README.md

Blackbox prober exporter sandbox

In this sandbox, the Blackbox prober exporter probes a simple web service, while Prometheus scrapes probe_* metrics from the Blackbox exporter.

Usage

To start the sandbox:

# In the foreground
make run # docker-compose up --build

# In detached mode
make run-detached # docker-compose up --build --detach

This will start up three services:

Service	Description
blackbox	A Prometheus Blackbox exporter running on port 9115, which runs probes against the web service using the http_2xx module.
prometheus	A Prometheus instance configured to scrape the Blackbox exporter and collect a wide variety of metrics (prefaced by probe_).
web	A simple web service with two endpoints: /hello returns a {"hello": "world"} JSON object and /health returns an HTTP 200 OK indicating that the service is running. The web service

Things to check out:

• The Blackbox exporter dashboard at http://localhost:9115. You'll see a Recent Probes table listing all probes, including the following information for each probe: module, target, result, and a link to debugging logs.
• The results of the most recent probe of the web service at http://localhost:9115/probe?target=web:2112/health&module=http_2xx. If the value of probe_success metric is 1, then the service is running properly (otherwise the value will be 0).
• The probe_success metric on Prometheus at http://localhost:9090/graph?g0.range_input=1h&g0.expr=probe_success%7Binstance%3D%22web%3A2112%2Fhealth%22%7D&g0.tab=1.

At first, the web service will be running normally, which means that the Blackbox probes of that service's /health will succeed. This will change if you shut down the service:

docker-compose stop web

Now you can navigate back to the most recent probe result and see that probe_success now has a value of 0. If you navigate back to the Prometheus expression browser you can see that probe_success for the web service now returns 0 as well (the scrape interval is 5 seconds, so you may need to wait a bit and hit refresh).

If you restart the web service, the probes will once again be successful:

docker-compose start web

Assets

Folder	Assets
prometheus	A prometheus.yml configuration file for Prometheus
blackbox	A blackbox.yml configuration file for the Blackbox exporter
web	Source files for the simple web server (written in Go)