schnie opened a new pull request #4027: [AIRFLOW-3177] Change scheduler_heartbeat from gauge to counter URL: https://github.com/apache/incubator-airflow/pull/4027 Make sure you have checked _all_ steps below. ### Jira - [x] My PR addresses the following [Airflow Jira](https://issues.apache.org/jira/browse/AIRFLOW-3177) issues and references them in the PR title. ### Description - [x] Here are some details about my PR, including screenshots of any UI changes: Currently, the `scheduler_heartbeat` metric exposed with the statsd integration is a gauge. I'm proposing to change the gauge to a counter for a better integration with Prometheus via the [statsd_exporter](https://github.com/prometheus/statsd_exporter.) Rather than pointing Airflow at an actual statsd server, you can point it at this exporter, which will accumulate the metrics and expose them to be scraped by Prometheus at /metrics. The problem is that once this value is set when the scheduler runs its first loop, it will always be exposed to Prometheus as 1. The scheduler can crash, or be turned off and the statsd exporter will report a 1 until it is restarted and rebuilds its internal state. By turning this metric into a counter, we can detect an issue with the scheduler by graphing and alerting using a rate. If the rate of change of the counter drops below what it should be at (determined by the scheduler_heartbeat_secs setting), we can fire an alert. This should be helpful for adoption in Kubernetes environments where Prometheus is pretty much the standard. ### Tests - [x] My PR adds the following unit tests __OR__ does not need testing for this extremely good reason: No existing tests around statsd ### Commits - [x] My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "[How to write a good git commit message](http://chris.beams.io/posts/git-commit/)": 1. Subject is separated from body by a blank line 1. Subject is limited to 50 characters (not including Jira issue reference) 1. Subject does not end with a period 1. Subject uses the imperative mood ("add", not "adding") 1. Body wraps at 72 characters 1. Body explains "what" and "why", not "how" ### Documentation - [x] In case of new functionality, my PR adds documentation that describes how to use it. - When adding new operators/hooks/sensors, the autoclass documentation generation needs to be added. ### Code Quality - [x] Passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
