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From Animesh Chaturvedi <animesh.chaturv...@citrix.com>
Subject RE: [MERGE] Support VM Snapshot
Date Wed, 20 Mar 2013 16:58:05 GMT
Mice any updates, when can you provide a global enable/disable flag for the feature?

Animesh

> -----Original Message-----
> From: Animesh Chaturvedi [mailto:animesh.chaturvedi@citrix.com]
> Sent: Monday, March 18, 2013 10:44 PM
> To: cloudstack-dev@incubator.apache.org
> Cc: Chandan Purushothama; Anthony Xu
> Subject: RE: [MERGE] Support VM Snapshot
>
> It would be best to enable/disable this feature  on a per hypervisor basis but
> if that's complicated adding a top level flag to enable/disable the functionality
> is reasonable.
>
> > -----Original Message-----
> > From: Mice Xia [mailto:mice_xia@tcloudcomputing.com]
> > Sent: Monday, March 18, 2013 9:59 PM
> > To: cloudstack-dev@incubator.apache.org
> > Cc: Chandan Purushothama; Anthony Xu; Mice Xia
> > Subject: RE: [MERGE] Support VM Snapshot
> >
> > Animesh,
> >
> > Do you mean limit the capability by adding global configurations or
> > adding in [global-setting--> hypervisor capabilities] ?
> >
> > Mice
> >
> > -----Original Message-----
> > From: Animesh Chaturvedi [mailto:animesh.chaturvedi@citrix.com]
> > Sent: Tuesday, March 19, 2013 9:47 AM
> > To: cloudstack-dev@incubator.apache.org; Mice Xia; Chandan
> > Purushothama; Anthony Xu
> > Subject: RE: [MERGE] Support VM Snapshot
> >
> > Mice any comments to my email below.
> >
> > Animesh
> >
> > > -----Original Message-----
> > > From: Animesh Chaturvedi [mailto:animesh.chaturvedi@citrix.com]
> > > Sent: Wednesday, March 13, 2013 6:03 PM
> > > To: Mice Xia; cloudstack-dev@incubator.apache.org; Chandan
> > > Purushothama; Anthony Xu
> > > Subject: RE: [MERGE] Support VM Snapshot
> > >
> > > Mice please see concerns from Anthony on Xenserver support., I guess
> > > they can only be proved conclusively by testing with xenserver.
> > > Chandan will test with xenserver.
> > >
> > > But given that there is some doubt on full support for xenserver and
> > > kvm dependency on libvirt-java binding and  I assume the effort in
> > > making the capability configurable is trivial. In my opinion we
> > > should make it configurable and turn on for xenserver and kvm when
> > > support is
> > clear.
> > >
> > >
> > > Thanks
> > > Animesh
> > > > -----Original Message-----
> > > > From: Mice Xia [mailto:weiran.xia1@gmail.com]
> > > > Sent: Monday, March 11, 2013 2:49 AM
> > > > To: cloudstack-dev@incubator.apache.org
> > > > Cc: Animesh Chaturvedi
> > > > Subject: Re: [MERGE] Support VM Snapshot
> > > >
> > > > Animesh,
> > > >
> > > > sorry for the late reply.
> > > >
> > > > 1. currently in master branch it supports both xenserver and
> > > > vmware, for KVM it needs a new-versioned libvirt java binding,
> > > > considering it's for 4.2, still three months away from the release
> > > > date, we have big chance to ship the new libvirt binding. I dont
> > > > see a strong need to make it configurable for hypervisors unless
> > > > some functions do not work
> > > at all..
> > > >
> > > > 2. now delta volume snapshot will become a full one. But I guess
> > > > volume snapshot will be improved soon for xenserver. please
> > > > correct me if we dont have this plan.
> > > >
> > > > Regards
> > > > -Mice
> > > >
> > > > 2013/3/8 Animesh Chaturvedi <animesh.chaturvedi@citrix.com>:
> > > > > Folks following up on this thread looks like support for
> > > > > XenServer is still not
> > > > settled.
> > > > >
> > > > > 1. Mice can we make the feature configurable for each hypervisor
> > > > > to enable/disable the feature 2. Test the feature with XenServer
> > > > > thoroughly to check if Volume Snapshot is affected / degraded
> > > > >
> > > > > Thanks
> > > > > Animesh
> > > > >
> > > > >
> > > > >> -----Original Message-----
> > > > >> From: Anthony Xu [mailto:Xuefei.Xu@citrix.com]
> > > > >> Sent: Friday, February 01, 2013 5:44 PM
> > > > >> To: 'Mice Xia'; cloudstack-dev@incubator.apache.org; Alex
> > > > >> Huang; Mice Xia
> > > > >> Subject: RE: [MERGE] Support VM Snapshot
> > > > >>
> > > > >> I see, snapshot manager detected the change in primary storage,
> > > > >> and create a full snapshot instead, which is supposed to be a
> > > > >> delta
> > snapshot.
> > > > >>
> > > > >> It doesn’t break volume snapshot function, but this degrades
> > > > >> the volume snapshot performance.
> > > > >>
> > > > >>
> > > > >>
> > > > >> This is just a simple test, it cannot prove there is no impact
> > > > >> to volume snapshot.
> > > > >>
> > > > >> I’m not sure what will happen if execute these two commands
at
> > > > >> the same time, is there any mechanism to sync/serialize these
> > > > >> two
> > > operation?
> > > > >>
> > > > >> I’m not sure if revert VM has impact to volume snapshot.
> > > > >>
> > > > >>
> > > > >>
> > > > >> For now, it is better to have a global configuration to only
choose
> one.
> > > > >>
> > > > >> later, we may support both of them in one setup.
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> Anthony
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> From: Mice Xia [mailto:mice_xia@tcloudcomputing.com]
> > > > >> Sent: Friday, February 01, 2013 5:30 PM
> > > > >> To: cloudstack-dev@incubator.apache.org; Alex Huang; Mice Xia;
> > > > >> Anthony Xu
> > > > >> Subject: 答复: [MERGE] Support VM Snapshot
> > > > >>
> > > > >>
> > > > >> Anthony,
> > > > >>
> > > > >> Thanks for your comments.
> > > > >>
> > > > >> Tested on a datadisk with steps you provide on xenserver, all
> > > > >> the files (test1, test2, test3) are present, the function is
not
> affected.
> > > > >> But as i have replied, volume snapshot (s2) is not a delta
> > > > >> snapshot, it is a full one. Users need to be aware of this if
> > > > >> they want to use both snapshots simultaneously.
> > > > >>
> > > > >> Regards
> > > > >> Mice
> > > > >>
> > > > >>
> > > > >> -----Original Message-----
> > > > >> From: Anthony Xu [mailto:Xuefei.Xu@citrix.com]
> > > > >> Sent: 2013-2-2 (星期六) 4:05
> > > > >> To: Alex Huang; Mice Xia; cloudstack-dev@incubator.apache.org
> > > > >> Subject: RE: [MERGE] Support VM Snapshot
> > > > >>
> > > > >> CS uses XenServer delta snapshot, snapshot manager records a
> > > > >> VHD chain in snapshot DB for each volume. VM snapshot
> > > > >> creation/revert also operate on volume snapshot, if snapshot
> > > > >> manager doesn't know the VM snapshot , volume snapshot might
> be broken.
> > > > >>
> > > > >>
> > > > >> You can try following test,
> > > > >>
> > > > >> 1. create a VM.
> > > > >> 2. create empty file test1 inside this VM.
> > > > >> 3. create a volume snapshot(s1) 4. create empty file test2
> > > > >> inside this VM 5. create a VM snapshot
> > > > >> (vm1)
> > > 6.
> > > > >> create empty file test3 inside this VM 7. create a volume
> > > > >> snapshot (s2)
> > > 8.
> > > > >> create a volume from snapshot (s2) 9. attach this volume to a
VM 10.
> > > > >> if one of test1, test2, test3 is missing in this volume, might
> > > > >> mean volume snapshot is broken.
> > > > >>
> > > > >>
> > > > >> It might be difficult to support both VM snapshot and volume
> > > > >> snapshot in the same time for hypervisor which supports delta
> > > snapshot.
> > > > >> Maybe we need to provide a zone level configuration for it,
> > > > >> only one is supported in a zone, volume snapshot or vm snapshot.
> > > > >>
> > > > >>
> > > > >>
> > > > >> Anthony
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> > -----Original Message-----
> > > > >> > From: Alex Huang
> > > > >> > Sent: Friday, February 01, 2013 10:54 AM
> > > > >> > To: Mice Xia; cloudstack-dev@incubator.apache.org
> > > > >> > Cc: Anthony Xu
> > > > >> > Subject: RE: [MERGE] Support VM Snapshot
> > > > >> >
> > > > >> > Mice,
> > > > >> >
> > > > >> > Thanks!
> > > > >> >
> > > > >> > Anthony,
> > > > >> >
> > > > >> > Can you comment on whether VM Snapshot breaks volume
> > > snapshot?
> > > > >> >
> > > > >> > --Alex
> > > > >> >
> > > > >> > > -----Original Message-----
> > > > >> > > From: Mice Xia [mailto:weiran.xia1@gmail.com]
> > > > >> > > Sent: Friday, February 01, 2013 8:53 AM
> > > > >> > > To: cloudstack-dev@incubator.apache.org; Alex Huang
> > > > >> > > Subject: Re: [MERGE] Support VM Snapshot
> > > > >> > >
> > > > >> > > as Alex suggested
> > > > >> > > updated vm-snapshot branch, commit ebca6890fd
> > > > >> > >
> > > > >> > > 1. remove snapshotting/revertting state from VM state
> > > > >> > > machine
> > > > >> > > 2  prevent VM state change if there are active vm snapshot
> > > > >> > > tasks
> > > > >> > > 3  change VMSnapshotService interface, except for
> > > > >> > > ListVMSnapshotCmd, need some time to replace it in
> > > > >> > > QueryService, maybe after merging to master
> > > > >> > > 4  remove unused methods and fix some typos
> > > > >> > >
> > > > >> > > Regards
> > > > >> > > Mice
> > > > >> > >
> > > > >> > > 2013/2/1 Mice Xia <mice_xia@tcloudcomputing.com>:
> > > > >> > > > Hi, Alex,
> > > > >> > > >
> > > > >> > > > Thanks for your feedbacks, please see my comments
inline.
> > > > >> > > >
> > > > >> > > > - VM states is designed for VM lifecycle.  Snapshot
is
> > > > >> > > > not part of
> > > > >> > VM life
> > > > >> > > cycle so therefore the state should not be there. 
I think
> > > > >> > > it make
> > > > >> > sense to add
> > > > >> > > attributes to VM that says "Do Not Change State" and
 who
> > > > >> > > changed the
> > > > >> > VM
> > > > >> > > to that state.  Then virtualmachinemanager must obey
that
> > > > >> > > until the
> > > > >> > external
> > > > >> > > caller changes the attribute to now you can change
state.
> > > > >> > > The would
> > > > >> > make
> > > > >> > > more sense and decouples snapshotting from vm lifecycle
> > > > management.
> > > > >> > > Snapshotting then has it's own state (which I see it
does
> already).
> > > > >> > If we want
> > > > >> > > to reflect that a vm snapshot is being taken of a VM,
> > > > >> > > that's a
> > > > >> > function of the
> > > > >> > > apiresponse module that gathers up everything about
a vm
> > > > >> > > but it
> > > > >> > shouldn't
> > > > >> > > be changed in the vm states.
> > > > >> > > >
> > > > >> > > > [mice] the reason that I added snapshotting/reverting
> > > > >> > > > state is that
> > > > >> > VM
> > > > >> > > could be in suspend/pause state during
> > > > >> > > snapshoting/reverting, which
> > > > >> > is
> > > > >> > > difficult to be categorized into existing states; and
> > > > >> > > during the
> > > > >> > process, VM
> > > > >> > > should not be allowed to take any operations; and by
adding
> > > > >> > > new
> > > > >> > states to
> > > > >> > > VM, the implementation seems more 'natural' and only
> > > > >> > > minimum codes
> > > > >> > are
> > > > >> > > changed to virtualmachinemanager.
> > > > >> > > > Of course there are some other ways to prevent
> > > > >> > > > operations, such as
> > > > >> > check
> > > > >> > > if associated snapshots are in snapshotting/reverting
> > > > >> > > states either
> > > > >> > in each
> > > > >> > > method (start/stop/migrate/delete...) or hook
> > > > >> > > stateTransitTo(), but
> > > > >> > in this
> > > > >> > > way, it does not reflect VM's real state in hypervisor
and
> > > > >> > > more
> > > > >> > existing codes
> > > > >> > > will be touched.
> > > > >> > > >
> > > > >> > > > -  Does VM Revert operation work in the following
way:
> > > > >> > > > Stop VM,
> > > > >> > restore
> > > > >> > > to snapshot, and run VM?  Shouldn't this be orchestration
> > > > >> > > inside
> > > > >> > snapshot
> > > > >> > > manager?
> > > > >> > > >
> > > > >> > > > [mice] if a running VM is reverted to a memory
enabled
> > > > >> > > > snapshot,
> > > > >> > current
> > > > >> > > implementation is running--> reverting-->running
> > > > >> > > > If a stopped VM is reverted to memory disabled
snapshot:
> > > > >> > > > stopped--
> > > > >> > > >reverting->stopped
> > > > >> > > > If a running VM is reverted to a memory disabled
snapshot:
> > > > >> > > > running-
> > > > >> > -(Stop
> > > > >> > > VM)-->stopped-->reverting--> stopped
> > > > >> > > > If a stopped VM is reverted to a memory enabled
snapshot:
> > > > >> > > > stopped--
> > > > >> > > (Start VM)-->running->reverting-->running
> > > > >> > > >
> > > > >> > > > These logics are implemented in snapshot manager.
> > > > >> > > >
> > > > >> > > > - Does VM snapshot interfere with volume snapshot?
> > > > >> > > > Volume snapshot
> > > > >> > > today makes the assumption that it is the only code
that's
> > > > >> > > making
> > > > >> > snapshots
> > > > >> > > and can break if there are additional snapshots in
between.
> > > > >> > > This is
> > > > >> > bad
> > > > >> > > design in volume snapshot but unfortunately that's
how it's
> > design.
> > > > >> > > >
> > > > >> > > > [mice] about volume snapshot, for xensever, if
parent VHD
> > > > >> > > > cannot be
> > > > >> > > found, it will take a full volume snapshot (this indeed
> > > > >> > > break current semantics but it still works)
> > > > >> > > > For vmware, the volume snapshot is always a full
one.
> > > > >> > > >
> > > > >> > > > - VMSnapshotService follows the other services
in passing
> > > > >> > > > the cmds
> > > > >> > to the
> > > > >> > > service.  That's really a bad practice that we should
stop.
> > > > >> > > Cmds are
> > > > >> > really
> > > > >> > > translations between over-the-wire api and java interface.
> > > > >> > > They
> > > > >> > shouldn't
> > > > >> > > have been passed to down to the java interface.
> > > > >> > > > [
> > > > >> > > > mice] I'll change it
> > > > >> > > >
> > > > >> > > > A small note: Would it be better to call it VM
restore
> > > > >> > > > than VM
> > > > >> > revert?
> > > > >> > > Revert really should be RevertTo which I think is in
the
> > > > >> > > code but is
> > > > >> > not
> > > > >> > > consistent.  Some places it's just REVERT (for example,
the
> > > > >> > > event is
> > > > >> > just
> > > > >> > > revert).
> > > > >> > > >
> > > > >> > > > [mice] there is already RESTORE, which is restoring
a
> > > > >> > > > destroyed VM
> > > > >> > to
> > > > >> > > stopped. RevertTo is fine with me.
> > > > >> > > >
> > > > >> > > > -Mice
> > > > >> > > >
> > > > >> > > >
> > > > >> > > > -----Original Message-----
> > > > >> > > > From: Alex Huang [mailto:Alex.Huang@citrix.com]
> > > > >> > > > Sent: Friday, February 01, 2013 9:24 AM
> > > > >> > > > To: CloudStack DeveloperList
> > > > >> > > > Cc: Mice Xia
> > > > >> > > > Subject: RE: [MERGE] Support VM Snapshot
> > > > >> > > >
> > > > >> > > > Hi Mice,
> > > > >> > > >
> > > > >> > > > Sorry it took so long to review this.  Wanted
to as soon
> > > > >> > > > as I saw
> > > > >> > it on the list
> > > > >> > > but was sick and didn't get a chance.  In general,
I think
> > > > >> > > the code
> > > > >> > is excellent.
> > > > >> > > I'm impressed how much Cloudstack internal code in
touch
> > > > >> > > and how comfortable the changes look.  Nicely done!
> > > > >> > > >
> > > > >> > > > I have a few comments:
> > > > >> > > > - VM states is designed for VM lifecycle.  Snapshot
is
> > > > >> > > > not part of
> > > > >> > VM life
> > > > >> > > cycle so therefore the state should not be there. 
I think
> > > > >> > > it make
> > > > >> > sense to add
> > > > >> > > attributes to VM that says "Do Not Change State" and
 who
> > > > >> > > changed the
> > > > >> > VM
> > > > >> > > to that state.  Then virtualmachinemanager must obey
that
> > > > >> > > until the
> > > > >> > external
> > > > >> > > caller changes the attribute to now you can change
state.
> > > > >> > > The would
> > > > >> > make
> > > > >> > > more sense and decouples snapshotting from vm lifecycle
> > > > management.
> > > > >> > > Snapshotting then has it's own state (which I see it
does
> already).
> > > > >> > If we want
> > > > >> > > to reflect that a vm snapshot is being taken of a VM,
> > > > >> > > that's a
> > > > >> > function of the
> > > > >> > > apiresponse module that gathers up everything about
a vm
> > > > >> > > but it
> > > > >> > shouldn't
> > > > >> > > be changed in the vm states.
> > > > >> > > > -  Does VM Revert operation work in the following
way:
> > > > >> > > > Stop VM,
> > > > >> > restore
> > > > >> > > to snapshot, and run VM?  Shouldn't this be orchestration
> > > > >> > > inside
> > > > >> > snapshot
> > > > >> > > manager?
> > > > >> > > > - Does VM snapshot interfere with volume snapshot?
> > > > >> > > > Volume snapshot
> > > > >> > > today makes the assumption that it is the only code
that's
> > > > >> > > making
> > > > >> > snapshots
> > > > >> > > and can break if there are additional snapshots in
between.
> > > > >> > > This is
> > > > >> > bad
> > > > >> > > design in volume snapshot but unfortunately that's
how it's
> > design.
> > > > >> > > > - VMSnapshotService follows the other services
in passing
> > > > >> > > > the cmds
> > > > >> > to the
> > > > >> > > service.  That's really a bad practice that we should
stop.
> > > > >> > > Cmds are
> > > > >> > really
> > > > >> > > translations between over-the-wire api and java interface.
> > > > >> > > They
> > > > >> > shouldn't
> > > > >> > > have been passed to down to the java interface.
> > > > >> > > >
> > > > >> > > > A small note: Would it be better to call it VM
restore
> > > > >> > > > than VM
> > > > >> > revert?
> > > > >> > > Revert really should be RevertTo which I think is in
the
> > > > >> > > code but is
> > > > >> > not
> > > > >> > > consistent.  Some places it's just REVERT (for example,
the
> > > > >> > > event is
> > > > >> > just
> > > > >> > > revert).
> > > > >> > > >
> > > > >> > > > --Alex
> > > > >> > > >
> > > > >> > > >> -----Original Message-----
> > > > >> > > >> From: Chiradeep Vittal
> > > > >> > > >> Sent: Wednesday, January 30, 2013 4:44 PM
> > > > >> > > >> To: CloudStack DeveloperList
> > > > >> > > >> Cc: Alex Huang
> > > > >> > > >> Subject: Re: [MERGE] Support VM Snapshot
> > > > >> > > >>
> > > > >> > > >> Can we get Alex to review this? He is the
designer of
> > > > >> > > >> the state
> > > > >> > machine.
> > > > >> > > >>
> > > > >> > > >> On 1/30/13 5:26 AM, "Murali Reddy"
> > > > >> > > >> <Murali.Reddy@citrix.com>
> > > > >> wrote:
> > > > >> > > >>
> > > > >> > > >> >On 30/01/13 2:24 PM, "Mice Xia"
> > > > >> > > >> ><mice_xia@tcloudcomputing.com>
> > > > >> > > wrote:
> > > > >> > > >> >
> > > > >> > > >> >>Agreed.
> > > > >> > > >> >>Adding VM states are likely to have
some side-effects,
> > > > >> > > >> >>but for moveVMToUser case, does it
explicitly reject
> > > > >> > > >> >>other transient
> > > > >> > states
> > > > >> > > >> >>such as stating/stopping/migrating?
> > > > >> > > >> >>
> > > > >> > > >> >>-Mice
> > > > >> > > >> >
> > > > >> > > >> >No, it just accepts any state other than
'Running'
> > > > >> > > >> >(though it
> > > > >> > should
> > > > >> > > >> >have checked for the valid states in which
VM can move
> > > > >> > > >> >to other
> > > > >> > user).
> > > > >> > > >> >
> > > > >> > > >> >I am just saying, there could such VM
state based
> > > > >> > > >> >assumptions,
> > > > >> > you
> > > > >> > > >> >might want to check.
> > > > >> > > >> >
> > > > >> > > >
> > > > >
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