Permission denied while executing script entrypoint.sh from dockerfile in Kubernetes

Question

I have a multistage dockerfile which I'm deploying in k8s with script as ENTRYPOINT ["./entrypoint.sh"].

Deployment is done though helm and env is Azure. While creating the container it errors out "./entrypoint.sh": permission denied: unknown

Warning  Failed     14s (x3 over 31s)  kubelet            Error: failed to create containerd task: OCI runtime create failed: container_linux.go:380: starting container process caused:
exec: "./entrypoint.sh": permission denied: unknown
Warning  BackOff    1s (x4 over 30s)   kubelet            Back-off restarting failed container

I have given chmod +x to make it executable and chmod 755 for permission.

Dockerfile

##############
##   Build   #
##############
FROM repo.azurecr.io/maven:3.8.1-jdk-11 AS BUILD
ARG WORKDIR=/opt/work

COPY . $WORKDIR/
WORKDIR ${WORKDIR}

COPY ./settings.xml /root/.m2/settings.xml

RUN --mount=type=cache,target=/root/.m2/repository \
    mvn clean package -pl app -am

RUN rm /root/.m2/settings.xml
RUN rm ./settings.xml

#################
###   Runtime   #
#################
FROM repo.azurecr.io/openjdk:11-jre-slim as RUNTIME
RUN mkdir /opt/app \
    && useradd -ms /bin/bash javauser \
    && chown -R javauser:javauser /opt/app \
    && apt-get update \
    && apt-get install curl -y \
    && rm -rf /var/lib/apt/lists/*

COPY --from=BUILD /opt/work/app/target/*.jar /opt/app/service.jar
COPY --from=BUILD /opt/work/entrypoint.sh /opt/app/entrypoint.sh

RUN chmod +x /opt/app/entrypoint.sh
RUN chmod 755 /opt/app/entrypoint.sh

WORKDIR /opt/app
USER javauser

ENTRYPOINT ["./entrypoint.sh"]

PS: Please don't make it duplicate of https://stackoverflow.com/a/46353378/2226710 as i have added RUN chmod +x entrypoint.sh and it didn't solved the issue.

Answer 1

Use bash (or your preferred shell if not bash) in the entrypoint:

ENTRYPOINT [ "bash", "-c", "./entrypoint.sh" ]

This will run the entrypoint script even if you haven't set the script as executable (which I see you have)

You an also use this similarly with other scripts, for example with Python:

ENTRYPOINT [ "python", "./entrypoint.py" ]

You could also try calling the script with full executable path:

ENTRYPOINT [ "/opt/app/entrypoint.sh" ]