Log guides
Hands-on guides that cover Log. Every command is run and verified on a live server before it is published.
GuideHow Linux Logging Works: journald and rsyslog
Linux logging on Ubuntu 24.04, destination-first: one journalctl query finds the failing request, make the journal persistent, then learn journald and rsyslog.
GuideStructured Logging and Log Rotation on Linux
Emit structured logging as JSON and query it with jq on Ubuntu 24.04, then rotate the file with logrotate and cap the journal so neither grows without bound.
GuideShipping Logs to a Central Server with rsyslog
A hands-on guide to shipping logs to a central rsyslog collector over TCP on Ubuntu 24.04, then reading the line back from the store to prove it arrived.
GuideQuerying Logs and Log Alerting on Linux
Query the journal and JSON logs with journalctl and jq, then build log alerting that fires on an error threshold and stays quiet otherwise, tested on Ubuntu 24.04.
GuideLog Retention, Compliance and DPDP Basics
Set a log retention policy on Ubuntu 24.04, mask personal data for DPDP, lock down file permissions, and make an audit trail tamper-evident with append-only.
GuideReading Logs With journalctl
When a service misbehaves, its logs live in the journal, not a text file. Read one service with journalctl, follow the systemd logs live, and filter by time.
GuideLogging and Observability
Read docker logs from a running stack, cap them with json-file rotation so they cannot fill the disk, and use docker stats and inspect to see inside.
GuideMonitoring and Slow Queries
Turn on the MariaDB slow query log, run a query slow enough to be caught, read the entry, then use the process list and status counters to find what to tune.