Hi All,
I know we can launch containers with a limit on RAM use - i.e. a high threshold for the total RAM consumed by all containers (please confirm this is total and not per-container)…
Can we apply a similar CPU limit?
I currently have one container I want to run and limit that to 1 vCPU. In Docker Engine I will typically test with
docker run --memory="200m" --cpus="1" container-name
Thank you.
That feature is not implemented in ROS afaik, but some services can have parallel threads limit in their configuration, which actually limits cores usage. If you have several containers running you cannot limit like that.
what would be the use case for such limitation?
Does container processes have lower cpu priority from ROS internal processes? If not, you can with containers cores limitation for eg. reserve at least 1 core to be available for ROS processes if containers can have high cpu usage.
In Linux it is not like in some other OSes, that a process demanding CPU at the same (default) priority will automatically starve other processes.
In fact, when a process is demanding a lot of CPU, its priority is automatically decreased a little, so that other processes will go first and it gets the remainder of CPU time available.
But if both ROS process and container process demands high cpu at same time then are both in same priority, you cannot prioritize ROS processes or reserve core(s) for eg. to prioritize ROS process performance agains containers. Did not test it, but I will try in one container create high cpu usage on all cores and see how will ROS perform on userspace, we will see…
It seems that there is some impact on ROS performance. Tested on some mine heavy script with command:
> :put [/system/clock get time]; /system/script/run sms-read; global smsRead; :local smsList [$smsRead]; set smsRead; :put ("--------\r\nSms count: ".[:len $smsList]."\r\n--------"); :put [/system/clock get time]
ROS on idle:
> /system/resource/monitor
cpu-used: 1%
cpu-used-per-cpu: 1%,4%,0%,0%
free-memory: 69580KiB
-- [Q quit|D dump|C-z pause]
Command result:
17:17:21
--------
Sms count: 4
--------
17:17:27
On high cpu usage when in container running:
# stress-ng --cpu 4 --aggressive
ROS on heavy load:
> /system/resource/monitor
cpu-used: 100%
cpu-used-per-cpu: 100%,100%,100%,100%
free-memory: 69240KiB
-- [Q quit|D dump|C-z pause]
Command result:
17:17:37
--------
Sms count: 4
--------
17:17:44
Each time I run script on heavy load, script returns 1s slower.
I’m sure you can always find scenarios and cook up tests that show a problem.
My only remark is that in normal situations it will not be that much of a problem.
Dear antonsb, I have seven containers running on a RouterOs v7.11rc on an x86, I got 2 CCR2116 which will also run these containers, four of these containers are used by Zabbix, and it is devouring cpus, it would be very useful to limit the usage cpus, just like you did with memory usage.
For example:
memory-limit: 8GB // this one already exists
cpus-limit: 0.7 // that would be 70% for containers and the remaining 30% is for RouterOs
…
Resources usually:
cpu-used: 3%
cpu-used-per-cpu: 4%,2%,0%,7%
free-memory: 14033348KiB
Resourses when refreshing Zabbix:
cpu-used: 100%
cpu-used-per-cpu: 100%,100%,100%,100%
free-memory: 13635712KiB
This is harming the operation of RouterOs.
Please consider this request and include cpus limit, it would bring RouterOs containers to a higher level.
SUP ticket number: SUP-125273
Thank you very much.
I have been using containers since version 7.4, it is scary to see the processing at 100%, but I have noticed that this does not affect the router’s performance.
But this feature would be very welcome, and there would be no reason to worry about the cpu anymore.
I think it is really important as Routeros users will start using more and more docker containers to be able to set limits such as CPU but also important memory limits
https://docs.docker.com/config/containers/resource_constraints/
Is there plans from MikroTik to expose such options in the docker containers. I totally agree this will protect us from overcapacity in CPU and memory.
we are looking into adding swap and other features, but keep in mind that this is not docker running on RouterOS, not all options can be added that easily.