Install local docker and docker-compose on CentOS 7

Configure the docker repository with yum

$ sudo tee /etc/yum.repos.d/docker.repo <<-'EOF' > [dockerrepo]
> name=Docker Repository
> baseurl=https://yum.dockerproject.org/repo/main/centos/7/
> enabled=1
> gpgcheck=1
> gpgkey=https://yum.dockerproject.org/gpg
> EOF

Install and start local docker

$ sudo yum install docker-engine
$ sudo systemctl enable docker.service
$ sudo systemctl start docker

Run a sanity check to see if docker is working properly

$ sudo docker run --rm hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
c04b14da8d14: Pull complete 
Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker Hub account:
 https://hub.docker.com

For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/

To allow the user to run docker without sudo, create a “docker” group and add yourusername to it.

$ sudo groupadd docker
$ sudo usermod -aG docker yourusername

Log out and log back in for the group changes to go into effect. Try it out:

$ docker run --rm hello-world

Enable docker to be run after reboot

$ sudo systemctl enable docker

Install docker-compose

$ sudo -i
# curl -L https://github.com/docker/compose/releases/download/1.9.0/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   600    0   600    0     0   2848      0 --:--:-- --:--:-- --:--:--  2870
100 7857k  100 7857k    0     0  15.5M      0 --:--:-- --:--:-- --:--:-- 15.5M
# chmod +x /usr/local/bin/docker-compose
# exit
$ logout

Check that docker is running

$ docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                                      NAMES

How to Install Rails on CentOS 7

Install prerequisite dependencies

$ sudo yum install -y git-core zlib zlib-devel gcc-c++ patch readline readline-devel libyaml-devel libffi-devel openssl-devel make bzip2 autoconf automake libtool bison curl sqlite-devel

Install rbenv

$ git clone https://github.com/rbenv/rbenv.git ~/.rbenv
$ cd ~/.rbenv && src/configure && make -C src
$ echo 'export PATH=$HOME/.rbenv/bin:$PATH' >> ~/.bash_profile

Run rbenv init, and follow the instructions.

$ rbenv init
# Load rbenv automatically by appending
# the following to ~/.bash_profile:

eval "$(rbenv init -)"

Restart your shell.

Install ruby-build plugin to get access to rbenv install.

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

Finally, install ruby, and confirm version.

$ rbenv install 2.2.2
...
$ ruby -v
ruby 2.2.2p95 (2015-04-13 revision 50295) [x86_64-linux]

Confirm sqlite3 is installed

$ sqlite3 --version
3.7.17 2013-05-20 00:56:22 118a3b35693b134d56ebd780123b7fd6f1497668

Install rails using gem.
NOTE: I originally had some trouble running this command because the version of ruby kept going back to 2.0.0, which is the default version for my installation of CentOS. I had to manually add a .ruby-version file into my working directory with the contents 2.2.2 in order for the gem command to proceed with the rails installation. I don’t know if this is the correct way of doing this.

$ gem install rails
...
$ rails --version
Rails 5.0.0.1