github.com/sablierapp/sablier @v1.14.0 sqlite

Free and open-source software that starts workloads on demand and stops them after a period of inactivity.

It integrates with reverse proxy plugins (Traefik, Caddy, Nginx, Envoy, etc.) to intercept incoming requests, wake up sleeping workloads, and display a waiting page until they're ready.

Whether you're running on a resource-constrained device like a Raspberry Pi, managing a QA environment used only once a week, or reducing cloud costs by scaling idle workloads to zero — Sablier is built for you.

Key features: - On-demand start/stop for Docker, Kubernetes, Podman, and Proxmox LXC workloads - Customizable waiting UI with themes while workloads warm up - Webhook notifications when instances start or stop - Prometheus metrics for monitoring session and workload activity - OpenTelemetry tracing for end-to-end request observability - Stop or pause strategies to maximize resource reclamation on constrained hardware - Scale mode: throttle CPU and memory when idle instead of stopping, for zero-cold-start workloads

• Installation
• Use the Docker image
• Use the binary distribution
• Compile your binary from the sources
• Use the Helm Chart
• Quick Start
• Configuration
• Configuration File
• Environment Variables
• Arguments
• Providers
• Docker
• Docker Swarm
• Podman
• Kubernetes
• Proxmox LXC
• Scale Mode
• Webhooks
• Observability
• Metrics
• Tracing
• Performance
• Usage with Reverse Proxies
• Apache APISIX
• Caddy
• Envoy
• Istio
• Nginx
• Traefik
• Community
• Support
• Sponsor
• DigitalOcean

Installation

You can install Sablier using one of the following methods:

• Use the Docker image
• Use the binary distribution
• Compile your binary from the sources
• Use the Helm Chart

Use the Docker image

• Docker Hub: sablierapp/sablier
• GitHub Container Registry: ghcr.io/sablierapp/sablier

Choose one of the Docker images and run it with a sample configuration file:

• sablier.yaml

docker run -p 10000:10000 -v /var/run/docker.sock:/var/run/docker.sock sablierapp/sablier:1.14.0

[!TIP] Verify the image signature to ensure authenticity: bash gh attestation verify --owner sablierapp oci://sablierapp/sablier:1.14.0

Use the binary distribution

Grab the latest binary from the releases page and run it:

./sablier --help

[!TIP] Verify the binary signature to ensure authenticity: bash gh attestation verify sablier-1.10.3-linux-amd64.tar.gz -R sablierapp/sablier

Compile your binary from the sources

git clone git@github.com:sablierapp/sablier.git
cd sablier
make
# Output will change depending on your distro
./sablier_draft_linux-amd64

Use the Helm Chart

Deploy Sablier to your Kubernetes cluster using the official Helm chart for production-ready deployments.

Add the Sablier Helm repository:

helm repo add sablierapp https://sablierapp.github.io/helm-charts
helm repo update

Install Sablier:

helm install sablier sablierapp/sablier

📚 Full Documentation | 💻 Chart Repository

Quick Start

[!NOTE] This quick start demonstrates Sablier with the Docker provider.

For other providers, see the Providers section.

1. Start your container to scale to zero

Run your container with Sablier labels:

docker run -d --health-cmd "/mimic healthcheck" -p 8080:80 --name mimic \
  --label sablier.enable=true \
  --label sablier.group=demo \
  sablierapp/mimic:v0.3.3 \
  -running -running-after=5s \
  -healthy=true -healthy-after=5s

Here we run sablierapp/mimic, a configurable web-server for testing purposes.

[!CAUTION] You should always use a healthcheck with your application that needs to be scaled to zero.

Without a healtheck, Sablier cannot distinguish a started container from a container ready to receive incoming requests.

2. Stop the Container

Stop the container to simulate a scaled-down state:

docker stop mimic

[!TIP] Sablier can automatically stop containers at startup using the --provider.auto-stop-on-startup flag, which will stop all containers with sablier.enable=true labels.

3. Start Sablier

Start the Sablier server with the Docker provider:

docker run --name sablier \
  -p 10000:10000 \
  -v /var/run/docker.sock:/var/run/docker.sock \
  sablierapp/sablier:1.10.5 \
  start --provider.name=docker

4. Request a Session

Call the Sablier API to start a session for the demo group:

curl -v http://localhost:10000/api/strategies/blocking\?group\=demo\&session_duration\=20s
* Request completely sent off
< HTTP/1.1 200 OK
< X-Sablier-Session-Status: ready

Sablier will start the mimic container automatically for 20 seconds..

[!TIP] Check out the Usage with Reverse Proxies section to integrate Sablier with Traefik, Caddy, Nginx, and more.

5. Verify the Container is Running

docker ps | grep mimic

6. Wait for Session Expiration

After the session duration (20 seconds in this example), Sablier will automatically stop the container.

# Wait 20 seconds, then check
docker ps -a | grep mimic

The container should be stopped.

Configuration

📚 Full Documentation

There are three ways to configure Sablier:

1. In a configuration file
2. As environment variables
3. As command-line arguments

Configuration sources are evaluated in the order listed above with later methods overriding earlier ones.

If no value is provided for a given option, a default value is used.

Configuration File

At startup, Sablier searches for a configuration file named sablier.yml (or sablier.yaml) in:

• /etc/sablier/
• $XDG_CONFIG_HOME/
• $HOME/.config/
• . (the working directory)

You can override this using the configFile argument.

sablier --configFile=path/to/myconfigfile.yml

provider:
  # Provider to use to manage containers (docker, swarm, kubernetes, podman, proxmox_lxc)
  name: docker
  # Reject requests for containers/services that don't have the Sablier enable label
  reject-unlabeled-requests: false
  # Verify that the Sablier enable label is present when an instance expires
  verify-enabled-on-expiration: false
  docker:
    # Strategy to use when stopping containers (stop or pause)
    strategy: stop
server:
  # The server port to use
  port: 10000
  # The base path for the API
  base-path: /
  metrics:
    # Enable Prometheus metrics endpoint
    enabled: true
storage:
  # File path to save the state (default stateless)
  file:
sessions:
  # The default session duration (default 5m)
  default-duration: 5m
  # The expiration checking interval.
  # Higher duration gives less stress on CPU.
  # If you only use sessions of 1h, setting this to 5m is a good trade-off.
  expiration-interval: 20s
logging:
  level: info
strategy:
  dynamic:
    # Custom themes folder, will load all .html files recursively (default empty)
    custom-themes-path:
    # Show instances details by default in waiting UI
    show-details-by-default: true
    # Default theme used for dynamic strategy (default "hacker-terminal")
    default-theme: hacker-terminal
    # Default refresh frequency in the HTML page for dynamic strategy
    default-refresh-frequency: 5s
  blocking:
    # Default timeout used for blocking strategy (default 1m)
    default-timeout: 1m
webhooks:
  endpoints:
    # Notify an uptime-monitoring service every time an instance starts or stops.
    # - url: https://uptime.example.com/api/push/xxxxxxxx
    #   headers:
    #     Authorization: "Bearer <token>"
    #   events:
    #     - started
    #     - stopped
tracing:
  # Set enabled: true to export OpenTelemetry traces.
  enabled: false
  # exporterType selects the trace backend: "otlphttp" (default) or "stdout".
  exporterType: otlphttp
  # endpoint is the OTLP collector base URL (scheme + host + optional port).
  # For Jaeger: http://jaeger:4318
  # For Grafana Tempo: http://tempo:4318
  endpoint: http://localhost:4318
  # serviceName is the logical name that appears in the tracing backend.
  serviceName: sablier
  # samplingRate controls the fraction of requests traced (0.0 – 1.0).
  samplingRate: 1.0

Environment Variables

Environment variables follow the same structure as the configuration file and are prefixed with SABLIER_. For example:

strategy:
  dynamic:
    custom-themes-path: /my/path

becomes

SABLIER_STRATEGY_DYNAMIC_CUSTOM_THEMES_PATH=/my/path

Arguments

To list all available arguments:

sablier --help

# or

docker run sablierapp/sablier:1.14.0 --help

Command-line arguments follow the same structure as the configuration file. For example:

strategy:
  dynamic:
    custom-themes-path: /my/path

becomes

sablier start --strategy.dynamic.custom-themes-path /my/path

Providers

Docker

Sablier integrates seamlessly with Docker Engine to manage container lifecycle based on demand.

Features: - Connects to the Docker socket - Starts/Stops containers - Compatible with Docker Compose

📚 Full Documentation

Docker Swarm

Sablier supports Docker Swarm mode for managing services across a cluster of Docker engines.

Features: - Connects to the Docker socket (Manager node) - Scales services to 0 and back - Compatible with Docker Stack

📚 Full Documentation

Podman

Sablier works with Podman, the daemonless container engine, providing the same dynamic scaling capabilities as Docker.

Features: - Connects to the Podman socket - Starts/Stops containers - Supports rootless containers

📚 Full Documentation

Kubernetes

Sablier provides native Kubernetes support for managing deployments, scaling workloads dynamically.

Features: - Connects to the Kubernetes API - Scales Deployments and StatefulSets to 0 and back - Supports in-cluster and out-of-cluster configuration

📚 Full Documentation

Proxmox LXC

Sablier supports Proxmox VE for managing LXC containers on demand via the Proxmox API.

Features: - Connects to the Proxmox VE API with token authentication - Starts/Stops LXC containers - Discovers containers by sablier tag

📚 Full Documentation

Scale Mode

By default, Sablier stops (or pauses) workloads when a session expires and restarts them on the next request. Scale mode is an alternative: instead of stopping a container, Sablier throttles its CPU and memory to a minimal idle allocati