Installing Opennebula On Clean Centos 7 Problem

akhfa

I got SP 64-S server from recent OVH BF deals. Usually I use Proxmox for virtualization on all of my servers, now I want to explore with opennebula on centos 7.

I install centos 7 with default kernel with about 10 G swap and / for the rest. Selinux was already disabled.

To install opennebula, I follow tutorial here:
http://docs.opennebula.org/4.8/design_and_installation/quick_starts/qs_centos7_kvm.html

The first error I got was I can't install one gem (I forget the name) because default centos ruby version is 2.0.0, and the gem installation needs 2.2.0 version.

After that, I try to install ruby version 2.3.0 first from here:
http://tecadmin.net/install-ruby-2-2-on-centos-rhel/
and then I follow the opennebula docs again.

The installation was successful with no error message, but when try this command:

service opennebula-sunstone start

it fail, and this is the error message from /var/log/one/sunstone.error

/usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- sinatra (LoadError)
        from /usr/share/rubygems/rubygems/core_ext/kernel_require.rb:55:in `require'
        from /usr/lib/one/sunstone/sunstone-server.rb:57:in `'

I try gem list, and there is sinatra there

addressable (2.5.0)
amazon-ec2 (0.9.17)
aws-sdk (2.6.28)
aws-sdk-core (2.6.28)
aws-sdk-resources (2.6.28)
aws-sigv4 (1.0.0)
azure (0.7.7)
azure-core (0.1.6)
bigdecimal (1.2.8)
builder (3.2.2)
bundler-unload (1.0.2)
configparser (0.1.4)
curb (0.9.3)
daemons (1.2.4)
did_you_mean (1.0.0)
eventmachine (1.2.1)
executable-hooks (1.3.2)
faraday (0.10.0)
faraday_middleware (0.10.1)
gem-wrappers (1.2.7)
io-console (0.4.5)
jmespath (1.3.1)
json (1.8.3)
mime-types (3.1)
mime-types-data (3.2016.0521)
mini_portile2 (2.1.0)
minitest (5.8.3)
multipart-post (2.0.0)
net-ldap (0.15.0)
net-telnet (0.1.1)
nokogiri (1.6.8.1)
ox (2.4.5)
parse-cron (0.1.4)
polyglot (0.3.5)
power_assert (0.2.6)
psych (2.0.17)
public_suffix (2.0.4)
rack (2.0.1, 1.6.5)
rack-protection (1.5.3)
rake (10.4.2)
rdoc (4.2.1)
rubygems-bundler (1.4.4)
rvm (1.11.3.9)
sequel (4.40.0)
sinatra (1.4.7)
softlayer_api (3.2.1)
sqlite3 (1.3.12)
systemu (2.6.5)
test-unit (3.1.5)
thin (1.7.0)
thor (0.19.3)
tilt (2.0.5)
treetop (1.6.8)
trollop (2.1.2)
uuidtools (2.1.5)
xml-simple (1.1.5)

I try to gem install sinatra, and the error is still occur.

This is my $GEM_HOME and $GEM_PATH

[root@host2 ~]# echo $GEM_PATH
/usr/local/rvm/gems/ruby-2.3.0:/usr/local/rvm/gems/ruby-2.3.0@global
[root@host2 ~]# echo $GEM_HOME
/usr/local/rvm/gems/ruby-2.3.0

What should I do next? Or maybe is there any better tutorial?