Docker：Springboot容器无法连接到PostgreSql容器连接错误 [英] Docker: Springboot container can not connect to PostgreSql Container Connection error

问题描述

我正在构建我的第一个Springboot 2.0应用程序。我试图将我的Springboot应用程序放入一个docker容器中，并将PostgresDB放入另一个容器。

I am building my first Springboot 2.0 application. I am trying to put my Springboot application into one docker container and my PostgresDB into another container.

我的Dockerfile

    FROM frolvlad/alpine-oraclejdk8:slim
    VOLUME /tmp
    ADD springboot-api-demo-0.1*.jar app.jar
    RUN sh -c 'touch /app.jar'
    EXPOSE 9443
    ENTRYPOINT [ "sh", "-c", "java $JAVA_OPTS -Djava.security.egd=file:/dev/urandom -jar /app.jar" ]

我的docker-compose.yml文件

version: "2.1"

services:
  springboot-api-demo:
    image: "fw/springboot-api-demo"
    mem_limit: 1024m
    ports:
      - "8080:8080"
    environment:
      - SPRING_PROFILES_ACTIVE=local
      - AWS_REGION=local
      - ENVIRONMENT=local
      - AUTH_ENABLED=false
  postgres:
    container_name: pgdb
    image: postgres:9.6-alpine
    environment:
    - 'POSTGRES_ROOT_PASSWORD=postgres'
    - 'POSTGRES_USER=postgres'
    - 'POSTGRES_PASSWORD=postgres'
    ports:
    - "54321:5432"

I我在 application.properties

spring.datasource.url= jdbc:postgresql://localhost:54321/java_learning
spring.datasource.username=postgres
spring.datasource.password=postgres

我可以测试两个图像是否都向上。同样从docker日志和docker事件中，我看到postgres Container运行良好，即使我可以访问它，也创建了一个数据库。
但是springboot容器启动了，但是我死了，因为它无法连接到postgress并在下面抛出错误。

I can test that Both of the Images are up. Also from docker log and docker events, I see that postgres Container is running fine, even I can access it and also created a DB too. But springboot container started but i died because it could not connect to postgress and throwing error below.

无法从数据库获取连接：连接尝试
失败

Unable to obtain connection from database: The connection attempt failed

请注意，我的主机已经在端口5432上安装了Postgres，这就是为什么我在postgres容器上进行了端口映射ofr 54321：5432的原因。这是证明:)-

Note that my host machine already has Postgres on port 5432 thats why I did a port mapping ofr 54321:5432 on my postgres container. Here is Proof :) -

➜  springboot-api-demo git:(master) ✗ lsof -i:54321              
COMMAND     PID             USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
com.docke 44345 shailendra.singh   18u  IPv4 0xf62897fbdd69e31d      0t0  TCP *:54321 (LISTEN)
com.docke 44345 shailendra.singh   21u  IPv6 0xf62897fbdd119975      0t0  TCP localhost:54321 (LISTEN)

➜  springboot-api-demo git:(master) ✗ lsof -i:5432 
COMMAND  PID             USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
postgres 715 shailendra.singh    5u  IPv6 0xf62897fbb43e03b5      0t0  TCP localhost:postgresql (LISTEN)
postgres 715 shailendra.singh    6u  IPv4 0xf62897fbbaeea9bd      0t0  TCP localhost:postgresql (LISTEN)

我不确定是什么问题。但是我的Springboot应用程序无法连接我的postgres容器，该容器运行良好且具有适当的凭据。

I am not sure what is the problem. But my Springboot application is not able to connect my postgres container which is running fine with proper creadentials.

推荐答案

尝试使用：

spring.datasource.url= jdbc:postgresql://pgdb:5432/java_learning

postgres数据库未在localhost上运行，而是在具有其他IP（但未知）的另一个容器中运行。

The postgres database is not running on localhost, it's running in the other container which has an other IP (yet unknown).

感谢docker-compose会自动在docker-compose.yml中的所有容器之间创建一个共享的网络（除非明确表示不这样做），因此您可以神奇地使用服务名作为主机名。

Thanksfully, docker-compose automatically create a network shared among all the containers in the docker-compose.yml (unless explicitly said to do not), as a result you can magically use the service name as an hostname.

此外，您的端口中有一个错字，Postgres使用 5432 默认，而不是 54321

Also, you have a typo in the port, Postgres use 5432 by default, not 54321

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