Re: lxc container startup error and RFC patch
On 8/2/21 10:20 PM, Jim Fehlig wrote:
On 7/29/21 3:28 PM, Cole Robinson wrote:
> Hi all,
>
> I'm seeing LXC container startup failures. This is with libvirt git,
> fedora 34 host with systemd-248.6-1.fc34.x86_64 (I didn't confirm with
> other versions). Reproducer:
From my experience its more related to cgroups. Works with V2-only,
doesn't work with V1 or hybrid.
Ah, that's the missing piece! I tried to reproduce on my fedora VMs but
all of them are fully switched to v2. Thanks Jim, I'll give it another try.
> sudo virt-install --connect lxc:/// --name test-container --memory 128
> --boot init=/bin/sh
>
> Starting install...
> ERROR error from service:
> GDBus.Error:org.freedesktop.machine1.NoMachineForPID: PID 2145047 does
> not belong to any known machine
>
> libvirt 7.0.0 works but 7.1.0+ does not. The root error seems to predate
> that, showing up in syslog, but commit 9c1693eff made it fatal:
>
> commit 9c1693eff427661616ce1bd2795688f87288a412
> Author: Pavel Hrdina <phrdina(a)redhat.com>
> Date: Fri Feb 5 16:17:35 2021 +0100
>
> vircgroup: use DBus call to systemd for some APIs
>
> The error comes from virSystemdGetMachineByPID. The PID that shows up in
> the above error message does not match the leader PID as reported by
> machinectl. This change fixes the error but I don't know if it's correct
> or if it has other implications:
I'm not familiar enough with the driver to review your change with
confidence.
I'll do the review.
> diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
> index 066e013ed4..54ecb1316b 100644
> --- a/src/lxc/lxc_controller.c
> +++ b/src/lxc/lxc_controller.c
> @@ -866,12 +866,12 @@ static int
> virLXCControllerSetupCgroupLimits(virLXCController *ctrl)
> nodeset = virDomainNumatuneGetNodeset(ctrl->def->numa,
> auto_nodeset, -1);
> if (!(ctrl->cgroup = virLXCCgroupCreate(ctrl->def,
> - ctrl->initpid,
> + getpid(),
> ctrl->nnicindexes,
> ctrl->nicindexes)))
> goto cleanup;
> - if (virCgroupAddMachineProcess(ctrl->cgroup, getpid()) < 0)
> + if (virCgroupAddMachineProcess(ctrl->cgroup, ctrl->initpid) < 0)
> goto cleanup;
> /* Add all qemu-nbd tasks to the cgroup */
>
>
> Maybe something else isn't working elsewhere. Clearly we try to add both
> pids to the systemd machine, but virSystemdGetMachineByPID is not
> working to match the non-leader pid, which is the one that the LXC
> driver knows about.
>
> Thoughts?
> Can anyone else reproduce?
https://gitlab.com/libvirt/libvirt/-/issues/182
Thanks for filing the issue.
Michal