Docker Image Entry Point Script Not Found

Question

I have a Dockerfile like:

FROM frolvlad/alpine-oraclejdk8:slim
ADD build/libs/zuul*.jar /app.jar
ADD src/main/script/startup.sh /startup.sh
EXPOSE 8080 8999
ENTRYPOINT ["/startup.sh"]

startup.sh looks like:

#!/bin/sh
set -e

if [ $# -eq 0 ]
then
    echo "Environment value required"
    exit 1
fi

java -jar -Xms400m -Xmx400m -Dlog4j.configurationFile=log4j2-qa2.xml -Djava.security.egd=file:/dev/./urandom -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=8999 -Dcom.sun.management.jmxremote.local.only=false -Dcom.sun.management.jmxremote.rmi.port=8999 app.jar

But when I run it with docker run, I got docker: Error response from daemon: Container command '/startup.sh' not found or does not exist... The shell script has execute permission.

I used the same way to run my other apps and they're all working fine. I wrote the files in Mac and tried to run the container in a Linux machine.

Answer 1

It turns out to be the ^M DOS-style line ending character that caused the issue. But since I'm editing in Mac and I checked several times with vim, I'm pretty sure the starting script in my local machine doesn't have that char. But when opened with vim inside the container, I can see ^M everywhere. So somehow that char gets added to startup.sh when copied into the image, which is weird. That prevents the script from being invoked.

The solution is to add dos2unix filename before the ENTRYPOINT in Dockerfile. But make sure that your base image has that utility.