码头-撰写:健康检查脚本(卷曲)，但服务始终(健康:开始)

Question

我有下面的docker-compose

version: '2.1'
services:
    myprogram-app:
        image: myprogram
        mem_limit: 1024m
        environment:
            - SPRING_PROFILES_ACTIVE=prod,swagger
            - EUREKA_CLIENT_SERVICE_URL_DEFAULTZONE=http://admin:$${jhipster.registry.password}@jhipster-registry:8761/eureka
            - SPRING_CLOUD_CONFIG_URI=http://admin:$${jhipster.registry.password}@jhipster-registry:8761/config
            - SPRING_DATASOURCE_URL=jdbc:postgresql://myprogram-postgresql:5432/myprogram
            - JHIPSTER_SLEEP=30
            - SPRING_DATA_ELASTICSEARCH_CLUSTER_NODES=myprogram-elasticsearch:9300
            - JHIPSTER_REGISTRY_PASSWORD=password
            - EMAIL_USERNAME
            - EMAIL_PASSWORD
        ports:
            - 8080:8080
        networks:
          - backend
        depends_on:
          jhipster-registry:
            condition: service_healthy
          myprogram-postgresql:
            condition: service_started
          myprogram-elasticsearch:
            condition: service_started
        restart: on-failure
    myprogram-postgresql:
        image: postgres:9.6.5
        mem_limit: 256m
        environment:
            - POSTGRES_USER=myprogram
            - POSTGRES_PASSWORD=myprogram
        networks:
          - backend
    myprogram-elasticsearch:
        image: elasticsearch:2.4.6
        mem_limit: 512m
        networks:
          - backend
    jhipster-registry:
        extends:
            file: jhipster-registry.yml
            service: jhipster-registry
        mem_limit: 512m
        ports:
            - 8761:8761
        networks:
          - backend
        healthcheck:
          test: ["CMD", "./isUp", "jhipster-registry:8761"]
          interval: 30s
          retries: 20
networks:
  backend:
    driver: "bridge"

并在同一个目录(项目根目录)中使用以下脚本：

echo Testing if $1 is UP

http_code=$(curl -LI $1 -o /dev/null -w '%{http_code}\n' -s)

if [ ${http_code} -eq 200 ]; then
    echo The service is UP and Running
    exit 0
else
    echo The service is DOWN
    exit 1
fi

我面临的问题是，即使在jhipster注册服务已经启动之后，它仍在继续向我展示

CONTAINER ID        IMAGE                               COMMAND                  CREATED             STATUS                            PORTS                    NAMES
8b16c572e0f2        jhipster/jhipster-registry:v3.2.4   "/bin/sh -c 'java   …"   6 minutes ago       Up 6 minutes (health: starting)   0.0.0.0:8761->8761/tcp   compose_jhipster-registry_1
ed86d15ea485        elasticsearch:2.4.6                 "/docker-entrypoint.…"   6 minutes ago       Up 6 minutes                      9200/tcp, 9300/tcp       compose_myprogram-elasticsearch_1
f268fa1a11f1        postgres:9.6.5                      "docker-entrypoint.s…"   6 minutes ago       Up 6 minutes                      5432/tcp                 compose_myprogram-postgresql_1

即使服务已经启动并运行(我也登录了它)。

通过在我的机器上执行isUp命令，我还做了一个测试，它的工作方式与预期的一样：

izio@1z10:~/Desktop/WorkSpace/myprogram/compose$ ./isUp.sh localhost:8761
Testing if localhost:8761 is UP
The service is UP and Running
izio@1z10:~/Desktop/WorkSpace/myprogram/compose$
izio@1z10:~/Desktop/WorkSpace/myprogram/compose$ echo $?
0
izio@1z10:~/Desktop/WorkSpace/myprogram/compose$ 

最后，注册表服务在终止重试后变得不健康。

izio@1z10:~/Desktop/WorkSpace/myprogram/compose$  docker ps
CONTAINER ID        IMAGE                               COMMAND                  CREATED             STATUS                      PORTS                    NAMES
8b16c572e0f2        jhipster/jhipster-registry:v3.2.4   "/bin/sh -c 'java   …"   10 minutes ago      Up 10 minutes (unhealthy)   0.0.0.0:8761->8761/tcp   compose_jhipster-registry_1
ed86d15ea485        elasticsearch:2.4.6                 "/docker-entrypoint.…"   10 minutes ago      Up 10 minutes               9200/tcp, 9300/tcp       compose_myprogram-elasticsearch_1
f268fa1a11f1        postgres:9.6.5                      "docker-entrypoint.s…"   10 minutes ago      Up 10 minutes               5432/tcp                 compose_myprogram-postgresql_1

我搞不懂这次健康检查有什么问题。怎么修呢？

相同的东西，使用127.0.0.1:8761

test: ["CMD", "./isUp", "127.0.0.1:8761"]

或本地主机:8761

test: ["CMD", "./isUp", "localhost:8761"]

Answer 1

这个docker-compose配置有几个问题：

1. jhipster-registry基于openjdk:8，没有安装curl。
2. isUp脚本没有复制到容器的文件系统，所以它甚至没有被执行。

为了解决这个问题，我找到的解决方案利用了基本容器功能。由于它是openjdk:8，所以可以通过在jar中导出的Java程序测试服务可用性。所以我就这么做了。

在目录的根目录中，放置一个与以下类对应的Ping.jar：

package ping;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.Socket;

public class Main {
    public static void main(String[] args) {
        if (args.length != 2) {
            System.exit(-1);
        }

        String host = args[0];
        int port = 0;

        try {
            port = Integer.parseInt(args[1]);
        } catch (NumberFormatException e) {
            e.printStackTrace();
            System.exit(-2);
        }

        try (Socket socket = new Socket()) {
            socket.connect(new InetSocketAddress(host, port), 10 * 1000);
            System.exit(0);
        } catch (IOException e) {
            System.exit(1);
        }
    }
}

然后，通过jhipster-registry字段使它在容器中可用：

    jhipster-registry:
    extends:
        file: jhipster-registry.yml
        service: jhipster-registry
    mem_limit: 512m
    ports:
        - 8761:8761
    networks:
      - backend
    volumes:
      - ${PWD}/Ping.jar:/Ping.jar
    healthcheck:
      test: ["CMD", "java", "-jar", "/Ping.jar", "localhost", "8761"]
      interval: 30s
      retries: 20

这样，一旦服务准备好接受连接，它将最终显示为健康：

CONTAINER ID        IMAGE                               COMMAND                   CREATED             STATUS                   PORTS                              NAMES
b3dd86605278        jhipster/jhipster-registry:v3.2.4   "/bin/sh -c 'java   …"    3 minutes ago       Up 3 minutes (healthy)   0.0.0.0:8761->8761/tcp             compose_jhipster-registry_1