Pod 深度解析#

# Pod 创建时，Pause 容器首先启动
# Pause 容器的 PID 1 进程持续运行，保持命名空间活跃

apiVersion: v1
kind: Pod
metadata:
  name: my-app-pod
spec:
  containers:
  # 用户容器依赖于 Pause 容器持有的命名空间
  - name: nginx
    image: nginx:1.25
    ports:
    - containerPort: 80

apiVersion: v1
kind: Pod
metadata:
  name: restart-policy-demo
spec:
  # RestartPolicy: Always | OnFailure | Never
  restartPolicy: OnFailure
  containers:
  - name: my-container
    image: myapp:1.0

apiVersion: v1
kind: Pod
metadata:
  name: myapp-with-init
spec:
  initContainers:
  # 等待 MySQL 就绪
  - name: wait-for-mysql
    image: mysql:8.0
    command: ['sh', '-c', 'until mysql -h mysql-service -u root -p$MYSQL_ROOT_PASSWORD -e "SELECT 1"; do echo "Waiting for MySQL..."; sleep 5; done']

  # 预热缓存
  - name: warm-cache
    image: redis:7.0
    command: ['redis-cli', '-h', 'redis-service', 'CONFIG', 'SET', 'save', '""']

  containers:
  - name: myapp
    image: myapp:1.0

apiVersion: v1
kind: Pod
metadata:
  name: myapp-with-sidecar
spec:
  containers:
  # 主容器
  - name: myapp
    image: myapp:1.0
    ports:
    - containerPort: 8080

  # Sidecar：日志收集器
  - name: log-collector
    image: fluent/fluentd:v1.16
    volumeMounts:
    - name: logs
      mountPath: /var/log/myapp
    - name: fluentd-config
      mountPath: /etc/fluent/config.d

  # Sidecar：Envoy 代理（服务网格）
  - name: envoy
    image: envoyproxy/envoy:v1.28
    ports:
    - containerPort: 15001
      name: envoy-http
    - containerPort: 15000
      name: envoy-admin

apiVersion: v1
kind: Pod
metadata:
  name: scheduled-pod
spec:
  # 节点亲和性：prefer 表示软偏好
  affinity:
    nodeAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 100
        preference:
          matchExpressions:
          - key: topology.kubernetes.io/zone
            operator: In
            values:
            - zone-a

    # Pod 亲和性：不要和某些 Pod 调度到同一节点
    podAntiAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchLabels:
            app: redis
        topologyKey: kubernetes.io/hostname

  # 容忍：容忍节点的 Taint
  tolerations:
  - key: "node.kubernetes.io/not-ready"
    operator: "Exists"
    effect: "NoSchedule"
    tolerationSeconds: 300

  # 节点选择器
  nodeSelector:
    disktype: ssd

  # 调度到指定节点（绕过调度器）
  nodeName: node-1

  # 优先级调度
  priorityClassName: high-priority

# 错误示例：Liveness Probe 检查数据库连接
livenessProbe:
  httpGet:
    path: /healthz
    port: 8080