Docker supports shared memory. The default is only 64MB though which is TINY.

The small size became a problem during a containerized OpenStack upgrade.

This will be a really short post because I haven't done much playing with the shared memory yet, I just think its really neat.

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Change the /dev/shm size on the system

This lets you change the size of shared memory on a host.

mount -o remount,size=1G /dev/shm

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Update Docker Daemon's Default Shared Memory Size

This will update the default across the whole Docker service.

vi /etc/docker/daemon.json

{
  "default-shm-size": "512M"
}

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Set a Containers Shared Memory Size

Here's how to change it for a specific container at runtime.

docker run -it --shm-size=512M