[libvirt-users] Running all my virtual machines with a low priority

R. Diez rdiezmail-temp2 at yahoo.de
Thu May 2 10:10:54 UTC 2019

> You could perhaps set  'cpu.shares' cgroup setting on /machine.slice.
> This isn't really a nice level in the traditional sense, rather it is
> a relative weighting evaluated against other cgroups at the same level.
> So if you change it from 1024 to 512, then processes under /machine.slice
> will get 1/2 the CPU time vs stuff under /system.slice or /user.slice,
> when there is contention for CPU time.

Thanks for your help.

There is no "machine.slice" on my system. This is an excerpt from "systemd-cgls".

??? ??????system.slice
???   ??????irqbalance.service
???   ??? ??????865 /usr/sbin/irqbalance --foreground
[... blah blah ...]
???   ??????wpa_supplicant.service
???   ??? ??????878 /sbin/wpa_supplicant -u -s -O /run/wpa_supplicant
???   ??????libvirtd.service
???   ??? ??????  987 /usr/sbin/libvirtd
???   ??? ?????? 1395 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro 
???   ??? ?????? 1396 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro 
???   ??? ??????12285 /usr/bin/qemu-system-x86_64 -name guest=UbuntuMATE1804,debug-threads=on -S -object 
secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-UbuntuMATE1804/master-key.aes -machine...

But I guess there are differences depending on the libvirt version.

I thought of 'nice' because it is an easy way to lower the priority for everything (CPU and disk) at once.

This is actually getting too complicated. I am a lone developer and sysadmin in a small company. I would need to learn too many things about 
control groups etc. One of the reasons I am trying libvirt is because of the "Virtual Machine Manager" GUI.

Is there not an easier way? I realised there is a "libvirtd.service" on my system. Is there a simple way in systemd to just lower the 
priority of everything under that service? I am assuming that this service is starting all the virtual machines.

Best regards,

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