从 docker 容器连接到主机 mysql db 时连接被拒绝

Question

I am trying to connect to mysql server running on host machine (localhost) from a spring app running inside a docker container

this is my Dockerfile

FROM openjdk:11
ADD build/libs/demo-0.0.1-SNAPSHOT.jar demo.jar
EXPOSE 8000
RUN mkdir -p tmp/scripts
RUN mkdir -p tmp/logs
ENTRYPOINT ["java","-jar","/demo.jar"]

I am using Docker desktop for mac v2.3.0.3 with engine version 19.03.8

This is may hikariCP datasource connection properties

spring.datasource.jdbcUrl=jdbc:mysql://**host.docker.internal:3306**/freshid
spring.datasource.username=sa
spring.datasource.password=test

When I build docker build -f Dockerfile -t demo. and run the image as docker run -p 8000:8000 demo

I get the following error on application start up

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
    at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
    at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
    at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:199)
    at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138)
    at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:354)
    at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:202)
    at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:473)
    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:554)
    ... 64 common frames omitted
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: 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 java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
    at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
    at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:91)
    at com.mysql.cj.NativeSession.connect(NativeSession.java:152)
    at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)
    at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
    ... 72 common frames omitted
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:403)
    at java.base/java.net.Socket.connect(Socket.java:609)
    at com.mysql.cj.protocol.StandardSocketFactory.connect(StandardSocketFactory.java:155)
    at com.mysql.cj.protocol.a.NativeSocketConnection.connect(NativeSocketConnection.java:65)
    ... 75 common frames omitted

Answer 1

I uninstalled and re-installed the docker (19.03.8) and it worked. The final connection string is jdbc:mysql://host.docker.internal:3306/db . This does not conclude any technical correctness but it worked. Thanks.

Answer 2

I would suggest a simple solution.

Step 1: Turboshooting: Try to run springboot appliction in you machine, outside container. If works fine, then there is no issue your application. (Make sure while testing locally you change your DB connection string from host.docker.internal to localhost )

Step 2: Please expose your DB port, that is 3306 by default in case of mysql when you run Docker Container with imperitive command

docker run -p 8000:8000 -p 3306:3306 demo

This should resolve your issue