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

[Daniel.MOLDOVAN at cs.utcluj.ro]

Answers inline.

>>What I mean is: suppose I, as a user
> of OpenNebula, using my created VM's, create a Web Service, which I
> publish on the Internet. Can anyone access this (someone who has no idea
> about the private cloud, someone who is simply accessing the URL), and by
> this way uses my Web Service (created on the VM's by the means of
> OpenNebula), so, basically, uses OpenNebula "remotely" (without knowing
> it)? Or this just doesn't make sense, since the whole idea of a private
> cloud is not to provide/publish information and services to the outside
> world, and this is not even possible since the virtual context?

    As Fabian said, consider each VM as a normal machine. Anything you
expose on it through a network will be visible, just as with a normal
machine. The idea of a "private cloud" is to hide the physical
location of the virtual machines (on what computer does each reside)
and hide the fact that the VM is not a physical machine.

>>Are the
> most important reasons for installing OpenNebula the performance needs? Is
> there any other reason because of which I may want to install it, besides
> the fact that I might need multiple VM's (that I can manage) to perform a
> task (and to achieve platform interoperability)?

   OpenNebula is a "hypervisor for hypervisors". The reason you want to
install it is to provide a means of managing a cluster of servers which
provide virtualization. OpenNebula most importantly allows migration of
VMs between physical machines and resource usage monitoring.


>>When the load reaches its maximum (on a task
> which a user tries to perform on OpenNebula VM's), are new VM's created
> automatically (it the physical resources allow this) to support the
> performace needs?

  I think you miss the point of what a "cloud manager" or a
"virtualization middleware" does. See OpenNebula as a middleware over
simple virtualization mechanisms such as KVN, Xen, HyperV, etc.
OpenNebula only provides a means of managing heterogeneous virtualized
environments. Automatic scaling of virtual machines is out of the scope
of this middleware.

 The basic idea is that a VM is created, deployed, and the life cycle of
the VM is monitored using OpenNebula. The VM can be
started/stopped/migrated but automatic scaling is not possible, due to
different factors, among which the unavailability of such a mechanism on
the underlying hypervisors (only XEN allows changing the VM allocated
memory without recreating the machine).

  Any scaling mechanism should be built on top of OpenNebula.


>>Suppose I have an intranet in a company
> environment, with more interconnected physical machine that I'm actually
> going to use, does this change anything? Do I have to set up a separate
> physical network for the physical machines that I'm planning to include
> in the private cloud?

  If you read the OpenNebula documentation, the only requirements are that
a bridge exists on each OpenNebula node to connect the virtual machines.
To what that bridge connects, it is up to the infrastructure provider,
but no special requirements are needed in terms of network for the VMs.

 The "live migration" mechanism requires a storage NAS and that can
influence the network, but mainly any network will do fine with
OpenNebula.

În Joi, Decembrie 15, 2011 10:54 am, biro lehel a scris:
> Hello Fabian. Thanks again for your reply. I really appreciate you for
> taking the time.
>
> I read what you wrote a couple of times, and (I think) it helped me to
> clarify some things. But still, I have a few questions and issues for
> which I am looking for a clear answer. I put them in bullets:
>
> As I understand so far, OpenNebula has two types of users: the
> administrator, who basically has control over "everything", and the
> users, who can authenticate securely, instantiate some VM's, and do the
> work necessary for them. My question: can OpenNebula have another "layer"
> of users, some kind of "end-users"? What I mean is: suppose I, as a user
> of OpenNebula, using my created VM's, create a Web Service, which I
> publish on the Internet. Can anyone access this (someone who has no idea
> about the private cloud, someone who is simply accessing the URL), and by
> this way uses my Web Service (created on the VM's by the means of
> OpenNebula), so, basically, uses OpenNebula "remotely" (without knowing
> it)? Or this just doesn't make sense, since the whole idea of a private
> cloud is not to provide/publish information and services to the outside
> world, and this is not even possible since the virtual context?Are the
> most important reasons for installing OpenNebula the performance needs? Is
> there any other reason because of which I may want to install it, besides
> the fact that I might need multiple VM's (that I can manage) to perform a
> task (and to achieve platform interoperability)? I mean this has be the
> main point of it, right?When the load reaches its maximum (on a task
> which a user tries to perform on OpenNebula VM's), are new VM's created
> automatically (it the physical resources allow this) to support the
> performace needs? Or the only way of creating VM's is the "manual"
> one?Can OpenNebula be installed on any type of physical network, or does
> it have some special needs? Suppose I have an intranet in a company
> environment, with more interconnected physical machine that I'm actually
> going to use, does this change anything? Do I have to set up a separate
> physical network for the physical machines that I'm planning to include
> in the private cloud?
>
>
> That's it for now, I don't want to ask for too much information all at
> once.:) I really hope that these questions are easy-to-answer for a
> professional, and will not take much time (for you Fabian, or for anyone
> else who thinks that can help me).
>
> Thank you, and waiting for your response,
> Biro Lehel.
>
>
>
> --- On Sun, 12/11/11, Fabian Wenk <fabian at wenks.ch> wrote:
>
>
> From: Fabian Wenk <fabian at wenks.ch>
> Subject: Re: [one-users] application integration (service publishing) in
> OpenNebula?
> To: users at lists.opennebula.org
> Date: Sunday, December 11, 2011, 7:04 PM
>
>
> 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
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