2015-01-06 13:08 GMT+08:00 Sage Weil <sage@xxxxxxxxxxxx>: > On Tue, 6 Jan 2015, Wei-Chung Cheng wrote: >> Dear all: >> >> I agree Robert opinion because I hit the similar problem once. >> I think that how to handle journal partition is another problem about >> destroy subcommand. >> (Although it will work normally most time) >> >> I also agree we need the "secure erase" feature. >> As my experience, I just make new label for disk by "parted" command. >> I will think how could we do a secure erase or someone have a good >> idea for this? > > The simplest secure erase is to encrypt the disk and destroy the key. You > can do that with dm-crypt today. Most drives also will do this in the > firmware but I'm not familiar with the toolchain needed to use that > feature. (It would be much preferable to go that route, though, since it > will avoid any CPU overhead.) > > sage I think I got some misunderstanding. The secure erase means how to handle the disk which have encrypt feature (SED disk)? or it means that encrypt the disk by dm-crypt? Would Travis describe the "secure erase" more detailly? very thanks! vicente > > >> >> Anyway, I rework and implement the deactivate first. >> >> >> >> >> 2015-01-06 8:42 GMT+08:00 Robert LeBlanc <robert@xxxxxxxxxxxxx>: >> > I do think the "find a journal partition" code isn't particularly robust. >> > I've had experiences with ceph-disk trying to create a new partition even >> > though I had wiped/zapped a disk previously. It would make the operational >> > component of Ceph much easier with replacing disks if the journal partition >> > is cleanly removed and able to be reused automatically. >> > >> > On Mon, Jan 5, 2015 at 11:18 AM, Sage Weil <sage@xxxxxxxxxxxx> wrote: >> >> On Mon, 5 Jan 2015, Travis Rhoden wrote: >> >>> On Mon, Jan 5, 2015 at 12:27 PM, Sage Weil <sage@xxxxxxxxxxxx> wrote: >> >>> > On Mon, 5 Jan 2015, Travis Rhoden wrote: >> >>> >> Hi Loic and Wido, >> >>> >> >> >>> >> Loic - I agree with you that it makes more sense to implement the core >> >>> >> of the logic in ceph-disk where it can be re-used by other tools (like >> >>> >> ceph-deploy) or by administrators directly. There are a lot of >> >>> >> conventions put in place by ceph-disk such that ceph-disk is the best >> >>> >> place to undo them as part of clean-up. I'll pursue this with other >> >>> >> Ceph devs to see if I can get agreement on the best approach. >> >>> >> >> >>> >> At a high-level, ceph-disk has two commands that I think could have a >> >>> >> corollary -- prepare, and activate. >> >>> >> >> >>> >> Prepare will format and mkfs a disk/dir as needed to make it usable by Ceph. >> >>> >> Activate will put the resulting disk/dir into service by allocating an >> >>> >> OSD ID, creating the cephx key, and marking the init system as needed, >> >>> >> and finally starting the ceph-osd service. >> >>> >> >> >>> >> It seems like there could be two opposite commands that do the following: >> >>> >> >> >>> >> deactivate: >> >>> >> - set "ceph osd out" >> >>> > >> >>> > I don't think 'out out' belongs at all. It's redundant (and extra work) >> >>> > if we remove the osd from the CRUSH map. I would imagine it being a >> >>> > possibly independent step. I.e., >> >>> > >> >>> > - drain (by setting CRUSH weight to 0) >> >>> > - wait >> >>> > - deactivate >> >>> > - (maybe) destroy >> >>> > >> >>> > That would make deactivate >> >>> > >> >>> >> - stop ceph-osd service if needed >> >>> >> - remove OSD from CRUSH map >> >>> >> - remove OSD cephx key >> >>> >> - deallocate OSD ID >> >>> >> - remove 'ready', 'active', and INIT-specific files (to Wido's point) >> >>> >> - umount device and remove mount point >> >>> > >> >>> > which I think make sense if the next step is to destroy or to move the >> >>> > disk to another box. In the latter case the data will likely need to move >> >>> > to another disk anyway so keeping it around it just a data safety thing >> >>> > (keep as many copies as possible). >> >>> > >> >>> > OTOH, if you clear out the OSD id then deactivate isn't reversible >> >>> > with activate as the OSD might be a new id even if it isn't moved. An >> >>> > alternative approach might be >> >>> > >> >>> > deactivate: >> >>> > - stop ceph-osd service if needed >> >>> > - remove 'ready', 'active', and INIT-specific files (to Wido's point) >> >>> > - umount device and remove mount point >> >>> >> >>> Good point. It would be a very nice result if activate/deactivate >> >>> were reversible by each other. perhaps that should be the guiding >> >>> principle, with any additional steps pushed off to other commands, >> >>> such as destroy... >> >>> >> >>> > >> >>> > destroy: >> >>> > - remove OSD from CRUSH map >> >>> > - remove OSD cephx key >> >>> > - deallocate OSD ID >> >>> > - destroy data >> >>> >> >>> I like this demarcation between deactivate and destroy. >> >>> >> >>> > >> >>> > It's not quite true that the OSD ID should be preserved if the data >> >>> > is, but I don't think there is harm in associating the two... >> >>> >> >>> What if we make destroy data optional by using the --zap flag? Or, >> >>> since zap is just removing the partition table, do we want to add more >> >>> of a "secure erase" feature? Almost seems like that is difficult >> >>> precedent. There are so many ways of trying to "securely" erase data >> >>> out there that that may be best left to the policies of the cluster >> >>> administrator(s). In that case, --zap would still be a good middle >> >>> ground, but you should do more if you want to be extra secure. >> >> >> >> Sounds good to me! >> >> >> >>> One other question -- should we be doing anything with the journals? >> >> >> >> I think destroy should clear the partition type so that it can be reused >> >> by another OSD. That will need to be tested, though.. I forget how smart >> >> the "find a journal partiiton" code is (it might blindly try to create a >> >> new one or something). >> >> >> >> sage >> >> >> >> >> >> >> >>> >> >>> > >> >>> > sage >> >>> > >> >>> > >> >>> > >> >>> >> >> >>> >> destroy: >> >>> >> - zap disk (removes partition table and disk content) >> >>> >> >> >>> >> A few questions I have from this, though. Is this granular enough? >> >>> >> If all the steps listed above are done in deactivate, is it useful? >> >>> >> Or are there usecases we need to cover where some of those steps need >> >>> >> to be done but not all? Deactivating in this case would be >> >>> >> permanently removing the disk from the cluster. If you are just >> >>> >> moving a disk from one host to another, Ceph already supports that >> >>> >> with no additional steps other than stop service, move disk, start >> >>> >> service. >> >>> >> >> >>> >> Is "destroy" even necessary? It's really just zap at that point, >> >>> >> which already exists. It only seems necessary to me if we add extra >> >>> >> functionality, like the ability to do a wipe of some kind first. If >> >>> >> it is just zap, you could call zap separate or with --zap as an option >> >>> >> to deactivate. >> >>> >> >> >>> >> And all of this would need to be able to fail somewhat gracefully, as >> >>> >> you would often be dealing with dead/failed disks that may not allow >> >>> >> these commands to run successfully. That's why I'm wondering if it >> >>> >> would be best to break the steps currently in "deactivate" into two >> >>> >> commands -- (1) deactivate: which would deal with commands specific to >> >>> >> the disk (osd out, stop service, remove marker files, umount) and (2) >> >>> >> remove: which would undefine the OSD within the cluster (remove from >> >>> >> CRUSH, remove cephx key, deallocate OSD ID). >> >>> >> >> >>> >> I'm mostly talking out loud here. Looking for more ideas, input. :) >> >>> >> >> >>> >> - Travis >> >>> >> >> >>> >> >> >>> >> On Sun, Jan 4, 2015 at 6:07 AM, Wido den Hollander <wido@xxxxxxxx> wrote: >> >>> >> > On 01/02/2015 10:31 PM, Travis Rhoden wrote: >> >>> >> >> Hi everyone, >> >>> >> >> >> >>> >> >> There has been a long-standing request [1] to implement an OSD >> >>> >> >> "destroy" capability to ceph-deploy. A community user has submitted a >> >>> >> >> pull request implementing this feature [2]. While the code needs a >> >>> >> >> bit of work (there are a few things to work out before it would be >> >>> >> >> ready to merge), I want to verify that the approach is sound before >> >>> >> >> diving into it. >> >>> >> >> >> >>> >> >> As it currently stands, the new feature would do allow for the following: >> >>> >> >> >> >>> >> >> ceph-deploy osd destroy <host> --osd-id <id> >> >>> >> >> >> >>> >> >> From that command, ceph-deploy would reach out to the host, do "ceph >> >>> >> >> osd out", stop the ceph-osd service for the OSD, then finish by doing >> >>> >> >> "ceph osd crush remove", "ceph auth del", and "ceph osd rm". Finally, >> >>> >> >> it would umount the OSD, typically in /var/lib/ceph/osd/... >> >>> >> >> >> >>> >> > >> >>> >> > Prior to the unmount, shouldn't it also clean up the 'ready' file to >> >>> >> > prevent the OSD from starting after a reboot? >> >>> >> > >> >>> >> > Although it's key has been removed from the cluster it shouldn't matter >> >>> >> > that much, but it seems a bit cleaner. >> >>> >> > >> >>> >> > It could even be more destructive, that if you pass --zap-disk to it, it >> >>> >> > also runs wipefs or something to clean the whole disk. >> >>> >> > >> >>> >> >> >> >>> >> >> Does this high-level approach seem sane? Anything that is missing >> >>> >> >> when trying to remove an OSD? >> >>> >> >> >> >>> >> >> >> >>> >> >> There are a few specifics to the current PR that jump out to me as >> >>> >> >> things to address. The format of the command is a bit rough, as other >> >>> >> >> "ceph-deploy osd" commands take a list of [host[:disk[:journal]]] args >> >>> >> >> to specify a bunch of disks/osds to act on at one. But this command >> >>> >> >> only allows one at a time, by virtue of the --osd-id argument. We >> >>> >> >> could try to accept [host:disk] and look up the OSD ID from that, or >> >>> >> >> potentially take [host:ID] as input. >> >>> >> >> >> >>> >> >> Additionally, what should be done with the OSD's journal during the >> >>> >> >> destroy process? Should it be left untouched? >> >>> >> >> >> >>> >> >> Should there be any additional barriers to performing such a >> >>> >> >> destructive command? User confirmation? >> >>> >> >> >> >>> >> >> >> >>> >> >> - Travis >> >>> >> >> >> >>> >> >> [1] http://tracker.ceph.com/issues/3480 >> >>> >> >> [2] https://github.com/ceph/ceph-deploy/pull/254 >> >>> >> >> -- >> >>> >> >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> >>> >> >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >>> >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >>> >> >> >> >>> >> > >> >>> >> > >> >>> >> > -- >> >>> >> > Wido den Hollander >> >>> >> > 42on B.V. >> >>> >> > Ceph trainer and consultant >> >>> >> > >> >>> >> > Phone: +31 (0)20 700 9902 >> >>> >> > Skype: contact42on >> >>> >> -- >> >>> >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> >>> >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >>> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >>> >> >> >>> >> >> >>> -- >> >>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >>> >> >>> >> >> -- >> >> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > -- >> > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >> > the body of a message to majordomo@xxxxxxxxxxxxxxx >> > More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
