docker: executable file not found in $PATH

I have a docker image which installs grunt, but when I try to run it, I get an error:

Error response from daemon: Cannot start container foo_1: \
    exec: "grunt serve": executable file not found in $PATH

If I run bash in interactive mode, grunt is available.

What am I doing wrong?

Here is my Dockerfile:

# https://registry.hub.docker.com/u/dockerfile/nodejs/ (builds on ubuntu:14.04)
FROM dockerfile/nodejs

MAINTAINER My Name, [email protected]

ENV HOME /home/web
WORKDIR /home/web/site

RUN useradd web -d /home/web -s /bin/bash -m

RUN npm install -g grunt-cli
RUN npm install -g bower

RUN chown -R web:web /home/web
USER web

RUN git clone https://github.com/repo/site /home/web/site

RUN npm install
RUN bower install --config.interactive=false --allow-root

ENV NODE_ENV development

# Port 9000 for server
# Port 35729 for livereload
EXPOSE 9000 35729
CMD ["grunt"]

This was the first result on google when I pasted my error message, and it's because my arguments were out of order.

The container name has to be after all of the arguments.

Bad:

docker run <container_name> -v $(pwd):/src -it

Good:

docker run -v $(pwd):/src -it <container_name>

When you use the exec format for a command (e.g. CMD ["grunt"], a JSON array with double quotes) it will be executed without a shell. This means that most environment variables will not be present.

If you specify your command as a regular string (e.g. CMD grunt) then the string after CMD will be executed with /bin/sh -c.

More info on this is available in the CMD section of the Dockerfile reference.