Docker swarm service autoscaler

Scales the number of docker containers for service based on threshold(s) for metrics

Configuration

poll_interval_seconds: 60
metric_stores:
  - name: monitoring
    type: prometheus
    prometheus:
      url: http://localhost:9090
autoscale_rules:
  - service_name: example_web
    scale_min: 1
    scale_max: 3
    scale_step: 1
    metric_store: monitoring
    metric_query: scalar(avg(rate(http_requests_total{job="web"}[5m])))
    scale_up_threshold: 300
    scale_down_threshold: 200

Running

This service must be run on a docker swarm manager node if the connection to docker daemon needs to be established via /var/run/docker.sock

You can alternatively pass docker host url via DOCKER_HOST environment variable. You can pass environment variable DOCKER_TLS_VERIFY to verify the host against a CA certificate and DOCKER_CERT_PATH for specifying path to a directory containing TLS certificates to use when connecting to the Docker host.

Using code (local)

# Ensure python 2.x and pip installed
pip install -r app/requirements.txt
python -m app.main example/autoscaler.yml --log-level debug

Using docker

# Change example/autoscaler.yml as per your need
docker run -v /var/run/docker.sock:/var/run/docker.sock -v $(pwd)/example/autoscaler.yml:/etc/docker-swarm-service-autoscaler/autoscaler.yml sahajsoft/docker-swarm-service-autoscaler /etc/docker-swarm-service-autoscaler/autoscaler.yml --log-level=DEBUG

Running in docker swarm

services:
  autoscaler:
    image: sahajsoft/docker-swarm-service-autoscaler
    command: "/etc/docker-swarm-service-autoscaler/autoscaler.yml --log-leve=DEBUG"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    configs:
      - source: autoscaler.yml
        target: /etc/docker-swarm-service-autoscaler/autoscaler.yml
    deploy:
      placement:
        constraints:
          - node.role == manager

Example

Please checkout the examples here

Running tests

# Run tests
py.test
# Run tests and print coverage
py.test --cov=app
# Run tests and create html covergae report
py.test --cov=app --cov-report html
# Run tests automatically on any file change
ptw

Demo

Metric stores

• Prometheus (Supported)
• InfluxDB (Pending): #4

Contributing

Please raise an issue for feature requests & bugs. Please submit a pull request to contribute code