Why do I have to use bash -l -c inside my container?
I’ve created a docker container using the following Dockerfile (truncated):
FROM ubuntu:12.04 # curl enables downloading of other things RUN apt-get install curl -y # download and install rvm... RUN \curl -L https://get.rvm.io | bash -s stable # ... so that we can install ruby RUN /bin/bash -l -c "rvm requirements"
And so on.
This all works, but the problem I have is how / where the packages are installed.
If I just run rvm using
docker run [...] rvm I get “Unable to locate rvm”, but if I run
docker run [...] /bin/bash -l -c "rvm" it works. (I found the “-l -c” options online, but have no idea what they do, and can’t find a satisfactory explanation of what I’m doing!)
This isn’t a docker question – it’s a bash / *nix question – I presume there’s something about how / where things are installed, possibly related to running the install under root?
Just to be clear – I want to be able to run the things that I install direct from the CLI.
Installing Ruby using rvm is the recommended method, however if you want to run things in a non-interactive, non-login shell (i.e. within a docker container), this just causes too much hassle with paths and environment variables and login scripts not running.
Given that I am using this to run a docker container, which by definition is isolated, and recoverable (just build another one), I don’t really care about switching versions, or isolating packages, and so I’ve decided to install Ruby from a package repo (http://brightbox.com/docs/ruby/ubuntu/) instead. This ‘just works’.
It may not work for you – I am only installing Ruby in order to get the Foreman gem, as I am running an app through a Procfile, so I’m not that fussed about the details, I just need it to work. If you’re building a Ruby app, I wouldn’t follow my advice.
My Dockerfile is here, FWIW, https://index.docker.io/u/yunojuno/dev/
One Solution collect form web for “Why do I have to use bash -l -c inside my container?”
-lMake bash act as if it had been invoked as a login shell
-cIf the -c option is present, then commands are read from string.
You’re running the command passed to the
-l makes it a login shell so bash first reads
/etc/profile, which probably has the path to
rvm which is what makes it work.
FWIW, here’s what I do to install
rvm in a docker container.
# Install some dependencies RUN apt-get -y -q install curl rubygems # Install rvm RUN curl -L https://get.rvm.io | bash -s stable # Install package dependencies RUN /usr/local/rvm/bin/rvm requirements # Install ruby RUN /usr/local/rvm/bin/rvm install ruby-2.0.0 # create first wrapper scripts RUN /usr/local/rvm/bin/rvm wrapper ruby-2.0.0 myapp rake rails gem