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items: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
items: Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
items: Re: Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?

Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
type: item
description: Hi everyone, I am running a lot of CTs with their roots located on an nfs share. Once in a while it happens that a process gets stuck which I fear has something to do with the nfs mount. See the dmesg out below. The problem now is that I can't kill this process anymore. This results into beeing unable to stop the CT running this process. vzctl stop <CTID> runs into a timeout. It is totally impossible to kill the process - The only solution is a reboot of the Host-System. Is there a way to forcefully kill the CT ? In this case I don't care if the process remains running. I just want the rest of the CT to be stopped so I can start the CT again. Here is the dmes output: [194043.649945] INFO: task which:810615 blocked for more than 120 seconds. [194043.650077] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [194043.650274] which D ffff882f74146d50 0 810615 682640 125 0x00000084 [194043.650281] ffff8825ba732f98 0000000000000086 0000000000000017 ffff8825ba732fc0 [194043.650293] 0000000000000000 0000000000000000 ffff8824d0186d70 0000000000000007 [194043.650301] ffff8825ba732f88 ffff882f74147308 ffff8825ba733fd8 ffff8825ba733fd8 [194043.650308] Call Trace: [194043.650318] [<ffffffff81122480>] ? sync_page+0x0/0x50 [194043.650325] [<ffffffff814e6b73>] io_schedule+0x73/0xc0 [194043.650330] [<ffffffff811224bd>] sync_page+0x3d/0x50 [194043.650334] [<ffffffff814e73da>] __wait_on_bit_lock+0x5a/0xc0 [194043.650339] [<ffffffff81122457>] __lock_page+0x67/0x70 [194043.650345] [<ffffffff81095550>] ? wake_bit_function+0x0/0x50 [194043.650351] [<ffffffff8113ac72>] ? pagevec_lookup+0x22/0x30 [194043.650357] [<ffffffff8113cc8e>] truncate_inode_pages_range+0x43e/0x450 [194043.650397] [<ffffffffa0314b80>] ? nfs_dq_delete_inode+0x0/0xd0 [nfs] [194043.650406] [<ffffffffa03a7c7f>] ? vzquota_data_unlock+0x2f/0x40 [vzdquota] [194043.650421] [<ffffffffa0314b80>] ? nfs_dq_delete_inode+0x0/0xd0 [nfs] [194043.650426] [<ffffffff8113ccb5>] truncate_inode_pages+0x15/0x20 [19404…
creator: svensirk
date: 2012-03-30T11:03:13-00:00

Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
type: item
description: On Fri, Mar 30, 2012 at 4:03 AM, Sirk Johannsen <s.johannsen@satzmedia.de> wrote: > Hi everyone, > > I am running a lot of CTs with their roots located on an nfs share. > Once in a while it happens that a process gets stuck which I fear has > something to do with the nfs mount. > See the dmesg out below. > The problem now is that I can't kill this process anymore. > This results into beeing unable to stop the CT running this process. > vzctl stop <CTID> runs into a timeout. > It is totally impossible to kill the process - The only solution is a > reboot of the Host-System. Yep, that's correct. Your only real option is to migrate all of the other CT's to another host node, then reboot this host node, then migrate the other CT's back. > Is there a way to forcefully kill the CT ? Nope, the kernel is hung waiting for IO which will wait until the cows come home. Are you using TCP or UDP nfs mounts? Try switching from one to the other and see if that affects your nfs timeout issue. > In this case I don't care if the process remains running. > I just want the rest of the CT to be stopped so I can start the CT again. I don't think it can be done. > Here is the dmes output: > [194043.649945] INFO: task which:810615 blocked for more than 120 seconds. > [194043.650077] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > disables this message. > [194043.650274] which D ffff882f74146d50 0 810615 682640 > 125 0x00000084 So the "which" command was scanning the directories in the path and that's what caused the nfs fault. Maybe you can tune your tcp settings to compensate (assuming your using tcp nfs mounts) but I've never tried to do anything like that, so I don't know if settings could actually fix anything. Network congestion is likely your biggest issue. > [194043.650308] Call Trace: Yeah, once you get a call trace, you're hosed. Does slabtop show that your nfs slabs are using up extremely large chunks of memory? ...Todd -- Always code as if the guy who ends up maintaining you…
creator: Todd Lyons
date: 2012-03-30T12:40:14-00:00

Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
type: item
description: Sirk Johannsen <s.johannsen@satzmedia.de> writes: > > Is there a way to forcefully kill the CT ? > In this case I don't care if the process remains running. > I just want the rest of the CT to be stopped so I can start the CT again. try this: vzctl chkpnt VEID --kill don't know where I got it, but it worked for me in a few cases; in some others it did not though.
creator: Aleksandar Ivanisevic
date: 2012-04-02T10:08:18-00:00

Re: Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
type: item
description: Vzctl stop --fast However it wont't help in case of tasks in D state. You need to mount nfs with softintr option for that. Sent from my iPhonespam SPAMSPAM On 02.04.2012, at 14:22, "Aleksandar Ivanisevic" <aleksandar@ivanisevic.de> wrote: > Sirk Johannsen <s.johannsen@satzmedia.de> > writes: > >> >> Is there a way to forcefully kill the CT ? >> In this case I don't care if the process remains running. >> I just want the rest of the CT to be stopped so I can start the CT again. > > try this: > > vzctl chkpnt VEID --kill > > don't know where I got it, but it worked for me in a few cases; in > some others it did not though. >
creator: Kirill Korotaev
date: 2012-04-02T10:31:15-00:00

Re: Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
type: item
description: Thanks for all the responses. I already have the NFS Mount mounted with intr but the processes still stay in D state and are not killable. Anyway, I'll try to convert all CTs to ploop this night and hope not to see stuck processes on NFS afterwards :-) best regards, Sirk 2012/4/2 Kirill Korotaev <dev@parallels.com>: > Vzctl stop --fast > However it wont't help in case of tasks in D state. You need to mount nfs with softintr option for that. > > Sent from my iPhonespam SPAMSPAM > > On 02.04.2012, at 14:22, "Aleksandar Ivanisevic" <aleksandar@ivanisevic.de> wrote: > >> Sirk Johannsen <s.johannsen@satzmedia.de> >> writes: >> >>> >>> Is there a way to forcefully kill the CT ? >>> In this case I don't care if the process remains running. >>> I just want the rest of the CT to be stopped so I can start the CT again. >> >> try this: >> >> vzctl chkpnt VEID --kill >> >> don't know where I got it, but it worked for me in a few cases; in >> some others it did not though. >> -- Satzmedia GmbH Altonaer Poststraße 9 22767 Hamburg Tel: +49 (0) 40 - 1 888 969 - 140 Fax: +49 (0) 40 - 1 888 969 - 200 E-Mail: s.johannsen@satzmedia.de E-Business-Lösungen: http://www.satzmedia.de Amtsgericht Hamburg, HRB 71729 Ust-IDNr. DE201979921 Geschäftsführer: Dipl.-Kfm. Christian Satz Dipl.-Inform. Markus Meyer-Westphal -- --
creator: svensirk
date: 2012-04-02T13:24:22-00:00

Re: Re: Hung Tasks on NFS (maybe not a OpenVZ Problem) - How to forcefully kill a container ?
type: item
description: On 04/02/2012 05:24 PM, Sirk Johannsen wrote: > Thanks for all the responses. > I already have the NFS Mount mounted with intr but the processes still > stay in D state and are not killable. Kirill probably meant the "soft" option. Plus, intr/nointr are deprecated and ignored since 2.6.25 so they make no difference. More details: man 5 nfs > Anyway, I'll try to convert all CTs to ploop this night and hope not > to see stuck processes on NFS afterwards :-) > > best regards, > > Sirk > > 2012/4/2 Kirill Korotaev<dev@parallels.com>: >> Vzctl stop --fast >> However it wont't help in case of tasks in D state. You need to mount nfs with softintr option for that. >> >> Sent from my iPhonespam SPAMSPAM >> >> On 02.04.2012, at 14:22, "Aleksandar Ivanisevic"<aleksandar@ivanisevic.de> wrote: >> >>> Sirk Johannsen<s.johannsen@satzmedia.de> >>> writes: >>> >>>> Is there a way to forcefully kill the CT ? >>>> In this case I don't care if the process remains running. >>>> I just want the rest of the CT to be stopped so I can start the CT again. >>> try this: >>> >>> vzctl chkpnt VEID --kill >>> >>> don't know where I got it, but it worked for me in a few cases; in >>> some others it did not though. >>>
creator: kir
date: 2012-04-02T15:56:51-00:00