On Tue, Jan 6, 2015 at 9:28 AM, Sage Weil <sage@xxxxxxxxxxxx> wrote: > On Tue, 6 Jan 2015, Wei-Chung Cheng wrote: >> 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? > > Normally secure erase simply means destroying the data on disk. > In practice, that can be hard. Overwriting it will mostly work, but it's > slow, and with effort forensics can often still recover the old data. > > Encrypting a disk and then destroying just the encryption key is an easy > way to "erase" a entire disk. It's not uncommon to do this so that old > disks can be RMAed or disposed of through the usual channels without fear > of data being recovered. > > sage > > >> >> Would Travis describe the "secure erase" more detailly? Encrypting and throwing away the key is a good way to go, for sure. But for now, I'm suggesting that we don't add a secure erase functionality. It can certainly be added later, but I'd rather focus on getting the baseline deactivate and destroy functionality in first, and use --zap with destroy to blow away a disk. I'd rather not have a secure erase feature hold up the other functionality. >> >> very thanks! >> >> vicente >> >> > >> > >> >> >> >> Anyway, I rework and implement the deactivate first. I started working on this yesterday as well, but don't want to duplicate work. I haven't pushed a wip- branch or anything yet, though. I can hold off if you are actively working on it. >> >> >> >> >> >> >> >> >> >> 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 >> >> -- 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
