Getting Started with Prometheus

Difficulty: beginner

Estimated Time: 10-15 minutes

In this scenario, you'll learn how to launch Prometheus to start collecting system metrics from nodes within your system.

Prometheus

Prometheus is an open source systems monitoring and alerting toolkit originally built at SoundCloud. Since its inception in 2012, many companies and organizations have adopted Prometheus, and the project has a very active developer and user community. It is now a standalone open source project and maintained independently of any company. To emphasize this and clarify the project's governance structure, Prometheus joined the Cloud Native Computing Foundation in 2016 as the second hosted project after Kubernetes. More details can be found at https://prometheus.io

More information on how to get started can be found at https://prometheus.io/docs/introduction/getting_started/

Your environment is currently being packaged as a Docker container and the download will begin shortly. To run the image locally, once Docker has been installed, use the commands

cat scrapbook_prometheus_getting-started_container.tar | docker load

docker run -it /prometheus_getting-started:20201203

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Step 1 of 4

Step 1 - Configure Prometheus

The Prometheus server requires a configuration file that defines the endpoints to scrape along with how frequently the metrics should be accessed.

The first half of the configuration defines the intervals.

global:
  scrape_interval:     15s
  evaluation_interval: 15s

The second half defines the servers and ports that Prometheus should scrape data from. In this example, we have defined two targets running on different ports.

scrape_configs:
  - job_name: 'prometheus'

    static_configs:
      - targets: ['127.0.0.1:9090', '127.0.0.1:9100']
        labels:
          group: 'prometheus'

9090 is Prometheus itself. Prometheus exposes information related to its internal metrics and performance and allows it to monitor itself.

9100 is the Node Exporter Prometheus process. This exposes information about the Node, such as disk space, memory and CPU usage.

More information on the default ports can be found at https://github.com/prometheus/prometheus/wiki/Default-port-allocations

Task

Copy the configuration to the editor to continue.

Step 2 - Start Prometheus

Prometheus can run as a Docker Container with a UI available on port 9090. Prometheus uses the configuration to scrape the targets, collect and store the metrics before making them available via API that allows dashboards, graphing and alerting.

Task

The following command launches the container with the prometheus configuration. Any data created by prometheus will be stored on the host, in the directory /prometheus/data. When we update the container, the data will be persisted.

docker run -d --net=host \
    -v /root/prometheus.yml:/etc/prometheus/prometheus.yml \
    --name prometheus-server \
    prom/prometheus

Once started, the dashboard is viewable on port 9090. The next steps will explain the details and how to view the data.

Step 3 - Start Node Exporter

To collect metrics related to a node it's required to run a Prometheus Node Exporter. Prometheus has many exporters that are designed to output metrics for a particular system, such as Postgres or MySQL.

Task

Launch the Node Exporter container. By mounting the host /proc and /sys directory, the container has accessed to the necessary information to report on.

docker run -d \
  -v "/proc:/host/proc" \
  -v "/sys:/host/sys" \
  -v "/:/rootfs" \
  --net="host" \
  --name=prometheus \
  quay.io/prometheus/node-exporter:v0.13.0 \
    -collector.procfs /host/proc \
    -collector.sysfs /host/sys \
    -collector.filesystem.ignored-mount-points "^/(sys|proc|dev|host|etc)($|/)"

If you're interested in seeing the raw metrics, they can be viewed with curl localhost:9100/metrics

prometheus.yml

Terminal

Prometheus

cd <directory>	Change directory
ls	List directory
echo 'contents' > <file>	Write contents to a file
cat <file>	Output contents of file

i	In Command Mode	Change into Insert Mode, you can now insert and edit text in the file
esc	In Insert Mode	Change into Command Mode, you can now execute commands
:wq	In Command Mode	Save and Exit

Welcome!

Getting Started with Prometheus

Prometheus

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