mirror_zfs/man/man8/zgenhostid.8

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.\" Copyright (c) 2017 by Lawrence Livermore National Security, LLC.
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.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
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 2017-07-19 04:11:08 +03:00			`.\"`
			`.\" 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`