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, and the dependencies of this service are installed when using the install_gems tool as explained in the installation guide

If you installed OpenNebula from source you can install the OCCI dependencias as explained at the end of the Building from Source Code guide

The OCCI Server included in the OpenNebula distribution does not implement the latest OCCI specification, it is based on the draft 0.8 of the OFG OCCI specification. The implementation of the latest specification is being developed by TU-Dortmund in a ecosystem project. You can check the documentation of this project in the following link

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

• 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.
• 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.
• 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

You must set the :bridge, otherwise the network creation will fail

Preserve YAML syntax in the occi-server.conf file

Example:

# OpenNebula sever contact information
:one_xmlrpc: http://localhost:2633/RPC2

# Host and port where OCCI server will run
:server: localhost
:port: 4567

# SSL proxy that serves the API (set if is being used)
#:ssl_server: fqdm.of.the.server

# Authentication driver for incomming requests
#   occi, for OpenNebula's user-password scheme
#   x509, for x509 certificates based authentication
:auth: occi

# Authentication driver to communicate with OpenNebula core
#   cipher, for symmetric cipher encryption of tokens
#   x509, for x509 certificate encryption of tokens
:core_auth: cipher

# Life-time in seconds for token renewal (that used to handle OpenNebula auths)
:token_expiration_delta: 1800

# VM types allowed and its template file (inside templates directory)
:instance_types:
  :small:
    :template: small.erb
    :cpu: 1
    :memory: 1024
  :medium:
    :template: medium.erb
    :cpu: 4
    :memory: 4096
  :large:
    :template: large.erb
    :cpu: 8
    :memory: 8192

# Default language setting for Self-Service UI
:lang: en_US

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

• Create a template for the new type and place it in /etc/one/occi_templates. This template will be completed with the data for each cloud occi-compute create request, and then submitted to OpenNebula.

CPU    = 1
MEMORY = 1024

OS = [ kernel     = /vmlinuz,
       initrd     = /initrd.img,
       root       = sda1,
       kernel_cmd = "ro xencons=tty console=tty1"]

• You can add common attributes for your cloud templates modifying the /etc/one/occi_templates/common.erb file.

The templates are processed by the OCCI service to include specific data for the instance, you should not need to modify the <%= … %> compounds inside the common.erb file.

To start the OCCI service just issue the following command <xterm> occi-server start </xterm> You can find the OCCI server log file in /var/log/one/occi-server.log.

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

The occi-server must be started by oneadmin and the ONE_AUTH environment variable must be defined to interact with the OpenNebula daemon.

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.

OpenNebula OCCI Server supports two authorization methods in order to log in. The method can be set in the occi-server.conf, as explained above. These two methods are:

In the basic mode, username and password(sha1) are matched to those in OpenNebula's database in order to authenticate the user in each request.

This method performs the request to OpenNebula based on a x509 certicate DN (Distinguished Name). The DN is extracted from the certificate and matched to the password value in the user database (remember spaces are removed from DNs).

In order to use this method, OpenNebula must be configured with the x509 for Public Clouds settings.

Note that OpenNebula will not verify that the user is holding a valid certificate at the time of login: this is expected to be done by the external container of the OCCI server (normally Apache), whose job is to tell the user's client that the site requires a user certificate and to check that the certificate is consistently signed by the chosen Certificate Authority (CA).

OCCI x509 auth method only handles the authorization of the user. Authentication of the user certificate is a complementary setup, which can rely on Apache.

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 EC2Query Service, and the port the one that the EC2Query Service is running on.

The occi.conf needs to define the following:

# Host and port where the occi server will run
:server: <FQDN OF OCCI SERVER>
:port: 4567

# SSL proxy that serves the API (set if is being used)
:ssl_server: https://localhost:443

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.