Grafana Loki

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Loki is a Prometheus-inspired logging service for cloud native infrastructure. It’s similar to well-known ELK stack but more simple use and is intended to be used mostly Kubernetes.

Loki components

Loki-stack consists of three main components:

  • promtail – agent to collect logs on a host and push them to a Loki instance
  • loki – TSDB (Time-series database) logs aggregation and processing server
  • Grafana – for querying and displaying logs

Deployment

yum install nginx -y
systemct start nginx

mkdir /opt/loki
cd /opt/loki/

nano loki-promtail-conf.yml
server:

  http_listen_port: 9080
  grpc_listen_port: 0

positions:

  filename: /tmp/positions.yaml

client:

  url: http://loki:3100/api/prom/push

scrape_configs:

  - job_name: system
    entry_parser: raw
    static_configs:
    - targets:
        - localhost
      labels:
        job: varlogs
        __path__: /var/log/*log

  - job_name: nginx
    entry_parser: raw
    static_configs:
    - targets:
        - localhost
      labels:
        job: nginx
        __path__: /var/log/nginx/*log

nano docker-compose.yml
version: "3"

networks:
  loki:

services:
  loki:
    image: grafana/loki:master
    ports:
      - "3100:3100"
    command: -config.file=/etc/loki/local-config.yaml
    networks:
      - loki

  promtail:
    image: grafana/promtail:master
    volumes:
       - /opt/loki/loki-promtail-conf.yml:/etc/promtail/docker-config.yaml
      - /var/log:/var/log
    command: -config.file=/etc/promtail/docker-config.yaml
    networks:
      - loki

  grafana:
    image: grafana/grafana:master
    ports:
      - "3000:3000"
    networks:
      - loki

docker-compose up -d

# add datasource
key=”{job=\”nginx\”}” appeared – all good.