Đặng Phương Nam

The version of Ruby in CentOS 7 repository is 2.0 but Install 2.2 with RPM package.

Install development packages.

[root@dlp ~]# yum -y groupinstall "Development Tools"
# install from EPEL
[root@dlp ~]# yum --enablerepo=epel -y install gdbm-devel libdb4-devel libffi-devel libyaml libyaml-devel ncurses-devel openssl-devel readline-devel tcl-devel

Download Ruby source and build RPM from it. Make sute the latest one and Download it from the site below.
⇒ https://www.ruby-lang.org/ 
The verion of it in this example is the latest Ruby 2.2.3 at Aug 2015 now.

[root@dlp ~]# mkdir -p rpmbuild/{BUILD,BUILDROOT,RPMS,SOURCES,SPECS,SRPMS} 

# dowload source
[root@dlp ~]# wget http://cache.ruby-lang.org/pub/ruby/2.3/ruby-2.3.1.tar.gz -P rpmbuild/SOURCES 

# download SPEC file
[root@dlp ~]# wget https://raw.githubusercontent.com/feedforce/ruby-rpm/master/ruby.spec -P rpmbuild/SPECS --no-check-certificate
[root@dlp ~]# rpmbuild -bb rpmbuild/SPECS/ruby22x.spec
[root@dlp ~]# rpm -Uvh rpmbuild/RPMS/x86_64/ruby-2.*.rpm 

Preparing...                          #################################
[100%]
Updating / installing...
   1:ruby-2.3.1-1.el7.centos          ################################# [100%]

[root@dlp ~]# ruby -v 
ruby 2.2.3p173 (2015-08-18 revision 51636) [x86_64-linux-gnu]
[root@dlp ~]# gem -v 
2.4.5.1

Install some other required packages.

# install from EPEL
[root@dlp ~]# yum --enablerepo=epel -y install nodejs mariadb-devel

Install Rails 4

[root@dlp ~]# gem install bundler 
[root@dlp ~]# gem install rails --no-ri --no-rdoc 
[root@dlp ~]# gem install mysql2 --no-ri --no-rdoc -- --with-mysql-config=/usr/bin/mysql_config 
[root@dlp ~]# rails -v
Rails 4.2.4

Create a sample application and make sure it works normally.

[root@dlp ~]# rails new SampleApp -d mysql 
[root@dlp ~]# cd SampleApp 
[root@dlp SampleApp]# vi config/database.yml
default: &default
  adapter: mysql2
  encoding: utf8
  pool: 5
  username: root
  password: password   # MariaDB password
  socket: /var/lib/mysql/mysql.sock
# create a sample app
[root@dlp SampleApp]# rake db:create:all 
[root@dlp SampleApp]# rails generate scaffold testapp name:string title:string body:text 
[root@dlp SampleApp]# rake db:migrate 
[root@dlp SampleApp]# rails server --binding=10.11.10.30 
=> Booting WEBrick
=> Rails 4.2.3 application starting in development on http://10.0.0.30:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
[2015-07-06 11:30:02] INFO  WEBrick 1.3.1
[2015-07-06 11:30:02] INFO  ruby 2.2.2 (2015-04-13) [x86_64-linux]
[2015-07-06 11:30:02] INFO  WEBrick::HTTPServer#start: pid=13735 port=3000

Access to the "http://(server's hostname or IP address):3000/" from a client computer