Alpine local backup
When you boot Alpine Linux in a run-from-RAM configuration, Alpine itself only loads a few required packages. But you probably want to do some personal adjustments (e.g., installing a package or doing some configuration). Since everything in RAM will get lost next time the box is rebooted or shut down, you will need to permanently save those modifications and adjustments. This is where
lbu comes in handy!
The first thing you need to know is this: By default
lbu only cares about modifications in /etc and its subfolders, with the exception of /etc/init.d!
Please have a look at lbu include to save files/folders located elsewhere than in /etc.
Alpine has the following tools for permanently storing your modifications:
- lbu commit (Same as 'lbu ci')
- lbu package (Same as 'lbu pkg')
- lbu status (Same as 'lbu st')
- lbu list (Same as 'lbu ls')
- lbu diff
- lbu include (Same as 'lbu inc' or 'lbu add')
- lbu exclude (Same as 'lbu ex' or 'lbu delete')
- lbu list-backup (Same as 'lbu lb')
- lbu revert
In the below examples you will find some characters with special meaning:
- | = or ('lbu commit|ci' means that you can type ether 'lbu commit' or 'lbu ci')
- [ ] = optional (In 'lbu commit|ci [-nv]' you can just skip the '-n', '-v' or '-nv' part if you don't want it)
Committing your changes
When you "commit" or save changes you've made to your system,
lbu will generate a file named something like myboxname.apkovl.tar.gz ('myboxname' will be the same as the hostname).
This file (that contains your modifications) is called your "apkovl".
You will need to save your apkovl on some suitable media (floppy, usb, cf, other).
usage: lbu commit|ci [-nv] [<media>] Options: -d Remove old apk overlay files. -e Protect configuration with a password. -n Don't commit, just show what would have been committed. -p <password> Give encryption password on the command-line -v Verbose mode. The following values for <media> is supported: floppy usb If <media> is not specified, the environment variable LBU_MEDIA will be used. Password protection will use aes-256-cbc encryption. Other ciphers can be used by setting the DEFAULT_CIPHER or ENCRYPTION environment variables. For possible ciphers, try: openssl -v The password used to encrypt the file, can either be specified with the -p option or using the PASSWORD environment variable. The environment variables can also be set in /etc/lbu/lbu.conf
Create a apkovl elsewhere than on your configured media
To "commit" changes, but overriding the destination of the generated apkovl file, use
lbu package instead of
usage: lbu package|pkg -v [<dirname>|<filename>] Options: -v Verbose mode. If <dirname> is a directory, a package named <hostname>.apkovl.tar.gz will be created in the specified directory. If <filename> is specified, and is not a directory, a package with the specified name will be created. If neither <dirname> nor <filename> is specified, a package named <hostname>.apkovl.tar.gz will be created in current work directory.
Use SSH to create an apkovl on a different host
To create an apkovl of client on a centralized server, use
lbu package with - as the apkovl name:
On the server:
ssh root@client "lbu package -" >client.apkovl.tar.gz
Check what will be added to your apkovl
lbu status lists what will be saved the next time you run
lbu commit. Its default output is incremental, that is, to only show what files have changed since the last commit; but this can be overridden with the
usage: lbu status|st [-av] Options: -a Compare all files, not just since last commit. -v Also show include and exclude lists.
Another option is
lbu list. This works like
lbu status -a but the format of the output is a bit different. (It's strictly equivalent to
lbu package -v /dev/null).
usage: lbu list|ls
A third option is
lbu diff. This shows the same incremental changes that
lbu status (without
-a) does, but in a different format.
usage: lbu diff
Include special files/folders to the apkovl
Assume that you have some files that you want to permanently save, but they are located somewhere else than in /etc.
It could be /root/.ssh/authorized_keys (used by
sshd to authenticate ssh-users). Such files/folders can be added to lbu's include list with the following command:
usage: lbu include|inc|add [-rv] <file> ... lbu include|inc|add [-v] -l Options: -l List contents of include list. -r Remove specified file(s) from include list instead of adding. -v Verbose mode.
Exclude specific files/folders from the apkovl
Assume that you have some files located in /etc or one of its subfolders that you do not want to permanently save.
It could be some log file or status file that for some reason isn't in /var/log/ but in some location that would otherwise be tracked by
Such files/folders can be added to lbu's exclude list by manually editing that file or using the following command:
usage: lbu exclude|ex|delete [-rv] <file> ... lbu exclude|ex|delete [-v] -l Options: -l List contents of exclude list. -r Remove specified file(s) from exclude list instead of adding. -v Verbose mode.
Execute a script as part of a backup
Sometimes it is necessary to run a script before or after a backup. Scripts in two optional directories allow for this:
Files in those directories are run using run-script rules (meaning they must have the executable bit set, they are run in alphabetical order, and cannot contain an extension: runme works, but runme.sh does not.)
The scripts in pre-package.d are run before the apkovl is created; scripts in post-package.d are run after the apkovl is created.
Rather than adding the raw database directories to /etc/lbu/include, you can do a "database dump". For purposes of example, we use :
- Create /etc/lbu/pre-package.d/sqldump with the following contents:
pg_dumpall -U postgres | gzip -c >/root/pgdatabases.gz
- Mark the file executable:
chmod +x /etc/lbu/pre-package.d/sqldump
- Create /etc/lbu/post-package.d/sqldumpdelete with the following contents:
rm -f /root/pgdatabases.gz
- Mark the file executable:
chmod +x /etc/lbu/post-package.d/sqldumpdelete
- Finally, add the database dump file to the list of files to back up:
lbu include root/pgdatabases.gz
Now whenever you do a
lbu commit, the sql databases are dumped and gzipped to /root/pgdatabases.gz, and then the temporary file is deleted at the end of the lbu commit.
On a catastrophic restore, the databases are not automatically restored (that's not lbu's responsibility), but you will find a complete database dump in the /root directory, where it can be restored manually.
Lbu can now keep backups so you can revert to older, good known config. Set BACKUP_LIMIT in /etc/lbu/lbu.conf to the number of backups you want to keep.
You can list the current backups with:
and you can revert to an older with:
Nothing is written to your main system when "reverting"; this only affects which apkovl is considered active. If you've set BACKUP_LIMIT, then the previously active apkovl will be backed up before being overwritten.