如何查看 docker-compose 健康检查日志？

Question

在我的docker-compose.yml 中，我有以下service healthcheck 部分。我想知道 MariaDB 是否真的准备好处理查询。一个名为 cmd 的 service 被配置为依赖于 condition: service_healthy。

  db:
    image: mariadb:10
    environment:
      MYSQL_RANDOM_ROOT_PASSWORD: 1
      MYSQL_USER: user
      MYSQL_PASSWORD: password
      MYSQL_DATABASE: database
    healthcheck:
      test: ["CMD", "mysql", "--user=user", "--password=password", "--execute='SELECT 1'", "--host=127.0.0.1", "--port=3306"]
      interval: 1s
      retries: 30

此健康检查不起作用，表明服务不健康。

如何检查test CMD 的输出？

Answer 1

你可以使用：

docker inspect --format "{{json .State.Health }}" <container name> | jq

输出：

{
    "Status": "unhealthy",
    "FailingStreak": 63,
    "Log": [
        {
            "Start": "2017-03-11T20:49:19.668895201+03:30",
            "End": "2017-03-11T20:49:19.735722044+03:30",
            "ExitCode": 1,
            "Output": "ERROR 1064 (42000) at line 1: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ''SELECT 1'' at line 1\n"
        }
    ]
}

然后寻找 输出 部分。

仅获取输出：

docker inspect --format "{{json .State.Health }}" mariadb_db_1 | jq '.Log[].Output'

对于 swarm 模式，请使用以下格式（感谢@shotgunner 指出）：

{{json.Spec.TaskTemplate.ContainerSpec.Healthcheck}}

请随意将jq 换成您用于 json 漂亮打印的任何工具。

Answer 2

docker-compose ps 将指示每个服务的状态，如果定义了 healthcheck，则包括其运行状况。这对基本概述很有帮助。

% docker-compose ps
                Name                                Command                       State                                       Ports                            
----------------------------------------------------------------------------------------------------------------------------------------------------------------
remix-theme-editor_analytics_1            /bin/sh -c /analytics/run. ...   Up                                                                                   
remix-theme-editor_base_1                 /bin/bash                        Exit 0                                                                               
remix-theme-editor_flower_1               /entrypoint --environment  ...   Exit 137                                                                             
remix-theme-editor_frontend_1             /bin/sh -c perl -p -i -e ' ...   Exit 137                                                                             
remix-theme-editor_js-app_1               npm run                          Exit 0                                                                               
remix-theme-editor_mq_1                   docker-entrypoint.sh rabbi ...   Up (healthy)            15671/tcp, 15672/tcp, 25672/tcp, 4369/tcp, 5671/tcp, 5672/tcp
remix-theme-editor_mysql-migration_1      /entrypoint_mysql-migratio ...   Exit 0                                                                               
remix-theme-editor_mysql_1                /bin/sh -c /entrypoint_wra ...   Up (health: starting)   127.0.0.2:3308->3306/tcp                                     
remix-theme-editor_page-renderer_1        npm run start:watch              Up                                                                                   
remix-theme-editor_python-app_1           /entrypoint                      Exit 2                                                                               
remix-theme-editor_redis_1                docker-entrypoint.sh /bin/ ...   Up (health: starting)   6379/tcp                                                     
remix-theme-editor_scheduler_1            /entrypoint --environment  ...   Exit 137                                                                             
remix-theme-editor_socket_1               /entrypoint --environment  ...   Exit 1                                                                               
remix-theme-editor_static-builder_1       npm run watch                    Up                                                                                   
remix-theme-editor_static-http_1          nginx -g daemon off;             Up                      127.0.0.2:6544->443/tcp, 80/tcp                              
remix-theme-editor_web_1                  /entrypoint --environment  ...   Exit 1                                                                               
remix-theme-editor_worker_1               /entrypoint --environment  ...   Exit 1                                                                               
remix-theme-editor_worker_screenshots_1   /entrypoint --environment  ...   Exit 1     

如果您想了解更多详细信息，请将docker inspect 与docker ps -q <service-name> 结合使用。

% docker inspect --format "{{json .State.Health }}" $(docker-compose ps -q mq) | jq
{
  "Status": "starting",
  "FailingStreak": 48,
  "Log": [
    {
      "Start": "2018-10-03T00:40:18.671527745-05:00",
      "End": "2018-10-03T00:40:18.71729051-05:00",
      "ExitCode": -1,
      "Output": "OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused \"exec: \\\"nc\\\": executable file not found in $PATH\": unknown"
    },
...

您始终可以自己调试运行状况检查，只需自己执行运行状况检查代码即可。例如：

% docker exec -it $(docker-compose ps -q socket) nc -w2 127.0.0.1 5672
(UNKNOWN) [127.0.0.1] 5672 (?) : Connection refused

你也可以在 shell 中做同样的事情：

% docker exec -it $(docker-compose ps -q socket) bash
root@b5da5207d344:~/src# nc -w2 127.0.0.1 5672
(UNKNOWN) [127.0.0.1] 5672 (?) : Connection refused
root@b5da5207d344:~/src# echo $?
1

最后，您可以在第一个终端窗口中简单地使用docker-compose up，在另一个终端窗口中使用docker-compose logs -f。这将显示来自 docker-compose-managed 容器的所有日志。

Answer 3

在群模式：

1. 首先在管理器中使用docker service ps service_name找到失败的任务id和对应的节点。

manager$ docker service ps service_name
ID                  NAME                 IMAGE            NODE                DESIRED STATE       CURRENT STATE               ERROR                              PORTS
liwww3qzg9dz        service_name.1       image_name:1.3   s-3                 Running             Running 27 seconds ago                                         
hcgxmwk2efj0         \_ service_name.1   image_name:1.3   s-3                 Shutdown            Failed about a minute ago   "task: non-zero exit (137): do…"  

在本例中，hcgxmwk2efj0 是任务 ID，s-3 是节点名称。

1. 然后在管理器中使用docker inspect --format "{{json .Status.ContainerStatus.ContainerID }}" task_id获取容器id。

manager$ docker inspect --format "{{json .Status.ContainerStatus.ContainerID }}" hcgxmwk2efj0
"412b09d5244047b31471248fd9a0807e5ea42406fb8f5b1701df2244933e30c8"

1. 然后 ssh 到 那个节点，并使用命令docker inspect --format "{{json .State.Health }}" container_id | jq 来获取健康检查的日志。 （此命令中不需要| jq）

s-3$ docker inspect --format "{{json .State.Health }}" 412b09d5244047b31471248fd9a0807e5ea42406fb8f5b1701df2244933e30c8 | jq
{
  "Status": "unhealthy",
  "FailingStreak": 3,
  "Log": [
    {
      "Start": "2021-09-07T06:10:05.233163051Z",
      "End": "2021-09-07T06:10:07.585487343Z",
      "ExitCode": 0,
      "Output": "... log 1 ..."
    },
    {
      "Start": "2021-09-07T06:10:37.644936244Z",
      "End": "2021-09-07T06:10:39.881196276Z",
      "ExitCode": 0,
      "Output": "... log 2 ..."
    },
    {
      "Start": "2021-09-07T06:11:10.16172012Z",
      "End": "2021-09-07T06:11:25.161912411Z",
      "ExitCode": -1,
      "Output": "Health check exceeded timeout (15s)"
    },
    {
      "Start": "2021-09-07T06:11:55.297395088Z",
      "End": "2021-09-07T06:12:10.302928565Z",
      "ExitCode": -1,
      "Output": "Health check exceeded timeout (15s)"
    },
    {
      "Start": "2021-09-07T06:12:40.371234778Z",
      "End": "2021-09-07T06:12:55.371393914Z",
      "ExitCode": -1,
      "Output": "Health check exceeded timeout (15s)"
    }
  ]
}