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apiVersion: apps/v1
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kind: StatefulSet
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metadata:
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  name: mysql
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spec:
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  serviceName: mysql
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  replicas: 3
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  selector:
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    matchLabels:
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      app: mysql
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  template:
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    metadata:
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      labels:
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        app: mysql
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    spec:
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      initContainers:
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      - name: init-mysql
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        image: reg.westos.org/library/mysql:8.0
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        command:
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        - bash
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        - "-c"
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        - |
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          set -ex
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          # 提取 Pod 编号
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          [[ $(hostname) =~ -([0-9]+)$ ]] || exit 1
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          ordinal=${BASH_REMATCH[1]}
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          echo "Pod ordinal: $ordinal"
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          # mysql-0 用主库配置，其他用从库配置
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          if [[ $ordinal -eq 0 ]]; then
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            cp /mnt/config-map/master.cnf /mnt/conf.d/
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          else
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            cp /mnt/config-map/slave.cnf /mnt/conf.d/
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            # 动态设置 server-id
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            sed -i "s/server-id=2/server-id=$((100 + $ordinal))/" /mnt/conf.d/slave.cnf
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          fi
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          cat /mnt/conf.d/*.cnf
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        volumeMounts:
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        - name: conf
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          mountPath: /mnt/conf.d
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        - name: config-map
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          mountPath: /mnt/config-map
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      containers:
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      - name: mysql
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        image: reg.westos.org/library/mysql:8.0
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        env:
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        - name: MYSQL_ROOT_PASSWORD
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          value: "Westos123"
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        - name: MYSQL_DATABASE
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          value: "testdb"
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        ports:
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        - name: mysql
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          containerPort: 3306
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        volumeMounts:
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        - name: data
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          mountPath: /var/lib/mysql
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          subPath: mysql
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        - name: conf
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          mountPath: /etc/mysql/conf.d
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        livenessProbe:
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          exec:
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            command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
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          initialDelaySeconds: 30
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          periodSeconds: 10
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        readinessProbe:
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          exec:
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            command: ["mysql", "-uroot", "-p${MYSQL_ROOT_PASSWORD}", "-e", "SELECT 1"]
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          initialDelaySeconds: 10
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          periodSeconds: 5
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      volumes:
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      - name: conf
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        emptyDir: {}
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      - name: config-map
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        configMap:
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          name: mysql-config
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      - name: data
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        emptyDir: {}  # 简化版：使用 emptyDir
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EOF
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kubectl apply -f mysql-statefulset.yaml

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[[ $(hostname) =~ -([0-9]+)$ ]] || exit 1
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ordinal=${BASH_REMATCH[1]}

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# 观察 Pod 启动顺序
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watch kubectl get pods -l app=mysql
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# 查看 init 容器日志
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kubectl logs mysql-0 -c init-mysql
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kubectl logs mysql-1 -c init-mysql
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# 查看 MySQL 日志
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kubectl logs mysql-0 -c mysql

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kubectl exec -it mysql-0 -c mysql -- mysql -uroot -pWestos123 <<EOF
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CREATE USER 'repl'@'%' IDENTIFIED BY 'Repl123!@#';
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GRANT REPLICATION SLAVE ON *.* TO 'repl'@'%';
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FLUSH PRIVILEGES;
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SHOW MASTER STATUS;
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EOF

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# 配置 mysql-1
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kubectl exec -it mysql-1 -c mysql -- mysql -uroot -pWestos123 <<EOF
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STOP SLAVE;
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CHANGE MASTER TO
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  MASTER_HOST='mysql-0.mysql',
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  MASTER_USER='repl',
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  MASTER_PASSWORD='Repl123!@#',
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  MASTER_LOG_FILE='mysql-bin.000003',
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  MASTER_LOG_POS=157;
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START SLAVE;
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SHOW SLAVE STATUS\G
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EOF
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# 配置 mysql-2
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kubectl exec -it mysql-2 -c mysql -- mysql -uroot -pWestos123 <<EOF
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STOP SLAVE;
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CHANGE MASTER TO
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  MASTER_HOST='mysql-0.mysql',
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  MASTER_USER='repl',
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  MASTER_PASSWORD='Repl123!@#',
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  MASTER_LOG_FILE='mysql-bin.000003',
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  MASTER_LOG_POS=157;
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START SLAVE;
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SHOW SLAVE STATUS\G
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EOF

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kubectl exec -it mysql-1 -c mysql -- mysql -uroot -pWestos123 -e "SHOW SLAVE STATUS\G" | grep -E "Slave_IO_Running|Slave_SQL_Running"

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kubectl exec -it mysql-0 -c mysql -- mysql -uroot -pWestos123 <<EOF
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USE testdb;
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CREATE TABLE users (
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  id INT PRIMARY KEY AUTO_INCREMENT,
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  name VARCHAR(50),
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  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
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);
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INSERT INTO users (name) VALUES ('Alice'), ('Bob'), ('Charlie');
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SELECT * FROM users;
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EOF

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# 从库1
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kubectl exec -it mysql-1 -c mysql -- mysql -uroot -pWestos123 -e "SELECT * FROM testdb.users;"
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# 从库2
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kubectl exec -it mysql-2 -c mysql -- mysql -uroot -pWestos123 -e "SELECT * FROM testdb.users;"

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# 主库插入
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kubectl exec -it mysql-0 -c mysql -- mysql -uroot -pWestos123 -e \
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  "INSERT INTO testdb.users (name) VALUES ('David'), ('Eve');"
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# 从库查询
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kubectl exec -it mysql-1 -c mysql -- mysql -uroot -pWestos123 -e \
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  "SELECT * FROM testdb.users;"

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kubectl run mysql-client --image=reg.westos.org/library/mysql:8.0 --rm -it --restart=Never -- bash

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# 写操作 → 主库
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mysql -h mysql-0.mysql -uroot -pWestos123 -e \
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  "INSERT INTO testdb.users (name) VALUES ('Frank');"
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# 读操作 → 负载均衡
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mysql -h mysql-read -uroot -pWestos123 -e "SELECT * FROM testdb.users;"
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# 多次查询观察负载均衡
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for i in {1..5}; do
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  mysql -h mysql-read -uroot -pWestos123 -e \
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    "SELECT @@hostname AS pod_name, COUNT(*) AS count FROM testdb.users;"
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done

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kubectl delete pod mysql-2
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watch kubectl get pods -l app=mysql

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kubectl scale statefulset mysql --replicas=4
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watch kubectl get pods -l app=mysql
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# 配置新从库 mysql-3
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kubectl exec -it mysql-3 -c mysql -- mysql -uroot -pWestos123 <<EOF
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CHANGE MASTER TO
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  MASTER_HOST='mysql-0.mysql',
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  MASTER_USER='repl',
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  MASTER_PASSWORD='Repl123!@#',
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  MASTER_LOG_FILE='mysql-bin.000003',
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  MASTER_LOG_POS=157;
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START SLAVE;
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EOF

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kubectl scale statefulset mysql --replicas=3
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# mysql-3 被删除

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kubectl delete statefulset mysql
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kubectl delete svc mysql mysql-read
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kubectl delete configmap mysql-config

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# 基本操作
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kubectl get statefulset
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kubectl describe sts <name>
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kubectl get pods -l app=mysql
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# 扩缩容
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kubectl scale sts mysql --replicas=5
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# 更新
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kubectl set image sts/mysql mysql=mysql:8.0.35
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kubectl rollout status sts/mysql
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# 回滚（手动）
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kubectl set image sts/mysql mysql=mysql:8.0.30
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# 删除（保留PVC）
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kubectl delete sts mysql
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kubectl get pvc
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kubectl delete pvc -l app=mysql  # 手动清理PVC