runner.pool-drain

Drain every alive runner instance in a warm-pool group (PENDING/IDLE/BUSY → DRAINING). BUSY instances finish their current job first. Org-scoped. Reason is recorded on each instance's transition event for audit.

Drain every warm-pool instance in a group.

IDLE and PENDING instances go straight to DRAINING. BUSY instances enter DRAINING immediately too; their currently-running job completes, then the workflow_job:completed handler skips the IDLE transition (Phase 4 logic) and the next sweep terminates them.

Replacement runners are NOT provisioned by this workflow — call runner.pool-rotate if you need drain + immediate top-up.

Overview

Property	Value
Workflow type	Atomic
Library	App-runners
Version	1.0

Input Schema

Field	Type	Required	Default	Description
runner_group_uuid	uuid	Yes	—	UUID of the RunnerGroup to drain, picked from the organization's list of runner groups.
reason	string	No	—	—

Output Schema

Field	Type	Required	Default	Description
runner_group_uuid	uuid	No	—	UUID of the RunnerGroup that was drained, echoed from input on output.
drained_count	integer	No	—	—
drain_errors	list	No	—	—
outcome	string	No	—	—
status	string	No	—	—
completed_at	string	No	—	—
failure_reason	string	No	—	—
failure_type	string	No	—	—
failed_action	string	No	—	—
failed_at_state	string	No	—	—
failed_step	string	No	—	—
failed_layer	string	No	—	—
error	string	No	—	—
error_type	string	No	—	—
reason	string	No	—	—

States

State	Initial	Terminal	Success	Auto-advance	Description
pending	Yes	No	—	drain	—
completed	No	Yes	Yes	—	—
failed	No	Yes	No	—	—

State Diagram

Transitions

From	Action	To	Description
pending	drain	completed	—
* (any state)	fail	failed	—

API Usage

POST /api/workflows/start
Content-Type: application/json

{
  "workflow_type": "runner.pool-drain",
  "initial_data": {
    "runner_group_uuid": "value"
  }
}