3 Administration using transactional updates #
This chapter describes the usage of the
transactional-update
command.
In case you do not reboot your machine before performing further changes,
the transactional-update
command will create a new
snapshot from the current root file system. This means that you will end
up with several parallel snapshots, each including that particular change
but not changes from the other invocations of the command. After reboot,
the most recently created snapshot will be used as your new root file
system, and it will not include changes done in the previous snapshots.
3.1 transactional-update
usage #
The transactional-update
command enables the atomic
installation or removal of updates; updates are applied only if all of
them can be successfully installed.
transactional-update
creates a snapshot of your system
and uses it to update the system. Later you can restore this snapshot. All
changes become active only after reboot.
The transactional-update
command syntax is as follows:
transactional-update [option]
[general_command] [package_command] standalone_command
transactional-update
without arguments
If you do not specify any command or option while running the
transactional-update
command, the system updates
itself.
Possible command parameters are described further.
transactional-update
options #--interactive, -i
Can be used along with a package command to turn on interactive mode.
--non-interactive, -n
Can be used along with a package command to turn on non-interactive mode.
--continue [number], -c
The
--continue
option is for making multiple changes to an existing snapshot without rebooting.The default
transactional-update
behavior is to create a new snapshot from the current root file system. If you forget something, such as installing a new package, you have to reboot to apply your previous changes, runtransactional-update
again to install the forgotten package, and reboot again. You cannot run thetransactional-update
command multiple times without rebooting to add more changes to the snapshot, because this will create separate independent snapshots that do not include changes from the previous snapshots.Use the
--continue
option to make as many changes as you want without rebooting. A separate snapshot is made each time, and each snapshot contains all the changes you made in the previous snapshots, plus your new changes. Repeat this process as many times as you want, and when the final snapshot includes everything you want, reboot the system, and your final snapshot becomes the new root file system.Another useful feature of the
--continue
option is that you may select any existing snapshot as the base for your new snapshot. The following example demonstrates runningtransactional-update
to install a new package in a snapshot based on snapshot 13, and then running it again to install another package:#
transactional-update pkg install package_1
#
transactional-update --continue 13 pkg install package_2
--no-selfupdate
Disables self-updating of
transactional-update
.--drop-if-no-change, -d
Discards the snapshot created by
transactional-update
if there were no changes to the root file system. If there are some changes to the/etc
directory, those changes are merged back to the current file system.--quiet
The
transactional-update
command will not output tostdout
.--help, -h
Prints help for the
transactional-update
command.--version
Displays the version of the
transactional-update
command.
The general commands are the following:
cleanup-snapshots
The command marks all unused snapshots that are intended to be removed.
cleanup-overlays
The command removes all unused overlay layers of
/etc
.cleanup
The command combines the
cleanup-snapshots
andcleanup-overlays
commands. For more details, refer to Section 3.2, “Snapshots cleanup”.grub.cfg
Use this command to rebuild the GRUB boot loader configuration file.
bootloader
The command reinstalls the boot loader.
initrd
Use the command to rebuild
initrd
.kdump
If you perform changes to your hardware or storage, you may need to rebuild the kdump initrd.
shell
Opens a read-write shell in the new snapshot before exiting. The command is typically used for debugging purposes.
reboot
The system reboots after the transactional-update is complete.
run
<command>Runs the provided command in a new snapshot.
setup-selinux
Installs and enables the targeted SELinux policy.
The package commands are the following:
The installation of packages from repositories other than
the official ones (for example, the SUSE Linux Enterprise Server repositories) is
not supported and not
recommended. To use the tools available for SUSE Linux Enterprise Server, run the
toolbox
container and install the tools inside
the container. For details about the toolbox
container, refer to Chapter 9, toolbox
for SLE Micro debugging.
dup
Performs an upgrade of your system. The default option for this command is
--non-interactive
.migration
The command migrates your system to a selected target. Typically, it is used to upgrade your system if it has been registered via SUSE Customer Center.
patch
Checks for available patches and installs them. The default option for this command is
--non-interactive
.pkg install
Installs individual packages from the available channels using the
zypper install
command. This command can also be used to install Program Temporary Fix (PTF) RPM files. The default option for this command is--interactive
.#
transactional-update pkg install package_name
or
#
transactional-update pkg install rpm1 rpm2
pkg remove
Removes individual packages from the active snapshot using the
zypper remove
command. This command can also be used to remove PTF RPM files. The default option for this command is--interactive
.#
transactional-update pkg remove package_name
pkg update
Updates individual packages from the active snapshot using the
zypper update
command. Only packages that are part of the snapshot of the base file system can be updated. The default option for this command is--interactive
.#
transactional-update pkg update package_name
register
The
register
command enables you to register/deregister your system. For a complete usage description, refer to Section 3.1.1, “Theregister
command”.up
Updates installed packages to newer versions. The default option for this command is
--non-interactive
.
The standalone commands are the following:
rollback
<snapshot number>This sets the default subvolume. The current system is set as the new default root file system. If you specify a number, that snapshot is used as the default root file system. On a read-only file system, it does not create any additional snapshots.
#
transactional-update rollback snapshot_number
rollback last
This command sets the last known to be working snapshot as the default.
3.1.1 The register
command #
The register
command enables you to handle all tasks
regarding registration and subscription management. You can supply the
following options:
--list-extensions
With this option, the command will list available extensions for your system. You can use the output to find a product identifier for product activation.
-p, --product
Use this option to specify a product for activation. The product identifier has the following format: <name>/<version>/<architecture>, for example,
sle-module-live-patching/15.3/x86_64
. The appropriate command will then be the following:#
transactional-update register -p sle-module-live-patching/15.3/x86_64-r, --regcode
Register your system with the provided registration code. The command will register the subscription and enable software repositories.
-d, --de-register
The option deregisters the system, or when used along with the
-p
option, deregisters an extension.-e, --email
Specify an email address that will be used in SUSE Customer Center for registration.
--url
Specify the URL of your registration server. The URL is stored in the configuration and will be used in subsequent command invocations. For example:
#
transactional-update register --url https://scc.suse.com-s, --status
Displays the current registration status in JSON format.
--write-config
Writes the provided options value to the
/etc/SUSEConnect
configuration file.--cleanup
Removes old system credentials.
--version
Prints the version.
--help
Displays the usage of the command.
3.2 Snapshots cleanup #
If you run the command transactional-update cleanup
,
all old snapshots without a cleanup algorithm will have one set. All
important snapshots are also marked. The command also removes all
unreferenced (and thus unused) /etc
overlay
directories in /var/lib/overlay
.
The snapshots with the set number
cleanup algorithm
will be deleted according to the rules configured in
/etc/snapper/configs/root
by the following
parameters:
- NUMBER_MIN_AGE
Defines the minimum age of a snapshot (in seconds) that can be automatically removed.
- NUMBER_LIMIT/NUMBER_LIMIT_IMPORTANT
Defines the maximum count of stored snapshots. The cleaning algorithms delete snapshots above the specified maximum value, without taking into account the snapshot and file system space. The algorithms also delete snapshots above the minimum value until the limits for the snapshot and file system are reached.
The snapshot cleanup is also regularly performed by systemd
.
3.3 System rollback #
GRUB 2 enables booting from btrfs snapshots and thus allows you to use any older functional snapshot in case the new snapshot does not work correctly.
When booting a snapshot, the parts of the file system included in the snapshot are mounted read-only; all other file systems and parts that are excluded from snapshots are mounted read-write and can be modified.
An initial bootable snapshot is created at the end of the initial
system installation. You can go back to that state at any time by
booting this snapshot. The snapshot can be identified by the
description after installation
.
There are two methods to perform a system rollback.
From a running system, you can set the default snapshot, see more in Procedure 3.1, “Rollback from a running system”.
Especially in cases where the current snapshot is broken, you can boot into the new snapshot and set it to default. For details, refer to Procedure 3.2, “Rollback to a working snapshot”.
If your current snapshot is functional, you can use the following procedure for a system rollback.
Choose the snapshot that should be set as default, run:
#
snapper listto get a list of available snapshots. Note the number of the snapshot to be set as default.
Set the snapshot as default by running:
#
transactional-update rollback snapshot_numberIf you omit the snapshot number, the current snapshot will be set as default.
Reboot your system to boot into the new default snapshot.
The following procedure is used in case the current snapshot is broken and you are not able to boot into it.
Reboot your system and select
Start bootloader from a read-only snapshot
.Choose a snapshot to boot. The snapshots are sorted according to the date of creation, with the latest one at the top.
Log in to your system and check whether everything works as expected. The data written to directories excluded from the snapshots will stay untouched.
If the snapshot you booted into is not suitable for the rollback, reboot your system and choose another one.
If the snapshot works as expected, you can perform the rollback by running the following command:
#
transactional-update rollback
And reboot afterwards.
3.4 Managing automatic transactional updates #
Automatic updates are controlled by systemd.timer
that runs once per day. This applies all updates and informs
rebootmgrd
that the machine should be rebooted. You
may adjust the time when the update runs, see systemd.timer(5)
documentation.
You can disable automatic transactional updates with this command:
#
systemctl --now disable transactional-update.timer