mirror of
https://github.com/offen/docker-volume-backup.git
synced 2024-12-23 17:30:20 +01:00
103 lines
4.1 KiB
Markdown
103 lines
4.1 KiB
Markdown
---
|
|
title: Run custom commands during the backup lifecycle
|
|
layout: default
|
|
nav_order: 5
|
|
parent: How Tos
|
|
---
|
|
|
|
# Run custom commands during the backup lifecycle
|
|
|
|
In certain scenarios it can be required to run specific commands before and after a backup is taken (e.g. dumping a database).
|
|
When mounting the Docker socket into the `docker-volume-backup` container, you can define pre- and post-commands that will be run in the context of the target container (it is also possible to run commands inside the `docker-volume-backup` container itself using this feature).
|
|
|
|
{: .important }
|
|
In a multi-node Swarm setup, commands can currently only be run on the node the `offen/docker-volume-backup` container is running on.
|
|
Labeled containers on other nodes are not visible to the backup command.
|
|
|
|
Such commands are defined by specifying the command in a `docker-volume-backup.[step]-[pre|post]` label where `step` can be any of the following phases of a backup lifecycle:
|
|
|
|
- `archive` (the tar archive is created)
|
|
- `process` (the tar archive is processed, e.g. encrypted - optional)
|
|
- `copy` (the tar archive is copied to all configured storages)
|
|
- `prune` (existing backups are pruned based on the defined ruleset - optional)
|
|
|
|
{: .note }
|
|
So that the `docker-volume-backup` container can access the labels on other containers, it is necessary that the docker socket is mounted into
|
|
the `docker-volume-backup` container as shown in the Quickstart example.
|
|
|
|
Taking a database dump using `mysqldump` would look like this:
|
|
|
|
```yml
|
|
version: '3'
|
|
|
|
services:
|
|
# ... define other services using the `data` volume here
|
|
database:
|
|
image: mariadb
|
|
volumes:
|
|
- backup_data:/tmp/backups
|
|
labels:
|
|
- docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump --all-databases > /backups/dump.sql'
|
|
|
|
volumes:
|
|
backup_data:
|
|
```
|
|
|
|
{: .note }
|
|
Due to Docker limitations, you currently cannot use any kind of redirection in these commands unless you pass the command to `/bin/sh -c` or similar.
|
|
I.e. instead of using `echo "ok" > ok.txt` you will need to use `/bin/sh -c 'echo "ok" > ok.txt'`.
|
|
|
|
If you have more than one `docker-volume-backup` container (possibly across several docker-compose environments) to backup or you are using
|
|
multiple backup schedules, you will need to use `EXEC_LABEL` in the configuration and a `docker-volume-backup.exec-label` label on each
|
|
container using custom commands to ensure that the commands are only run by the correct `docker-volume-backup` instance.
|
|
|
|
{: .important }
|
|
In case you use `EXEC_LABEL` together with configuration mounted from `conf.d` it's important to understand that a distinct `EXEC_LABEL` __should be set in each configuration__.
|
|
Else, schedules that do not specify an `EXEC_LABEL` will still trigger commands on all containers with such labels, no matter whether they specify `docker-volume-backup.exec-label` or not.
|
|
|
|
```yml
|
|
version: '3'
|
|
|
|
services:
|
|
database:
|
|
image: mariadb
|
|
volumes:
|
|
- backup_data:/tmp/backups
|
|
labels:
|
|
- docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump --all-databases > /tmp/volume/dump.sql'
|
|
- docker-volume-backup.exec-label=database
|
|
|
|
backup:
|
|
image: offen/docker-volume-backup:v2
|
|
environment:
|
|
EXEC_LABEL: database
|
|
volumes:
|
|
- data:/backup/dump:ro
|
|
- /var/run/docker.sock:/var/run/docker.sock:ro
|
|
|
|
volumes:
|
|
backup_data:
|
|
```
|
|
|
|
|
|
The backup procedure is guaranteed to wait for all `pre` or `post` commands to finish before proceeding.
|
|
However, there are no guarantees about the order in which they are run, which could also happen concurrently.
|
|
|
|
By default the backup command is executed by the user provided by the container's image.
|
|
It is possible to specify a custom user that is used to run commands in dedicated labels with the format `docker-volume-backup.[step]-[pre|post].user`:
|
|
|
|
```yml
|
|
version: '3'
|
|
|
|
services:
|
|
gitea:
|
|
image: gitea/gitea
|
|
volumes:
|
|
- backup_data:/tmp
|
|
labels:
|
|
- docker-volume-backup.archive-pre.user=git
|
|
- docker-volume-backup.archive-pre=/bin/bash -c 'cd /tmp; /usr/local/bin/gitea dump -c /data/gitea/conf/app.ini -R -f dump.zip'
|
|
```
|
|
|
|
Make sure the user exists and is present in `passwd` inside the target container.
|