HardenedBSD/sbin/zfsbootcfg/zfsbootcfg.8
Toomas Soome e307eb94ae loader: zfs should support bootonce an nextboot
bootonce feature is temporary, one time boot, activated by
"bectl activate -t BE", "bectl activate -T BE" will reset the bootonce flag.

By default, the bootonce setting is reset on attempt to boot and the next
boot will use previously active BE.

By setting zfs_bootonce_activate="YES" in rc.conf, the bootonce BE will
be set permanently active.

bootonce dataset name is recorded in boot pool labels, bootenv area.

in case of nextboot, the nextboot_enable boolean variable is recorded in
freebsd:nvstore nvlist, also stored in boot pool label bootenv area.
On boot, the loader will process /boot/nextboot.conf if nextboot_enable
is "YES", and will set nextboot_enable to "NO", preventing /boot/nextboot.conf
processing on next boot.

bootonce and nextboot features are usable in both UEFI and BIOS boot.

To use bootonce/nextboot features, the boot loader needs to be updated on disk;
if loader.efi is stored on ESP, then ESP needs to be updated and
for BIOS boot, stage2 (zfsboot or gptzfsboot) needs to be updated
(gpart or other tools).

At this time, only lua loader is updated.

Sponsored by:	Netflix, Klara Inc.
Differential Revision:	https://reviews.freebsd.org/D25512
2020-09-21 09:01:10 +00:00

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.\" Copyright (c) 2016 Andriy Gapon
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" $FreeBSD$
.\"
.Dd July 22, 2020
.Dt ZFSBOOTCFG 8
.Os
.Sh NAME
.Nm zfsbootcfg
.Nd "specify zfsboot options for the next boot"
.Sh SYNOPSIS
.Nm
.Ao Ar options Ac
.Nm
.Op Fl n Ar name
.Op Fl k Ar key
.Op Fl p
.Op Fl t Ar type
.Op Fl v Ar value
.Op Fl z Ar pool
.Nm
.Sh DESCRIPTION
.Nm
is used to set
.Xr boot.config 5 Ns -style
options to be used by
.Xr zfsboot 8 ,
.Xr gptzfsboot 8
or
.Xr loader 8
the next time the machine is booted.
Once
.Xr zfsboot 8
or
.Xr gptzfsboot 8
or
.Xr loader 8
reads the information, it is deleted.
If booting fails, the machine automatically reverts to the previous
boot configuration.
The information is stored in a special boot environment area of a ZFS pool.
.Pp
If used without arguments,
.Nm
will output the current boot configuration, if set.
.Pp
The following options are supported by
.Nm :
.Bl -tag -width indent
.It Fl k Ar key
Define key for
.Ao key , value Ac
pair.
.It Fl n Ar name
Update nvlist
.Ar name .
.It Fl p
Print all information stored in ZFS pool bootenv area.
.It Fl t Ar type
Set type of
.Ar value
used in
.Ao key , value Ac
pair.
Currently supported types are:
.Bl -tag -width indent -compact
.It Ar DATA_TYPE_BYTE
.It Ar DATA_TYPE_INT8
.It Ar DATA_TYPE_UINT8
.It Ar DATA_TYPE_INT16
.It Ar DATA_TYPE_UINT16
.It Ar DATA_TYPE_INT32
.It Ar DATA_TYPE_UINT32
.It Ar DATA_TYPE_INT64
.It Ar DATA_TYPE_UINT64
.It Ar DATA_TYPE_BOOLEAN_VALUE
.It Ar DATA_TYPE_STRING
.El
.Pp
If not specified, the default is
.Ar DATA_TYPE_STRING .
.It Fl v Ar value
Define value for
.Ao key , value Ac
pair.
.It Fl z Ar pool
Operate on
.Ar pool .
.El
.Sh ENVIRONMENT
.Bl -tag -width vfs.root.mountfrom -compact
.It Ev vfs.root.mountfrom
The
.Xr kenv 1
variable that identifies a pool for which the options are written.
.El
.Sh EXAMPLES
Try to boot to a new
.Em boot environment
without changing the
.Cm bootfs
property of a pool:
.Pp
.Dl "zfsbootcfg ""zfs:tank/ROOT/newbe:""
.Pp
To clear the boot options:
.Pp
.Dl "zfsbootcfg """"
.Sh SEE ALSO
.Xr boot.config 5 ,
.Xr bectl 8 ,
.Xr gptzfsboot 8 ,
.Xr loader 8 ,
.Xr zfsboot 8
.Sh HISTORY
.Nm
appeared in
.Fx 11.1 .
.Sh AUTHORS
This manual page was written by
.An Andriy Gapon Aq Mt avg@FreeBSD.org .