e307eb94ae
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
139 lines
3.8 KiB
Groff
139 lines
3.8 KiB
Groff
.\" Copyright (c) 2002 Gordon Tetlow
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd September 19, 2020
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.Dt NEXTBOOT 8
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.Os
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.Sh NAME
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.Nm nextboot
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.Nd "specify an alternate kernel and boot flags for the next reboot"
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.Sh SYNOPSIS
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.Nm
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.Op Fl af
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.Op Fl e Ar variable=value
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.Op Fl k Ar kernel
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.Op Fl o Ar options
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.Nm
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.Fl D
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.Sh DESCRIPTION
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The
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.Nm
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utility allows specifying some combination of an alternate kernel, boot flags
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and kernel environment for the
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next time the machine is booted.
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Once the
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.Xr loader 8
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loads in the new kernel
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information, it is deleted so in case the new kernel hangs the machine,
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once it is rebooted, the machine will automatically revert to its previous
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configuration.
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.Pp
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The options are as follows:
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.Bl -tag -width ".Fl o Ar options"
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.It Fl a
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This option causes
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.Nm
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to append to an existing configuration in
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.Pa /boot/nextboot.conf .
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By default any existing configuration is overwritten.
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.It Fl D
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Invoking
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.Nm
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with this
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option removes an existing
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.Nm
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configuration.
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.It Fl e Ar variable=value
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This option adds the provided variable and value to the kernel environment.
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The value is quoted when written to the
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.Nm
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configuration.
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.It Fl f
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This
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option disables the sanity checking which checks if the kernel really exists
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before writing the
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.Nm
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configuration.
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.It Fl k Ar kernel
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This option specifies a kernel directory relative to
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.Pa /boot
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to load the kernel and any modules from.
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.It Fl o Ar options
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This option
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allows the passing of kernel flags for the next boot.
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.El
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.Sh FILES
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.Bl -tag -width ".Pa /boot/nextboot.conf" -compact
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.It Pa /boot/nextboot.conf
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The configuration file that the
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.Nm
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configuration is written into.
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.El
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.Sh EXAMPLES
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To boot the
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.Pa GENERIC
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kernel with the
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.Nm
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command:
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.Pp
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.Dl "nextboot -k GENERIC"
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.Pp
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To enable into single user mode with the normal kernel:
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.Pp
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.Dl "nextboot -o ""-s"" -k kernel"
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.Pp
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To remove an existing nextboot configuration:
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.Pp
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.Dl "nextboot -D"
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.Sh SEE ALSO
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.Xr boot 8 ,
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.Xr loader 8
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.Sh HISTORY
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The original
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.Nm
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manual page first appeared in
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.Fx 2.2 .
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It used a very different interface to achieve similar results.
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.Pp
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The current incarnation of
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.Nm
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appeared in
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.Fx 5.0 .
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.Sh AUTHORS
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This manual page was written by
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.An Gordon Tetlow Aq Mt gordon@FreeBSD.org .
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.Sh BUGS
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The
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.Nm
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code is implemented in the
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.Xr loader 8 .
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It is not the most thoroughly tested code.
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It is also my first attempt to write in Forth.
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.Pp
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Finally, it does some evil things like writing to the file system before it
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has been checked.
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If it scrambles your file system, do not blame me.
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