HDFS Architecture

How to install Hadoop on RHEL 8 / CentOS 8 Linux

Apache Hadoop is an open source framework used for distributed storage as well as distributed processing of big data on clusters of computers which runs on commodity hardwares. Hadoop stores data in Hadoop Distributed File System (HDFS) and the processing of these data is done using MapReduce. YARN provides API for requesting and allocating resource in the Hadoop cluster.

The Apache Hadoop framework is composed of the following modules:

  • Hadoop Common
  • Hadoop Distributed File System (HDFS)
  • YARN
  • MapReduce

This article explains how to install Hadoop Version 2 on RHEL 8 or CentOS 8. We will install HDFS (Namenode and Datanode), YARN, MapReduce on the single node cluster in Pseudo Distributed Mode which is distributed simulation on a single machine. Each Hadoop daemon such as hdfs, yarn, mapreduce etc. will run as a separate/individual java process.

In this tutorial you will learn:

  • How to add users for Hadoop Environment
  • How to install and configure the Oracle JDK
  • How to configure passwordless SSH
  • How to install Hadoop and configure necessary related xml files
  • How to start the Hadoop Cluster
  • How to access NameNode and ResourceManager Web UI

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Allowing access from a certain network segment to sshd.

How to install and setup an example service with xinetd on RHEL 8 / CentOS 8 Linux

Xinetd, or the Extended Internet Services Daemon, is a so-called super-server. You can configure it to listen in the place of many services, and start the service that should handle an incoming request only when there it actually arrives to the system – thus saving resources. While this may not seem to be a big deal on a system where traffic is relatively permanent, this service in the front of another approach does have some neat advantages, like logging or access control.

In this article we will install xinetd on a RHEL 8 / CentOS 8, and we’ll put the sshd daemon under it’s care. After verifying the setup, we’ll tweak the configuration a bit to see the access control in action.

In this tutorial you will learn:

  • How to install xinetd
  • How to setup sshd on RHEL 8 / CentOS 8 as an xinetd service
  • How to allow access only from a specific network to the sshd service from xinetd
  • How to audit traffic from xinetd log entries

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HAProxy Architecture

Install and Configure HAProxy on RHEL 8 / CentOS 8 Linux

HAProxy or High Availability Proxy is an open source TCP and HTTP load balancer and proxy server software. HAProxy has been written by Willy Tarreau in C, it supports SSL, compressions, keep-alive, custom log formats and header rewriting. HAProxy is a fast and lightweight proxy server and load balancer with a small memory footprint and low CPU usage. It is used by large sites like Github, StackOverflow, Reddit, Tumblr, Twitter and others. It has become the most popular software load balancer and proxy server in the past years.

In this tutorial, you will get through the HAProxy installation and configuration on RHEL 8 / CentOS 8. We will install HAProxy on a single server and then install Nginx web server on the other servers. HAProxy will act as a load balancer for the Nginx web servers.

In this tutorial you will learn:

  • HAProxy Architecture and Concepts
  • Configure hosts file for name resolution
  • Install and Configure HAProxy
  • Install and Configure Nginx
  • Testing the Load Balancing feature
  • Access the HAProxy Stats URL

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Ansible Architecture

How to install and configure Ansible on Redhat Enterprise Linux 8

This tutorial covers step by step installation and configuration of Ansible on Redhat Enterprise Linux 8.
Ansible is the leading Open Source configuration management system. It makes it easy for administrators and operations teams to control thousands of servers from central machine without installing agents on them.

In this tutorial you will learn:

  • Ansible Overview
  • Install and Configure Python
  • Set Password-less SSH
  • Install Ansible
  • Testing and Managing the Ansible

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How To Launch Containers With Docker Compose

This article is going to introduce Docker Compose and show how to put it to work for your needs. We will install it, write a simple Compose file and launch the container.

We will then see how to launch multiple containers. Then we will see how to build images and lately how to use multiple Compose files to launch containers in different environments, like development and production, for example.

In this tutorial you will learn:

  • How to install Docker Compose
  • How to write a simple Compose file
  • How to execute docker-compose commands to start and stop containers
  • How to launch multiple containers
  • How to build images with Docker Compose
  • How to override using multiple Docker Compose files

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Examples page served by Apache Tomcat

How to install apache tomcat on Linux RHEL 8 / CentOS 8

In this tutorial we will learn how to install Apache Tomcat 8 application container to RHEL 8 / CentOS 8. We will be using the zip package available to download from the Apache Tomcat website. As this package will not handle setting up the environment, we will create it from the command line.

In this tutorial you will learn:

  • How to install Apache Tomcat from zip file
  • How to create the environment for the Tomcat server from command line
  • How to add basic service file to systemd
  • How to enable autostart, start and stop the Tomcat server
  • How to verify Tomcat is reachable

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HTTPS is enabled

How To Customize Docker Images With Dockerfiles

This article shows how to customize Docker images using a description file named Dockerfile. You’ll see how to extend existing images, customizing them to your needs, and also how to publish the resulting image to Docker Hub.

In this tutorial you will learn:

  • How to customize an image with a Dockerfile.
  • How to publish the resulting image in Docker Hub.

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Zookeeper Architectural Overview

How to install and configure Zookeeper in Ubuntu 18.04

Zookeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.
All of these kinds of services are used in some form or another by distributed applications.

In this article, we have explained the necessary steps to install and configure 3 Node Zookeeper Cluster with a definite quorum on Ubuntu 18.04.

In this tutorial you will learn:

  • What is Zookeeper and its Overview.
  • What is the Architecture of Zookeeper.
  • How to Configure the Zookeeper hosts and Add Zookeeper User.
  • How to Install and Configure Oracle JDK.
  • How to Configure and Setup the Zookeeper.
  • How to Configure Worker Nodes to join the Swarm Cluster.
  • How to Verify the Zookeeper Cluster and Ensemble.

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How to perform python input/output operations on files with python open function

The manipulation of files is an operation which sooner or later we’ll need to perform in our programs. The python built-in open function returns a file object, which lets us interact with files in different modes: we will see them in this article.

In this python tutorial you will learn:

  • How to use the python open function.
  • What are the various modes of operation which can be used with the python open function.
  • How to interact with a file object.
  • Why is important to close a file object, and how to do it.

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PHP installed

How To Interact With Docker Containers

This article extends the previous Docker article and shows how to interact with Docker containers by executing commands inside containers, installing software inside containers, inspecting container status, accessing containers using Bash, persisting changes into images and removing unused containers and images.

In this tutorial you will learn:

  • How to execute commands inside containers
  • How to install software inside containers
  • How to inspect container status
  • How to access containers using Bash
  • How to persist changes into images
  • How to remove unused containers and images

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