Ferret - Service Monitoring as a Service
Ferret is a framework to write monitor processes for network services.
Monitor processes output structured log data for all successes and failures against the service, from which uptime is derived. Monitor processes both run locally and are deployed to Heroku to run continuously.
Ferret also includes tools for managing services. These are generally disposable canary Heroku apps.
Copy env.sample to .env
- APP is the name that you want to prefix your ferret deployment.
- HEROKU_USERNAME is a unprivileged user that will be deploying ferret. We use an unprivileged user because we deploy the api key to the app and don't want sudo api keys on the platform
- HEROKU_API_KEY is the api key for the username. You can easily obtain one (if you have sudo) by running
bin/unprivileged [email address]
- ORG is the organization that the ferret is deploying to
- L2MET_URL can be obtained at l2met
- METRICS_URL is the prefix for the metrics dashboard, this should be fairly static but if it is not working ask email@example.com
- METRICS_TOKEN is the api key for l2met
# Run all monitors locally foreman start # Run monitors with increased concurrency locally foreman start --formation="monitor_git_clone=2" # Run a single monitor foreman run path/to/monitor
Platform Setup and Teardown
#Set up and run on the platform (the first time) bin/setup # Build and release the app if you make any changes heroku build -r # Scale all monitors bin/scale [Path to monitors] [How many of each] #Teardown ferret and all of the service apps bin/teardown
# Push changes to ferret heroku build -r # Scale all monitors bin/scale [path to monitors] [how many of each] # Regenerate the profile bin/create_proc [path to monitors] # Get an unprivileged API key bin/unprivileged [an email]
Ferret is designed to easily apply the canary pattern to Heroku kernel services. Much thought should be given on how to measure properties of services in isolation.
Ferret does not implement complex platform integration tests, though these Would be easy to build with the framework.
Ferret uses many of the latest features of Heroku to make the tools secure, discoverable, configuration free, and maintenance free:
- Custom Buildpack (https://github.com/nzoschke/buildpack-ferret)
- Heroku Toolbelt
- Dot Profile (dot-profile-d feature)
- Heroku Manager
- HTTP Log Drains