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p4u1 40db4e79f7 . 2024-04-26 16:46:26 +02:00
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p4u1 9b90b76fd0 maintainers guide 2024-04-17 14:42:23 +02:00
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p4u1 e95dd23504 add maintainers docs 2024-04-08 17:20:03 +02:00
p4u1 a2ecb767aa more words 2024-04-08 13:23:50 +02:00
p4u1 81c2a43128 add specification 2024-04-08 12:53:40 +02:00
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Maintainers.md Normal file
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# For Maintainers
From the perspective of the recipe maintainer, backup/restore is just more
`deploy: ...` labels. Tools can read these labels and then perform the
backup/restore logic.
## Tools
Two of the current "blessed" options are, which both implement the [backupbot specification](link to spec)
- [`backup-bot-two`](https://git.coopcloud.tech/coop-cloud/backup-bot-two)
- [`abra`](https://git.coopcloud.tech/coop-cloud/abra)
### `backup-bot-two`
`backup-bot-two` is a recipe which gets deployed on the server, it can perform automatic backups and uses restic.
Please see the [`README.md`](https://git.coopcloud.tech/coop-cloud/backup-bot-two#backupbot-ii) for the full docs.
### `abra`
`abra` will read labels and store backups in `~/.abra/backups/...` .
It also provides an integration for `backup-bot-two`.
## Backup
### How to Configure backups
Unless otherwise stated all labels should be added to the main service (which should be named `app`).
1. Enable backups for the recipe:
You need to enable backups for the recipe by adding the following deploy label:
```
backupbot.backup=true
```
2. Decide wich volumes should be backed up:
By default all volumes will be backed up. To disable a certain volume you can add the following deploy label:
```
backupbot.backup.volumes.{volume_name}=false
```
3. Decide which path should be backed up on each volume
By default all files get backed up for a volume. To only include certain paths you can add the following deploy label:
```
backupbot.backup.volumes.{volume_name}.path=/mypath1/foo,/mypath2/bar
```
Note: You can include multiple paths by providing a comma seperated list
Note: All paths are specified relativ to the volume root
4. Run commands before the backup
For certain services like a database it is not reccomend to just backup files, because the backup might end up in a corrupted state. Instead it is reccomended to make a database dump. You can run arbitrary commands in any container before the files are backed up.
To do this add the following deploy label to the service on which you want the command being run:
```
backupbot.backup.pre-hook=mysqldump -u root -pghost ghost --tab /var/lib/foo
```
5. Run commands after the backup
Sometimes you want to clean up after the backup. You can run arbitrary commands in any container after the files were backed up.
To do this add the following deploy label to the service on which you want the command being run:
```
backupbot.backup.post-hook=rm -rf /var/lib/mysql-files/*
```
### Testing the backup
To test that your backup is configured correctly you can deploy the recipe you are working on in a test app either [locally](link to local server deployment) or on a test server.
After the deployment is succesfull run the backup and inspect its content
```
abra app backup myrecipe.example.com
tar -tf ~/.abra/backups/mybackup
```
TODO: this is not complete yet
## Restore
When restoring an app, it takes the files from a backup and copies them to their correct location.
In the case of restoring database tables, you can use the `pre-hook` & `post-hook` commands to run the insertion logic.
## Pre and Post hooks
To back up some services correctly it involves more than just copying a few files from one location to another. Some services already have specific backup tools that allow taking a coherent snapshot of its data like `mysqldump`.
The pre and post hooks can be used to prepare the files which should get backed up and clean up afterwards.
Here are some examples:
### Example 1: Execute simple command
```
backupbot.backup.pre-hook: "echo 'foo' > /path/to/volume/bar.txt
```
### Example 2: Access environment variable
```
backupbot.backup.pre-hook: "cat $${POSTGRES_PASSWORD_FILE}"
```
### Example 3: Access secret
```
backupbot.backup.pre-hook: "cat /var/run/secrets/mysupersecret"
```
```
backupbot.backup.pre-hook: 'mysqldump -p"$$(cat /run/secrets/mysupersecret)" mydatabase'
```
### Example 4: Complex script
Sometimes the logic to backup up a service can get quite complex. In that case it might be easier to add a script (via mount or config) inside the container and call that from the pre and post hook:
```
backupbot.backup.pre-hook: "/scripts/my-pre-backup-scripts"
backupbot.backup.post-hook: "/scripts/my-post-backup-scripts"
```
## Configuration Examples
### Mariadb
```
services:
db:
image: mariadb
volumes:
- "mariadb:/var/lib/mysql"
deploy:
labels:
backupbot.backup: "true"
backupbot.backup.pre-hook: "sh -c 'mariadb-dump --single-transaction -u root -p\"$$(cat /run/secrets/db_root_password)\" wordpress | gzip > /var/lib/mysql/dump.sql.gz'"
backupbot.backup.volume.mariadb.path: "dump.sql.gz"
backupbot.backup.post-hook: "rm -f /var/lib/mysql/dump.sql.gz"
backupbot.restore.post-hook: "sh -c 'gzip -d /var/lib/mysql/dump.sql.gz && mariadb -u root -p\"$$(cat /run/secrets/db_root_password)\" wordpress < /var/lib/mysql/dump.sql && rm -f /var/lib/mysql/dump.sql'"
```
### Postgres
```
version: '3.8'
services:
db:
image: "postgres"
volumes:
- "postgres:/var/lib/postgresql/data"
secrets:
- db_password
deploy:
labels:
backupbot.backup: "true"
backupbot.backup.pre-hook: "PGPASSWORD=$$(cat $${POSTGRES_PASSWORD_FILE}) pg_dump -U $${POSTGRES_USER} $${POSTGRES_DB} > /var/lib/postgresql/data/backup.sql"
backupbot.backup.post-hook: "rm -rf /var/lib/postgresql/data/backup.sql"
backupbot.backup.volume.postgres.path: "backup.sql"
volumes:
postgres:
```

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# Specification
## Summary
Creating automated backups of docker swarm services is an often needed task. This specification describes how backups can be configured via [service labels](https://docs.docker.com/compose/compose-file/compose-file-v3/#labels-1) in a standardised way.
## Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this specification are to be interpreted as described in [RFC-2119](https://datatracker.ietf.org/doc/html/rfc2119).
## Backup
To enable backups for a docker stack, the `backupbot.backup=true` label MUST be set on one of its services. The label MUST NOT be set multiple times for a docker stack. Otherwise the implementation MUST show an error. The label SHOULD be declared on the main service.
### Volumes and paths
By default all volumes MUST be backed up. A volume MUST be excluded from the backup when `backupbot.backup.volumes.{volume_name}=false` is set, where `{volume_name}` is the name of the volume.
By default all files MUST be backed up on a volume. `backupbot.backup.volumes.{volume_name}.path` MAY be set to limit the paths for that volume. The value MUST be a valid path relative to the volume root. It MAY contain multiple paths which get separated by a comma. When the label is set only the given paths MUST be backed up.
### Pre/Post Hooks
A `backupbot.backup.pre-hook` and `backupbot.backup.post-hook` MAY be set on a service. When set the command MUST be executed inside the running container of the service before/after backing up files.
There is no guaranteed order in which different hooks MUST be executed.
TODO: escaping
### Output
A backup implementation SHOULD provide the backup of one or multiple stacks in a `.tar.gz` format. In that case each volume MUST be in `/var/lib/docker/volumes/{stack_name}_{volume_name}`, where `{stack_name}` is the name of the docker stack and `{volume_name}` is the name of each volume that got backed up.
## Restore
By default all files MUST be restored into their volume. A volume or path MAY be excluded from restoring. When restoring a backup from a `.tar.gz` it expects the directory layout as described in the [backup output](#output) section.
### Pre/Post Hooks
A `backupbot.restore.pre-hook` and `backupbot.restore.post-hook` MAY be set on a service. When set the command MUST be executed inside the running container of the service before/after restoring the files.
There is no guaranteed order in which different hooks MUST be executed.
## Labels
### `backupbot.backup`
**Type:** boolean
**Default:** false
**Description:**
Enables backups for this compose stack. The label should be added to the main service of the compose stack.
**Example:**
```
backupbot.backup: true
```
### `backupbot.backup.volumes.{volume_name}`
**Type:** boolean
**Default:** true
**Description:** When set to false the volume is excluded from backups.
**Example:**
```
backupbot.backup.volumes.{volume_name}: false
```
### `backupbot.backup.volumes.{volume_name}.path`
**Type:** string
**Default:** ""
**Description:**
A comma seperated list of paths. When one or more paths are set, it only backs up those on the given volume instead of the whole volume.
**Example 1:**
```
backupbot.backup.volumes.{volume_name}.path: '/var/lib/mariadb/dump.sql.gz'
```
**Example 2:**
```
backupbot.backup.volumes.{volume_name}.path: '/var/lib/myapp/foo,/var/lib/myapp/bar'
```
### `backupbot.backup.pre-hook`
**Type:** string
**Default:** ""
**Description:**
A command, that gets executed before the files are backed up.
**Example:**
```
backupbot.backup.pre-hook: 'mysqldump -u root -p"$(cat /run/secrets/db_root_password)" -f /volume_path/dump.db'
```
### `backupbot.backup.post-hook`
**Type:** string
**Default:** ""
**Description:**
A command, that gets executed after the files are backed up.
**Example:**
```
backupbot.backup.post-hook: "rm -rf /volume_path/dump.db"
```
### `backupbot.restore.pre-hook`
**Type:** string
**Default:** ""
**Description:**
A command, that gets executed before the files are restored.
Note, that there is no guaranteed order in which multiple hooks get executed.
**Example:**
```
backupbot.restore.pre-hook: "lock db"
```
### `backupbot.restore.post-hook`
**Type:** string
**Default:** ""
**Description:**
A command, that gets executed after the files are restored.
**Example:**
```
backupbot.restore.post-hook: "sqldump dump.sql && unlock db && rm dump.sql"
```