freebsd-dev/man/man8/zgenhostid.8
Olaf Faaland b9373170e3 Add zgenhostid utility script
Turning the multihost property on requires that a hostid be set to allow
ZFS to determine when a foreign system is attemping to import a pool.
The error message instructing the user to set a hostid refers to
genhostid(1).

Genhostid(1) is not available on SUSE Linux.  This commit adds a script
modeled after genhostid(1) for those users.

Zgenhostid checks for an /etc/hostid file; if it does not exist, it
creates one and stores a value.  If the user has provided a hostid as an
argument, that value is used.  Otherwise, a random hostid is generated
and stored.

This differs from the CENTOS 6/7 versions of genhostid, which overwrite
the /etc/hostid file even though their manpages state otherwise.

A man page for zgenhostid is added. The one for genhostid is in (1), but
I put zgenhostid in (8) because I believe it's more appropriate.

The mmp tests are modified to use zgenhostid to set the hostid instead
of using the spl_hostid module parameter.  zgenhostid will not replace
an existing /etc/hostid file, so new mmp_clear_hostid calls are
required.

Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
Closes #6358
Closes #6379
2017-07-25 13:22:03 -04:00

73 lines
2.0 KiB
Groff

.\"
.\" CDDL HEADER START
.\"
.\" The contents of this file are subject to the terms of the
.\" Common Development and Distribution License (the "License").
.\" You may not use this file except in compliance with the License.
.\"
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
.\" or http://www.opensolaris.org/os/licensing.
.\" See the License for the specific language governing permissions
.\" and limitations under the License.
.\"
.\" When distributing Covered Code, include this CDDL HEADER in each
.\" file and include the License file at usr/src/OPENSOLARIS.LICENSE.
.\" If applicable, add the following below this CDDL HEADER, with the
.\" fields enclosed by brackets "[]" replaced with your own identifying
.\" information: Portions Copyright [yyyy] [name of copyright owner]
.\"
.\" CDDL HEADER END
.\"
.\"
.\" Copyright (c) 2017 by Lawrence Livermore National Security, LLC.
.\"
.Dd July 24, 2017
.Dt ZGENHOSTID 8 SMM
.Os Linux
.Sh NAME
.Nm zgenhostid
.Nd generate and store a hostid in
.Em /etc/hostid
.Sh SYNOPSIS
.Nm
.Op Ar hostid
.Sh DESCRIPTION
If
.Em /etc/hostid
does not exist, create it and store a hostid in it. If the user provides
.Op Ar hostid
on the command line, store that value. Otherwise, randomly generate a
value to store.
.Pp
This emulates the
.Xr genhostid 1
utility and is provided for use on systems which do not include the utility.
.Pp
.Sh OPTIONS
.Op Ar hostid
Specifies the value to be placed in
.Em /etc/hostid .
It must be a number with a value between 1 and 2^32-1. This value
.Sy must
be unique among your systems. It must be expressed in hexadecimal and be
exactly 8 digits long.
.Sh EXAMPLES
.Bl -tag -width Ds
.It Generate a random hostid and store it
.Bd -literal
# zgenhostid
.Ed
.It Record the libc-generated hostid in Em /etc/hostid
.Bd -literal
# zgenhostid $(hostid)
.Ed
.It Record a custom hostid (0xdeadbeef) in Em etc/hostid
.Bd -literal
# zgenhostid deadbeef
.Ed
.El
.Sh SEE ALSO
.Xr spl-module-parameters 5 ,
.Xr genhostid 1 ,
.Xr hostid 1