spring boot application in docker terminates immediately

Question

Simple spring boot application trying to run in docker, however after docker run, exits immediately. Here is my Dockerfile

FROM anapsix/alpine-java:latest
VOLUME /tmp

RUN mkdir -p /opt/app
ADD app.jar /opt/app/app.jar
EXPOSE 8080

ENTRYPOINT ["java", "-Djava.security.egd=file:/dev/./urandom", "-jar", "/opt/app/app.jar"]

Docker run command

docker run -t -p 8080:8080 --name app -d app

In the container logs, the only output is the spring banner, and then the container terminates.

Am I missing something here.

Answer 1

I don't find any reason to use anapsix/alpine-java:latest

I recommand you to use the openjdk:8-jre-alpine, light weight and less in size comparitively.

create a war files instead of jar.

use the following

Dockerfile

FROM openjdk:8-jre-alpine

ENV SPRING_OUTPUT_ANSI_ENABLED=ALWAYS \
    SLEEP_TIME=0 \
    JAVA_OPTS=""

# add directly the war
ADD *.war /app.war

EXPOSE 8080
CMD echo "The application will start in ${SLEEP_TIME}s..." && \
    sleep ${SLEEP_TIME} && \
    java ${JAVA_OPTS} -Djava.security.egd=file:/dev/./urandom -jar /app.war

Answer 2

In my case the reason container was failing to start was that the app couldn't connect to one of the external services and the reason I only saw Spring logo was that I had logback configured to work only under specific Spring profile and I overrode spring active profile with an environment variable but forgot to define that variable, so it was trying to start with an empty active profile.