Why Do We Need Centralized Logging? Making Sense of Log Chaos

We’ve already discussed the importance of metrics monitoring for understanding the health of your IT infrastructure. But metrics are only part of the picture. To truly understand what’s happening inside your systems and applications, you need logs.

Logs are records of events generated by operating systems, applications, network devices, and nearly any software component. They capture what, when, where, and why something happened. Think of them as the “black box” of your infrastructure — an invaluable source of information for debugging, auditing, and incident investigation.

Problems with Non-Centralized Logging

Imagine you have multiple servers, each with its own applications writing logs to different files. What happens when something breaks?

• Scattered data: Logs are spread across dozens of machines — you have to collect them manually.
• Lack of context: It’s hard to correlate events between servers.
• Search is hard: Grepping through log files doesn’t scale.
• Volume growth: The more infrastructure you have, the more logs you generate. Manual handling becomes unmanageable.
• Storage issues: Servers run out of space, old logs get deleted or archived.

As a result, logs turn from a useful tool into a source of chaos.

Benefits of Centralized Logging

Centralized logging means collecting logs from all infrastructure components in one place with the ability to search, visualize, and analyze them.

This provides:

• A single access point: A user-friendly web interface — no need to SSH into every server.
• Fast search and filtering: By time, level, keywords, and other parameters.
• Event correlation: Connecting logs from different sources to uncover causal chains.
• Long-term storage: Archive logs for months or years.
• Visualization: Build graphs, reports, and dashboards from log data.
• Alerts: Trigger notifications for errors, anomalies, or suspicious activity.

Key Stages of Centralized Logging

Any logging system typically includes several core stages:

1. Collection
   Agents like Filebeat, Promtail, or Zabbix Agent gather logs from sources.

2. Transportation
   Logs are transmitted to storage via TCP, UDP, Syslog, HTTP, etc.

3. Processing & Enrichment
   Parsing, filtering, and adding extra fields (e.g., geolocation, hostname).

4. Storage & Indexing
   Logs are stored in a database optimized for fast search by time and content.

5. Analysis & Visualization
   Queries, filters, charts, dashboards — everything needed for insight.

6. Alerting
   Notifications for specific events: 5xx errors, anomalies, mass failures.

What’s Next?

Centralized logging isn’t just a convenience — it’s a necessity in modern distributed environments. It allows you to:

• gain deeper operational visibility,
• shorten incident response times,
• enhance system security and transparency.

In upcoming articles, we’ll dive into:

• ELK Stack (Elasticsearch, Logstash, Kibana) — a powerful and flexible toolkit.
• OpenSearch — a community-driven ELK fork with an open license.
• Graylog — an alternative with a clean architecture and role-based access.
• Loki + Grafana — a lightweight and cost-effective solution for DevOps teams.

Get ready to tame the log chaos — and turn it into a source of insight and control!