Hello, I'm 
id:onk, Mackerel team engineering manager.
As previously announced, Mackerel has been working on supporting OpenTelemetry. We are pleased to announce that support for OpenTelemetry is now available in public beta.
What is OpenTelemetry?
OpenTelemetry is an open source project that stipulates a standard for collecting telemetry data such as metrics, logs, traces, etc., and exporting them to an arbitrary backend.
It is a vendor-independent standard that is standardized in the way it is handled, so any kind of telemetry data that you wish to output can first be exported in the OpenTelemetry format. Mackerel has also been working on supporting OpenTelemetry because of how easy it is to start collecting telemetry data even with middleware that does not support it as a plugin, and because the metrics have metadata (attributes) that increases observability.
What you can do with Mackerel's support for OpenTelemetry
- Storing labeled metrics using OTLP
- Displaying graphs on custom dashboards
- Monitoring and issuing alerts through queries
The following is a brief outline of each of these functions.
Storing labeled metrics using OTLP
Traditional metrics (simple <metric path> <metric value> <metric timestamp> text format) posted to Mackerel through agents and cloud integration are sent to the endpoint api.mackerel.io and stored. In contrast, OpenTelemetry-supported labeled metric posts are saved by using the OpenTelemetry Protocol (OTLP) and sending them to a new endpoint (otlp.mackerelio.com:4317). Please refer to the following help page for more information.
The instrumentation for collecting metrics to be sent can be found in OpenTelemetry's Registry. Of course, users can also design their own instrumentation.
Displaying graphs on custom dashboards
Labeled metrics that are saved can be displayed as graphs on custom dashboards. Please refer to the following help page for more information. You can freely retrieve data from labeled metrics that are saved by using a PromQL-like query language.
Supported operators and functions can be found on the following help page.
Mackerel has long had the capability to combine and process graphs using expressions, but using a query language allows you to display arbitrary data on dashboards with even greater flexibility.
Monitoring and issuing alerts through queries
“Monitoring through queries” using labeled metrics provides a different approach to issuing alerts from the traditional method of monitoring host metrics and service metrics. This method allows calculated values to be monitored using the query language used to display graphs.
Please refer to the following help page for more information and configuration instructions.
Monitoring through formulas provided similar functionality but with the limitation of a 5-minute interval. Monitoring through queries allows for more rapid minute-by-minute monitoring, and alerts can be issued more quickly.
What is public beta?
Support for OpenTelemetry is currently available as a public beta feature. Due to the feature currently being available in public beta, please note that there may be some fluctuations in its operability and stability. We have made every effort to ensure that these issues will not cause major problems in the feature's early stages of use, so we hope you can take advantage of this new feature and provide us with your feedback.
Please note that displaying labeled metrics as graphs requires custom dashboards, which are not available on the Free plan but are available on Standard and Trial plans. Up to this release, there are no additional charges for posting labeled metrics and monitoring through queries (although we will get in touch with users individually in the event of excessive server load).
How to use
No special action is necessary. Metric posts in OTLP format are accepted at the otlp.mackerel.com endpoint, while settings for placing graphs on custom dashboards and monitoring through queries can be configured from the Mackerel web console.
How to submit feedback
Please submit feedback via the “Feedback” link on the upper right corner of the web console.
We hope you will make good use of Mackerel's support for OpenTelemetry.
