两个Docker容器之间的通讯出现问题 [英] Trouble communicating between two docker containers

问题描述

我是docker的新手，正在尝试将运行在 boot-example docker容器中的spring boot应用程序连接到运行在 mymysql 中的mysql服务器上端口6603上的docker容器，两者都在同一台物理计算机上运行. 事实是:如果我将spring-boot应用程序连接到 mymysql Docker容器以便与数据库进行通信，则我没有任何错误，并且一切正常.

当我将自己的spring boot应用程序移到我的 boot-example 容器中并尝试(通过Hibernate)与我的 mymysql 容器通信时，然后我得到这个错误:

2018-02-05 09:58:38.912 ERROR 1 --- [           main] o.a.tomcat.jdbc.pool.ConnectionPool      : Unable to create initial connections of pool.

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111]

我的spring boot application.properties是:

server.port=8083
spring.jpa.hibernate.ddl-auto=create-drop
spring.datasource.url=jdbc:mysql://localhost:6603/mydockerdb
spring.datasource.username=root
spring.datasource.password=mypassword

在我的春季启动应用在端口8082上的Docker容器中运行之前，它工作正常(在正确构建Docker映像之后):

docker run -it -p 8082:8083 boot-example 

解决方案

按照上面的建议，Docker-compose是一种方法，但是如果您不想使用组合/组合模式.

1. 使用docker network create myNet
轻松创建自己的网络
2. 部署容器以侦听已创建的网络--network myNet
3. 将您的spring.datasource.url更改为jdbc:mysql://mymysql:6603/mydockerdb

通过使用docker demon的DNS解析，容器可以彼此发现并因此可以通信. [默认网桥不支持DNS.使用网桥的用户定义网络.]

有关更多信息: https://docs.docker.com/engine/userguide/联网/

I’m new to docker and I’m trying to connect my spring boot app running into my boot-example docker container to a mysql server running into my mymysql docker container on port 6603, both running on the same phisical machine. The fact is: if I connect my spring-boot app to my mymysql docker container in order to communicate with the database, I get no errors and everything works fine.

When I move my spring boot application into my boot-example container and try to communicate (through Hibernate) to my mymysql container, then I get this error:

2018-02-05 09:58:38.912 ERROR 1 --- [           main] o.a.tomcat.jdbc.pool.ConnectionPool      : Unable to create initial connections of pool.

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_111]

My spring boot application.properties are:

server.port=8083
spring.jpa.hibernate.ddl-auto=create-drop
spring.datasource.url=jdbc:mysql://localhost:6603/mydockerdb
spring.datasource.username=root
spring.datasource.password=mypassword

It works fine until my spring boot app runs in a docker container on port 8082, (after the docker image is correctly built):

docker run -it -p 8082:8083 boot-example 

解决方案

As per above suggestion, Docker-compose is a way but if you don't want to go with compose/swarm mode.

1. Simply create your own network using docker network create myNet
2. Deploy your containers listening on a created network --network myNet
3. Change your spring.datasource.url to jdbc:mysql://mymysql:6603/mydockerdb

By using DNS resolution of docker demon, containers can discover each other and hence can communicate. [DNS is not supported by default bridge. A user-defined network using bridge does.]

For more information: https://docs.docker.com/engine/userguide/networking/

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