Watchtower自动升级Docker容器并发送邮件提醒教程

# 监视容器更新最简范例：

version: "3"
services:
  watchtower:
    image: containrrr/watchtower
    container_name: watchtower
    restart: unless-stopped
    environment: 
        - TZ=Asia/Shanghai
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    command: nginx portainer-ce next-terminal guacd --cleanup --schedule "0 0 4 * * *"

# 邮件提醒参数：

注：每次启动带邮件参数的Watchtower容器，会立即发送一封基本信息邮件到设置邮箱，若未收到请排错：

        - WATCHTOWER_NOTIFICATION_TITLE_TAG=vpsname
        - WATCHTOWER_NOTIFICATIONS=email
        - WATCHTOWER_NOTIFICATION_EMAIL_FROM=fromaddress@gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_TO=toaddress@gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER=smtp.gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=587
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=fromaddress@gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=app_password
        - WATCHTOWER_NOTIFICATION_EMAIL_DELAY=2

# 监视容器更新并发送邮件提醒范例：

version: "3"
services:
  watchtower:
    image: containrrr/watchtower
    container_name: watchtower
    restart: unless-stopped
    environment: 
#        - WATCHTOWER_MONITOR_ONLY=true    #使用此参数则仅提醒有更新而不自动升级容器
        - TZ=Asia/Shanghai
        - WATCHTOWER_NOTIFICATION_TITLE_TAG=vpsname      #邮件标题前缀添加自定义内容
        - WATCHTOWER_NOTIFICATIONS=email
        - WATCHTOWER_NOTIFICATION_EMAIL_FROM=fromaddress@gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_TO=toaddress@gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER=smtp.gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PORT=587
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_USER=fromaddress@gmail.com
        - WATCHTOWER_NOTIFICATION_EMAIL_SERVER_PASSWORD=app_password
        - WATCHTOWER_NOTIFICATION_EMAIL_DELAY=2
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    command: hello-world freenom nginx portainer-ce next-terminal guacd watchtower --cleanup --schedule "0 33 3 * * *"
#--schedule "0 0 4 * * *" 秒分时日月周、每天早上4点检测
#--schedule "0 */1 * * * *" 每分钟检查一次

前台运行模式，方便查看容器实时日志：docker-compose -f watchtower.yml up 。

检测日志无误后，切换到后台运行模式：docker-compose -f watchtower.yml up -d 。

后台运行时查看日志的方法：docker logs --since 30m watchtower （输出30分内的容器日志）

# 测试Watchtower是否正确升级旧容器的范例：

#拉取一个旧镜像
docker pull dockercloud/hello-world:staging
#将旧镜像标记为latest镜像
docker tag dockercloud/hello-world:staging dockercloud/hello-world:latest
#运行容器
docker run -d --name hello-world dockercloud/hello-world:latest
#然后等待Watchtower到达计划任务执行时间，会检测到hello-world此时所用的latest标签镜像与服务器上的latest镜像不一致，容器日志中显示信息变化，并收到设置的邮件提醒。