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I am new to Docker and I want to run Docker with ram only storage. In other words, I do not want Docker to save anything on persistent storage. I found out that on Linux Docker supports tmpfs. Is there any such support for MacOS? I have tried setting --tmpfs flag and docker run commands run fine on mac with that flag.

Jiri Klouda
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muhammad haris
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  • You might find this useful if you try to make Docker run read only. https://devops.stackexchange.com/questions/3872/how-do-i-make-read-only-mount-in-docker-container-writable – Jiri Klouda Apr 30 '18 at 04:45

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According to the docs tmpfs is linux only.

RAM disk

If you want "RAM only storage", you can literally use a RAM disk. ie: 

diskutil erasevolume HFS+ 'DockerDisk' `hdiutil attach -nomount ram://2097152 `

Then you can point volumes at /Volumes/DockerDisk. Drop and recreate at will.

Docker will still store its VM and images on disk. See: Docker > Preferences > Disk.

Jacob Vanus
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    Thanks for your reply can you tell me about inmemory filesystem. It looks like it does exactly what I require. https://docs.docker.com/registry/storage-drivers/inmemory/ However I dont know how to configure it. – muhammad haris Apr 30 '18 at 16:02
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    What I describe does not require the use of any special storage drivers from docker. MacOS is handling that for you. Just use it as a standard volume. eg: -v /Volumes/DockerDisk/foo:/etc/foo – Jacob Vanus Apr 30 '18 at 16:42
  • okay sweet I have accepted your answer. Can you tell me how I can move the volume without using GUI on mac.. or should I ask it as a new question? – muhammad haris Apr 30 '18 at 16:45
  • Might be better as its own question, just to keep the answers separate. Off hand, I'm not sure what you mean by "move the volume". – Jacob Vanus Apr 30 '18 at 16:52
  • Here is my new question: https://devops.stackexchange.com/questions/4023/macos-how-to-move-disk-image-in-command-line – muhammad haris Apr 30 '18 at 16:57
  • The "In-memory storage driver" referenced in the first comment is for registry specifically. It is not docker storage backend, but a docker registry storage backend, so irrelevant to the described problem. – alexykot Oct 12 '20 at 14:27