Deployment interface reference

Complete specification of the interface a deployment plugin must implement.

Class attributes

Attribute	Type	Required	Description
config_type	type	Yes	A dataclass (or list) that defines the typed configuration for this plugin
schema	dict	Yes	A JSON schema dict for validating the user’s config

Methods

__init__(self, config)

Initialize the installer with a validated configuration instance.

Parameter	Type	Description
config	instance of config_type	Validated configuration

check(self, label_to_machines)

Validate that the deployment configuration is consistent with available nodes.

Parameter	Type	Description
label_to_machines	enoslib.objects.Roles	Mapping from label name to list of machine objects

Must raise a descriptive exception if:

• Any label referenced in the config does not exist in label_to_machines

• An invalid combination of daemon kinds is configured (e.g. central-manager without any execute nodes)

• Any other configuration invariant is violated

__call__(self, env)

Install and configure the deployment system on the specified nodes.

Parameter	Type	Description
env	enoslib.task.Environment	EnOSlib environment dict. For e.g., env["roles"] maps label → list of host objects

Must be idempotent.

Must raise a descriptive exception if the deployment fails to install or configure correctly.

Configuration dataclass conventions

Deployments typically configure multiple daemon types. Model this as a list of daemon specifications:

@dataclass
class DaemonSpec:
    kind: str  # Daemon type (enum)
    labels: list[str]  # Target nodes
    config_file: Optional[str] = None  # Optional custom config

The top-level config_type for a deployment is typically a list of daemon specs.

JSON schema conventions

Deployment schemas are typically arrays:

schema = {
    "type": "array",
    "items": {
        "type": "object",
        "properties": {
            "kind": {"type": "string", "enum": ["controller", "worker"]},
            "labels": {"type": "array", "items": {"type": "string"}, "minItems": 1},
        },
        "required": ["kind", "labels"],
        "additionalProperties": False,
    },
    "minItems": 1,
}

Error conditions

The check() method must handle:

Condition	Action
Label not found in label_to_machines	Raise ValueError with label name
Invalid kind value	Raise ValueError with allowed values
Incompatible daemon combination	Raise ValueError with explanation

See also

• Add a deployment — step-by-step implementation guide

• How Kiso extensions work — extension model overview