CMD vs ENTRYPOINT on Dockerfile

If you use shell mode for ENTRYPOINT, CMD is ignored. When using exec mode for ENTRYPOINT, CMD arguments are appended. When using exec mode for an ENTRYPOINT instruction, you must also use exec mode for the CMD instruction. Failure to do so will cause Docker to attempt to append sh -c to the arguments already appended, which may lead to unpredictable results. ENTRYPOINT and CMD instructions can be overridden using command-line flags.