Docker windows container memory limit

According to talks on Docker for windows Github issues (https://github.com/moby/moby/issues/31604), when Docker for Windows is run under Windows 10, it is actually using a Hyper-V isolation model (and process model is not accessible in Win 10 scenario).

And in that isolation type, your container is run inside a lightweight VM, which DOES have a default limit, and it is 1 Gb. So if you want to have more memory you should use -m param.

If using a Linux container

For me, on Windows 10 using Docker Desktop, I could not get the --memory= and --cpus= options to work. Here's what does work:

1. Right click on the Docker whale in the system tray and choose "Settings"
2. Go to "Advanced" on the left
3. Set how many CPUs and memory is available to containers here.

Surprise! Surprise!

I have 32Gb RAM on my host but I can see only 1Gb RAM given to Windows containers:

D:\>systeminfo | findstr "Memory"Total Physical Memory:     1,023 MBAvailable Physical Memory: 634 MBVirtual Memory: Max Size:  1,023 MBVirtual Memory: Available: 674 MBVirtual Memory: In Use:    349 MBD:\>wmic OS get FreePhysicalMemory /ValueFreePhysicalMemory=648340D:\>wmic computersystem get TotalPhysicalMemoryTotalPhysicalMemory1072742400

The same limit on images made from:

• microsoft/windowsservercore
• microsoft/nanoserver

I think it's coming from the Hyper-V layer in --isolation=hyperv mode, where a container is some sort of lightweight VM.

You can check isolation mode used for your existing container by docker inspect command.