sbt-native-packager: Scala App on Alpine Docker Image fails with permission denied

run the sbt task docker:stage. Then analyze the output created in the folder target/docker/stage.

In my case the Dockerfile contains the following:

FROM openjdk:11-jre-slim as stage0WORKDIR /opt/dockerCOPY opt /optUSER rootRUN ["chmod", "-R", "u=rX,g=rX", "/opt/docker"]RUN ["chmod", "u+x,g+x", "/opt/docker/bin/sample"]FROM openjdk:11-jre-slimLABEL MAINTAINER="your name"USER rootRUN id -u demiourgos728 2> /dev/null || useradd --system --create-home --uid 1001 --gid 0 demiourgos728WORKDIR /opt/dockerCOPY --from=stage0 --chown=demiourgos728:root /opt/docker /opt/dockerEXPOSE 9000USER 1001ENTRYPOINT ["/opt/docker/bin/sample"]CMD []

I had the problem that the PID file could not be created. I think in your case it will be something similar. There is no magic involved here.

The folder /opt/docker does not have write permissions by default. As the documentation states, you could add the following line to your build.sbt:

dockerAdditionalPermissions += (DockerChmodType.UserGroupWriteExecute, "/opt/docker")

which will add an additional line:

RUN ["chmod", "u=rwX,g=rwX", "/opt/docker"]

to the stage0 container. See nativer packager docs.

Alternatively, disable the PID file by passing a parameter to the JVM:

bashScriptExtraDefines ++= Seq( "addJava '-Dpidfile.path=/dev/null'" )

to your build.sbt. Play Production configuration Docs