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From: "Fabian Grünbichler" <f.gruenbichler@proxmox.com>
To: Denis Kanchev <denis.kanchev@storpool.com>
Cc: Wolfgang Bumiller <w.bumiller@proxmox.com>,
	Proxmox VE development discussion <pve-devel@lists.proxmox.com>
Subject: Re: [pve-devel] PVE child process behavior question
Date: Wed, 28 May 2025 08:33:36 +0200 (CEST)	[thread overview]
Message-ID: <11746909.21389.1748414016786@webmail.proxmox.com> (raw)
In-Reply-To: <CAHXTzuk7tYRJV_j=88RWc3R3C7AkiEdFUXi88m5qwnDeYDEC+A@mail.gmail.com>


> Denis Kanchev <denis.kanchev@storpool.com> hat am 28.05.2025 08:13 CEST geschrieben:
> 
> 
> Here is the task log
> 2025-04-11 03:45:42 starting migration of VM 2282 to node 'telpr01pve05' (10.10.17.5)
> 2025-04-11 03:45:42 starting VM 2282 on remote node 'telpr01pve05' 
> 2025-04-11 03:45:45 [telpr01pve05] Warning: sch_htb: quantum of class 10001 is big. Consider r2q change. 
> 2025-04-11 03:45:46 [telpr01pve05] Dump was interrupted and may be inconsistent. 
> 2025-04-11 03:45:46 [telpr01pve05] kvm: failed to find file '/usr/share/qemu-server/bootsplash.jpg' 
> 2025-04-11 03:45:46 start remote tunnel 
> 2025-04-11 03:45:46 ssh tunnel ver 1 
> 2025-04-11 03:45:46 starting online/live migration on unix:/run/qemu-server/2282.migrate 
> 2025-04-11 03:45:46 set migration capabilities 
> 2025-04-11 03:45:46 migration downtime limit: 100 ms 
> 2025-04-11 03:45:46 migration cachesize: 4.0 GiB 
> 2025-04-11 03:45:46 set migration parameters 
> 2025-04-11 03:45:46 start migrate command to unix:/run/qemu-server/2282.migrate 
> 2025-04-11 03:45:47 migration active, transferred 152.2 MiB of 24.0 GiB VM-state, 162.1 MiB/s 
> ... 
> 2025-04-11 03:46:49 migration active, transferred 15.2 GiB of 24.0 GiB VM-state, 2.0 GiB/s 
> 2025-04-11 03:46:50 migration status error: failed 
> 2025-04-11 03:46:50 ERROR: online migrate failure - aborting 
> 2025-04-11 03:46:50 aborting phase 2 - cleanup resources 
> 2025-04-11 03:46:50 migrate_cancel 
> 2025-04-11 03:46:52 ERROR: migration finished with problems (duration 00:01:11) 
> TASK ERROR: migration problems

okay, so no local disks involved.. not sure which process got killed then? ;)
the state transfer happens entirely within the Qemu process, perl is just polling
it to print the status, and that perl task worker is not OOM killed since it
continues to print all the error handling messages..

> > that has weird implications with regards to threads, so I don't think that
> > is a good idea..
> What you mean by that? Are any threads involved?

not intentionally, no. the issue is that the whole "pr_set_deathsig" machinery
works on the thread level, not the process level for historical reasons. so it
actually would kill the child if the thread that called pr_set_deathsig exits..

I think we do want to improve how run_command handles the parent disappearing.
but it's not that straight-forward to implement in a race-free fashion (in Perl).


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  parent reply	other threads:[~2025-05-28  6:33 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-21 13:13 Denis Kanchev via pve-devel
2025-05-22  6:30 ` Fabian Grünbichler
2025-05-22  6:55   ` Denis Kanchev via pve-devel
     [not found]   ` <857cbd6c-6866-417d-a71f-f5b5297bf09c@storpool.com>
2025-05-22  8:22     ` Fabian Grünbichler
2025-05-28  6:13       ` Denis Kanchev via pve-devel
     [not found]       ` <CAHXTzuk7tYRJV_j=88RWc3R3C7AkiEdFUXi88m5qwnDeYDEC+A@mail.gmail.com>
2025-05-28  6:33         ` Fabian Grünbichler [this message]
2025-05-29  7:33           ` Denis Kanchev via pve-devel
     [not found]           ` <CAHXTzumXeyJQQCj+45Hmy5qdU+BTFBYbHVgPy0u3VS-qS=_bDQ@mail.gmail.com>
2025-06-02  7:37             ` Fabian Grünbichler
2025-06-02  8:35               ` Denis Kanchev via pve-devel
     [not found]               ` <CAHXTzukAMG9050Ynn-KRSqhCz2Y0m6vnAQ7FEkCmEdQT3HapfQ@mail.gmail.com>
2025-06-02  8:49                 ` Fabian Grünbichler
2025-06-02  9:18                   ` Denis Kanchev via pve-devel
     [not found]                   ` <CAHXTzu=AiNx0iTWFEUU2kdzx9-RopwLc7rqGui6f0Q=+Hy52=w@mail.gmail.com>
2025-06-02 11:42                     ` Fabian Grünbichler
2025-06-02 13:23                       ` Denis Kanchev via pve-devel
     [not found]                       ` <CAHXTzu=qrZe2eEZro7qteR=fDjJQX13syfB9fs5VfFbG7Vy6vQ@mail.gmail.com>
2025-06-02 14:31                         ` Fabian Grünbichler
2025-06-04 12:52                           ` Denis Kanchev via pve-devel

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