So it only affects managed storage? From: Mike Tutkowski <mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>> Date: Friday, March 28, 2014 at 4:10 PM To: Alena Prokharchyk <alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>> Cc: "dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>" <dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>, "shadow...@gmail.com<mailto:shadow...@gmail.com>" <shadow...@gmail.com<mailto:shadow...@gmail.com>> Subject: Re: [PROPOSAL] ROOT volume detach - feature for CS 4.5
Let me illustrate this with an example: * User creates a VM whose root disk is placed on managed storage * Storage plug-in creates a volume on its SAN * VMware server resource creates a datastore based on the newly created SAN volume (let me stress that this datastore was created by the VMware server resource - not manually by an admin as would be the case for non-managed storage) * Inside the datastore are placed the VMDK file (root disk) along with VM config files like VMX, NVRAM, etc. * User detaches the root volume (the VMDK file and VM config files remain in the datastore) * User attaches another root volume to the VM (the VMDK file is stored in a datastore different from the datastore where the VM config files reside, which is fine for now) * User deletes and expunges the original root disk (this leads to the datastore the VMDK file is on being removed...as a side effect, you will also lose your VM config files), SAN volume is deleted, CloudStack volume is marked as deleted in the database On Fri, Mar 28, 2014 at 5:05 PM, Mike Tutkowski <mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>> wrote: So, do you guys see my concern with VMware, though? VMware is different from XenServer and KVM in that its VM config files are stored in the datastore along side the root volume (in CloudStack 4.3, for example). If you switch the VM to use a VMDK file in a different datastore, the config files will remain in the original datastore (unless we transfer them ourselves to the new datastore). If they remain in the original datastore and that disk is deleted later, the datastore that contains that disk will be removed (along with the VM config files that are new being used in conjunction with a disk in another datastore). On Fri, Mar 28, 2014 at 4:58 PM, Alena Prokharchyk <alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>> wrote: On 3/28/14, 3:50 PM, "Marcus" <shadow...@gmail.com<mailto:shadow...@gmail.com>> wrote: > I see this feature as mainly just shuffling around object properties >in the database. I don't expect any major issues to arise with any >storage if an inactive "root" disk is marked as a "data" disk in the >DB, for example. In the end, when you start a VM you're always going >to have a root disk in the vm instance object, and volumes that are >attached/detached are going to be passed as data disks (If I >understand correctly). It doesn't really matter to the storage drivers >if the volume object was previously of type root or data. Correct. That¹s what I reflected in the spec. But I¹m going to test it on all major supported hypervisors - KVM/Xen/VmWare - anyway, just to be 100% sure nothing breaks. > >On Fri, Mar 28, 2014 at 12:48 PM, Alena Prokharchyk ><alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>> wrote: >> I will look into it more, Mike. vmWare indeed can be different. >> >> -Alena. >> >> From: Mike Tutkowski >><mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>>> >> Date: Friday, March 28, 2014 at 11:39 AM >> To: Alena Prokharchyk >><alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>>> >> Cc: >> "dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>" >><dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>> >> Subject: Re: [PROPOSAL] ROOT volume detach - feature for CS 4.5 >> >> VMware is also different because when you shut a VMware VM down from >>CloudStack, the VM still exists in vCenter Server (whereas for XenServer >>and KVM, the VM is gone). >> >> Since the life of a datastore that was created for managed storage is >>tied to the life of the CloudStack volume it stores, when the CloudStack >>volume is deleted, the datastore goes away, as well. >> >> If the datastore in question was automatically created to store a root >>disk (alongside VM config files) and you switch the VM to another root >>disk (which has to necessarily be in another datastore), you won't see a >>problem until the original root volume is expunged by CloudStack. At >>this point, its datastore will go away along with your VM config files. >> >> >> On Fri, Mar 28, 2014 at 12:31 PM, Mike Tutkowski >><mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>>> >>wrote: >> Well, the reason I brought it up was mainly due to VMware. >> >> Let's use that as an example: >> >> I initiate the process of spinning up a VM based on managed storage. >> A volume is dynamically created on a SAN. >> VmwareStorageProcessor dynamically creates a datastore to consume the >>newly created SAN volume. >> All VMware VM files (ex. VMX, NVRAM) are placed in the datastore >>alongside the VMDK file that represents the root volume. >> >> Now, let's say we want to detach this root volume and give the VM a new >>root volume. >> >> The new root volume will necessarily be on a different datastore than >>the datastore of the previous root volume (because a datastore created >>to consume managed storage will have at most one VMDK file*). >> >> Is it going to be a problem that the VM's files (ex. VMX, NVRAM) are on >>one datastore, but its root disk is on another? >> >> I don't think it's really a problem until you go to delete the original >>root volume from CloudStack. At that point, its datastore will be >>removed (including, of course, your VM's VMX, NVRAM, etc. files). >> >> This is not really a problem on XenServer because XenServer does not >>store VM config files in the SR, so I think we're OK there. >> >> We should also be OK for KVM. >> >> * Technically it can have many if those other VMDK files are delta >>snapshots, but they still - together - represent a single disk. >> >> >> On Fri, Mar 28, 2014 at 10:36 AM, Alena Prokharchyk >><alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>>> >>wrote: >> Mike, thank you for the explanation on managed storage.. As far as I >>understand from your email, the main difference is instead of creating >>an SR on the PS, CloudStack will recognize pre-existing volume created >>outside of the CS. Am I correct? >> >> If so, I don't think there would be any difference. When root volume >>detach happens, no storage attributes - path, clusterId - are being >>changed. And we would apply the same set of checks to the root volume >>attach, as for a dataDisk attach. >> >> -Alena. >> >> From: Mike Tutkowski >><mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>>> >> Date: Thursday, March 27, 2014 at 9:40 PM >> To: Alena Prokharchyk >><alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>>> >> Cc: >> "dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>" >><dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>> >> Subject: Re: [PROPOSAL] ROOT volume detach - feature for CS 4.5 >> >> Hi Alena, >> >> I was wondering if you've taken "managed" storage into consideration >>for this? >> >> If you're unfamiliar with it, managed storage is named as such because >>CloudStack manages it on behalf of the admin (ex. dynamically creating >>SRs as needed). >> >> For example, when I add primary storage to CloudStack that is based on >>the SolidFire SAN, I use the SolidFire plug-in, which is an example of >>managed storage. >> >> In this case, the primary storage represents a SAN as opposed to a >>preallocated volume. >> >> When the time comes to, say, attach a data disk to a VM for the first >>time, the SolidFire plug-in goes off to its SAN and dynamically creates >>a new volume on it (with the appropriate size and IOPS requirements). >> >> CloudStack has logic that recognizes managed storage. >> >> For example, for XenServer, its logic has been augmented to >>automatically create an SR based on the iSCSI target that was created on >>the SAN and to create a VDI within it that is attached to the VM in >>question. >> >> The big takeaway is that each CloudStack volume here will be associated >>with a unique volume on a SAN and consumed as an SR (XenServer) or >>datastore (ESX) (KVM handles this differently). In this situation, there >>is a 1:1 mapping between a SAN volume and an SR. No other VDIs are >>stored on the SR except for the one representing this one CloudStack >>volume. >> >> That being the case, I was wondering what you thought of this with >>regards to your root-volume-detach feature? >> >> If we don't want to look into this for 4.5, it might be best to simply >>fail to detach a root volume from a VM if the volume is based on managed >>storage or to fail to attach a bootable volume to a VM if it is based on >>managed storage. >> >> Talk to you later, >> Mike >> >> >> On Tue, Mar 25, 2014 at 1:24 PM, Alena Prokharchyk >><alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>>> >>wrote: >> Mike, >> >> Volume has a template_id referencing vm_template table. Vm_template has >> bootable flag, so we will derive information from there. >> And sure, this information will not change if the root disk is detached. >> >> On 3/25/14, 12:18 PM, "Mike Tutkowski" >><mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>>> >> wrote: >> >>>Hi Alena, >>> >>>I was wondering how we plan to keep track of the new "bootable" >>>property? >>>When we create a VM, would we just mark its root disk as bootable and >>>then >>>that property becomes immutable (for the upgrade case, all root disks >>>would >>>be marked as bootable)? >>> >>>I'm thinking we'd want to keep track of bootable disks even when there >>>are >>>detached and turned into data disks. Is that what you had in mind? >>> >>>Thanks! >>>Mike >>> >>> >>>On Tue, Mar 25, 2014 at 12:20 PM, Alena Prokharchyk < >>>alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>>> >>>wrote: >>> >>>> Here is the link to the corresponding FS (placed in "4.5 Design >>>>documents" >>>> section) >>>> >>>> >>>>https://cwiki.apache.org/confluence/display/CLOUDSTACK/ROOT+volume+deta >>>>ch >>>> >>>> -Alena. >>>> >>>> From: Alena Prokharchyk >>>><alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>><mail >>>>to: >>>> alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com><mailto:alena.prokharc...@citrix.com<mailto:alena.prokharc...@citrix.com>>>> >>>> Date: Monday, March 24, 2014 at 11:37 AM >>>> To: >>>>"dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>><mailto:dev<mailto:dev> >>>>@cloudstack.apache.org<http://cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>>" >>>> < >>>> >>>>dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>><mailto:dev@<mailto:dev@> >>>>cloudstack.apache.org<http://cloudstack.apache.org><mailto:dev@cloudstack.apache.org<mailto:dev@cloudstack.apache.org>>>> >>>> Subject: [PROPOSAL] ROOT volume detach - feature for CS 4.5 >>>> >>>> I would like to propose a new feature for CS 4.5 - "ROOT volume >>>>detach" >>>>- >>>> that enables support for following use cases: >>>> >>>> 1) Replace current ROOT volume with the new one for existing vm. >>>> 2) Case when ROOT volume of vm1 gets corrupted, and you want to attach >>>>it >>>> to vm2 to run the recovery utils on it. With current CS implemntation, >>>>you >>>> have to perform several steps - create snapshot of vm1's volume, >>>>create >>>> volume from snapshot, attach volume to the vm2. New implementation >>>>will >>>> merge it all to one step. >>>> >>>> >>>> With the planned implementation, once the ROOT volume is detached, it >>>>can >>>> be attached to any existing vm (with respect to Admin/Domain/Physical >>>> resources limitations), either as a DataDisk or a Root disk. >>>> >>>> Amazon EC2 already has this functionality in place, so I think CS >>>>would >>>> only benefit from having it. Storage experts (Edison, others) please >>>>raise >>>> your concerns if you have any, or if you see any potential problems >>>>with >>>> the planned implementation. And if anyone can think of other use cases >>>>this >>>> feature can possible solve, I would appreciate this input as well. >>>> >>>> >>>> Feature limitations: >>>> >>>> * ROOT volume can be detached only when vm is in Stopped state >>>> * CS will fail to start the vm not having a ROOT volume >>>> >>>> I will send out the link to the FS once I start getting feedback on >>>>the >>>> proposal. >>>> >>>> -Alena. >>>> >>> >>> >>> >>>-- >>>*Mike Tutkowski* >>>*Senior CloudStack Developer, SolidFire Inc.* >>>e: >>>mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>> >>>o: 303.746.7302<tel:303.746.7302><tel:303.746.7302<tel:303.746.7302>> >>>Advancing the way the world uses the >>>cloud<http://solidfire.com/solution/overview/?video=play> >>>*(tm)* >> >> >> >> >> -- >> Mike Tutkowski >> Senior CloudStack Developer, SolidFire Inc. >> e: >> mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>> >> o: 303.746.7302<tel:303.746.7302><tel:303.746.7302<tel:303.746.7302>> >> Advancing the way the world uses the >>cloud<http://solidfire.com/solution/overview/?video=play>(tm) >> >> >> >> -- >> Mike Tutkowski >> Senior CloudStack Developer, SolidFire Inc. >> e: >> mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>> >> o: 303.746.7302<tel:303.746.7302><tel:303.746.7302<tel:303.746.7302>> >> Advancing the way the world uses the >>cloud<http://solidfire.com/solution/overview/?video=play>(tm) >> >> >> >> -- >> Mike Tutkowski >> Senior CloudStack Developer, SolidFire Inc. >> e: >> mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com><mailto:mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com>> >> o: 303.746.7302<tel:303.746.7302> >> Advancing the way the world uses the >>cloud<http://solidfire.com/solution/overview/?video=play>(tm) -- Mike Tutkowski Senior CloudStack Developer, SolidFire Inc. e: mike.tutkow...@solidfire.com<mailto:mike.tutkow...@solidfire.com> o: 303.746.7302<tel: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<mailto:mike.tutkow...@solidfire.com> o: 303.746.7302 Advancing the way the world uses the cloud<http://solidfire.com/solution/overview/?video=play>™
