Docker container knows rbenv global but not ruby

Question

When running my docker container it knows rbenv global. But when ever it try to find ruby via ruby or which ruby or whereis ruby I get nothing. It also doesn't recognize rails-api or gem. What is going on?

Dockerfile

FROM centos:6.6

RUN yum update -y
RUN yum install git openssl-devel openssh-server sudo openssl readline-devel readline zlib-devel zlib libxml2-devel libxml2 libxslt-devel libxslt nginx tar gcc libaio libaio-devel -y
RUN rpm -Uvh https://opscode-omnibus-packages.s3.amazonaws.com/el/6/x86_64/chef-12.5.1-1.el6.x86_64.rpm
RUN sed -i -e "s/Defaults    requiretty.*/ #Defaults    requiretty/g" /etc/sudoers

RUN mkdir -p /var/run/sshd

RUN useradd -m -u 1000 -G wheel deploy && echo '%wheel  ALL=(ALL)  NOPASSWD: ALL' >> /etc/sudoers.d/wheel
USER deploy
RUN mkdir ~/dev

RUN git clone https://github.com/sstephenson/rbenv.git ~/.rbenv/
RUN git clone https://github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build

ENV PATH ~/.rbenv/bin:$PATH
RUN echo 'eval "$(rbenv init -)"' >> ~/.bash_profile
RUN source ~/.bash_profile
ENV CONFIGURE_OPTS --disable-install-doc

RUN rbenv install 2.2.3
RUN rbenv global 2.2.3
RUN bash -l -c 'gem update --system'
RUN bash -l -c 'gem update'
RUN bash -l -c 'gem install nokogiri -- --use-system-libraries'
RUN bash -l -c 'gem install bundler rails-api --no-rdoc --no-ri'

COPY oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm /tmp/oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm
COPY oracle-instantclient12.1-devel-12.1.0.2.0-1.x86_64.rpm /tmp/oracle-instantclient12.1-devel-12.1.0.2.0-1.x86_64.rpm
COPY oracle-instantclient12.1-sqlplus-12.1.0.2.0-1.x86_64.rpm /tmp/oracle-instantclient12.1-sqlplus-12.1.0.2.0-1.x86_64.rpm

RUN sudo rpm -Uvh /tmp/oracle-instantclient12.1-basic-12.1.0.2.0-1.x86_64.rpm
RUN sudo rpm -Uvh /tmp/oracle-instantclient12.1-devel-12.1.0.2.0-1.x86_64.rpm
RUN sudo rpm -Uvh /tmp/oracle-instantclient12.1-sqlplus-12.1.0.2.0-1.x86_64.rpm

RUN sudo touch /etc/sysconfig/network

RUN NLS_LANG=American_America.UTF8
ENV ORACLE_HOME=/usr/lib/oracle/12.1/client64
ENV LD_LIBRARY_PATH=/usr/lib/oracle/12.1/client64/lib

EXPOSE 22
EXPOSE 3000
EXPOSE 5000

Answer 1

Have you tried rbenv rehash after installing the new Ruby version?

Answer 2

The issue at hand here is that every RUN statement in the Dockerfile happens in its own environment. The RUN source ~/.bash_profile will set $PATH to have /root/.rbenv/shims in it. But subsequent RUN will not have this environment set as they won't source .bash_profile since this isn't an interactive shell.

The easy way to solve this is to just add a ENV PATH $HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH somewhere before the ruby and gem commands. This is really the only bit you should need from the rbenv init shell script.