selfhosted-apps-docker/prometheus_grafana

Prometheus+Grafana in docker

guide-by-example

Purpose

Monitoring of the host and the running cointaners.

• Official site
• Github
• DockerHub

Good overview of Prometheus.
Everything here is based on the magnificent stefanprodan/dockprom,
So maybe just go get that.

---

Prometheus is an open source system application used for monitoring and alerting. It collects metrics from configured targets at given intervals, expose collected metrics for visualization, evaluates rule expressions, and can trigger alerts if some condition is observed to be true.

Prometheus is relatively new project, it is a pull type monitoring and consists of several components.

• Prometheus Server is the core of the system, responsible for
  • pulling new metrics
  • storing the metrics in a database and evaluating them
  • making metrics available through PromQL API
• Targets - machines, services, applications that are monitored.
  These needs to have an exporter.
  • exporter - a script or a service that gathers metrics on the target, converts them for prometheus server format, and exposes them at an endpoint so they can be pulled
• AlertManager - responsible for handling alerts from Prometheus Server, and sending notifications through email, slack, pushover,..
• pushgateway - allows push type of monitoring. Should not be overused as it goes against the pull philosophy of prometheus. Most commonly it is used to collect data from batch jobs, or from services that have short execution time. Like a backup script.
• Grafana - for web UI visualization of the collected metrics

glossary

Files and directory structure

/home/
└── ~/
    └── docker/
        └── prometheus/
            │ 
            ├── grafana/
            │   └── provisioning/
            │       ├── dashboards/
            │       │   ├── dashboard.yml            
            │       │   ├── docker_host.json
            │       │   ├── docker_containers.json
            │       │   └── monitor_services.json
            │       │
            │       └── datasources/ 
            │           └── datasource.yml
            │
            ├── grafana-data/
            ├── prometheus-data/
            │
            ├── .env
            ├── docker-compose.yml
            └── prometheus.yml

• grafana/ - a directory containing grafanas configs and dashboards
• grafana-data/ - a directory where grafana stores its data
• prometheus-data/ - a directory where prometheus stores its database and data
• .env - a file containing environmental variables for docker compose
• docker-compose.yml - a docker compose file, telling docker how to build the containers
• prometheus.yml - a configuration file for prometheus

All files must be provided.
As well as grafana directory and its subdirectories and files.

the directories grafana-data and prometheus-data are created by docker compose on the first run.

docker-compose

Four containers to spin up.
While stefanprodan/dockprom also got alertmanager and pushgateway, this is a simpler setup for now.
Just want pretty graphs.

• Prometheus - prometheus server, pulling, storing, evaluating metrics
• Grafana - web UI visualization of the collected metrics in nice dashboards
• NodeExporter - an exporter for linux machines, in this case gathering the metrics of the linux machine runnig docker, like uptime, cpu load, memory use, network bandwidth use, disk space,...
• cAdvisor - exporter for gathering docker containers metrics, showing cpu, memory, network use of each container

docker-compose.yml

version: '3'
services:

  # MONITORING SYSTEM AND THE METRICS DATABASE
  prometheus:
    image: prom/prometheus
    container_name: prometheus
    hostname: prometheus
    restart: unless-stopped
    user: root
    depends_on:
      - cadvisor
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
      - '--storage.tsdb.retention.time=200h'
      - '--web.console.libraries=/etc/prometheus/console_libraries'
      - '--web.console.templates=/etc/prometheus/consoles'
      - '--web.enable-lifecycle'
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml
      - ./prometheus_data:/prometheus
    labels:
      org.label-schema.group: "monitoring"

  # WEB BASED UI VISUALISATION OF THE METRICS
  grafana:
    image: grafana/grafana
    container_name: grafana
    hostname: grafana
    restart: unless-stopped
    user: root
    environment:
      - GF_SECURITY_ADMIN_USER
      - GF_SECURITY_ADMIN_PASSWORD
      - GF_USERS_ALLOW_SIGN_UP
    volumes:
      - ./grafana_data:/var/lib/grafana
      - ./grafana/provisioning:/etc/grafana/provisioning
    labels:
      org.label-schema.group: "monitoring"

  # HOSTS METRICS COLLECTOR
  nodeexporter:
    image: prom/node-exporter
    container_name: nodeexporter
    hostname: nodeexporter
    restart: unless-stopped
    command:
      - '--path.procfs=/host/proc'
      - '--path.rootfs=/rootfs'
      - '--path.sysfs=/host/sys'
      - '--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($$|/)'
    volumes:
      - /proc:/host/proc:ro
      - /sys:/host/sys:ro
      - /:/rootfs:ro
    labels:
      org.label-schema.group: "monitoring"

  # DOCKER CONTAINERS METRICS COLLECTOR
  cadvisor:
    image: google/cadvisor
    container_name: cadvisor
    hostname: cadvisor
    restart: unless-stopped
    volumes:
      - /:/rootfs:ro
      - /var/run:/var/run:rw
      - /sys:/sys:ro
      - /var/lib/docker:/var/lib/docker:ro
      - /cgroup:/cgroup:ro
    labels:
      org.label-schema.group: "monitoring"

networks:
  default:
    external:
      name: $DEFAULT_NETWORK

.env

# GENERAL
MY_DOMAIN=example.com
DEFAULT_NETWORK=caddy_net
TZ=Europe/Bratislava

# GRAFANA
GF_SECURITY_ADMIN_USER=admin
GF_SECURITY_ADMIN_PASSWORD=admin
GF_USERS_ALLOW_SIGN_UP=false

All containers must be on the same network.
Which is named in the .env file.
If one does not exist yet: docker network create caddy_net

Prometheus configuration

prometheus.yml

• /prometheus/prometheus.yml

Official documentation.

A config file for prometheus, bind mounted in to prometheus container.
Contains the bare minimum setup of targets from where metrics are to be pulled.

prometheus.yml

global:
  scrape_interval:     15s
  evaluation_interval: 15s

# A scrape configuration containing exactly one endpoint to scrape.
scrape_configs:
  - job_name: 'nodeexporter'
    scrape_interval: 5s
    static_configs:
      - targets: ['nodeexporter:9100']

  - job_name: 'cadvisor'
    scrape_interval: 5s
    static_configs:
      - targets: ['cadvisor:8080']

  - job_name: 'prometheus'
    scrape_interval: 10s
    static_configs:
      - targets: ['localhost:9090']

Grafana configuration

Some of the grafana config files could be ommited and info passed on the first run, or through settings. But setting it through GUI wont generate these files which hinders backup and ease of migration.

datasource.yml

• /prometheus/grafana/provisioning/datasources/datasource.yml

Official documentation.

Grafana's datasources config file, from where it suppose to get metrics.
In this case it points at the prometheus container.

datasource.yml

apiVersion: 1

datasources:
  - name: Prometheus
    type: prometheus
    access: proxy
    orgId: 1
    url: http://prometheus:9090
    basicAuth: false
    isDefault: true
    editable: false

dashboard.yml

• /prometheus/grafana/provisioning/dashboards/dashboard.yml

Official documentation

Config file telling grafana from where to load dashboards.

dashboard.yml

apiVersion: 1

providers:
  - name: 'Prometheus'
    orgId: 1
    folder: ''
    type: file
    disableDeletion: false
    editable: false
    allowUiUpdates: false
    options:
      path: /etc/grafana/provisioning/dashboards

<dashboards>.json

• /prometheus/grafana/provisioning/dashboards/<dashboards.json>

Official documentation.

The dashboards files are in the dashboards directory of this repository.

Preconfigured dashboards from stefanprodan/dockprom.
Mostly unchanged, except for the default time range shown, changed from 15min to 1hour, and a fix for host network monitoring not showing traffick.

• docker_host.json - dashboard showing linux host metrics
• docker_containers.json - dashboard showing docker containers metrics, except the ones labeled as monitoring in the compose file
• monitoring_services.json - dashboar showing docker containers metrics of containers that are labeled monitoring, which are this repo containers.

Reverse proxy

Caddy v2 is used, details here.

The setup is accessed through grafana. But occasionally there might be need to check with prometheus, which will be available on <docker-host-ip>:9090.
For that to work, Caddy will also need port 9090 published.

Caddyfile

grafana.{$MY_DOMAIN} {
    reverse_proxy grafana:3000
}

:9090 {
    reverse_proxy prometheus:9090
}

Extra info: :9090 is short notation for localhost:9090

---

Update

Watchtower updates the image automatically.

Manual image update:

• docker-compose pull
  
• docker-compose up -d
  
• docker image prune

Backup and restore

Backup

Using borg that makes daily snapshot of the entire directory.

Restore

• down the prometheus containers docker-compose down
  
• delete the entire prometheus directory
  
• from the backup copy back the prometheus directory
  
• start the containers docker-compose up -d