docker-compose.yaml中healthcheck配置项

作用：可用于检查容器是否正常运行，初始状态为starting，最后一次检查完成后显示sucess或者unhealthy，以下是命令执行返回的状态对应容器状态
0：状态是sucess，容器正常运行
1：状态是unhealthy，容器非正常运行
2：忽略执行命令的状态
包含healthcheck的docker-compose文件

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version: "3.7"   #docker compose的版本
services:
  tomcat:
    image: tomcat:v10.0.7
    ports: 
      - 18080:8080   # 暴露端口信息  - "宿主机端口:容器暴露端口"
    container_name: tomcat_test   #设置启动容器的名称，若不设置会默认生成一个
    links: 
      - mysql:db  #指定关联的容器
  mysql:
    image: mysql
    ports: 
      - 13306:3306  # 暴露端口信息  - "宿主机端口:容器暴露端口"
    container_name: mysql_test
    environment:    #设置环境变量
      - MYSQL_ROOT_PASSWORD=123456
    healthcheck:
      test: ["CMD-SHELL","mysql -u root -p123451"]  #密码是错误的，检查执行完后，状态会变成unhealthy
      interval: 10s
      timeout: 1s
      retries: 3   #重试次数
      start_period: 30s

初始状态时starting，检查完后由于检查不通过变为unhealthy

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root@test:/home/test# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                             PORTS                                NAMES
95388eefd716        tomcat:v10.0.7      "./bin/catalina.sh r…"   17 seconds ago      Up 12 seconds                      0.0.0.0:18080->8080/tcp              tomcat_test
468c29ab4ed3        mysql               "docker-entrypoint.s…"   20 seconds ago      Up 17 seconds (health: starting)   33060/tcp, 0.0.0.0:13306->3306/tcp   mysql_test
root@test:/home/test# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS                          PORTS                                NAMES
95388eefd716        tomcat:v10.0.7      "./bin/catalina.sh r…"   About a minute ago   Up About a minute               0.0.0.0:18080->8080/tcp              tomcat_test
468c29ab4ed3        mysql               "docker-entrypoint.s…"   About a minute ago   Up About a minute (unhealthy)   33060/tcp, 0.0.0.0:13306->3306/tcp   mysql_test

docker-compose中控制容器的启动顺序

  • 通过links或者depends-on等选项可以控制容器的启动顺序，但是不能判断到容器是否启动好，只是容器开始运行就会运行下一个容器
  • 检查关联容器是否启动好，启动好了后再启动对应的容器（使用wait-for-it.sh脚本文件）

实例

  • 修改制作tomcat镜像的dockerfile文件如下，并且编译成tomcatone镜像文件
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FROM daocloud.io/library/centos
MAINTAINER ZD

ADD jdk-8u291-linux-x64.tar.gz /usr/local
ENV JAVA_HOME /usr/local/jdk1.8.0_291

ADD apache-tomcat-10.0.7.tar.gz /usr/local

RUN rm -f /usr/local/*.tar.gz

COPY wait-for-it.sh /usr/local/apache-tomcat-10.0.7

WORKDIR /usr/local/apache-tomcat-10.0.7
EXPOSE 8080
CMD ["./wait-for-it.sh ","db:3306","--strict"," -- ./bin/catalina.sh run"]

cmd 中的命令是执行wait-for-it脚本，如果可以访问到对应容器db的3306端口，则启动tomcat

  • docker-compose.yaml文件内容修改为如下
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version: "3.7"   #docker compose的版本
services:
  tomcat:
    image: tomcatone
    volumes:
      - type: bind
        source: /home/test
        target: /home
    links: 
      - mysql:db  #指定关联的容器
    command: ./wait-for-it.sh db:3306 --timeout=60 --strict --  ./bin/catalina.sh run  #指定的容器db,3306端口可以访问，设置60s超时，--strict表示访问不到则不执行后面的命令（启动tomcat)
    ports:
      - 18080:8080   # 暴露端口信息  - "宿主机端口:容器暴露端口"
    container_name: tomcat_test   #设置启动容器的名称，若不设置会默认生成一个
    
  mysql:
    image: mysql
    ports: 
      - 13306:3306  # 暴露端口信息  - "宿主机端口:容器暴露端口"
    container_name: mysql_test
    environment:    #设置环境变量
      - MYSQL_ROOT_PASSWORD=123456
  • 通过docker-compose up 启动后，可以看到tomcat和mysql均启动起来了
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root@test:/home/test# docker ps --no-trunc
CONTAINER ID                                                       IMAGE               COMMAND                                                                     CREATED             STATUS              PORTS                                NAMES
c04a1f7dbb7440894ad4ea3ac827049f4d6d0d432eac12fd3a3ea204bf11e1a8   tomcatone           "./wait-for-it.sh db:3306 --strict -- ./bin/catalina.sh run - 18080:8080"   26 seconds ago      Up 21 seconds       8080/tcp                             tomcat_test
3fb9d523bf9f6697d152a627e831504c82087d6dfa1abd0b7551637513c0fffe   mysql               "docker-entrypoint.sh mysqld"                                               6 minutes ago       Up 26 seconds       33060/tcp, 0.0.0.0:13306->3306/tcp   mysql_test
  • 修改docker-compose.yaml文件command命令中的端口改为13306，执行docker-compose up后，由于访问不到对应的13306端口，tomcat没有启动“tomcat_test | wait-for-it.sh: strict mode, refusing to execute subprocess”
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root@test:/home/test# docker-compose -f docker-compose.yaml up
Starting mysql_test ... done
Recreating tomcat_test ... done
Attaching to mysql_test, tomcat_test
……
mysql_test | 2021-07-06T16:15:19.030658Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.25'  socket: '/var/run/mysqld/mysqld.sock'  port: 3306  MySQL Community Server - GPL.
tomcat_test | wait-for-it.sh: timeout occurred after waiting 60 seconds for db:13306
tomcat_test | wait-for-it.sh: strict mode, refusing to execute subprocess
tomcat_test exited with code 124