selfhostblocks/modules/contracts/datasetbackup/docs/default.md

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# Dataset Backup Contract {#contract-dataset-backup}
This NixOS contract represents a backup job
that will backup one ZFS dataset.
It is a contract between a service that manages ZFS datasets
and a service that backs up ZFS datasets.
## Contract Reference {#contract-datatsetbackup-options}
These are all the options that are expected to exist for this contract to be respected.
```{=include=} options
id-prefix: contracts-datasetbackup-options-
list-id: selfhostblocks-options
source: @OPTIONS_JSON@
```
## Usage {#contract-datasetbackup-usage}
A service that manages ZFS datasets that can be backed up will provide a `datasetbackup` option.
Here is an example module defining such a `backup` option,
which defines what directories to backup (`sourceDirectories`)
and the user to backup with (`user`).
```nix
{
options = {
myservice.datasetbackup = mkOption {
type = lib.types.submodule {
options = shb.contracts.datasetbackup.mkRequester {
dataset = "root/test";
};
};
};
};
};
```
Now, on the other side we have a service that uses this `datasetbackup` option and actually backs up the dataset.
This service is a `provider` of this contract and will provide a `result` option.
Let's assume such a module is available under the `backupService` option
and that one can create multiple backup instances under `backupService.instances`.
Then, to actually backup the `myservice` service, one would write:
```nix
backupService.instances.myservice = {
request = myservice.datasetbackup.request;
settings = {
enable = true;
targetDataset = "backup/myservice";
# ... Other options specific to backupService like scheduling.
};
};
```
It is advised to backup files to different location, to improve redundancy.
Thanks to using contracts, this can be made easily either with the same `backupService`:
```nix
backupService.instances.myservice_2 = {
request = myservice.datasetbackup.request;
settings = {
enable = true;
targetDataset = "backup2/myservice";
};
};
```
Or with another module `backupService_2`!
## Providers of the Backup Contract {#contract-datasetbackup-providers}
- [Sanoid block](blocks-sanoid.html).
## Requester Blocks and Services {#contract-datasetbackup-requesters}
- [ZFS](blocks-zfs.html#blocks-zfs-backup).