Posted on Dec 8, 2022

A solution for Monitoring and Logging Containers

domolo

A monitoring and logging solution for Docker hosts and containers with Prometheus, Grafana, Loki, cAdvisor, NodeExporter and alerting with AlertManager.

Inspired by dockprom

Full source code in here

Install

Clone this repository on your Docker host, cd into domolo directory and run docker-compose up -d:

git clone https://github.com/ductnn/domolo.git cd domolo docker-compose up -d

Containers:

Prometheus (metrics database): http://<host-ip>:9090
Prometheus-Pushgateway (push acceptor for ephemeral and batch jobs): http://<host-ip>:9091
AlertManager (alerts management): http://<host-ip>:9093
Grafana (visualize metrics): http://<host-ip>:3000
Loki (likes prometheus, but for logs): http://<host-ip>:3100
Promtail (is the agent, responsible for gathering logs and sending them to Loki)
NodeExporter (host metrics collector)
cAdvisor (containers metrics collector)
Caddy (reverse proxy and basic auth provider for prometheus and alertmanager)

Grafana

Change the credentials in file config:

GF_SECURITY_ADMIN_USER=admin GF_SECURITY_ADMIN_PASSWORD=changeme GF_USERS_ALLOW_SIGN_UP=false

Grafana is preconfigured with dashboards, setup Prometheus(default) and Loki in datasources

apiVersion: 1 datasources: - name: Prometheus type: prometheus access: proxy orgId: 1 url: http://prometheus:9090 basicAuth: false isDefault: true editable: true - name: Loki type: loki access: proxy jsonData: maxLines: 1000 basicAuth: false url: http://loki:3100 isDefault: false editable: true

Prometheus + Node Exporter

Config prometheus for receiving metrics from node_exporter. First, setup node_exporter in servers we need monitor with docker-compose.agents.yml and run command:

docker-compose -f docker-compose.agents.yml up -d

This file will setup 3 agents:

node_exporter
cAdvisor
promtail

Then, we need config scrape metric on prometheus server:

Live monitoring prometheus server:

scrape_configs: - job_name: 'nodeexporter' scrape_interval: 5s static_configs: - targets: ['nodeexporter:9100']

Monitoring other Server, we need to add external_labels:

external_labels: monitor: 'docker-host-alpha' scrape_configs: - job_name: 'ApiExporter' scrape_interval: 5s static_configs: - targets: ['<IP Server need Monitor>:Port']

Grafana Dashboards

Simple dashboards on Grafana:

Node Exporter

Monitor Services

Docker Host

Loki

Setup config loki in file loki-config

TODO: Setup s3

Config scrape logs with promtail, create file promtail-config.yaml and setup:

Scrape logs container:

- job_name: container_logs docker_sd_configs: - host: unix:///var/run/docker.sock refresh_interval: 5s relabel_configs: - source_labels: ['__meta_docker_container_name'] regex: '/(.*)' target_label: 'container'

Scrape logs systems:

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

Demo

Create simple tool generate logs and containerization this tool. Navigate to file entrypoint.sh and run test:

➜ domolo git:(master) cd fake-logs ➜ fake-logs git:(master) ✗ chmod +x entrypoint.sh ➜ fake-logs git:(master) ✗ ./entrypoint.sh 2022-12-08T13:20:00Z ERROR An error is usually an exception that has been caught and not handled. 2022-12-08T13:20:00Z DEBUG This is a debug log that shows a log that can be ignored. 2022-12-08T13:20:01Z WARN A warning that should be ignored is usually at this level and should be actionable. 2022-12-08T13:20:03Z ERROR An error is usually an exception that has been caught and not handled. 2022-12-08T13:20:05Z ERROR An error is usually an exception that has been caught and not handled. 2022-12-08T13:20:09Z INFO This is less important than debug log and is often used to provide context in the current task. 2022-12-08T13:20:13Z ERROR An error is usually an exception that has been caught and not handled. 2022-12-08T13:20:15Z DEBUG This is a debug log that shows a log that can be ignored. 2022-12-08T13:20:16Z INFO This is less important than debug log and is often used to provide context in the current task. 2022-12-08T13:20:17Z INFO This is less important than debug log and is often used to provide context in the current task. ...

Then, add fake-logs in docker-compose.yml

# Fake Logs flogs: image: ductn4/flog:v1 # Set your name image :) build: context: ./fake-logs dockerfile: Dockerfile container_name: fake-logs restart: always networks: - monitor-net labels: org.label-schema.group: "monitoring"