Difference between revisions of "util-vserver:Cgroups"
From Linux-VServer
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mkdir /etc/vservers/<guestname>/cgroup | mkdir /etc/vservers/<guestname>/cgroup | ||
echo '2048' > /etc/vservers/<guestname>/cgroup/cpu.shares | echo '2048' > /etc/vservers/<guestname>/cgroup/cpu.shares | ||
| + | # if you use those then enable them if not put 0 instead of 1 | ||
echo 1 > /etc/vservers/<guestname>/cgroup/cpuset.cpus | echo 1 > /etc/vservers/<guestname>/cgroup/cpuset.cpus | ||
| − | echo | + | echo 1 > /etc/vservers/<guestname>/cgroup/cpuset.mems |
</pre> | </pre> | ||
Revision as of 07:17, 15 July 2009
Draft - Cgroups and vservers
to make cgroups works with vserver your kernel must have the following settings:
CONFIG_CGROUPS=y # CONFIG_CGROUP_DEBUG is not set # CONFIG_CGROUP_NS is not set CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_DEVICE=y CONFIG_CGROUP_SCHED=y CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_MEM_RES_CTLR=y
Or in the menu:
[*] Control Group support [ ] Example debug cgroup subsystem
[ ] Namespace cgroup subsystem
[*] control group freezer subsystem
[*] Device controller for cgroups
[*] Cpuset support
[*] Group CPU scheduler
[*] Group scheduling for SCHED_OTHER
[ ] Group scheduling for SCHED_RR/FIFO
Basis for grouping tasks (Control groups) --->
[*] Simple CPU accounting cgroup subsystem
[*] Resource counters
[*] Memory Resource Controller for Control Groups
You must have the /dev/cgroup mounted with the 'cpu' option. For exemple for cpuset, memory and cpu cgroup handling:
(root)> grep cgroup /etc/fstab cpuset /dev/cgroup cgroup rw,cpuset,cpu,memory 0 0
Then you must create on you guest /etc/vservers/<guest>/cgroup/ all the files put here will be copied to the guest cgroup when created. The doc for cgroup is not on the great flower page but in the source of the latests utils. You can have a default cgroup directory for all guest that can be overrided by each guest's cgroup directory.
From what i gathered in sched-design-CFS.txt [1]
This is simply done by adjusting the cpu.shares. Just do:
echo '512' > /dev/cgroup/<guest name>/cpu.shares
The share you get is equal to the guest's share divided by the sum of the cpu shares of all the guest. So for exemple :
vserver guest 1 => 512 vserver guest 2 => 512 vserver guest 3 => 2048 vserver guest 4 => 512
so you have a total of 3584 cpu shares (2048+512+512+512) , then you get :
vserver guest 1 => 512 / 3584 = 14% cpu vserver guest 2 => 512 / 3584 = 14% cpu vserver guest 3 => 2048 / 3584 = 57% cpu vserver guest 4 => 512 / 3584 = 14% cpu
Note that this is fair scheduling and this will not enfore HARD limit (as far as i know).
You must use the "cgroup" directory. You can apply defaults to all vservers or choose different settings for each guest:
- /etc/vservers/.default/cgroup , this directory contains settings applying to all guest when they start
- /etc/vservers/<guestname>/cgroup , this directory contains settings for the guest when it starts.
Exemple :
mkdir /etc/vservers/.defaults/cgroup mkdir /etc/vservers/<guestname>/cgroup echo '2048' > /etc/vservers/<guestname>/cgroup/cpu.shares # if you use those then enable them if not put 0 instead of 1 echo 1 > /etc/vservers/<guestname>/cgroup/cpuset.cpus echo 1 > /etc/vservers/<guestname>/cgroup/cpuset.mems
Note that /etc/vservers is an exemple, in my Aqueos install i use /usr/local/etc/vservers but /etc/vservers seems to be the defaults for the classic installs.
Regards, Ghislain.
