[Pkg-libvirt-maintainers] Bug#908186: libvirt-clients: UNable to limit swap by editing guest xml configuration, but virsh memtune swap_hard_limit works
reusser
reusser.mb at gmail.com
Fri Sep 7 08:43:49 BST 2018
Package: libvirt-clients
Version: 3.0.0-4+deb9u3
Severity: normal
Dear Maintainer,
I'm trying to limit swap usage of guest systems. Libvirt offers the
memory tuning option 'swap_hard_limit' [1]. To enable setting of the swap
hard limit, we need to enable swap control in the kernel by adding
swapaccounting to the grub commandline [2].
Now, I'm able to set a swap limit with virsh memtune:
> virsh --connect qemu:///system memtune demo --hard-limit 614400
> virsh --connect qemu:///system memtune demo --swap-hard-limit 714400
However, if I edit the guest xml configuration by adding
<memtune>
<swap_hard_limit unit='KiB'>614402</swap_hard_limit>
</memtune>
The guest does not start. Instead, I get an error:
virsh --connect qemu:///system start demo
error: Failed to start domain demo error: Invalid value '629146624' for 'memory.memsw.limit_in_bytes': Das Argument ist ungültig
I expect the guest to start with a limitation on swap usage.
[1] https://libvirt.org/formatdomain.html#elementsMemoryTuning
[2] https://askubuntu.com/questions/417215/how-does-kernel-support-swap-limit
-- System Information:
Debian Release: 9.5
APT prefers stable
APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-8-amd64 (SMP w/8 CPU cores)
Locale: LANG=de_DE.utf8, LC_CTYPE=de_DE.utf8 (charmap=UTF-8) (ignored: LC_ALL set to de_DE.utf8), LANGUAGE=de_DE.utf8 (charmap=UTF-8) (ignored: LC_ALL set to de_DE.utf8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages libvirt-clients depends on:
ii libapparmor1 2.11.0-3+deb9u2
ii libaudit1 1:2.6.7-2
ii libavahi-client3 0.6.32-2
ii libavahi-common3 0.6.32-2
ii libc6 2.24-11+deb9u3
ii libcap-ng0 0.7.7-3+b1
ii libdbus-1-3 1.10.26-0+deb9u1
ii libdevmapper1.02.1 2:1.02.137-2
ii libgnutls30 3.5.8-5+deb9u3
ii libnl-3-200 3.2.27-2
ii libnl-route-3-200 3.2.27-2
ii libnuma1 2.0.11-2.1
ii libreadline7 7.0-3
ii libsasl2-2 2.1.27~101-g0780600+dfsg-3
ii libselinux1 2.6-3+b3
ii libssh2-1 1.7.0-1
ii libvirt0 3.0.0-4+deb9u3
ii libxen-4.8 4.8.4+xsa273+shim4.10.1+xsa273-1+deb9u10
ii libxml2 2.9.4+dfsg1-2.2+deb9u2
ii libyajl2 2.1.0-2+b3
libvirt-clients recommends no packages.
Versions of packages libvirt-clients suggests:
ii libvirt-daemon 3.0.0-4+deb9u3
-- no debconf information
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