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namespaces.7: ffix 

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
Michael Kerrisk 2017-08-12 22:45:48 +02:00
parent 6e2ef46bb8
commit 77eaf0524b
1 changed files with 14 additions and 14 deletions
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man7/namespaces.7
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@ -34,7 +34,7 @@ have their own isolated instance of the global resource.
Changes to the global resource are visible to other processes Changes to the global resource are visible to other processes
that are members of the namespace, but are invisible to other processes. that are members of the namespace, but are invisible to other processes.
One use of namespaces is to implement containers. One use of namespaces is to implement containers.
.PP
Linux provides the following namespaces: Linux provides the following namespaces:
.TS .TS
lB lB lB lB lB lB
@ -48,7 +48,7 @@ PID CLONE_NEWPID Process IDs
User CLONE_NEWUSER User and group IDs User CLONE_NEWUSER User and group IDs
UTS CLONE_NEWUTS Hostname and NIS domain name UTS CLONE_NEWUTS Hostname and NIS domain name
.TE .TE
.PP
This page describes the various namespaces and the associated This page describes the various namespaces and the associated
.I /proc .I /proc
files, and summarizes the APIs for working with namespaces. files, and summarizes the APIs for working with namespaces.
@ -115,7 +115,7 @@ Each process has a
subdirectory containing one entry for each namespace that subdirectory containing one entry for each namespace that
supports being manipulated by supports being manipulated by
.BR setns (2): .BR setns (2):
.PP
.in +4n .in +4n
.nf .nf
$ \fBls \-l /proc/$$/ns\fP $ \fBls \-l /proc/$$/ns\fP
@ -130,7 +130,7 @@ lrwxrwxrwx. 1 mtk mtk 0 Apr 28 12:46 user \-> user:[4026531837]
lrwxrwxrwx. 1 mtk mtk 0 Apr 28 12:46 uts \-> uts:[4026531838] lrwxrwxrwx. 1 mtk mtk 0 Apr 28 12:46 uts \-> uts:[4026531838]
.fi .fi
.in .in
.PP
Bind mounting (see Bind mounting (see
.BR mount (2)) .BR mount (2))
one of the files in this directory one of the files in this directory
@ -138,7 +138,7 @@ to somewhere else in the filesystem keeps
the corresponding namespace of the process specified by the corresponding namespace of the process specified by
.I pid .I pid
alive even if all processes currently in the namespace terminate. alive even if all processes currently in the namespace terminate.
.PP
Opening one of the files in this directory Opening one of the files in this directory
(or a file that is bind mounted to one of these files) (or a file that is bind mounted to one of these files)
returns a file handle for returns a file handle for
@ -149,7 +149,7 @@ the namespace will remain alive,
even if all processes in the namespace terminate. even if all processes in the namespace terminate.
The file descriptor can be passed to The file descriptor can be passed to
.BR setns (2). .BR setns (2).
.PP
In Linux 3.7 and earlier, these files were visible as hard links. In Linux 3.7 and earlier, these files were visible as hard links.
Since Linux 3.8, Since Linux 3.8,
.\" commit bf056bfa80596a5d14b26b17276a56a0dcb080e5 .\" commit bf056bfa80596a5d14b26b17276a56a0dcb080e5
@ -162,14 +162,14 @@ field returned by
.BR stat (2). .BR stat (2).
The content of this symbolic link is a string containing The content of this symbolic link is a string containing
the namespace type and inode number as in the following example: the namespace type and inode number as in the following example:
.PP
.in +4n .in +4n
.nf .nf
$ \fBreadlink /proc/$$/ns/uts\fP $ \fBreadlink /proc/$$/ns/uts\fP
uts:[4026531838] uts:[4026531838]
.fi .fi
.in .in
.PP
The symbolic links in this subdirectory are as follows: The symbolic links in this subdirectory are as follows:
.TP .TP
.IR /proc/[pid]/ns/cgroup " (since Linux 4.6)" .IR /proc/[pid]/ns/cgroup " (since Linux 4.6)"
@ -324,13 +324,13 @@ POSIX message queues (see
The common characteristic of these IPC mechanisms is that IPC The common characteristic of these IPC mechanisms is that IPC
objects are identified by mechanisms other than filesystem objects are identified by mechanisms other than filesystem
pathnames. pathnames.
.PP
Each IPC namespace has its own set of System V IPC identifiers and Each IPC namespace has its own set of System V IPC identifiers and
its own POSIX message queue filesystem. its own POSIX message queue filesystem.
Objects created in an IPC namespace are visible to all other processes Objects created in an IPC namespace are visible to all other processes
that are members of that namespace, that are members of that namespace,
but are not visible to processes in other IPC namespaces. but are not visible to processes in other IPC namespaces.
.PP
The following The following
.I /proc .I /proc
interfaces are distinct in each IPC namespace: interfaces are distinct in each IPC namespace:
@ -357,7 +357,7 @@ The System V IPC interfaces in
When an IPC namespace is destroyed When an IPC namespace is destroyed
(i.e., when the last process that is a member of the namespace terminates), (i.e., when the last process that is a member of the namespace terminates),
all IPC objects in the namespace are automatically destroyed. all IPC objects in the namespace are automatically destroyed.
.PP
Use of IPC namespaces requires a kernel that is configured with the Use of IPC namespaces requires a kernel that is configured with the
.B CONFIG_IPC_NS .B CONFIG_IPC_NS
option. option.
@ -379,12 +379,12 @@ A virtual network device ("veth") pair provides a pipe-like abstraction
that can be used to create tunnels between network namespaces, that can be used to create tunnels between network namespaces,
and can be used to create a bridge to a physical network device and can be used to create a bridge to a physical network device
in another namespace. in another namespace.
.PP
When a network namespace is freed When a network namespace is freed
(i.e., when the last process in the namespace terminates), (i.e., when the last process in the namespace terminates),
its physical network devices are moved back to the its physical network devices are moved back to the
initial network namespace (not to the parent of the process). initial network namespace (not to the parent of the process).
.PP
Use of network namespaces requires a kernel that is configured with the Use of network namespaces requires a kernel that is configured with the
.B CONFIG_NET_NS .B CONFIG_NET_NS
option. option.
@ -421,7 +421,7 @@ and can be retrieved using
.BR gethostname (2), .BR gethostname (2),
and and
.BR getdomainname (2). .BR getdomainname (2).
.PP
Use of UTS namespaces requires a kernel that is configured with the Use of UTS namespaces requires a kernel that is configured with the
.B CONFIG_UTS_NS .B CONFIG_UTS_NS
option. option.