docker-compose：CMD 变量替换

Question

I am building a new Docker image but my CMD command with variable substitution does not work.

I know that I need to turn on the interpreter with -c like this:

CMD ["sh", "-c", "hello.sh $VARIABLE"]

But my use case is different because I need to execute something with sudo :

CMD ["sudo", "-u", "oracle", "$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/startWebLogic.sh"]

This works properly:

CMD $ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/startWebLogic.sh

Ho to make it works with sudo ?

Answer 1

是一样的，只是前面加了sudo ：

CMD ["sudo", "-u", "oracle", "sh", "-c", "hello.sh $VARIABLE"]

Answer 2

Try:

CMD ["sudo", "-E", "-u", "oracle", "sh", "-c", "\"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/startWebLogic.sh\""]

By default sudo starts a new environment. To have sudo preserve the environment you need to pass -E option.

Then to have $variables expand, you need to run it under a shell, so they can expand. But then to protect against word splitting shell expansion I think you have to quote the variables expansions, thus the additional \\" .

Maybe this would be easier and also work:

CMD ["sh", "-c", "sudo -u oracle \"$ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/startWebLogic.sh\""]

But in docker I think it's preferable to just set the user:

USER oracle
CMD $ORACLE_HOME/user_projects/domains/$DOMAIN_NAME/startWebLogic.sh