composer文件中的Docker健康检查

Question

问题是，我的数据库容器需要比启动我的主应用程序的容器更多的时间来启动和初始化数据库。结果：主容器无法正确启动，导致缺少数据库连接。我编写了一个healthcheck.sh脚本来检查数据库容器的连通性，因此主容器在连通性可用后开始引导。但我不知道如何在Dockerfile和我的docker-compose.yml中正确地集成它

healthcheck.sh类似于：

#!bin/bash
COUNTER=0
while [[ $COUNTER = 0 ]]; do
  mysql --host=HOST --user="user" --password="password" --database="databasename" --execute="SELECT 1";
  if [[ $? == 1 ]]; then
    sleep 1
    echo "Let's sleep again"
  else
    COUNTER=1
    echo "OK, lets go!"
  fi
done

mysql容器DockerFile：

FROM repository/mysql-5.6:latest
MAINTAINER Me

... some copies, chmod and so on 

VOLUME ["/..."]

EXPOSE 3306

CMD [".../run.sh"]

HEALTHCHECK --interval=1s --timeout=3s CMD ./healthcheck.sh

version: '2'
services:
  db:
    image: db image
    restart: always
    dns:
      - 10.
    ports:
      - "${MYSQL_EXTERNAL_PORT}:${MYSQL_INTERNAL_PORT}"
    environment:
      TZ: Europe/Berlin
  data:
    image: data image

  main application:
    image: application image
    restart: always
    dns:
      - 10.
    ports:
      - "${..._EXTERNAL_PORT}:${..._INTERNAL_PORT}"
    environment:
      TZ: Europe/Berlin
    volumes:
      - ${HOST_BACKUP_DIR}:/...
    volumes_from:
      - data
      - db

Thx马库斯

Answer 1

我相信这类似于Docker Compose在启动Y之前等待容器X

您的db_image需要支持curl。
为此，创建您自己的db_image如下：

FROM base_image:latest
RUN apt-get update
RUN apt-get install -y curl 
EXPOSE 3306

那么您应该只需要一个docker-compose.yml,它如下所示：

version: '2'
services:
  db:
    image: db_image
    restart: always
    dns:
      - 10.
    ports:
      - "${MYSQL_EXTERNAL_PORT}:${MYSQL_INTERNAL_PORT}"
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:${MYSQL_INTERNAL_PORT}"]
      interval: 30s
      timeout: 10s
      retries: 5
    environment:
      TZ: Europe/Berlin
  main_application:
    image: application_image
    restart: always
    depends_on:
      db:
        condition: service_healthy
    links: 
        - db
    dns:
      - 10.
    ports:
      - "${..._EXTERNAL_PORT}:${..._INTERNAL_PORT}"
    environment:
      TZ: Europe/Berlin
    volumes:
      - ${HOST_BACKUP_DIR}:/...
    volumes_from:
      - data
      - db