From: Thomas Lamprecht <t.lamprecht@proxmox.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,
Fabian Ebner <f.ebner@proxmox.com>,
Wolfgang Bumiller <w.bumiller@proxmox.com>
Subject: Re: [pve-devel] [RFC container] Improve feedback for startup
Date: Thu, 20 Aug 2020 11:36:39 +0200 [thread overview]
Message-ID: <1ef68f7f-437a-a160-05e2-f3b111ece024@proxmox.com> (raw)
In-Reply-To: <20200819103037.15143-1-f.ebner@proxmox.com>
On 19.08.20 12:30, Fabian Ebner wrote:
> Since it was necessary to switch to 'Type=Simple' in the systemd
> service (see 545d6f0a13ac2bf3a8d3f224c19c0e0def12116d ),
> 'systemctl start pve-container@ID' would not wait for the 'lxc-start'
> command anymore. Thus every container start was reported as a success
> and the 'post-start' hook would trigger immediately after the
> 'systemctl start' command.
>
> Use 'lxc-monitor' to get the necessary information and detect
> startup failure and only run the 'post-start' hookscript after
> the container is effectively running. If something goes wrong
> with the monitor, fall back to the old behavior.
>
> Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
> ---
> src/PVE/LXC.pm | 36 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 35 insertions(+), 1 deletion(-)
>
appreciate the effort!
We could also directly connect to /run/lxc/var/lib/lxc/monitor-fifo (or the abstract
unix socket, but not much gained/difference here) of the lxc-monitord which publishes
all state changes and unpack the new state [0] directly.
[0] https://github.com/lxc/lxc/blob/8bdacc22a48f9c09902a1d2febd71439cb38c082/src/lxc/state.h#L10
@Wolfgang, what do you think?
> diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
> index db5b8ca..35dc54c 100644
> --- a/src/PVE/LXC.pm
> +++ b/src/PVE/LXC.pm
> @@ -2191,10 +2191,44 @@ sub vm_start {
>
> PVE::Storage::activate_volumes($storage_cfg, $vollist);
>
> + my $monitor_pid = open(my $monitor_fh, '-|', "/usr/bin/lxc-monitor -n $vmid")
> + or warn "could not open pipe to lxc-monitor\n";
> +
> my $cmd = ['systemctl', 'start', "pve-container\@$vmid"];
>
> PVE::GuestHelpers::exec_hookscript($conf, $vmid, 'pre-start', 1);
> - eval { PVE::Tools::run_command($cmd); };
> + eval {
> + PVE::Tools::run_command($cmd);
> +
> + my $success;
> + if ($monitor_pid) {
> + eval {
> + local $SIG{ALRM} = sub { die "got timeout\n" };
> + alarm(10); # 'STARTING' should appear quickly
> +
> + while (my $line = <$monitor_fh>) {
> + if ($line =~ m/^'$vmid' changed state to \[([A-Z]*)\]$/) {
> + my $status = $1;
> + alarm(0);
> + $success = 1 if $status eq 'RUNNING';
> + $success = 0 if $status eq 'ABORTING'
> + || $status eq 'STOPPING'
> + || $status eq 'STOPPED';
> + if (defined($success)) {
> + kill('KILL', $monitor_pid);
> + waitpid($monitor_pid, 0);
> + }
> + } else {
> + die "unexpected output from lxc-monitor: $line\n";
> + }
> + }
> + };
> + warn "Problem with lxc-monitor: $@" if $@;
> + alarm(0);
> + }
> + die "'lxc-start' failed for container '$vmid'\n"
> + if defined($success) && !$success;
> + };
> if (my $err = $@) {
> unlink $skiplock_flag_fn;
> die $err;
>
next prev parent reply other threads:[~2020-08-20 9:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 10:30 Fabian Ebner
2020-08-20 9:36 ` Thomas Lamprecht [this message]
2020-08-27 8:44 ` Wolfgang Bumiller
2020-09-07 16:32 ` Thomas Lamprecht
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