Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/25/2012 11:13 PM, Itamar Heim wrote: On 06/25/2012 10:14 AM, Deepak C Shetty wrote: On 06/25/2012 07:47 AM, Shu Ming wrote: On 2012-6-25 10:10, Andrew Cathrow wrote: - Original Message - From: Andy Grover agro...@redhat.com To: Shu Ming shum...@linux.vnet.ibm.com Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org, VDSM Project Development vdsm-devel@lists.fedorahosted.org Sent: Sunday, June 24, 2012 10:05:45 PM Subject: Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration On 06/24/2012 07:28 AM, Shu Ming wrote: On 2012-6-23 20:40, Itamar Heim wrote: On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM. OK my mistake, we don't pause the VM during live snapshot, we block on access to the luns while snapshotting. Does this keep live snapshots working and mean ovirt-engine can use libsm to config the storage array instead of vdsm? Because that was really my main question, should we be talking about engine-libstoragemgmt integration rather than vdsm-libstoragemgmt integration. for snapshotting wouldn't we want VDSM to handle the coordination of the various atomic functions? I think VDSM-libstoragemgmt will let the storage array itself to make the snapshot and handle the coordination of the various atomic functions. VDSM should be blocked on the following access to the specific luns which are under snapshotting. I kind of agree. If snapshot is being done at the array level, then the array takes care of quiesing the I/O, taking the snapshot and allowing the I/O, why does VDSM have to worry about anything here, it should all happen transparently for VDSM, isnt it ? I may be misssing something, but afaiu you need to ask the guest to perform the quiesce, and i'm sure the storage array can't do that. No, you are not, I missed it. After Tony Shu Ming's reply, I realised that the guest has to quiese the I/O before VDSM can ask storage array to take the snapshot. ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/19/2012 01:45 AM, Saggi Mizrahi wrote: First of all I'd like to suggest not using the LSM acronym as it can also mean live-storage-migration and maybe other things. Sure, what do you suggest ? libSM ? Secondly I would like to avoid talking about what needs to be changed in VDSM before we figure out what exactly we want to accomplish. Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? Per my original discussion on this with Ayal, this is what he had suggested... In addition, I'm assuming we will either need a new 'storage array' entity in engine to keep credentials, or, in case of storage array as storage domain, just keep this info as part of the domain at engine level. Either we can have the libstoragemgmt cred stored in the engine as part of engine-setup or have the user input them as part of Storage Prov and user clicks on remember cred button, so engine saves it and passes it to VDSM as needed ? In any way, the cred should come from the user/admin, no other way correct ? In the array as domain case. How are the luns being mapped to initiators. What about setting discovery credentials. In the array set up case. How will the hosts be represented in regards to credentials? How will the different schemes and capabilities in regard to authentication methods will be expressed. Not clear on what the concern here is. Can you pls provide more clarity on the problem here ? Maybe providing some examples will help. Rest of the comments inline - Original Message - From: Deepak C Shettydeepa...@linux.vnet.ibm.com To: VDSM Project Developmentvdsm-devel@lists.fedorahosted.org Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org Sent: Wednesday, May 30, 2012 5:38:46 AM Subject: [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration Hello All, I have a draft write-up on the VDSM-libstoragemgmt integration. I wanted to run this thru' the mailing list(s) to help tune and crystallize it, before putting it on the ovirt wiki. I have run this once thru Ayal and Tony, so have some of their comments incorporated. I still have few doubts/questions, which I have posted below with lines ending with '?' Comments / Suggestions are welcome appreciated. thanx, deepak [Ccing engine-devel and libstoragemgmt lists as this stuff is relevant to them too] -- 1) Background: VDSM provides high level API for node virtualization management. It acts in response to the requests sent by oVirt Engine, which uses VDSM to do all node virtualization related tasks, including but not limited to storage management. libstoragemgmt aims to provide vendor agnostic API for managing external storage array. It should help system administrators utilizing open source solutions have a way to programmatically manage their storage hardware in a vendor neutral way. It also aims to facilitate management automation, ease of use and take advantage of storage vendor supported features which improve storage performance and space utilization. Home Page: http://sourceforge.net/apps/trac/libstoragemgmt/ libstoragemgmt (LSM) today supports C and python plugins for talking to external storage array using SMI-S as well as native interfaces (eg: netapp plugin ) Plan is to grow the SMI-S interface as needed over time and add more vendor specific plugins for exploiting features not possible via SMI-S or have better alternatives than using SMI-S. For eg: Many of the copy offload features require to use vendor specific commands, which justifies the need for a vendor specific plugin. 2) Goals: 2a) Ability to plugin external storage array into oVirt/VDSM virtualization stack, in a vendor neutral way. 2b) Ability to list features/capabilities and other statistical info of the array 2c) Ability to utilize the storage array offload capabilities from oVirt/VDSM. 3) Details: LSM will sit as a new repository engine in VDSM. VDSM Repository Engine WIP @ http://gerrit.ovirt.org/#change,192 Current plan is to have LSM co-exist with VDSM on the virtualization nodes. *Note : 'storage' used below is generic. It can be a file/nfs-export for NAS targets and LUN/logical-drive for SAN targets. VDSM can use LSM and do the following... - Provision storage - Consume storage 3.1) Provisioning Storage using LSM Typically this will be done by a Storage administrator. oVirt/VDSM should provide storage admin the - ability to list the different storage arrays along with their types (NAS/SAN), capabilities, free/used space. - ability to provision storage using any of the array capabilities (eg: thin provisioned lun or new NFS export ) - ability to manage the provisioned storage
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/25/2012 08:28 PM, Ryan Harper wrote: * Andrew Cathrowacath...@redhat.com [2012-06-24 21:11]: - Original Message - From: Andy Groveragro...@redhat.com To: Shu Mingshum...@linux.vnet.ibm.com Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org, VDSM Project Development vdsm-devel@lists.fedorahosted.org Sent: Sunday, June 24, 2012 10:05:45 PM Subject: Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration On 06/24/2012 07:28 AM, Shu Ming wrote: On 2012-6-23 20:40, Itamar Heim wrote: On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM. OK my mistake, we don't pause the VM during live snapshot, we block on access to the luns while snapshotting. Does this keep live snapshots working and mean ovirt-engine can use libsm to config the storage array instead of vdsm? Because that was really my main question, should we be talking about engine-libstoragemgmt integration rather than vdsm-libstoragemgmt integration. for snapshotting wouldn't we want VDSM to handle the coordination of the various atomic functions? Absolutely. Requiring every management application (engine, etc) to integrate with libstoragemanagement is a win here. We want to simplify working with KVM, storage, etc not require every mgmt application to know deep details about how to create a live VM snapshot. Sorry, but not clear to me. Are you saying engine-libstoragemgmt integration is a win here ? VDSM is the common factor here.. so integrating libstoragemgmt with VDSM helps anybody talkign with VDSM in future AFAIU. ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
* Deepak C Shetty deepa...@linux.vnet.ibm.com [2012-06-25 10:14]: On 06/25/2012 08:28 PM, Ryan Harper wrote: * Andrew Cathrowacath...@redhat.com [2012-06-24 21:11]: - Original Message - From: Andy Groveragro...@redhat.com To: Shu Mingshum...@linux.vnet.ibm.com Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org, VDSM Project Development vdsm-devel@lists.fedorahosted.org Sent: Sunday, June 24, 2012 10:05:45 PM Subject: Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration On 06/24/2012 07:28 AM, Shu Ming wrote: On 2012-6-23 20:40, Itamar Heim wrote: On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM. OK my mistake, we don't pause the VM during live snapshot, we block on access to the luns while snapshotting. Does this keep live snapshots working and mean ovirt-engine can use libsm to config the storage array instead of vdsm? Because that was really my main question, should we be talking about engine-libstoragemgmt integration rather than vdsm-libstoragemgmt integration. for snapshotting wouldn't we want VDSM to handle the coordination of the various atomic functions? Absolutely. Requiring every management application (engine, etc) to integrate with libstoragemanagement is a win here. We want to simplify working with KVM, storage, etc not require every mgmt application to know deep details about how to create a live VM snapshot. Sorry, but not clear to me. Are you saying engine-libstoragemgmt integration is a win here ? Sorry if I wasn't clear. To answer your question: No. The mgmt app should *NOT* have to learn all of the ins and outs of the end-point storage and the management of it. VDSM is the common factor here.. so integrating libstoragemgmt with VDSM helps anybody talkign with VDSM in future AFAIU. Yes. 100% agree. -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx ry...@us.ibm.com ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/25/2012 08:17 AM, Ryan Harper wrote: * Deepak C Shetty deepa...@linux.vnet.ibm.com [2012-06-25 10:14]: On 06/25/2012 08:28 PM, Ryan Harper wrote: The mgmt app should *NOT* have to learn all of the ins and outs of the end-point storage and the management of it. VDSM is the common factor here.. so integrating libstoragemgmt with VDSM helps anybody talkign with VDSM in future AFAIU. Yes. 100% agree. Thanks, this has helped me understand vdsm's role much better. -- Andy ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/25/2012 10:14 AM, Deepak C Shetty wrote: On 06/25/2012 07:47 AM, Shu Ming wrote: On 2012-6-25 10:10, Andrew Cathrow wrote: - Original Message - From: Andy Grover agro...@redhat.com To: Shu Ming shum...@linux.vnet.ibm.com Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org, VDSM Project Development vdsm-devel@lists.fedorahosted.org Sent: Sunday, June 24, 2012 10:05:45 PM Subject: Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration On 06/24/2012 07:28 AM, Shu Ming wrote: On 2012-6-23 20:40, Itamar Heim wrote: On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM. OK my mistake, we don't pause the VM during live snapshot, we block on access to the luns while snapshotting. Does this keep live snapshots working and mean ovirt-engine can use libsm to config the storage array instead of vdsm? Because that was really my main question, should we be talking about engine-libstoragemgmt integration rather than vdsm-libstoragemgmt integration. for snapshotting wouldn't we want VDSM to handle the coordination of the various atomic functions? I think VDSM-libstoragemgmt will let the storage array itself to make the snapshot and handle the coordination of the various atomic functions. VDSM should be blocked on the following access to the specific luns which are under snapshotting. I kind of agree. If snapshot is being done at the array level, then the array takes care of quiesing the I/O, taking the snapshot and allowing the I/O, why does VDSM have to worry about anything here, it should all happen transparently for VDSM, isnt it ? I may be misssing something, but afaiu you need to ask the guest to perform the quiesce, and i'm sure the storage array can't do that. ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 2012-6-23 20:40, Itamar Heim wrote: On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM. engine - libstoragemgmt snapshot luns 1, 2 to luns 3, 4 engine - vdsm snapshot running state of X to Y engine - vdsm unpause vm X if engine had any failure before this step, the VM will remain paused. i.e., we compromised the VM to take a live snapshot. engine - vdsm change Y to use luns 3, 4 ? -- Andy ___ Engine-devel mailing list engine-de...@ovirt.org http://lists.ovirt.org/mailman/listinfo/engine-devel -- Shu Ming shum...@linux.vnet.ibm.com IBM China Systems and Technology Laboratory ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
- Original Message - From: Andy Grover agro...@redhat.com To: Shu Ming shum...@linux.vnet.ibm.com Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org, VDSM Project Development vdsm-devel@lists.fedorahosted.org Sent: Sunday, June 24, 2012 10:05:45 PM Subject: Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration On 06/24/2012 07:28 AM, Shu Ming wrote: On 2012-6-23 20:40, Itamar Heim wrote: On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. Tough we don't expect to do a pausing operation to the VM when live snaphot is undergoing, the VM should be blocked on the access to specific luns for a while. The blocking time should be very short to avoid the storage IO time out in the VM. OK my mistake, we don't pause the VM during live snapshot, we block on access to the luns while snapshotting. Does this keep live snapshots working and mean ovirt-engine can use libsm to config the storage array instead of vdsm? Because that was really my main question, should we be talking about engine-libstoragemgmt integration rather than vdsm-libstoragemgmt integration. for snapshotting wouldn't we want VDSM to handle the coordination of the various atomic functions? Thanks -- Regards -- Andy ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/23/2012 03:09 AM, Andy Grover wrote: On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X that's pausing the VM. live snapshot isn't supposed to do so. engine - libstoragemgmt snapshot luns 1, 2 to luns 3, 4 engine - vdsm snapshot running state of X to Y engine - vdsm unpause vm X if engine had any failure before this step, the VM will remain paused. i.e., we compromised the VM to take a live snapshot. engine - vdsm change Y to use luns 3, 4 ? -- Andy ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? Thanks -- Regards -- Andy ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
On 06/22/2012 04:46 PM, Itamar Heim wrote: On 06/23/2012 02:31 AM, Andy Grover wrote: On 06/18/2012 01:15 PM, Saggi Mizrahi wrote: Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? It seems to me more natural to have the oVirt-engine use libstoragemgmt directly to allocate and export a volume on the storage array, and then pass this info to the vdsm on the node creating the vm. This answers Saggi's question about creds -- vdsm never needs array modification creds, it only gets handed the params needed to connect and use the new block device (ip, iqn, chap, lun). Is this usage model made difficult or impossible by the current software architecture? what about live snapshots? I'm not a virt guy, so extreme handwaving: vm X uses luns 1 2 engine - vdsm pause vm X engine - libstoragemgmt snapshot luns 1, 2 to luns 3, 4 engine - vdsm snapshot running state of X to Y engine - vdsm unpause vm X engine - vdsm change Y to use luns 3, 4 ? -- Andy ___ vdsm-devel mailing list vdsm-devel@lists.fedorahosted.org https://fedorahosted.org/mailman/listinfo/vdsm-devel
Re: [vdsm] [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration
First of all I'd like to suggest not using the LSM acronym as it can also mean live-storage-migration and maybe other things. Secondly I would like to avoid talking about what needs to be changed in VDSM before we figure out what exactly we want to accomplish. Also, there is no mention on credentials in any part of the process. How does VDSM or the host get access to actually modify the storage array? Who holds the creds for that and how? How does the user set this up? In the array as domain case. How are the luns being mapped to initiators. What about setting discovery credentials. In the array set up case. How will the hosts be represented in regards to credentials? How will the different schemes and capabilities in regard to authentication methods will be expressed. Rest of the comments inline - Original Message - From: Deepak C Shetty deepa...@linux.vnet.ibm.com To: VDSM Project Development vdsm-devel@lists.fedorahosted.org Cc: libstoragemgmt-de...@lists.sourceforge.net, engine-de...@ovirt.org Sent: Wednesday, May 30, 2012 5:38:46 AM Subject: [Engine-devel] RFC: Writeup on VDSM-libstoragemgmt integration Hello All, I have a draft write-up on the VDSM-libstoragemgmt integration. I wanted to run this thru' the mailing list(s) to help tune and crystallize it, before putting it on the ovirt wiki. I have run this once thru Ayal and Tony, so have some of their comments incorporated. I still have few doubts/questions, which I have posted below with lines ending with '?' Comments / Suggestions are welcome appreciated. thanx, deepak [Ccing engine-devel and libstoragemgmt lists as this stuff is relevant to them too] -- 1) Background: VDSM provides high level API for node virtualization management. It acts in response to the requests sent by oVirt Engine, which uses VDSM to do all node virtualization related tasks, including but not limited to storage management. libstoragemgmt aims to provide vendor agnostic API for managing external storage array. It should help system administrators utilizing open source solutions have a way to programmatically manage their storage hardware in a vendor neutral way. It also aims to facilitate management automation, ease of use and take advantage of storage vendor supported features which improve storage performance and space utilization. Home Page: http://sourceforge.net/apps/trac/libstoragemgmt/ libstoragemgmt (LSM) today supports C and python plugins for talking to external storage array using SMI-S as well as native interfaces (eg: netapp plugin ) Plan is to grow the SMI-S interface as needed over time and add more vendor specific plugins for exploiting features not possible via SMI-S or have better alternatives than using SMI-S. For eg: Many of the copy offload features require to use vendor specific commands, which justifies the need for a vendor specific plugin. 2) Goals: 2a) Ability to plugin external storage array into oVirt/VDSM virtualization stack, in a vendor neutral way. 2b) Ability to list features/capabilities and other statistical info of the array 2c) Ability to utilize the storage array offload capabilities from oVirt/VDSM. 3) Details: LSM will sit as a new repository engine in VDSM. VDSM Repository Engine WIP @ http://gerrit.ovirt.org/#change,192 Current plan is to have LSM co-exist with VDSM on the virtualization nodes. *Note : 'storage' used below is generic. It can be a file/nfs-export for NAS targets and LUN/logical-drive for SAN targets. VDSM can use LSM and do the following... - Provision storage - Consume storage 3.1) Provisioning Storage using LSM Typically this will be done by a Storage administrator. oVirt/VDSM should provide storage admin the - ability to list the different storage arrays along with their types (NAS/SAN), capabilities, free/used space. - ability to provision storage using any of the array capabilities (eg: thin provisioned lun or new NFS export ) - ability to manage the provisioned storage (eg: resize/delete storage) Once the storage is provisioned by the storage admin, VDSM will have to refresh the host(s) for them to be able to see the newly provisioned storage. [SM] What about the clustered case, The management or the mailbox will have to be involved. Pros\Cons? Is there a capability for the storage to announce a change in topology? Can libstoragemgmt consume it? Does it even make sense? 3.1.1) Potential flows: Mgmt - vdsm - lsm: create LUN + LUN Mapping / Zoning / whatever is needed to make LUN available to list of hosts passed by mgmt Mgmt - vdsm: getDeviceList (refreshes host and gets list of devices) Repeat above for all relevant hosts (depending on list passed earlier, mostly relevant
