Hey Marcus,
I wonder if the iSCSI storage pool type for libvirt won't work when you
take into consideration hypervisor snapshots?
On XenServer, when you take a hypervisor snapshot, the VDI for the snapshot
is placed on the same storage repository as the volume is on.
Same idea for VMware, I believe.
So, what would happen in my case (let's say for XenServer and VMware for
4.3 because I don't support hypervisor snapshots in 4.2) is I'd make an
iSCSI target that is larger than what the user requested for the CloudStack
volume (which is fine because our SAN thinly provisions volumes, so the
space is not actually used unless it needs to be). The CloudStack volume
would be the only "object" on the SAN volume until a hypervisor snapshot is
taken. This snapshot would also reside on the SAN volume.
If this is also how KVM behaves and there is no creation of LUNs within an
iSCSI target from libvirt (which, even if there were support for this, our
SAN currently only allows one LUN per iSCSI target), then I don't see how
using this model will work.
Perhaps I will have to go enhance the current way this works with DIR?
What do you think?
Thanks
On Fri, Sep 13, 2013 at 6:28 PM, Mike Tutkowski <
mike.tutkow...@solidfire.com> wrote:
> That appears to be the way it's used for iSCSI access today.
>
> I suppose I could go that route, too, but I might as well leverage what
> libvirt has for iSCSI instead.
>
>
> On Fri, Sep 13, 2013 at 6:26 PM, Marcus Sorensen <shadow...@gmail.com>wrote:
>
>> To your question about SharedMountPoint, I believe it just acts like a
>> 'DIR' storage type or something similar to that. The end-user is
>> responsible for mounting a file system that all KVM hosts can access,
>> and CloudStack is oblivious to what is providing the storage. It could
>> be NFS, or OCFS2, or some other clustered filesystem, cloudstack just
>> knows that the provided directory path has VM images.
>>
>> On Fri, Sep 13, 2013 at 6:23 PM, Marcus Sorensen <shadow...@gmail.com>
>> wrote:
>> > Oh yes, you can use NFS, LVM, and iSCSI all at the same time.
>> > Multiples, in fact.
>> >
>> > On Fri, Sep 13, 2013 at 6:19 PM, Mike Tutkowski
>> > <mike.tutkow...@solidfire.com> wrote:
>> >> Looks like you can have multiple storage pools:
>> >>
>> >> mtutkowski@ubuntu:~$ virsh pool-list
>> >> Name State Autostart
>> >> -----------------------------------------
>> >> default active yes
>> >> iSCSI active no
>> >>
>> >>
>> >> On Fri, Sep 13, 2013 at 6:12 PM, Mike Tutkowski
>> >> <mike.tutkow...@solidfire.com> wrote:
>> >>>
>> >>> Reading through the docs you pointed out.
>> >>>
>> >>> I see what you're saying now.
>> >>>
>> >>> You can create an iSCSI (libvirt) storage pool based on an iSCSI
>> target.
>> >>>
>> >>> In my case, the iSCSI target would only have one LUN, so there would
>> only
>> >>> be one iSCSI (libvirt) storage volume in the (libvirt) storage pool.
>> >>>
>> >>> As you say, my plug-in creates and destroys iSCSI targets/LUNs on the
>> >>> SolidFire SAN, so it is not a problem that libvirt does not support
>> >>> creating/deleting iSCSI targets/LUNs.
>> >>>
>> >>> It looks like I need to test this a bit to see if libvirt supports
>> >>> multiple iSCSI storage pools (as you mentioned, since each one of its
>> >>> storage pools would map to one of my iSCSI targets/LUNs).
>> >>>
>> >>>
>> >>> On Fri, Sep 13, 2013 at 5:58 PM, Mike Tutkowski
>> >>> <mike.tutkow...@solidfire.com> wrote:
>> >>>>
>> >>>> LibvirtStoragePoolDef has this type:
>> >>>>
>> >>>> public enum poolType {
>> >>>>
>> >>>> ISCSI("iscsi"), NETFS("netfs"), LOGICAL("logical"),
>> DIR("dir"),
>> >>>> RBD("rbd");
>> >>>>
>> >>>> String _poolType;
>> >>>>
>> >>>> poolType(String poolType) {
>> >>>>
>> >>>> _poolType = poolType;
>> >>>>
>> >>>> }
>> >>>>
>> >>>> @Override
>> >>>>
>> >>>> public String toString() {
>> >>>>
>> >>>> return _poolType;
>> >>>>
>> >>>> }
>> >>>>
>> >>>> }
>> >>>>
>> >>>>
>> >>>> It doesn't look like the iSCSI type is currently being used, but I'm
>> >>>> understanding more what you were getting at.
>> >>>>
>> >>>>
>> >>>> Can you tell me for today (say, 4.2), when someone selects the
>> >>>> SharedMountPoint option and uses it with iSCSI, is that the "netfs"
>> option
>> >>>> above or is that just for NFS?
>> >>>>
>> >>>>
>> >>>> Thanks!
>> >>>>
>> >>>>
>> >>>>
>> >>>> On Fri, Sep 13, 2013 at 5:50 PM, Marcus Sorensen <
>> shadow...@gmail.com>
>> >>>> wrote:
>> >>>>>
>> >>>>> Take a look at this:
>> >>>>>
>> >>>>> http://libvirt.org/storage.html#StorageBackendISCSI
>> >>>>>
>> >>>>> "Volumes must be pre-allocated on the iSCSI server, and cannot be
>> >>>>> created via the libvirt APIs.", which I believe your plugin will
>> take
>> >>>>> care of. Libvirt just does the work of logging in and hooking it up
>> to
>> >>>>> the VM (I believe the Xen api does that work in the Xen stuff).
>> >>>>>
>> >>>>> What I'm not sure about is whether this provides a 1:1 mapping, or
>> if
>> >>>>> it just allows you to register 1 iscsi device as a pool. You may
>> need
>> >>>>> to write some test code or read up a bit more about this. Let us
>> know.
>> >>>>> If it doesn't, you may just have to write your own storage adaptor
>> >>>>> rather than changing LibvirtStorageAdaptor.java. We can cross that
>> >>>>> bridge when we get there.
>> >>>>>
>> >>>>> As far as interfacing with libvirt, see the java bindings doc.
>> >>>>> http://libvirt.org/sources/java/javadoc/ Normally, you'll see a
>> >>>>> connection object be made, then calls made to that 'conn' object.
>> You
>> >>>>> can look at the LibvirtStorageAdaptor to see how that is done for
>> >>>>> other pool types, and maybe write some test java code to see if you
>> >>>>> can interface with libvirt and register iscsi storage pools before
>> you
>> >>>>> get started.
>> >>>>>
>> >>>>> On Fri, Sep 13, 2013 at 5:31 PM, Mike Tutkowski
>> >>>>> <mike.tutkow...@solidfire.com> wrote:
>> >>>>> > So, Marcus, I need to investigate libvirt more, but you figure it
>> >>>>> > supports
>> >>>>> > connecting to/disconnecting from iSCSI targets, right?
>> >>>>> >
>> >>>>> >
>> >>>>> > On Fri, Sep 13, 2013 at 5:29 PM, Mike Tutkowski
>> >>>>> > <mike.tutkow...@solidfire.com> wrote:
>> >>>>> >>
>> >>>>> >> OK, thanks, Marcus
>> >>>>> >>
>> >>>>> >> I am currently looking through some of the classes you pointed
>> out
>> >>>>> >> last
>> >>>>> >> week or so.
>> >>>>> >>
>> >>>>> >>
>> >>>>> >> On Fri, Sep 13, 2013 at 5:26 PM, Marcus Sorensen
>> >>>>> >> <shadow...@gmail.com>
>> >>>>> >> wrote:
>> >>>>> >>>
>> >>>>> >>> Yes, my guess is that you will need the iscsi initiator
>> utilities
>> >>>>> >>> installed. There should be standard packages for any distro.
>> Then
>> >>>>> >>> you'd call
>> >>>>> >>> an agent storage adaptor to do the initiator login. See the
>> info I
>> >>>>> >>> sent
>> >>>>> >>> previously about LibvirtStorageAdaptor.java and libvirt iscsi
>> >>>>> >>> storage type
>> >>>>> >>> to see if that fits your need.
>> >>>>> >>>
>> >>>>> >>> On Sep 13, 2013 4:55 PM, "Mike Tutkowski"
>> >>>>> >>> <mike.tutkow...@solidfire.com>
>> >>>>> >>> wrote:
>> >>>>> >>>>
>> >>>>> >>>> Hi,
>> >>>>> >>>>
>> >>>>> >>>> As you may remember, during the 4.2 release I developed a
>> SolidFire
>> >>>>> >>>> (storage) plug-in for CloudStack.
>> >>>>> >>>>
>> >>>>> >>>> This plug-in was invoked by the storage framework at the
>> necessary
>> >>>>> >>>> times
>> >>>>> >>>> so that I could dynamically create and delete volumes on the
>> >>>>> >>>> SolidFire SAN
>> >>>>> >>>> (among other activities).
>> >>>>> >>>>
>> >>>>> >>>> This is necessary so I can establish a 1:1 mapping between a
>> >>>>> >>>> CloudStack
>> >>>>> >>>> volume and a SolidFire volume for QoS.
>> >>>>> >>>>
>> >>>>> >>>> In the past, CloudStack always expected the admin to create
>> large
>> >>>>> >>>> volumes ahead of time and those volumes would likely house many
>> >>>>> >>>> root and
>> >>>>> >>>> data disks (which is not QoS friendly).
>> >>>>> >>>>
>> >>>>> >>>> To make this 1:1 mapping scheme work, I needed to modify logic
>> in
>> >>>>> >>>> the
>> >>>>> >>>> XenServer and VMware plug-ins so they could create/delete
>> storage
>> >>>>> >>>> repositories/datastores as needed.
>> >>>>> >>>>
>> >>>>> >>>> For 4.3 I want to make this happen with KVM.
>> >>>>> >>>>
>> >>>>> >>>> I'm coming up to speed with how this might work on KVM, but I'm
>> >>>>> >>>> still
>> >>>>> >>>> pretty new to KVM.
>> >>>>> >>>>
>> >>>>> >>>> Does anyone familiar with KVM know how I will need to interact
>> with
>> >>>>> >>>> the
>> >>>>> >>>> iSCSI target? For example, will I have to expect Open iSCSI
>> will be
>> >>>>> >>>> installed on the KVM host and use it for this to work?
>> >>>>> >>>>
>> >>>>> >>>> Thanks for any suggestions,
>> >>>>> >>>> Mike
>> >>>>> >>>>
>> >>>>> >>>> --
>> >>>>> >>>> Mike Tutkowski
>> >>>>> >>>> Senior CloudStack Developer, SolidFire Inc.
>> >>>>> >>>> e: mike.tutkow...@solidfire.com
>> >>>>> >>>> o: 303.746.7302
>> >>>>> >>>> Advancing the way the world uses the cloud™
>> >>>>> >>
>> >>>>> >>
>> >>>>> >>
>> >>>>> >>
>> >>>>> >> --
>> >>>>> >> Mike Tutkowski
>> >>>>> >> Senior CloudStack Developer, SolidFire Inc.
>> >>>>> >> e: mike.tutkow...@solidfire.com
>> >>>>> >> o: 303.746.7302
>> >>>>> >> Advancing the way the world uses the cloud™
>> >>>>> >
>> >>>>> >
>> >>>>> >
>> >>>>> >
>> >>>>> > --
>> >>>>> > Mike Tutkowski
>> >>>>> > Senior CloudStack Developer, SolidFire Inc.
>> >>>>> > e: mike.tutkow...@solidfire.com
>> >>>>> > o: 303.746.7302
>> >>>>> > Advancing the way the world uses the cloud™
>> >>>>
>> >>>>
>> >>>>
>> >>>>
>> >>>> --
>> >>>> Mike Tutkowski
>> >>>> Senior CloudStack Developer, SolidFire Inc.
>> >>>> e: mike.tutkow...@solidfire.com
>> >>>> o: 303.746.7302
>> >>>> Advancing the way the world uses the cloud™
>> >>>
>> >>>
>> >>>
>> >>>
>> >>> --
>> >>> Mike Tutkowski
>> >>> Senior CloudStack Developer, SolidFire Inc.
>> >>> e: mike.tutkow...@solidfire.com
>> >>> o: 303.746.7302
>> >>> Advancing the way the world uses the cloud™
>> >>
>> >>
>> >>
>> >>
>> >> --
>> >> Mike Tutkowski
>> >> Senior CloudStack Developer, SolidFire Inc.
>> >> e: mike.tutkow...@solidfire.com
>> >> o: 303.746.7302
>> >> Advancing the way the world uses the cloud™
>>
>
>
>
> --
> *Mike Tutkowski*
> *Senior CloudStack Developer, SolidFire Inc.*
> e: mike.tutkow...@solidfire.com
> o: 303.746.7302
> Advancing the way the world uses the
> cloud<http://solidfire.com/solution/overview/?video=play>
> *™*
>
--
*Mike Tutkowski*
*Senior CloudStack Developer, SolidFire Inc.*
e: mike.tutkow...@solidfire.com
o: 303.746.7302
Advancing the way the world uses the
cloud<http://solidfire.com/solution/overview/?video=play>
*™*
