How to Monitor Website Performance with Blackbox Exporter and Grafana

Website uptime and performance are critical for any online business today. According to various studies, even a 1 second delay in page load times can cause up to 20% drop in conversion rates. Slow websites lead to unhappy visitors, lost revenue and damage to brand reputation.

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To avoid these outcomes, modern DevOps and SRE teams need effective ways to monitor their website infrastructures. Three open-source tools that work very well together for this purpose are:

  • Blackbox Exporter – Probes endpoints like HTTP, HTTPS, DNS etc. and exports metrics to timeseries databases
  • Prometheus – A popular timeseries database that aggregates metrics sent by exporters
  • Grafana – Takes aggregated metrics and visualizes them in dashboards with graphs, gauges etc.

In this comprehensive guide, you will learn how to:

  • Install and configure Blackbox Exporter to monitor your websites
  • Integrate it with Prometheus for metrics storage and aggregation
  • Visualize the website performance data in Grafana dashboards
  • Set up alerts based on critical metrics like uptime and response times
  • Troubleshoot issues and scale out the monitoring infrastructure

So let‘s get started!

An Overview of Blackbox Exporter

Blackbox Exporter is an open-source project created by Prometheus to allow monitoring external endpoints like web URLs, DNS servers, databases and more. It works by making requests to endpoints at regular intervals, recording metrics like:

  • Response time
  • HTTP status codes
  • SSL certificate expiry
  • DNS lookup times
  • TCP connection build/close timings
  • ICMP Echo Request response

These metrics can indicate overall availability and responsiveness of websites, APIs and infrastructure components. Blackbox Exporter runs self-contained probes and exports the metrics in a format Prometheus can ingest.

Some key capabilities of Blackbox Exporter:

  • Monitors endpoints on HTTP, HTTPS, DNS, TCP and ICMP protocols
  • Highly customizable probes with modules and settings for timing, validation etc.
  • Authentication support – Add basic auth or client certs to probes
  • Honors robots.txt restrictions while probing endpoints
  • Runs checks from multiple vantage points if needed
  • Extensive metrics exported for visibility into responsiveness and uptime

Now that you understand what Blackbox Exporter does, let‘s look at how it fits into the Prometheus and Grafana stack:

Prometheus is a popular open-source timeseries database designed specially for monitoring. It scrapes and stores metrics from exporters like Blackbox.

Grafana is a analytics and visualization frontend that can use Prometheus as a data source. It allows creating rich dashboards with graphs, gauges etc. for metrics analysis.

Together, Blackbox Exporter, Prometheus and Grafana provide a full-stack monitoring solution for modern infrastructures, including website monitoring.

Next, we will go through the steps of setting this up from scratch.

Prerequisites

Before we install Blackbox Exporter, make sure you have Prometheus and Grafana already setup. If not, refer to this article on how to get them installed on Linux servers quickly using Docker.

The examples here use CentOS 7, but all commands should work fine on any mainstream Linux distro. Now let‘s get started with deploying Blackbox Exporter.

Installing and Configuring Blackbox Exporter

The Blackbox Exporter binary is available for Linux, Windows and MacOS. We will use the Linux AMD64 build suitable for production use.

Step 1: Download Blackbox Exporter

Go to the official releases page and download the latest blackbox_exporter file for Linux.

$ wget https://github.com/prometheus/blackbox_exporter/releases/download/v0.19.0/blackbox_exporter-0.19.0.linux-amd64.tar.gz

$ tar -xzf blackbox_exporter-0.19.0.linux-amd64.tar.gz

This will extract the Exporter binary along with formats, notices etc. Navigate inside this extracted folder to see all files:

$ cd blackbox_exporter-0.19.0.linux-amd64

$ ls -l
total 18116
-rwxr-xr-x 1 ubuntu ubuntu 18519684 Sep  2 04:05 blackbox_exporter
-rw-r--r-- 1 ubuntu ubuntu      611 Sep  2 04:05 blackbox.yml
-rw-r--r-- 1 ubuntu ubuntu    11357 Sep  2 04:04 LICENSE 
-rw-r--r-- 1 ubuntu ubuntu       94 Sep  2 04:04 NOTICE

The blackbox_exporter binary is the executable that needs to run, while blackbox.yml contains the configuration of endpoints to monitor.

Step 2: Create a Dedicated User

For security, best practice is to create a non-root user that will run the Blackbox Exporter process. We will also assign ownership of the whole extractor folder to this user:

$ sudo useradd -rs /bin/false blackbox
$ sudo mkdir /etc/blackbox_exporter
$ sudo mv blackbox_exporter-0.19.0.linux-amd64 /etc/blackbox_exporter/
$ sudo chown -R blackbox:blackbox /etc/blackbox_exporter/

Step 3: Configure Systemd Service

To manage the Exporter properly, we will setup a Systemd service. Create a file called /etc/systemd/system/blackbox_exporter.service.

Add the following contents:

[Unit]
Description=Blackbox Exporter
Wants=network-online.target
After=network-online.target

[Service]
User=blackbox
Group=blackbox
Type=simple
ExecStart=/etc/blackbox_exporter/blackbox_exporter \
    --config.file=/etc/blackbox_exporter/blackbox.yml

[Install]
WantedBy=multi-user.target

This will run the blackbox_exporter binary on system startup using the blackbox.yml config file.

Step 4: Start the Blackbox Exporter Service

Your exporter service is now ready! Let‘s start it up:

$ sudo systemctl daemon-reload
$ sudo systemctl enable blackbox_exporter
$ sudo systemctl start blackbox_exporter

Check status to ensure its running:

$ sudo systemctl status blackbox_exporter
● blackbox_exporter.service - Blackbox Exporter
     Loaded: loaded (/etc/systemd/system/blackbox_exporter.service; enabled; vendor preset: enabled)
     Active: active (running) since Thu 2022-09-15 05:18:27 UTC; 3min 2s ago

You can also check http://<serverip>:9115/metrics to see raw metrics, and http://<serverip>:9115/probe?target=prometheus.io&module=http_2xx to run test probes.

This confirms your Blackbox Exporter is installed and ready! Now let‘s look at integrating it with Prometheus.

Integrating Blackbox Exporter with Prometheus

Prometheus needs to be explicitly configured to scrape metrics from the Exporter. Let‘s add the required scrape job.

Step 1: Configure Prometheus Scrape Job

Edit Prometheus config file at /etc/prometheus/prometheus.yml. Add the Blackbox Exporter under scrape_configs using its IP/hostname:

scrape_configs:

  - job_name: ‘blackbox‘
    metrics_path: /probe  
    params:
      module: [http_2xx] 
    static_configs: 
      - targets:
        - https://www.example.com   
    relabel_configs:
      - source_labels: [__address__]  
        target_label: __param_target
      - source_labels: [__param_target]  
        target_label: instance  
      - target_label: __address__
        replacement: 127.0.0.1:9115

Let‘s understand this configuration:

  • job_name: Names this specific Prometheus scrape job
  • metrics_path: The Exporter‘s metrics endpoint
  • module: http_2xx Check for HTTP 200 responses
  • targets: The URL to monitor
  • relabel_configs: Maps Blackbox metrics to Prometheus labeling
  • replacement: 127.0.0.1:9115 Actual Blackbox Exporter address

Step 2: Restart Prometheus

Apply the changes:

$ sudo systemctl restart prometheus

Step 3: Check Targets Page

Now go to http://<prometheus-ip>:9090/targets in your browser. You should see a blackbox job, probed successfully every 15 seconds.

This means metrics are now being scraped from Blackbox Exporter!

Step 4: Query Metrics

Let‘s check some sample metrics at http://<prometheus-ip>:9090/graph:

  • probe_http_duration_seconds – Response time
  • probe_http_status_code – HTTP status code
  • probe_ssl_earliest_cert_expiry – SSL/TLS expiry

This proves Prometheus has started collecting Blackbox Exporter metrics. Pretty cool!

Now Grafana comes in to visualize this data in dashboards.

Visualizing Blackbox Metrics in Grafana

Grafana needs to be configured to use Prometheus as a data source. Once that‘s setup, we can create a Blackbox dashboard with various graphs and gauges.

Step 1: Add Prometheus Data Source

Login to your Grafana instance and click on Configuration > Data Sources in the side menu. Click on "Add Data Source". Choose Prometheus as the type.

Specify the Prometheus server‘s URL where Grafana can access it. Leave other fields to default values and click Save & Test.

Step 2: Import Blackbox Dashboard

Grafana has many community dashboards which you can import. Search for Blackbox Exporter on Grafana dashboards homepage.

Click on the Blackbox overview dashboard and scroll down to find its ID – 2859. Note this down.

Now in you Grafana instance, click on the + icon on left menu and choose Import. Enter dashboard ID 2859. Select your Prometheus data source and click Import.

This will import the pre-built Blackbox Exporter dashboard with panels for uptime, response times, status codes and more. Play around with the visualizations, queries and options.

Here are some key things you can monitor:

[Insert relevant dashboard screenshots and descriptions]

And that‘s it! You now have a slick Grafana setup to monitor your website‘s availability, responsiveness and performance.

Setting Up Alerts and Notifications

Simply visualizing metrics is useful, but you also want to get notified if something goes wrong. Grafana allows creating alert rules that will send notifications.

Here are some alerts that are useful for website monitoring:

1. Website Down Alert

Criteria – probe_http_status_code != 200
For – 5 minutes
Notify on – Email, Slack, PagerDuty

2. High HTTP Error Rate Alert

Criteria – rate(probe_http_status_code{status=~"5.."}[5m]) > 0
For – 10 minutes
Notify on – Email, Slack, PagerDuty

3. High HTTP Response Time Alert

Criteria – probe_http_duration_seconds > 1
For – 15 minutes
Notify on – Email, Slack

Set these up based on your website‘s SLOs!

Advanced Configurations

Here are some best practices for production setups:

Multi Target Monitoring

Setup multiple Blackbox exporter instances, each monitoring a different set of targets. Aggregate in Prometheus.

Authentication

Use modules like http_2xx_auth to add basic auth or client certificates to probes.

Run Behind a Proxy

If Blackbox exporters need to run behind an internal proxy, use proxy_url setting.

Scrape from Multiple Locations

Run Blackbox exporters in each region to monitor targets from multiple vantage points.

Deploy inside Kubernetes

For containerized environments, deploy exporters as pods using Kubernetes YAML declarations.

Monitor Log Files

In addition to synthetic probes, ingest server-side application logs into Prometheus using the LogQL library.

Troubleshooting Guide

Here are solutions for some common issues seen with Blackbox Exporter:

Exported metrics are empty

  • Check network or firewall rules blocking requests
  • Is config file valid? Any YAML errors?
  • Try to curl monitored endpoints from server directly

Connection errors to Prometheus/Grafana

  • Is metrics path accessible? Set correct authorization
  • Are server ports open in security groups?
  • Test connectivity using telnet/nc between servers

Slow Blackbox Exporter metrics

  • Create separate scrape jobs for different targets/protocols
  • Optimize timeouts and intervals for each job
  • Scale horizontally with multiple exporters if needed

Dashboard panels show "No Data"

  • Is Prometheus actually scraping those metrics? Check /targets and /metrics
  • Do dashboard queries match metric names in Prometheus?
  • Have all parseable metrics been captured over last 6-12 hours?

Alerts not firing for issues detected

  • Check alert rule syntax – use metric names as shown in Prometheus
  • Is alert evaluation interval less than scrape interval?
  • Have notifications channels been setup properly?

Debugging monitoring systems require attention to multiple components. Follow logs at each layer and validate metrics flow end-to-end. Reach out to Prometheus/Grafana community forums if needed.

Conclusion

I hope this article served as a comprehensive guide to effectively monitor your website performance and uptime with Prometheus Blackbox Exporter, Prometheus and Grafana.

These open source tools provide enterprise-grade monitoring capabilities at minimal cost. The Blackbox -> Prometheus -> Grafana combo is scalable, reliable and versatile enough to handle modern web monitoring needs.

Setting up the exporters, scrapers, dashboards and alerts take some initial effort. But once in place, you get complete visibility and control to catch issues before customers notice them!

Have you used Blackbox Exporter in your stacks? What other use cases have you leveraged it for? Feel free to share your experiences below!

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