Capacity Planning

How to Configure Kubernetes Persistent Volumes on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Kubernetes Persistent Volumes on RHEL 9

Kubernetes separates storage provisioning (creating storage volumes) from storage consumption (using volumes in pods) through two resource types: PersistentVolumes (PVs) and PersistentVolumeClaims (PVCs). A PersistentVolume is a piece of storage in the cluster provisioned by an administrator or dynamically by a StorageClass. A PersistentVolumeClaim is a request for storage by a user — it specifies […]

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How to Set Up Windows Event Forwarding (WEF) on Windows Server 2012 R2 — step-by-step Windows Server 2012 R2 tutorial on Progressive Robot

How to Set Up Windows Event Forwarding (WEF) on Windows Server 2012 R2

How to Set Up Windows Event Forwarding (WEF) on Windows Server 2012 R2 Windows Event Forwarding (WEF) is a native Windows mechanism that allows you to centralize security events from dozens or hundreds of servers onto a dedicated collector server—without deploying an agent or purchasing additional software. WEF uses the WS-Management protocol (the same protocol […]

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How to Manage Docker Images and Containers on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Manage Docker Images and Containers on RHEL 9

Efficient Docker image and container management is fundamental to maintaining a healthy container environment. Docker images accumulate on hosts — old base images, build cache layers, and unused intermediate images can consume tens of gigabytes of disk space if not managed regularly. Understanding the Docker image layer model is key: images consist of read-only layers […]

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How to Monitor MySQL with Prometheus mysqld_exporter on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor MySQL with Prometheus mysqld_exporter on RHEL 9

MySQL’s built-in metrics are powerful but not easily scraped. Prometheus mysqld_exporter is the standard exporter that translates MySQL status variables, InnoDB engine metrics, and replication lag statistics into the Prometheus exposition format. Combined with Grafana, the mysqld_exporter provides real-time dashboards covering query throughput, connection pool usage, InnoDB buffer pool hit rates, disk I/O, and replication […]

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How to Install ClickHouse Columnar Database on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install ClickHouse Columnar Database on RHEL 9

ClickHouse is a column-oriented database management system (DBMS) designed for Online Analytical Processing (OLAP). Unlike row-oriented databases (MySQL, PostgreSQL) where each row is stored together — efficient for retrieving full records — ClickHouse stores each column separately, making it extremely efficient for aggregation queries that scan specific columns across billions of rows. ClickHouse can process […]

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How to Install Elasticsearch 8 on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install Elasticsearch 8 on RHEL 9

Elasticsearch is a distributed, RESTful search and analytics engine built on Apache Lucene. It stores data as JSON documents in indices and provides near-real-time full-text search, log aggregation, metrics analysis, and complex aggregation queries through a simple HTTP/JSON API. Elasticsearch is the core component of the Elastic Stack (ELK Stack) — Elasticsearch stores and searches […]

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How to Monitor Nginx with Prometheus nginx-exporter on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor Nginx with Prometheus nginx-exporter on RHEL 9

Prometheus is a time-series metrics collection and alerting system widely used for monitoring cloud infrastructure and web servers. The nginx-prometheus-exporter (nginx-exporter) is a lightweight Go binary that reads Nginx’s built-in stub_status page and exposes the metrics in Prometheus format — active connections, total requests, connection states (reading, writing, waiting), and request rate. Combined with Grafana […]

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How to Perform a System Security Audit with auditd on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Perform a System Security Audit with auditd on RHEL 9

Security auditing is the practice of recording and reviewing system calls, file accesses, user actions, and configuration changes to detect policy violations, investigate incidents, and demonstrate compliance with standards like PCI DSS, HIPAA, and SOC 2. On RHEL 9, the Linux Audit Framework — provided by the auditd daemon — captures events at the kernel […]

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How to Monitor Disk Usage with df, du, lsblk and ncdu on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor Disk Usage with df, du, lsblk and ncdu on RHEL 9

Running out of disk space is one of the most disruptive failures a server can experience. When a filesystem fills up, applications crash, log files stop writing (losing audit trails), databases corrupt transactions, and web servers return 500 errors. Proactive disk monitoring is essential — and RHEL 9 provides a full set of tools for […]

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How to Use rsync for Efficient File Synchronisation on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Use rsync for Efficient File Synchronisation on RHEL 9

rsync is the Swiss Army knife of file synchronisation for Linux administrators. Unlike scp, which blindly copies every file every time, rsync computes a rolling checksum to identify changed file blocks and transfers only what has changed — making subsequent syncs dramatically faster and less bandwidth-intensive. It preserves file attributes (permissions, ownership, timestamps, ACLs, extended […]

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