CODEWITHSUNDEEP
javadockerspring-bootkitematic
J.Olufsen
J.Olufsen

Reputation: 13915

Spring boot inside docker container throws java.net.ConnectException: Connection refused (Connection refused)

The client application sends json data to server on localhost:8080 that is packaged and run as docker image. Servers work fine when manually sending json using Postman chrome app. The problem is with dockerized client that throws java.net.ConnectException: Connection refused (Connection refused) when trying to write json to HttpURLConnection using OutputStreamWriter. How to make it work?

Dockerfile:

FROM openjdk:8-jdk-alpine
VOLUME /tmp
ARG JAR_FILE=target/client-0.0.1-SNAPSHOT.jar
COPY ${JAR_FILE} app.jar
EXPOSE 8088
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

Upvotes: 1

Views: 4108

Answers (2)

codica
codica

Reputation: 76

Both clients should run on the same network. So create a network bridge MY_BRIDGE:

docker network create MY_BRIDGE

Attach both container to the bridge, when running them. Give the server container a name MY_SERVER:

docker run --network MY_BRIDGE --name MY_SERVER MY_SERVER_IMAGE

docker run --network MY_BRIDGE MY_CLIENT_IMAGE

Your application code has to be changed from localhost:8080 to MY_SERVER:8080 prior to running the client container.

See Docker Bridge Documentation

Upvotes: 2

teppic
teppic

Reputation: 7286

In docker each container has it's own virtualised network stack - localhost is the address of the container's loopback interface, not the address of the host's loopback interface.

You'll have to configure your client to connect to the server using its hostname. Simply the container name of the server if you're using docker-compose, or the hostname of the docker host machine if you're running the containers up manually.

Reference: Networking with standalone containers.

Upvotes: 0

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