Edward Edward - 1 year ago 86
Ruby Question

How to install jekyll to a Docker image?

I'd like to generate a docker image that has the command


I generated a
with the following content:

# https://hub.docker.com/_/ruby/
FROM ruby:slim

RUN gem install jekyll

Unfortunately throws an error:

ERROR: Error installing jekyll:
ERROR: Failed to build gem native extension.

current directory: /usr/local/bundle/gems/ffi-1.9.10/ext/ffi_c
/usr/local/bin/ruby -r ./siteconf20160615-7-12pthrg.rb extconf.rb
checking for ffi.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.

Provided configuration options:
/usr/local/lib/ruby/2.3.0/mkmf.rb:456:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /usr/local/lib/ruby/2.3.0/mkmf.rb:587:in `try_cpp'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:1091:in `block in have_header'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:942:in `block in checking_for'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:350:in `block (2 levels) in postpone'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:320:in `open'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:350:in `block in postpone'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:320:in `open'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:346:in `postpone'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:941:in `checking_for'
from /usr/local/lib/ruby/2.3.0/mkmf.rb:1090:in `have_header'
from extconf.rb:16:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:


extconf failed, exit code 1

Gem files will remain installed in /usr/local/bundle/gems/ffi-1.9.10 for inspection.
Results logged to /usr/local/bundle/extensions/x86_64-linux/2.3.0-static/ffi-1.9.10/gem_make.out

What am I doing wrong?

Answer Source

To diagnose the issue you can jump into the container and dig into what's causing the issue.

$ docker run -ti --rm ruby:slim /bin/bash
root@bda37983a585:/# gem install jekyll
# ...

Alternatively there is always the jekyll docker image: https://hub.docker.com/u/jekyll/

Good luck!