java - Keycloak docker容器在启动期间抛出 `java.net.UnknownHostException`

Question

我正在尝试在我的 docker 主机上设置一个 keycloak 容器。不幸的是，keycloak 容器无法连接到我的数据库容器并且总是抛出 java.net.UnknownHostException .

我的 docker-compose文件:

version: '2' 

services:
  keycloak:
      image: quay.io/keycloak/keycloak:latest
      container_name: keycloak
      restart: always
      networks:
        - webgateway
        - keycloak-net
      environment:
        - DB_VENDOR=MYSQL
        - DB_ADDR=keycloak-db
        - DB_DATABASE=keycloak
        - DB_USER=keycloak
        - DB_PASSWORD=password
        - KEYCLOAK_USER=admin
        - KEYCLOAK_PASSWORD=password
      depends_on:
        - keycloak-db

  keycloak-db:
      image: mysql:5.7
      container_name: keycloak-db
      restart: always
      volumes:
        - /var/keycloak/database:/var/lib/mysql
      networks:
        - keycloak-net
      environment:
        - MYSQL_ROOT_PASSWORD=root
        - MYSQL_DATABASE=keycloak
        - MYSQL_USER=keycloak
        - MYSQL_PASSWORD=password

networks:
  keycloak-net:
  webgateway:
    external:
      name: docker_webgateway

错误信息:

Caused by: java.net.UnknownHostException: keycloak-db: Name or service not known,
    at java.base/java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method),
    at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:929),
    at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1515),
    at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:848),
    at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1505),
    at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1364),
    at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298),
    at com.mysql.jdbc@8.0.19//com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:132),
    at com.mysql.jdbc@8.0.19//com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65),
    ... 64 more,
,
23:44:04,490 FATAL [org.keycloak.services] (ServerService Thread Pool -- 72) java.lang.RuntimeException: Failed to connect to database,

有人知道我做错了什么吗？

附言docker 主机在本地运行，所以不用担心我的弱密码。

Answer 1

标记 depends_on仅确保容器启动的顺序，但不确保容器是否准备好为请求提供服务，这就是这里发生的情况，SQL 容器已启动但尚未准备好接收请求，因为它需要时间。请按照以下命令和文件，我在其中添加了 health checks在 docker-compose 中也是如此，您需要将版本更改为 2.1 or higher .

创建外部 docker 网络

docker network create docker_webgateway

docker-compose.yaml

      container_name: keycloak
      restart: always
      networks:
        - webgateway
        - keycloak-net
      environment:
        - DB_VENDOR=MYSQL
        - DB_ADDR=keycloak-db
        - DB_DATABASE=keycloak
        - DB_USER=keycloak
        - DB_PASSWORD=password
        - KEYCLOAK_USER=admin
        - KEYCLOAK_PASSWORD=password
      depends_on:
        - keycloak-db
  keycloak-db:
      image: mysql:5.7
      container_name: keycloak-db
      restart: always
      healthcheck:
          test: ["CMD", "mysqladmin" ,"ping", "-h", "localhost"]
          timeout: 20s
          retries: 10
      volumes:
        - /var/keycloak/database:/var/lib/mysql
      networks:
        - keycloak-net
      environment:
        - MYSQL_ROOT_PASSWORD=root
        - MYSQL_DATABASE=keycloak
        - MYSQL_USER=keycloak
        - MYSQL_PASSWORD=password
networks:
  keycloak-net:
  webgateway:
    external:
      name: docker_webgateway

通过运行以下命令创建堆栈

docker-compose up