What is the purpose of Docker’s –ipc flag and when would you use –ipc=host or –ipc=container?

Question

Docker Fundamentals — Hard

What is the purpose of Docker’s –ipc flag and when would you use –ipc=host or –ipc=container?

Accepted Answer

The --ipc flag in Docker controls access to shared memory and POSIX message queues. Using --ipc=host shares the host's IPC namespace, useful for legacy apps needing large shared memory. On the other hand, --ipc=container shares the IPC namespace with a specific named container, ideal for tightly coupled processes that communicate via shared memory.