Kexec - Revision history

Zcrayfish: Re-added accidentally trimmed content.

2024-01-02T22:41:09Z

Re-added accidentally trimmed content.

← Older revision		Revision as of 22:41, 2 January 2024
Line 30:		Line 30:
	{{cat\|/etc/init.d/kexec-load\|{{:Kexec/kexec-load}}}}		{{cat\|/etc/init.d/kexec-load\|{{:Kexec/kexec-load}}}}
	{{cat\|/etc/init.d/kexec-exec\|{{:Kexec/kexec-exec}}}}		{{cat\|/etc/init.d/kexec-exec\|{{:Kexec/kexec-exec}}}}

			Now give these services execute permission and assign them to the appropriate runlevels:
			{{cmd\|chmod a+x /etc/init.d/kexec-load
			chmod a+x /etc/init.d/kexec-exec
			rc-update add kexec-load default
			rc-update add kexec-exec shutdown
			rc-service kexec-load start
			}}

	kexec will run on your next <code>reboot</code> or <code>poweroff</code> enjoy!		kexec will run on your next <code>reboot</code> or <code>poweroff</code> enjoy!

Zcrayfish: /* Automatically on every reboot/shutdown */ Transclude kexec-exec instead of having the entire contents inline

2024-01-02T19:08:57Z

Automatically on every reboot/shutdown: Transclude kexec-exec instead of having the entire contents inline

@@ Line 29: / Line 29: @@
 First create two openrc services and edit the <code>BOOTPART</code>, <code>KERNEL</code>, and <code>INITRD</code> variables if not using the defaults:
 {{cat|/etc/init.d/kexec-load|{{:Kexec/kexec-load}}}}
-{{cat|/etc/init.d/kexec-exec|<nowiki>#! /sbin/openrc-run
+{{cat|/etc/init.d/kexec-exec|{{:Kexec/kexec-exec}}}}
 kexec will run on your next <code>reboot</code> or <code>poweroff</code> enjoy!

Zcrayfish: Transclude kexec-load and don't screw up the other script this time :)

2024-01-02T19:05:56Z

Transclude kexec-load and don't screw up the other script this time :)

@@ Line 28: / Line 28: @@
 First create two openrc services and edit the <code>BOOTPART</code>, <code>KERNEL</code>, and <code>INITRD</code> variables if not using the defaults:
-{{cat|/etc/init.d/kexec-load|<nowiki>#!/sbin/openrc-run
+{{cat|/etc/init.d/kexec-load|{{:Kexec/kexec-load}}}}
 {{cat|/etc/init.d/kexec-exec|<nowiki>#! /sbin/openrc-run
 description="kexec for faster reboot"

Zcrayfish: Undo revision 26110 by Zcrayfish (talk) Deleted too much. =)

2024-01-02T19:04:23Z

Undo revision 26110 by Zcrayfish (talk) Deleted too much. =)

@@ Line 28: / Line 28: @@
 First create two openrc services and edit the <code>BOOTPART</code>, <code>KERNEL</code>, and <code>INITRD</code> variables if not using the defaults:
-{{cat|/etc/init.d/kexec-load|{{:Kexec/kexec-load}}}}
+{{cat|/etc/init.d/kexec-load|<nowiki>#!/sbin/openrc-run
 Now give these services execute permission and assign them to the appropriate runlevels:
 {{cmd|chmod a+x /etc/init.d/kexec-load

Zcrayfish: /* Automatically on every reboot/shutdown */ transclude the kexec-load file instead of doing it inline.

2024-01-02T19:02:49Z

Automatically on every reboot/shutdown: transclude the kexec-load file instead of doing it inline.

@@ Line 28: / Line 28: @@
 First create two openrc services and edit the <code>BOOTPART</code>, <code>KERNEL</code>, and <code>INITRD</code> variables if not using the defaults:
-{{cat|/etc/init.d/kexec-load|<nowiki>#!/sbin/openrc-run
+{{cat|/etc/init.d/kexec-load|{{:Kexec/kexec-load}}}}
 Now give these services execute permission and assign them to the appropriate runlevels:
 {{cmd|chmod a+x /etc/init.d/kexec-load

Zcrayfish: Move stuff around and get everything factually correct. As of 3.19 installing the userspace tools can be done on any flavor. Trivial grammar improvements.

2024-01-02T17:17:14Z

Move stuff around and get everything factually correct. As of 3.19 installing the userspace tools can be done on any flavor. Trivial grammar improvements.

@@ Line 2: / Line 2: @@
 [https://en.wikipedia.org/wiki/Kexec kexec] is a system call that enables loading and booting into another kernel. This is useful for faster reboots that skip the firmware initialisation process and the bootloader.
-==Installing kexec-tools==
+==Preparing==
-The userspace tools required to use it can be installed via {{cmd|apk add {{pkg|kexec-tools}} {{pkg|kexec-tools-doc}}}} The tools are not available on all flavors of Alpine, additionally not all kernels are compiled with the kexec syscall enabled. You will most likely want to check your {{path|/boot/config-*}} file for {{codeline|CONFIG_KEXEC&equals;y}}
+In Alpine 3.19 and up, the userspace tools required to use it can be installed via {{cmd|apk add {{pkg|kexec-tools}} {{pkg|kexec-tools-doc}}}} But note that not all kernels are compiled with the kexec syscall enabled. You should check the {{path|/boot/config-*}} file for {{codeline|CONFIG_KEXEC&equals;y}}
 ==Usage==
@@ Line 15: / Line 23: @@
 && openrc shutdown
 &#35; kexec -e}}
 ===Automatically on every reboot/shutdown===

Bro: fix wiki link

2024-01-02T14:10:10Z

fix wiki link

← Older revision		Revision as of 14:10, 2 January 2024
Line 22:		Line 22:
	<code>kexec_load_disabled=0</code>.		<code>kexec_load_disabled=0</code>.

	Without it the [https://linux.die.net/man/8/sysctl sysctl setting] <code>kernel.kexec_load_disabled</code> defaults to 1 and it can't be turned off in the running kernel, so you need to add the parameter to your [[#Bootloaders\|bootloader]] configuration and reboot.		Without it the [https://linux.die.net/man/8/sysctl sysctl setting] <code>kernel.kexec_load_disabled</code> defaults to 1 and it can't be turned off in the running kernel, so you need to add the parameter to your [[Bootloaders\|bootloader]] configuration and reboot.

	There are no other Alpine-specific considerations for Kexec. Please review the man page and existing references below for more details. This page is deliberately kept short in order to avoid duplicating existing documentation.		There are no other Alpine-specific considerations for Kexec. Please review the man page and existing references below for more details. This page is deliberately kept short in order to avoid duplicating existing documentation.

Bro: Explain the boot parameter kexec_load_disabled=0 which unlocks kexec in current (hardened) Alpine kernels.

2024-01-02T14:03:38Z

Explain the boot parameter kexec_load_disabled=0 which unlocks kexec in current (hardened) Alpine kernels.

← Older revision		Revision as of 14:03, 2 January 2024
Line 16:		Line 16:
	# kexec -e}}		# kexec -e}}

	There are no Alpine-specific considerations for Kexec. Please review the man page and existing references below for more details. This page is deliberately kept short in order to avoid duplicating existing documentation.		Current Alpine kernels have been [https://gitlab.alpinelinux.org/alpine/aports/-/commit/909d020b81c09bf0df649f8aa6b7da10377a0667 hardened] and return
			<code>kexec_load failed: Operation not permitted</code>
			if kexec is called without unlocking it with the kernel boot parameter

			<code>kexec_load_disabled=0</code>.

			Without it the [https://linux.die.net/man/8/sysctl sysctl setting] <code>kernel.kexec_load_disabled</code> defaults to 1 and it can't be turned off in the running kernel, so you need to add the parameter to your [[#Bootloaders\|bootloader]] configuration and reboot.

			There are no other Alpine-specific considerations for Kexec. Please review the man page and existing references below for more details. This page is deliberately kept short in order to avoid duplicating existing documentation.

	===Automatically on every reboot/shutdown===		===Automatically on every reboot/shutdown===

Zcrayfish: /* Usage */ Added note about kexec unable to deal with multiple initrd

2023-11-15T16:25:05Z

Usage: Added note about kexec unable to deal with multiple initrd

← Older revision		Revision as of 16:25, 15 November 2023
Line 7:		Line 7:
	==Usage==		==Usage==
	===Manually===		===Manually===

			{{note\|Currently multiple initrd (e.g. for loading CPU microcode) is not supported}}
	On a typical Alpine setup, it can be used via:		On a typical Alpine setup, it can be used via:

Zcrayfish: Added the word "default" to the note; because it makes more sense that way.

2023-10-20T00:10:15Z

Added the word "default" to the note; because it makes more sense that way.

← Older revision		Revision as of 00:10, 20 October 2023
Line 67:		Line 67:
	kexec will run on your next <code>reboot</code> or <code>poweroff</code> enjoy!		kexec will run on your next <code>reboot</code> or <code>poweroff</code> enjoy!

	{{Note\|With both of the above service enabled, the system will reboot via kexec even if you are attempting to <code>poweroff</code>. To temporarily restore <code>poweroff</code> or <code>reboot</code> behavior, simply run <code>rc-service kexec-load stop</code> beforehand.}}		{{Note\|With both of the above service enabled, the system will reboot via kexec even if you are attempting to <code>poweroff</code>. To temporarily restore default <code>poweroff</code> or <code>reboot</code> behavior, simply run <code>rc-service kexec-load stop</code> beforehand.}}

	== See also ==		== See also ==