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This article mainly introduces "how to limit the memory size of docker container". In daily operation, I believe many people have doubts about how to limit the memory size of docker container. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful for you to answer the question of "how to limit the memory size of docker container". Next, please follow the editor to study!

In the process of using a docker container, it is often necessary to limit the host resources that the container can use.

It is important to limit the container's ability to use host memory too much. For linux hosts, once the kernel detects that there is not enough memory to allocate, it throws OOME (Out Of Memmory Exception) and starts killing some processes to free up memory space.

Memory limit

Similar to the operating system, the memory available to the container consists of two parts: physical memory and swap. Docker controls container memory usage through the following two sets of parameters.

-m or-memory: sets the memory usage limit, such as 100m, 2G.

-memory-swap: sets the usage limit of memory + swap.

When we execute the following command:

Docker run-m 200m-- memory-swap=300M ubuntu

The implication is to allow the container to use up to 200m of memory and 100m of swap. By default, the above two sets of parameters are-1, which means there are no restrictions on the use of container memory and swap.

Let's use the progrium/stress image to allocate memory for the container. This image can be used to perform pressure tests on the container. Execute the following command:

Docker run-it-m 200m-memory-swap=300M progrium/stress-- vm 1-- vm-bytes 280m

-vm 1: starts a memory worker thread.

-vm-bytes 280m: each thread allocates 280m memory.

Because 280m is within the allocable range (300m), the worker thread can work normally. If the worker thread allocates more than 300m memory, the allocated memory exceeds the limit, the stress thread reports an error, and the container exits.

If you specify only-m instead of-memory-swap when starting the container, then-memory-swap defaults to twice-m, for example:

Docker run-it-m 200m ubuntu

The container uses up to 200m physical memory and 200m swap.

At this point, the study on "how to limit the memory size of the docker container" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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