From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id C33981FF13E for ; Fri, 20 Feb 2026 15:51:06 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id BF27FC2D2; Fri, 20 Feb 2026 15:51:54 +0100 (CET) Message-ID: Date: Fri, 20 Feb 2026 15:51:11 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH qemu-server v2] fix #7119: qm cleanup: wait for process exiting for up to 30 seconds To: Fiona Ebner , =?UTF-8?Q?Fabian_Gr=C3=BCnbichler?= , pve-devel@lists.proxmox.com References: <20260210111612.2017883-1-d.csapak@proxmox.com> <7ee8d206-36fd-4ade-893b-c7c2222a8883@proxmox.com> <1770985110.nme4v4xomn.astroid@yuna.none> <9d501c98-a85c-44d4-af0e-0301b203d691@proxmox.com> <1771231158.rte62d97r5.astroid@yuna.none> <38236a30-a249-4ebe-bf89-788d67f36bd1@proxmox.com> <7bbce03b-d8d6-4459-876c-2a71257959a4@proxmox.com> <8099db49-d35a-4ab1-9e33-c82689aee016@proxmox.com> Content-Language: en-US From: Dominik Csapak In-Reply-To: <8099db49-d35a-4ab1-9e33-c82689aee016@proxmox.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1771599068692 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.032 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: J2CJRXQIMCT522SQNNIGDIW22574KWMZ X-Message-ID-Hash: J2CJRXQIMCT522SQNNIGDIW22574KWMZ X-MailFrom: d.csapak@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox VE development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 2/20/26 3:30 PM, Fiona Ebner wrote: > Am 20.02.26 um 10:36 AM schrieb Dominik Csapak: >> On 2/19/26 2:27 PM, Fiona Ebner wrote: >>> Am 19.02.26 um 11:15 AM schrieb Dominik Csapak: >>>> On 2/16/26 10:15 AM, Fiona Ebner wrote: >>>>> Am 16.02.26 um 9:42 AM schrieb Fabian Grünbichler: >>>>>> On February 13, 2026 2:16 pm, Fiona Ebner wrote: >>>>> >>>>> I guess the actual need is to have more consistent behavior. >>>>> >>>> >>>> ok so i think we'd need to >>>> * create a cleanup flag for each vm when qmevent detects a vm shutting >>>> down (in /var/run/qemu-server/VMID.cleanup, possibly with timestamp) >>>> * removing that cleanup flag after cleanup (obviously) >>>> * on start, check for that flag and block for some timeout before >>>> starting (e.g. check the timestamp in the flag if it's longer than some >>>> time, start it regardless?) >>> >>> Sounds good to me. >>> >>> Unfortunately, something else: turns out that we kinda rely on qmeventd >>> not doing the cleanup for the optimization with keeping the volumes >>> active (i.e. $keepActive). And actually, the optimization applies >>> randomly depending on who wins the race. >>> >>> Output below with added log line >>> "doing cleanup for $vmid with keepActive=$keepActive" >>> in vm_stop_cleanup() to be able to see what happens. >>> >>> We try to use the optimization but qmeventd interferes: >>> >>>> Feb 19 14:09:43 pve9a1 vzdump[168878]: starting task >>>> UPID:pve9a1:000293AF:0017CFF8:69970B97:vzdump:102:root@pam: >>>> Feb 19 14:09:43 pve9a1 vzdump[168879]: INFO: starting new backup job: >>>> vzdump 102 --storage pbs --mode stop >>>> Feb 19 14:09:43 pve9a1 vzdump[168879]: INFO: Starting Backup of VM >>>> 102 (qemu) >>>> Feb 19 14:09:44 pve9a1 qm[168960]: shutdown VM 102: >>>> UPID:pve9a1:00029400:0017D035:69970B98:qmshutdown:102:root@pam: >>>> Feb 19 14:09:44 pve9a1 qm[168959]: starting task >>>> UPID:pve9a1:00029400:0017D035:69970B98:qmshutdown:102:root@pam: >>>> Feb 19 14:09:47 pve9a1 qm[168960]: VM 102 qga command failed - VM 102 >>>> qga command 'guest-ping' failed - got timeout >>>> Feb 19 14:09:50 pve9a1 qmeventd[166736]: read: Connection reset by peer >>>> Feb 19 14:09:50 pve9a1 pvedaemon[166884]: end task >>>> UPID:pve9a1:000290CD:0017B515:69970B52:vncproxy:102:root@pam: OK >>>> Feb 19 14:09:50 pve9a1 systemd[1]: 102.scope: Deactivated successfully. >>>> Feb 19 14:09:50 pve9a1 systemd[1]: 102.scope: Consumed 41.780s CPU >>>> time, 1.9G memory peak. >>>> Feb 19 14:09:51 pve9a1 qm[168960]: doing cleanup for 102 with >>>> keepActive=1 >>>> Feb 19 14:09:51 pve9a1 qm[168959]: end task >>>> UPID:pve9a1:00029400:0017D035:69970B98:qmshutdown:102:root@pam: OK >>>> Feb 19 14:09:51 pve9a1 qmeventd[168986]: Starting cleanup for 102 >>>> Feb 19 14:09:51 pve9a1 qm[168986]: doing cleanup for 102 with >>>> keepActive=0 >>>> Feb 19 14:09:51 pve9a1 qmeventd[168986]: Finished cleanup for 102 >>>> Feb 19 14:09:51 pve9a1 systemd[1]: Started 102.scope. >>>> Feb 19 14:09:51 pve9a1 vzdump[168879]: VM 102 started with PID 169021. >>> >>> We manage to get the optimization: >>> >>>> Feb 19 14:16:01 pve9a1 qm[174585]: shutdown VM 102: >>>> UPID:pve9a1:0002A9F9:0018636B:69970D11:qmshutdown:102:root@pam: >>>> Feb 19 14:16:04 pve9a1 qm[174585]: VM 102 qga command failed - VM 102 >>>> qga command 'guest-ping' failed - got timeout >>>> Feb 19 14:16:07 pve9a1 qmeventd[166736]: read: Connection reset by peer >>>> Feb 19 14:16:07 pve9a1 systemd[1]: 102.scope: Deactivated successfully. >>>> Feb 19 14:16:07 pve9a1 systemd[1]: 102.scope: Consumed 46.363s CPU >>>> time, 2G memory peak. >>>> Feb 19 14:16:08 pve9a1 qm[174585]: doing cleanup for 102 with >>>> keepActive=1 >>>> Feb 19 14:16:08 pve9a1 qm[174582]: end task >>>> UPID:pve9a1:0002A9F9:0018636B:69970D11:qmshutdown:102:root@pam: OK >>>> Feb 19 14:16:08 pve9a1 systemd[1]: Started 102.scope. >>>> Feb 19 14:16:08 pve9a1 qmeventd[174685]: Starting cleanup for 102 >>>> Feb 19 14:16:08 pve9a1 qmeventd[174685]: trying to acquire lock... >>>> Feb 19 14:16:08 pve9a1 vzdump[174326]: VM 102 started with PID 174718. >>>> Feb 19 14:16:08 pve9a1 qmeventd[174685]:  OK >>>> Feb 19 14:16:08 pve9a1 qmeventd[174685]: vm still running >>> >>> For regular shutdown, we'll also do the cleanup twice. >>> >>> Maybe we also need a way to tell qmeventd that we already did the >>> cleanup? >> >> >> ok well then i'd try to do something like this: >> >> in >> >> 'vm_stop' we'll create a cleanup flag with timestamp + state (e.g. >> 'queued') >> >> in vm_stop_cleanup we change/create the flag with >> 'started' and clear the flag after cleanup > > Why is the one in vm_stop needed? Is there any advantage over creating > it directly in vm_stop_cleanup()? > after a bit of experimenting and re-reading the code, i think I can simplify the logic at the beginning of vm_stop, we create the cleanup flag in 'qm cleanup', we only do the cleanup if the flag does not exist in 'vm_start' we clean the flag this should work because these parts are under a config lock anyway: * from vm_stop to vm_stop_cleanup * most of the qm cleanup code * vm_start so we only really have to mark that the cleanup was done from the vm_stop codepath (we have to create the flag at the beginning of vm_stop, because then there is no race between calling it's cleanup and qmeventd picking up the vanishing process) does that make sense to you? >> (if it's here already in 'started' state within a timelimit, ignore it) >> >> in vm_start we block until the cleanup flag is gone or until some timeout >> >> in 'qm cleanup' we only start it if the flag does not exist > > Hmm, it does also call vm_stop_cleanup() so we could just re-use the > check there for that part? I guess doing an early check doesn't hurt > either, as long as we do call the post-stop hook. > >> I think this should make the behavior consistent? > >