Introduction to Private Cloud Computing 3.4

The aim of a Private Cloud is not to expose to the world a cloud interface to sell capacity over the Internet, but to provide local cloud users and administrators with a flexible and agile private infrastructure to run virtualized service workloads within the administrative domain. OpenNebula virtual infrastructure interfaces expose user and administrator functionality for virtualization, networking, image and physical resource configuration, management, monitoring and accounting. This guide briefly describes how OpenNebula operates to build a Cloud infrastructure. After reading this guide you may be interested in reading the guide describing how an hybrid cloud operates and the guide describing how a public cloud operates.

The User View

An OpenNebula Private Cloud provides infrastructure users with an elastic platform for fast delivery and scalability of services to meet dynamic demands of service end-users. Services are hosted in VMs, and then submitted, monitored and controlled in the Cloud by using Sunstone or any of the OpenNebula interfaces:

Lets do a sample session to illustrate the functionality provided by the OpenNebula CLI for Private Cloud Computing. First thing to do, check the hosts in the physical cluster:

 $ onehost list
  ID NAME               RVM   TCPU   FCPU   ACPU   TMEM   FMEM   AMEM   STAT
   0 host01               0    800    800    800    16G    16G    16G     on
   1 host02               0    800    800    800    16G    16G    16G     on

We can then register an image in OpenNebula, by using oneimage. We are going to build an image template to register the image file we had previously placed in the /home/cloud/images directory.

NAME          = Ubuntu
PATH          = /home/cloud/images/ubuntu-desktop/disk.0
PUBLIC        = YES
DESCRIPTION   = "Ubuntu 10.04 desktop for students."

$ oneimage create ubuntu.oneimg
ID: 0

$ oneimage list
   1 oneadmin oneadmin Ubuntu           10G   OS   09/29 07:24:35 Yes  No  rdy     0

This image is now ready to be used in a virtual machine. We need to define a virtual machine template to be submitted using the onetemplate command.

NAME   = my_vm
CPU    = 1
MEMORY = 2056

DISK = [ IMAGE_ID  = 0 ]

DISK = [ type   = swap,
         size   = 1024 ]

NIC    = [ NETWORK_ID = 0 ]

Once we have tailored the requirements to our needs (specially, CPU and MEMORY fields), ensuring that the VM fits into at least one of both hosts, let's submit the VM (assuming you are currently in your home folder):

$ onetemplate create vm 
ID: 0

$ onetemplate list
  ID USER     GROUP    NAME                         REGTIME PUB
   0 oneadmin oneadmin my_vm                 09/29 07:28:41  No

The listed template is just a VM definition. To execute an instance, we can use the onetemplate command again:

$ onetemplate instantiate 1
VM ID: 0

This should come back with an ID, that we can use to identify the VM for monitoring and controlling, this time through the use of the onevm command:

$ onevm list
    ID USER     GROUP    NAME         STAT CPU     MEM        HOSTNAME        TIME
     0 oneadmin oneadmin one-0        runn   0      0K          host01 00 00:00:06

The STAT field tells the state of the virtual machine. If there is an runn state, the virtual machine is up and running. Depending on how we set up the image, we may be aware of it's IP address. If that is the case we can try now and log into the VM.

To perform a migration, we use yet again the onevm command. Let's move the VM (with VID=0) to host02 (HID=1):

$ onevm livemigrate 0 1

This will move the VM from host01 to host02. The onevm list shows something like the following:

$ onevm list
    ID USER     GROUP    NAME         STAT CPU     MEM        HOSTNAME        TIME
     0 oneadmin oneadmin one-0        runn   0      0K          host02 00 00:00:48

You can also reproduce this sample session using the graphical interface provided by Sunstone, that will simplify the typical management operations.