Mount an ISO image Mounting an ISO on Linux requires a loop device. Modern systems support this directly with mount: sudo mount -o loop /path/to/image.iso /mnt/mount-point Or use the -t iso9660 option for explicit filesystem specification: sudo mount -t iso9660 -o loop /path/to/image.iso /mnt/mount-point To unmount: sudo umount /mnt/mount-point For temporary mounts that don’t require…
Crontab Basics Crontab controls what runs and when. Each crontab entry has this format: .—————- minute (0-59) | .————- hour (0-23) | | .———- day of month (1-31) | | | .——- month (1-12) OR jan,feb,mar,apr … | | | | .—- day of week (0-6) (Sunday=0 or 7) OR sun,mon,tue … | | |…
Compression Tools in Linux File compression is a routine task in Linux administration. You’ll encounter several tools, each with different tradeoffs between compression ratio, speed, and compatibility. This guide covers the most common compression formats: gzip, bzip2, 7z, xz, and zip. The examples below assume you’re compressing a directory called dir. Each tool supports compression…
PUMA MapReduce Benchmark Suite MapReduce remains a foundational programming model for processing large-scale distributed datasets, though its role has evolved alongside modern data processing frameworks. Hadoop implementations and other MapReduce systems require objective performance evaluation to guide infrastructure decisions and optimization efforts. PUMA (Princeton University MapReduce Benchmark) is a comprehensive benchmark suite developed by Faraz…
TeraSort Benchmark on Hadoop 3.x TeraSort is Hadoop’s standard benchmark for measuring distributed sorting performance across clusters. It consists of three components: TeraGen generates random input data, TeraSort performs the distributed sort, and TeraValidate confirms the output is globally sorted. Modern Hadoop deployments typically run on Hadoop 3.x or higher, with improvements in YARN resource…
Note Hadoop 1.x reached end-of-life in 2014 and is no longer maintained. This post documents a deprecated architecture for historical reference only. For new deployments, use Hadoop 3.x+ with YARN, which offers significant improvements in resource management, multi-tenancy, and reliability. See the Apache Hadoop documentation for current versions. For managed services, consider AWS EMR, Google…
Managing Repositories with Gitosis Gitosis provides a lightweight way to manage Git repositories and user access on a self-hosted server. This post covers user management, repository configuration, and access control. For initial server setup, refer to your Gitosis installation documentation. Adding a New User Each user needs an SSH key pair for authentication. The user…
Setting Up a Self-Hosted Git Server Gitosis is unmaintained and shouldn’t be used for new deployments. Use Gitolite or Forgejo instead. This guide covers Gitolite, which provides fine-grained access control, is actively maintained, and handles multiple repositories under a single system user. Prerequisites A server running Linux (Debian, Ubuntu, CentOS, or similar) SSH access to…
Hadoop Default Ports Reference Hadoop daemons communicate over specific TCP ports that you’ll need to know for cluster setup, firewall configuration, and application development. These ports are configurable but come with sensible defaults in Hadoop 3.x. HDFS Ports Service Port Configuration Property Purpose Namenode HTTP UI 9870 dfs.namenode.http-address Web UI and metadata operations Namenode HTTPS…
Hadoop Sort Benchmark: Testing Your Cluster Running benchmarks after a Hadoop installation helps validate that your cluster works correctly and gives you baseline performance metrics. The Sort benchmark is a standard test that exercises the MapReduce execution engine and HDFS, making it useful for stress-testing both the distributed storage layer and computation framework. What the…
Hadoop Cluster Configuration and Tuning Pitfalls Hadoop 3.x remains the current stable version with YARN improvements, HDFS federation, and erasure coding. Hadoop 1.x and 2.x are no longer maintained. For new deployments, evaluate whether Hadoop fits your needs or if managed services like AWS EMR, Google Dataproc, or Azure HDInsight better suit your infrastructure. This…
Standalone Hadoop Setup Hadoop’s default configuration runs in standalone (local) mode as a single JVM process — no HDFS daemons, no YARN, no distributed overhead. This mode is useful for development, testing MapReduce jobs, and debugging before moving to a clustered deployment. For new deployments, evaluate whether you need Hadoop at all. Consider cloud-native alternatives…