'\" t
.TH "SYSTEMD\-MACHINE\-ID\-SETUP" "1" "" "systemd 254" "systemd-machine-id-setup"
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.SH "NAME"
systemd-machine-id-setup \- Initialize the machine ID in /etc/machine\-id
.SH "SYNOPSIS"
.HP \w'\fBsystemd\-machine\-id\-setup\fR\ 'u
\fBsystemd\-machine\-id\-setup\fR
.SH "DESCRIPTION"
.PP
\fBsystemd\-machine\-id\-setup\fR
may be used by system installer tools to initialize the machine ID stored in
/etc/machine\-id
at install time, with a provisioned or randomly generated ID\&. See
\fBmachine-id\fR(5)
for more information about this file\&.
.PP
If the tool is invoked without the
\fB\-\-commit\fR
switch,
/etc/machine\-id
is initialized with a valid, new machine ID if it is missing or empty\&. The new machine ID will be acquired in the following fashion:
.sp
.RS 4
.ie n \{\
\h'-04' 1.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  1." 4.2
.\}
If a valid D\-Bus machine ID is already configured for the system, the D\-Bus machine ID is copied and used to initialize the machine ID in
/etc/machine\-id\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 2.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  2." 4.2
.\}
If run inside a KVM virtual machine and a UUID is configured (via the
\fB\-uuid\fR
option), this UUID is used to initialize the machine ID\&. The caller must ensure that the UUID passed is sufficiently unique and is different for every booted instance of the VM\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 3.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  3." 4.2
.\}
Similarly, if run inside a Linux container environment and a UUID is configured for the container, this is used to initialize the machine ID\&. For details, see the documentation of the
\m[blue]\fBContainer Interface\fR\m[]\&\s-2\u[1]\d\s+2\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 4.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  4." 4.2
.\}
Otherwise, a new ID is randomly generated\&.
.RE
.PP
The
\fB\-\-commit\fR
switch may be used to commit a transient machined ID to disk, making it persistent\&. For details, see below\&.
.PP
Use
\fBsystemd-firstboot\fR(1)
to initialize the machine ID on mounted (but not booted) system images\&.
.SH "OPTIONS"
.PP
The following options are understood:
.PP
\fB\-\-root=\fR\fB\fIpath\fR\fR
.RS 4
Takes a directory path as argument\&. All paths operated on will be prefixed with the given alternate
\fIroot\fR
path, including the path for
/etc/machine\-id
itself\&.
.RE
.PP
\fB\-\-image=\fR\fB\fIpath\fR\fR
.RS 4
Takes a path to a device node or regular file as argument\&. This is similar to
\fB\-\-root=\fR
as described above, but operates on a disk image instead of a directory tree\&.
.RE
.PP
\fB\-\-image\-policy=\fR\fB\fIpolicy\fR\fR
.RS 4
Takes an image policy string as argument, as per
\fBsystemd.image-policy\fR(7)\&. The policy is enforced when operating on the disk image specified via
\fB\-\-image=\fR, see above\&. If not specified defaults to the
"*"
policy, i\&.e\&. all recognized file systems in the image are used\&.
.RE
.PP
\fB\-\-commit\fR
.RS 4
Commit a transient machine ID to disk\&. This command may be used to convert a transient machine ID into a persistent one\&. A transient machine ID file is one that was bind mounted from a memory file system (usually
"tmpfs") to
/etc/machine\-id
during the early phase of the boot process\&. This may happen because
/etc/
is initially read\-only and was missing a valid machine ID file at that point\&.
.sp
This command will execute no operation if
/etc/machine\-id
is not mounted from a memory file system, or if
/etc/
is read\-only\&. The command will write the current transient machine ID to disk and unmount the
/etc/machine\-id
mount point in a race\-free manner to ensure that this file is always valid and accessible for other processes\&.
.sp
This command is primarily used by the
\fBsystemd-machine-id-commit.service\fR(8)
early boot service\&.
.RE
.PP
\fB\-\-print\fR
.RS 4
Print the machine ID generated or committed after the operation is complete\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Print a short help text and exit\&.
.RE
.PP
\fB\-\-version\fR
.RS 4
Print a short version string and exit\&.
.RE
.SH "EXIT STATUS"
.PP
On success, 0 is returned, a non\-zero failure code otherwise\&.
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBmachine-id\fR(5),
\fBsystemd-machine-id-commit.service\fR(8),
\fBdbus-uuidgen\fR(1),
\fBsystemd-firstboot\fR(1)
.SH "NOTES"
.IP " 1." 4
Container Interface
.RS 4
\%https://systemd.io/CONTAINER_INTERFACE
.RE