Table of Contents

Introduction

Here we discuss one way to monitor the nodes in a docker swarm1 cluster using Prometheus,2 Grafana,3 and node-exporter.4

Metrics Stack

NOTE: This guide assumes you already have a docker swarm1 setup.

Node-Exporter Service

The following command will create a docker service on your docker swarm composed of the node-exporter application written by Prometheus.2

docker service create --mode global \
                      --name=metrics_node-exporter \
                      --network=host \
                      prom/node-exporter \
                      --path.rootfs=/host

Prometheus/Grafana Stack

The following command will deploy a docker stack5 composed of two docker services6: Prometheus2, and Grafana.3 Before we look at how to create the docker stack we need to look at the config file for Prometheus:

$ cat prometheus_grafana/prometheus.yml
global:
  scrape_interval: 1m
  scrape_timeout: 10s
  evaluation_interval: 1m

scrape_configs:
  - job_name: node-exporter
    static_configs:
      - targets:
        - 192.168.100.30:9100
        - 192.168.100.31:9100
        - 192.168.100.32:9100

Next we will write a stack file which has the same syntax as a docker-compose file7:

$ cat prometheus_grafana/metrics-stack.yml

version: "3.7"

volumes:
  prometheus-data:
  grafana-data:

configs:
  prometheus-config:
    file: ./prometheus.yaml

services:
  prometheus:
    deploy:
      placement:
        constraints:
          - node.role == manager
    hostname: prometheus
    configs:
      - source: prometheus-config
        target: /prometheus.yaml
    volumes:
      - prometheus-data:/prometheus
    ports:
      - 9090:9090
    image: prom/prometheus
    command: [
      --config.file, /prometheus.yaml,
      --storage.tsdb.path, /prometheus
    ]

  grafana:
    deploy:
      placement:
        constraints:
          - node.role == manager
    hostname: grafana
    volumes:
      - grafana-data:/var/lib/grafana
    ports:
      - 3000:3000
    image: grafana/grafana

Finally we can deploy the stack as follows:

$ docker stack deploy -c prometheus_grafana/metrics_stack.yml metrics

References

  1. Docker Swarm ↩ ↩2

  2. Prometheus ↩ ↩2 ↩3

  3. Grafana ↩ ↩2

  4. Node-Exporter ↩

  5. Docker Stack ↩

  6. Docker Service ↩

  7. Docker Stack File Syntax ↩