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.chaturv...@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...@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_...@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...@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.x...@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_...@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.hu...@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.re...@citrix.com> >> wrote: >> > > >> >> > > >> >On 30/01/13 2:24 PM, "Mice Xia" <mice_...@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. >> > > >> > >> > > > >
