Snapper 3.1.4
Taking snapshot pairs upon installing packages with YaST or Zypper is handled by the snapper-zypp-plugin. An XML configuration file, /etc/snapper/zypp-plugin.conf defines, when to make snapshots. By default the file looks like the following:
Snapper 3.1.4
Get a list of changed files for a snapshot pair with snapper status PRE..POST. Files with content changes are marked with c, files that have been added are marked with + and deleted files are marked with -.
After running sudo snapper rollback snapshot 3 is created and contains the state of the system before the rollback was executed. Snapshot 4 is the new default Btrfs subvolume and thus the system after a reboot.
pam_snapper provides integration with the useradd command, pluggable authentication modules (PAM), and Snapper. By default it creates snapshots at user login and logout, and also creates time-based snapshots as some users remain logged in for extended periods of time. You may change the defaults using the normal Snapper commands and configuration files.
Use the /usr/lib/pam_snapper/pam_snapper_useradd.sh script to create a new user and home directory. By default the script performs a dry run. Edit the script to change DRYRUN=1 to DRYRUN=0. Now you can create a new user:
Remove users with the /usr/lib/pam_snapper/pam_snapper_userdel.sh script. By default it performs a dry run, so edit it to change DRYRUN=1 to DRYRUN=0. This removes the user, the user's home subvolume, Snapper configuration, and deletes all snapshots.
After a configuration has been created, you can either use snapper itself or the YaST Snapper module to restore files from these snapshots. In YaST you need to select your Current Configuration, while you need to specify your configuration for snapper with the global switch -c (for example, snapper -c myconfig list).
Default values for a new configuration are taken from /etc/snapper/config-templates/default. To use your own set of defaults, create a copy of this file in the same directory and adjust it to your needs. To use it, specify the -t option with the create-config command:
Each configuration contains a list of options that can be modified from the command line. The following list provides details for each option. To change a value, run snapper -c CONFIG set-config "KEY=VALUE".
To create a snapshot, run snapper create or click Create in the YaST module Snapper. The following examples explain how to create snapshots from the command line. The YaST interface for Snapper is not explicitly described here but provides equivalent functionality.
The Btrfs quota group used by Snapper. If not set, run snapper setup-quota. If already set, only change if you are familiar with man 8 btrfs-qgroup. This value is set with snapper setup-quota and should not be changed.
Robustness on administrative errors and improved management capabilities with full system rollback based on btrfs as the default file system for the operating system partition and SUSE's snapper technology.
During boot, you can select an old snapshot. This snapshot will then be booted in something like a read-only mode. All the snapshot data is read-only, all other filesystems or btrfs subvolumes are in read-write mode and can be modified. To make this snapshot the default for the next reboot and switch it into a read-write mode, use "snapper rollback".
When a rollback is done via Snapper, the system will notify the registration server to ensure access to the correct repositories is set up during the boot process. If the system was restored any other way or the communication with the registration server failed for any reason (for example, because the server was not accessible due to network issues), trigger the rollback on the client manually by calling snapper rollback.
With SUSE Linux Enterprise 12, Btrfs is the default file system for the operating system, xfs is the default for all other use cases. We also continue to support the Ext-family of file systems, Reiserfs and ocfs2. Each file system offers distinct advantages. Customers are advised to use the YaST partitioner (or AutoYaST) to build their systems: YaST will prepare the Btrfs file system for use with subvolumes and snapshots. Snapshots will be automatically enabled for the root file system using SUSE's snapper infrastructure. For more information about snapper, its integration into ZYpp and YaST, and the YaST snapper module, see the SUSE Linux Enterprise documentation. 041b061a72
