How to increase/check default memory Docker has on linux?

On native Linux, Docker can use all available host memory. It uses a lightweight kernel-based isolation mechanism that generally shares resources like CPU cores and memory (and on modern installations, disk space) using the standard kernel mechanism. There isn't a control or setting to limit or increase this.

On other platforms Docker runs a hidden Linux VM to be able to run a Linux kernel to use these isolation mechanisms, and the Docker Desktop memory control affects the memory allocation for that VM.

This is how I "check" the Docker container memory:

Open the linux command shell and -

Step 1: Check what containers are running.

docker ps

Step 2: Note down the 'CONTAINER ID' of the container you want to check and issue the following command:

docker container stats <containerID>

eg:

docker container stats c981

This will give an output like:

CONTAINER ID        NAME                CPU %               MEM USAGE / LIMIT     MEM %               NET I/O             BLOCK I/O           PIDS
c981c9482284        registry            0.00%               4.219MiB / 1.944GiB   0.21%               9.66kB / 0B         0B / 0B             14

'MEM USAGE / LIMIT' column will give you the actual memory usage and default memory allocated.

Note : press ctrl+c to come out of the view and back to command prompt.