ipc_namespaces(7) Miscellaneous Information Manual ipc_namespaces(7)
NAME
ipc_namespaces - overview of Linux IPC namespaces
DESCRIPTION
IPC namespaces isolate certain IPC resources, namely, System V IPC ob-
jects (see sysvipc(7)) and (since Linux 2.6.30) POSIX message queues
(see mq_overview(7)). The common characteristic of these IPC mechanisms
is that IPC objects are identified by mechanisms other than filesystem
pathnames.
Each IPC namespace has its own set of System V IPC identifiers and its
own POSIX message queue filesystem. Objects created in an IPC namespace
are visible to all other processes that are members of that namespace,
but are not visible to processes in other IPC namespaces.
The following /proc interfaces are distinct in each IPC namespace:
• The POSIX message queue interfaces in /proc/sys/fs/mqueue.
• The System V IPC interfaces in /proc/sys/kernel, namely: msgmax, ms-
gmnb, msgmni, sem, shmall, shmmax, shmmni, and shm_rmid_forced.
• The System V IPC interfaces in /proc/sysvipc.
When an IPC namespace is destroyed (i.e., when the last process that is
a member of the namespace terminates), all IPC objects in the namespace
are automatically destroyed.
Use of IPC namespaces requires a kernel that is configured with the CON-
FIG_IPC_NS option.
SEE ALSO
nsenter(1), unshare(1), clone(2), setns(2), unshare(2), mq_overview(7),
namespaces(7), sysvipc(7)
Linux man-pages 6.9.1 2024-05-02 ipc_namespaces(7)
Generated by dwww version 1.16 on Tue Dec 16 03:58:14 CET 2025.