Tilt — Kubernetes Dev Toolkit

Tilt automates the local Kubernetes development loop: watch files, build images, deploy to cluster. Configuration lives in a Tiltfile (Starlark, a Python dialect). A resource bundles an image build + k8s deploy (or a local command) into a single manageable unit.

CLI Operations

The commands an agent uses to interact with a running Tilt instance.

Lifecycle

On Ctrl+C from tilt up: K8s and Docker Compose resources keep running. Local serve_cmd processes stop. Use tilt down to clean up.

Viewing Logs

Resource Management

Inspection & Debugging

The Tilt API server runs on localhost:10350 by default. All tilt get/describe/trigger commands talk to it.

Build Strategy Selector

Live Update Decision Tree

Live update replaces full image rebuilds with in-place container file syncs — seconds instead of minutes.

docker_build('myapp', '.', live_update=[
    fall_back_on(['requirements.txt']),
    sync('./src', '/app/src'),
    run('pip install -r requirements.txt', trigger=['requirements.txt']),
])

When live update breaks: Changes to files outside the docker_build context trigger a full rebuild. Changes outside any sync() path also trigger a full rebuild. First tilt up always does a full build — live update requires a running container.

Resource Configuration

# Kubernetes resource with port forwarding and dependencies
k8s_resource('frontend',
    port_forwards=['3000:3000'],
    resource_deps=['api', 'database'],
    labels=['web'],
    trigger_mode=TRIGGER_MODE_MANUAL,
)

# Local resource (build tool, test runner, code generator)
local_resource('codegen',
    cmd='make generate',
    deps=['./proto'],
    labels=['tools'],
)

# Local server (runs continuously)
local_resource('storybook',
    serve_cmd='npm run storybook',
    deps=['./src/components'],
    allow_parallel=True,
    readiness_probe=probe(http_get=http_get_action(port=6006)),
)

Parallelism: Local resources run serially by default. Set allow_parallel=True for independent resources. Image builds default to 3 concurrent — adjust with update_settings(max_parallel_updates=N).

Dependencies: resource_deps gates on first-ever readiness only — once a dependency is ready once, dependents unlock permanently for that session.

Debugging Flow

Service crashing?     → tilt logs -f <resource> --source runtime
Build failing?        → tilt logs -f <resource> --source build
                        tilt docker -- build <args>  (reproduces Tilt's exact build)
Wrong files rebuild?  → tilt get filewatches
                        tilt describe filewatch <name>
                        Check .tiltignore, watch_settings(ignore=), ignore= param
Force a rebuild?      → tilt trigger <resource>
Resource stuck?       → tilt describe uiresource <name>
                        Check resource_deps chain
                        For CRDs: pod_readiness='ignore'
General diagnostics?  → tilt doctor
Full state dump?      → tilt dump engine | jq .

Top 10 Pitfalls

Additional Resources

Reference Files

For detailed API signatures and advanced patterns, consult:

• references/api-reference.md — Complete Tiltfile API catalog organized by category, Starlark language notes, ignore mechanism comparison
• references/patterns.md — Multi-service architectures, environment config, CI integration, performance optimization, programmatic Tilt interaction, extension ecosystem