Your kernel does not support CPU real-time scheduler - on Ubuntu Server 20.04.4 LTS

I am trying to run Oracle RAC in Docker Containers. As a requirement I need to enable Real Time Kernel.
Starting the docker container with:

–cpu-rt-runtime=95000 --ulimit rtprio=99

fails with:

Error response from daemon: Your kernel does not support CPU real-time scheduler

There is no RT Kernel in Ubuntu. Instead I have installed the low latency kernel.
Ubuntu is stating about the low latency kernel the following:

and also these series:

Basically they’re saying that the low latency kernel is almost as good as the real time kernel.
So, does this mean that I might simply ignore the requirements for RT and go with low latency?

Or maybe someone knows a simple way to install a RT kernel in Ubuntu?


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I am getting this error with the same setup on Ubuntu 22.04 and would like to solve it as well.

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You could try to install in the host machine Ubuntu RT and later install docker + ubuntu image