The OpenNebula OCCI is a web service that enables you to launch and manage virtual machines in your OpenNebula installation using the latest draft of the OGF OCCI API specification. The OpenNebula OCCI service is implemented upon the new OpenNebula Cloud API (OCA) layer that exposes the full capabilities of an OpenNebula private cloud; and Sinatra, a widely used light web framework.

The current implementation includes all the resource referenced in the latest draft of the OGF OCCI API specification, namely:

• Compute: launching, retrieve, update and deletion
• Network: creation, retrieve and deletion
• Storage: upload, retrieve and deletion

The following sections explain how to install and configure the OCCI service on top of a running OpenNebula cloud.

The OpenNebula OCCI service provides an OCCI interface to your cloud instance, that can be used alongside the native OpenNebula CLI, the libvirt interface or even the EC2 Query API

The OpenNebula distribution includes the tools needed to use the OpenNebula OCCI service

You must have an OpenNebula site properly configured and running to install the OpenNebula OCCI service, be sure to check the OpenNebula Installation and Configuration Guides to set up your private cloud first. This guide also assumes that you are familiar with the configuration and use of OpenNebula.

The OpenNebula OCCI service was installed during the OpenNebula installation, so you just need to install the following packages to meet the runtime dependencies:

• The Sinatra web framework and the thin web server:

<xterm>$ sudo gem install thin $ sudo gem install sinatra $ sudo gem install crack</xterm>

• The libraries for the Storage Repository and Client Tools:

<xterm> $ sudo gem install sequel $ sudo gem install curb $ sudo gem install multipart-post $ apt-get install ruby-sqlite3 $ apt-get install libopenssl-ruby </xterm>

curb is just neccessary to upload files faster. If not installed, upload file with occi-storage -M that uses the multipart-post library

The service is configured through the $ONE_LOCATION/etc/occi-server.conf file, where you can set up the basic operational parameters for the OCCI service, namely:

• Administration Account, the web server need to perform some operation using the oneadmin account, mainly to check the identity of the cloud users. You have to specify the USER and PASSWORD of oneadmin.
• Connection Parameters, the xml-rpc service of the oned daemon; and the server and port for the OpenNebula OCCI service web server. This will be the URL of your cloud.
• Storage Repository, the storage repository provides an easy-to-use repository to store Compute images. You need to specify the DATABASE and IMAGE_DIR for this service.
• Computes, the name of the bridge that the VM needs to connect to in the physical host to get network connection. See the Managing Virtual Networks guide for more details.
• Filesystem format, the default format in which the empty filesystems (needed for certain Computes) will be formatted in. In case of ommission, by default is ext3.
• Compute Types, a VM_TYPE defines the name and the OpenNebula templates for each type of Compute, to enable different sizes of Computes.

The following table summarizes the available options:

The SERVER must be a FQDN, do not use IP's here

IMAGE_DIR must be an existing directory

Preserve bash syntax in the occi-server.conf file

Example:

# OpenNebula administrator user
USER=oneadmin
PASSWORD=mypass

# OpenNebula sever contact information
ONE_XMLRPC=http://localhost:2633/RPC2

# Host and port where OCCI service will run
SERVER=cloud.opennebula.org
PORT=4567

# Configuration for the image repository
DATABASE=/srv/cloud/one/var/occi.db
IMAGE_DIR=/srv/cloud/images/

# Configuration for OpenNebula's Virtual Networks
BRIDGE=eth0

# Default format for FS
FS_FORMAT=ext3

# VM types allowed and its template file (inside templates directory)
VM_TYPE=[NAME=small,  TEMPLATE=small.erb]
VM_TYPE=[NAME=medium, TEMPLATE=medium.erb]
VM_TYPE=[NAME=large,  TEMPLATE=large.erb]

OpenNebula OCCI runs natively just on normal HTTP connections. If the extra security provided by SSL is needed, a proxy can be set up to handle the SSL connection that forwards the petition to the OCCI Service and takes back the answer to the client.

This set up needs:

• A server certificate for the SSL connections
• An HTTP proxy that understands SSL
• OCCI Service configuration to accept petitions from the proxy

If you want to try out the SSL setup easily, you can find in the following lines an example to set a self-signed certificate to be used by a lighttpd configured to act as an HTTP proxy to a correctly configured OCCI Service.

Let's assume the server were the lighttpd proxy is going to be started is called cloudserver.org. Therefore, the steps are:

We are going to generate a snakeoil certificate. If using an Ubuntu system follow the next steps (otherwise your milleage may vary, but not a lot):

• Install the ssl-cert package

<xterm> $ sudo apt-get install ssl-cert </xterm>

• Generate the certificate

<xterm> $ sudo /usr/sbin/make-ssl-cert generate-default-snakeoil </xterm>

• As we are using lighttpd, we need to append the private key with the certificate to obtain a server certificate valid to lighttpd

<xterm> $ sudo cat /etc/ssl/private/ssl-cert-snakeoil.key /etc/ssl/certs/ssl-cert-snakeoil.pem > /etc/lighttpd/server.pem </xterm>

You will need to edit the /etc/lighttpd/lighttpd.conf configuration file and

• Add the following modules (if not present already)
  • mod_access
  • mod_alias
  • mod_proxy
  • mod_accesslog
  • mod_compress
• Change the server port to 443 if you are going to run lighttpd as root, or any number above 1024 otherwise:

server.port               = 8443

• Add the proxy module section:

#### proxy module
## read proxy.txt for more info
proxy.server               = ( "" =>
                                ("" =>
                                 (
                                   "host" => "127.0.0.1",
                                   "port" => 4567
                                 )
                                 )
                             )


#### SSL engine
ssl.engine                 = "enable"
ssl.pemfile                = "/etc/lighttpd/server.pem"

The host must be the server hostname of the computer running the OCCI Service, and the port the one that the OCCI Service is running on.

The econe.conf needs to define the following:

# Host and port where OCA server will run
SERVER=127.0.0.1
PORT=4567	
# SSL proxy that serves the API (set if is being used)
SSL_SERVER=cloudserver.org

Once the lighttpd server is started, OCCI petitions using HTTPS uris can be directed to https://cloudserver.org:8443, that will then be unencrypted, passed to localhost, port 4567, satisfied (hopefully), encrypted again and then passed back to the client.

You can define as many Compute types as you want, just:

• Create a template for the new type and place it in $ONE_LOCATION/etc/occi_templates. This template will be completed with the data for each cloud occi-vm create request, and then submitted to OpenNebula. You can start by modifying the small.erb example, to adjust it to your cloud:

NAME   = <%= @vm_info['NAME']%>

CPU    = 1
MEMORY = 1024

OS = [ kernel     = /vmlinuz,
       initrd     = /initrd.img,
       root       = sda1,
       kernel_cmd = "ro xencons=tty console=tty1"]
       
<% if vm_info['STORAGE']
       vm_info['STORAGE'].each do |key, image| 
  image=[image].flatten
case key
    when "SWAP" 
        image.each do |img|
%>
DISK = [ type = "swap", 
         size=<%= img['size']%>, 
         target=<%= img['dev']%> ]
<% 
        end
    when "DISK"  
        image.each do |img|  
%>
DISK = [ type = "disk", 
         target=<%= img['dev']%>, 
         source=<%= img['source']%>, 
         image_id=<%= img['image']%> ]
<%  
        end
    when "FS" 
        image.each do |img| 
%>
DISK = [ type = "fs", 
         target=<%= img['dev']%>, 
         size=<%= img['size']%>,
         format=<%= @config[:fs_format]||"ext3"%>  ]   
<%      end %>
<% end %>
<% end %>
<% end %>
<% if vm_info['NETWORK'] and vm_info['NETWORK']['NIC'] %>
<% vm_info['NETWORK']['NIC'].each do |nic| %>
NIC = [ 
<% if nic['ip'] %>
        IP=<%= nic['ip'] %>,
<% end %>
        NETWORK="<%= nic['network']%>", 
        NETWORK_ID=<%= nic['network_id'] %>      
]
<% end %>
<% end %>
INSTANCE_TYPE = <%= vm_info[:instance_type ]%>

The templates are processed by the OCCI service to include specific data for the instance, you should not need to modify the <%= … %> compounds. Start by adjusting the OS, CPU and MEMORY to your needs

To start the OCCI service just issue the following command <xterm> occi-server start </xterm> You can find the econe server log file in $ONE_LOCATION/var/occi-server.log if OpenNebula has been installed in standalone, or in /var/log/one/occi-server.log if installed in system-wide.

To stop the OCCI service: <xterm> occi-server stop </xterm>

The cloud users have to be created in the OpenNebula system by oneadmin using the oneuser utility. Once a user is registered in the system, using the same procedure as to create private cloud users, they can start using the system. The users will authenticate using the HTTP basic authentication with user-ID their OpenNebula's username and password their OpenNebula's password.