[one-users] application integration (service publishing) in OpenNebula?

[Fabian Wenk]

Hello Lehel

On 11.12.2011 14:33, biro lehel wrote:
> what I've been referring to. I will have OpenNebula set up,
> and (as common sense would tell) I will have my application
> installed on the created VM's. My question only referred to:
> how can I install an application on these VM's (should I only
> just copy it, or is it more complex than this), or stuff like:

Look at the VM like at any other physical computer. It is just a 
container (eg. a virtual computer) where you can install the OS 
of your choice. The installation of your application inside the 
OS of your VM needs to be done the same as you would do it on a 
physical computer. But the installation of the OS in the VM needs 
to be done first. See my recent posting "Re: Creating virtual 
machines from scratch" [1] to this mailing list.

   [1] 
http://lists.opennebula.org/pipermail/users-opennebula.org/2011-December/007156.html

Look at an OpenNeubla cluster / cloud like on an additional 
abstraction layer between a physical computer and your OS 
installation.

An example:
If you have 3 computers, you can install on each one the OS of 
your choice and run it, but then you have only 3 concurrent 
running OS installation available. With OpenNebula you need to 
install Linux on all 3 computers (1x front-end and 2x cluster 
nodes). The cluster nodes also need to support some kind of 
hypervisor (eg. KVM or XEN). Then you install OpenNebula on the 
front-end and then adjust the configuration for the shared file 
systems to be used by the cluster nodes. Then you can create VMs 
(virtual machines / virtual computers) and deploy them through 
the front-end (with Sunstone you also have a web GUI). Now you 
can create as many VMs as the two cluster nodes can support 
(depending on CPU power an available memory). You even can stop 
or terminate VMs and reuse them (with persistent image) at a 
later time.

> can the different tiers of the application (interface,
> business logic, and data repository) be on different VM's, but

Sure, they can.

> most importantly: how can an end-user (not the administrator,
> but a potencial client) use the application? Or there is no
> such thing as the "end-user / client" concept in OpenNebula,
> since the only user is the administrator who has control over
> the infrastructure? If OpenNebula provides IaaS support, I

In OpenNebula the administrator has full control over the running 
VMs, eg. he can stop (pause), resume or even shutdown / destroy 
them. OpenNebula also knows users, which eg. could create their 
own VMs (with their choice of OS installation) or can use 
pre-created shared system image to boot a VM. But as far as I 
know, out of the box OpenNebula is not able to provide 
virtualization on application level. But it has a very open and 
flexible design and you should be able to customize it to your 
needs, eg. with contextualization.

> suppose this means that he does not have control over the
> application only as a service, but rather he, as the admin,
> has control over the whole "physical" application?

What do you understand as "physical" application?

OpenNebula controls the distribution and monitoring of the VMs. 
It will place a newly created VM on a cluster node which has the 
requested requirements and resources available. It also manages 
all the system images (persistent and public / shared) and 
network interfaces (done through bridges) which the VMs need to run.


bye
Fabian