From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate001.proxmox.com (gate001.proxmox.com [IPv6:2a0f:8001:1:32::40]) by lore.proxmox.com (Postfix) with ESMTPS id 51E4F1FF09B for ; Mon, 12 Oct 2026 15:26:19 +0200 (CEST) Received: from gate001.proxmox.com (localhost.localdomain [127.0.0.1]) by gate001.proxmox.com (Proxmox) with ESMTP id 1B0C121776; Mon, 12 Oct 2026 15:26:18 +0200 (CEST) Message-ID: Date: Mon, 12 Oct 2026 15:26:08 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH manager v2] fix #8093: pvestatd: remove stale lxc console reaper To: Elias Huhsovitz , pve-devel@lists.proxmox.com References: <20261009123819.136563-1-e.huhsovitz@proxmox.com> Content-Language: en-US From: Filip Schauer In-Reply-To: <20261009123819.136563-1-e.huhsovitz@proxmox.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1791811572039 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.492 Adjusted score from AWL reputation of From: address DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment (newer systems) RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust 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: ESFABAPM3UGUCCPTEZB7O75ITSAHYJJB X-Message-ID-Hash: ESFABAPM3UGUCCPTEZB7O75ITSAHYJJB X-MailFrom: f.schauer@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: As far as my testing is concerned, the only way to produce an orphaned lxc-console process is to manually send a SIGSTOP to the lxc-console process and then stop the container. So I don't think this cleanup serves any purpose. As a test I started 50 containers and measured how long the remove_stale_lxc_console call was taking: It took about 0.8 seconds on my machine. Which is quite long considering it runs every 10 seconds. Calling lxc-info twice for every running container every 10 seconds sounds inefficient. So I am in favor of removing this so we at least drop this from two lxc-info calls down to one lxc-info call per running container every 10 seconds. I applied this patch locally and bulk shutdown hundreds of containers with lxc-consoles. Not a single stale lxc-console remained. Tested-by: Filip Schauer Reviewed-by: Filip Schauer On 09/10/2026 14:38, Elias Huhsovitz wrote: > remove_stale_lxc_consoles() calls PVE::LXC::vmstatus() every cycle, > which runs `lxc-info` once per running container. Since > update_lxc_status() already calls vmstatus() in the same cycle, this > doubles the overhead of running `lxc-info`. Thus, this overhead is > scaling linearly with the number of containers. > > Under normal operation, lxc-console and dtach exit automatically when > the container stops. The reaper only fires in broken system states, such > as deleting the container config file while the container is still > running. A continuous polling reaper is not an appropriate mechanism for > these situations. Even in this situation (deleting the container config while the container is running) the reaper is not needed, since lxc-console exits automatically when the container stops. > > Remove the reaper entirely. > > Signed-off-by: Elias Huhsovitz > --- > This patch removes the reaper entirely. No replacement mechanism is > added. If a console process becomes orphaned due to manual system > interference, the administrator can identify and kill it directly. > > A type of "replacement" machenanism that bridges this gap is > currently being discussed [1], based on patch [2]. > > Alternatives considered > ----------------------- > * Wrapping console commands in transient systemd scopes bound via > PartOf= to the container service. > Verdict: rejected because lxc-stop ends the > service without a systemd stop job, so PartOf= does not propagate. > > * A manual `pct cleanup console` CLI tool. > Verdict: cleanup shouldn't be manual. > > * An ExecStopPost= hook on pve-container@.service. > > Changes v1->v2: > --------------- > * scrap the idea of binding console sessions to container lifetime via > systemd scoopes. > > Previous versions > ----------------- > v1: https://lore.proxmox.com/pve-devel/20261007083726.26067-1-e.huhsovitz@proxmox.com/ > > References > ---------- > [1] https://lore.proxmox.com/pve-devel/82fceb8e-f52d-4e56-9dcf-5cd61393fa26@proxmox.com/ > [2] https://lore.proxmox.com/pve-devel/20260121112335.84473-1-f.schauer@proxmox.com/ > > Summary of Changes > ------------------ > PVE/Service/pvestatd.pm | 18 ------------------ > 1 file changed, 18 deletions(-) > > diff --git a/PVE/Service/pvestatd.pm b/PVE/Service/pvestatd.pm > index 34f9da71..cec66e00 100755 > --- a/PVE/Service/pvestatd.pm > +++ b/PVE/Service/pvestatd.pm > @@ -444,20 +444,6 @@ sub update_qemu_status { > PVE::PullMetric::update($pull_txn, 'qemu', $vmstatus, $ctime); > } > > -sub remove_stale_lxc_consoles { > - > - my $vmstatus = PVE::LXC::vmstatus(); > - my $pidhash = PVE::LXC::find_lxc_console_pids(); > - > - foreach my $vmid (keys %$pidhash) { > - next if defined($vmstatus->{$vmid}); > - syslog('info', "remove stale lxc-console for CT $vmid"); > - foreach my $pid (@{ $pidhash->{$vmid} }) { > - kill(9, $pid); > - } > - } > -} > - > my $rebalance_error_count = {}; > > my $NO_REBALANCE; > @@ -848,10 +834,6 @@ sub update_status { > $err = $@; > syslog('err', "storage status update error: $err") if $err; > > - eval { remove_stale_lxc_consoles(); }; > - $err = $@; > - syslog('err', "lxc console cleanup error: $err") if $err; > - > eval { rotate_authkeys(); }; > $err = $@; > syslog('err', "authkey rotation error: $err") if $err;