Annotated kranz.yaml

One file using every part of the format, with a comment on each field. Nothing here is required except project and one service or action group — copy the parts you need and delete the rest.

For field types, defaults, and validation rules, see the configuration reference.

This page includes examples/reference/kranz.yaml from the repository, and a test loads and validates that file, so what you read here always parses.

# Project identity
project: Northstar          # Required. Shown in the header.
version: "1.0"              # Optional label for you; Kranz does not read it.
runtime:
  name: northstar-dev       # Stable name for -p and KRANZ_PROJECT addressing.

# Appearance for this project
# Personal preferences live in your user settings file instead. Ctrl+T opens
# the live picker and can write either place.
ui:
  theme: tokyo-night        # A named built-in theme.
  accent: "#7AA2F7"         # Overrides the theme accent.
  background: terminal      # terminal | theme | #RRGGBB
  color_mode: auto          # auto | dark | light

# Shared execution context
# Inherited by every service that does not override it.
defaults:
  dir: .                    # Relative to this file, not to your shell.
  shell: /bin/sh            # Default is /bin/bash.
  env:
    NODE_ENV: development
  env_files: [.env.shared]  # Applied in order, before service-level files.

# Project-level one-shot commands
# For work that belongs to no single service.
action_groups:
  infrastructure:
    description: Shared development infrastructure
    dir: infra              # Inherited by the actions below.
    env_files: [.env.infra]
    actions:
      up:
        command: docker compose up -d
        timeout: 2m         # Covers the whole command.
      inspect:
        command: docker compose ps
      reset:
        command: docker compose down --volumes
        confirm: true       # Destructive, so ask first.

services:
  # A plain long-running process
  api:
    description: REST API and background scheduler
    command: npm run dev    # Shorthand for lifecycle.start.command.
    dir: apps/api           # Relative to this file.
    shell: /bin/bash
    env_files: [.env, .env.local]
    env:
      PORT: "3001"          # Highest precedence; wins over every dotenv file.
    ports: [3001]           # Checked before start; conflicts are reported.
    tags: [backend, core]   # Expandable groups in the list.

    # What "ready" means for anything depending on this service.
    healthcheck:
      readiness:
        type: http
        url: http://127.0.0.1:3001/ready
        interval: 2s
        timeout: 1s
        failure_threshold: 5
      liveness:             # Independent of readiness.
        type: tcp
        port: 3001
        initial_delay: 10s
        interval: 15s

    # Recovery for this process only. Detached resources are never restarted.
    availability:
      restart: on_failure   # no | always | on_failure | exit_on_failure
      backoff: 2s
      max_restarts: 3

    # How the process group is stopped.
    shutdown:
      signal: 15            # SIGTERM.
      timeout: 10s          # Then the group is killed.

    # One-shot commands owned by this service.
    actions:
      migrate:
        command: npm run db:migrate
        description: Apply pending database migrations
        timeout: 2m
        confirm: true
      test:
        command: npm test
        timeout: 5m
      console:
        command: npm run console
        interactive: true   # Hands the terminal over until the command exits.

    # Work that must succeed before this service starts. Each entry points at
    # an action that also stays runnable on its own.
    before_start:
      - group: infrastructure
        action: up
        run: always         # Before every start; default is once per session.
      - action: migrate     # This service's own action, once per session.

  # A service that waits for another one
  web:
    command: npm run dev
    dir: apps/web
    tags: [frontend]
    detect_ports: true      # Discover the port Vite actually chose.
    depends_on: [api]
    dependency_conditions:
      api:
        condition: process_healthy   # Wait for readiness, not just for a PID.
    healthcheck:
      readiness:
        type: tcp           # No port: use the first detected listener.
        interval: 3s

  # A worker with no endpoint to probe
  worker:
    command: npm run worker
    dir: apps/worker
    is_dotenv_disabled: true             # Do not load the adjacent .env.
    tags: [backend]
    depends_on: [api]
    ready_log_line: "worker listening"   # Readiness from output instead.
    success_exit_codes: [0, 2]           # 2 is also a clean exit here.
    disabled: true                       # Visible, but not started by `a`.

  # An external resource Kranz does not own
  # The start command finishes while the thing it started keeps running.
  remote-stack:
    description: Docker stack on the build host
    supervision: detached   # process (default) | detached
    stop_on_exit: false     # Survives Kranz. This is the detached default.
    detect_ports: false     # No local process group to inspect.
    tags: [infra, remote]
    lifecycle:
      start:
        command: ssh build-host 'cd app && docker compose up -d'
        timeout: 2m
      stop:
        command: ssh build-host 'cd app && docker compose down'
        timeout: 2m
      status:
        # Does the resource exist? This is not a health check.
        type: command
        command: ssh build-host 'cd app && docker compose ps -q api | grep -q .'
        interval: 10s
        stopped_interval: 30s
        timeout: 15s
        # With no exit codes declared, 0 means running and anything else means
        # stopped. Declare stopped_exit_codes only when the probe can also say
        # "I could not tell" — see the note below this file.
      logs:
        command: ssh build-host 'cd app && docker compose logs -f --tail=100'
    ports: [5432, 6379]     # Documentation; discovery is unavailable here.
    actions:
      status:
        command: ssh build-host 'cd app && docker compose ps -a'
        timeout: 30s

The three-way status contract

The remote-stack probe above uses the default: exit 0 is running, anything else is stopped. Declare both code sets when your probe can distinguish "not running" from "I could not find out":

status:
  type: command
  # 0 = running, 3 = stopped, anything else = the host did not answer
  command: ssh build-host ./stack-status.sh
  running_exit_codes: [0]
  stopped_exit_codes: [3]
  failure_threshold: 2      # Two unclassified probes in a row → unknown

Without stopped_exit_codes, an unreachable host would be reported as stopped, which is a claim Kranz has no evidence for. With it, the service goes unknown and Kranz stops guessing.

Layering personal overrides

Keep the shared file in version control and your own tweaks out of it:

kranz -f kranz.yaml --override kranz.local.yaml

# kranz.local.yaml — only the differences
services:
  api:
    env:
      LOG_LEVEL: debug
    lifecycle:
      start:
        confirm: true       # Overrides only this, keeping the command above.