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Inventory

Inventory is an abstract service layer for consistently configuring distributed services across machine boundaries.

See Inventory API Documentation

This guide will walk you through setting up a backup service, where the inventory becomes useful.

Experimental status

The inventory implementation is not considered stable yet. We are actively soliciting feedback from users.

Stabilizing the API is a priority.

Prerequisites

Services

The inventory defines services. Membership of machines is defined via roles exclusively.

See the each module documentation for available roles.

Note

It is possible to use any clanModule in the inventory and add machines via roles.default.*

Adding services to machines

A module can be added to one or multiple machines via Roles. clan's Role interface provide sane defaults for a module this allows the module author to reduce the configuration overhead to a minimum.

Each service can still be customized and configured according to the modules options.

  • Per instance configuration via services.<serviceName>.<instanceName>.config
  • Per role configuration via services.<serviceName>.<instanceName>.roles.<roleName>.config
  • Per machine configuration via services.<serviceName>.<instanceName>.machines.<machineName>.config

Setting up the Backup Service

Borgbackup Example

To configure a service it needs to be added to the machine. It is required to assign the service (borgbackup) an arbitrary instance name. (instance_1)

See also: Multiple Service Instances

buildClan {
    inventory = {
        services = {
            borgbackup.instance_1 = {
                # Machines can be added here.
                roles.client.machines = [ "jon" ];
                roles.server.machines = [ "backup_server" ];
            };
        };
    };
}

Scaling the Backup

The inventory allows machines to set Tags

It is possible to add services to multiple machines via tags as shown

Tags Example

buildClan {
    inventory = {
        machines = {
            "jon" = {
                tags = [ "backup" ];
            };
            "sara" = {
                tags = [ "backup" ];
            };
            # ...
        };
        services = {
            borgbackup.instance_1 = {
                roles.client.tags = [ "backup" ];
                roles.server.machines = [ "backup_server" ];
            };
        };
    };
}

Multiple Service Instances

Important

Not all modules implement support for multiple instances yet. Multiple instance usage could create complexity, refer to each modules documentation, for intended usage.

Example

In this example backup_server has role client and server in different instances.

buildClan {
    inventory = {
        machines = {
            "jon" = {};
            "backup_server" = {};
            "backup_backup_server" = {}
        };
        services = {
            borgbackup.instance_1 = {
                roles.client.machines = [ "jon" ];
                roles.server.machines = [ "backup_server" ];
            };
            borgbackup.instance_2 = {
                roles.client.machines = [ "backup_server" ];
                roles.server.machines = [ "backup_backup_server" ];
            };
        };
    };
}

API specification

The complete schema specification is available here

Or it can build anytime via:

nix build git+https://git.clan.lol/clan/clan-core#inventory-schema
> result
> ├── schema.cue
> └── schema.json