Successful build with Maven.

How to install maven on RHEL 8 / CentOS 8

Maven is a handy project management tool for Java projects. It helps handling multiple projects, can integrate with various IDE (Integrated Development Environment) software, and above all, simplifies build processes. In this tutorial we will install maven on a RHEL 8 / CentOS 8 Linux system, and to test the tool, we’ll build and run a simple example application.

In this tutorial you will learn:

  • How to install Maven
  • How to create a basic project
  • How to build the project with Maven
  • How to test the built application

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Successful cpan perl module install with cpan on RHEL 8

How to install cpan on RHEL 8 / CentOS 8

Perl is a well-known programming language with long development history. The same long history provides the countless modules written in it, and distributed in various channels throughout the World Wide Web. As with most programming languages, if you implement something that you find useful, and maybe write it in a generic way, there are high chances others would find it useful too.

If you share your work with others, they don’t need to re-implement the wheel, they can spend time on other tools, thus making the community as a whole richer, and we have found the spirit of open source with a short walk. But as many people write perl modules, and perl runs on just about anything, it can be hard to find the module you are looking for, let alone build it in your environment. And that’s where cpan comes into play. CPAN itself is a large perl module repository, the cpan tool is a client that is able to fetch and compile needed modules to the local system.

In this tutorial we’ll install cpan on a RHEL 8 / CentOS 8, run the initial configuration, and install a module with this tool’s help.

In this tutorial you will learn:

  • How to install cpan
  • How to run initial configuration
  • How to install a perl module with cpan

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Compiling the ffmpeg code we have downloaded from Git

How to install ffmpeg on RHEL 8 / CentOS 8

If you ever need a quick way to convert between video or audio formats in Linux and want something that doesn’t munch on resources but does the job well, then you might want to give ffmpeg a try. There are many GUI interfaces for the ffmpeg package but in this article we’ll learn how to install it in RHEL 8 / CentOS 8 using the command line and compiling tools.

FFMpeg has many command line options when it comes to converting files and therefore it is advisable to use it from the CLI. From there you can fine-tune its options using attributes and even learn how to create BASH scripts to make automatic conversion scripts.

In this tutorial you will learn:

  • How to compile the ffmpeg source code from scrach

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Nginx web-server on RHEL 8 Linux server.

How to install nginx on RHEL 8 / CentOS 8 server

The aim of this article is to get you started with basic Nginx web-server installation using the dnf install nginx command and configuration on RHEL 8 / CentOS 8. Nginx web server is an Apache alternative with a capability to be also used as reverse proxy, load balancer, mail proxy and HTTP cache.

In this tutorial you will learn:

  • How to install Nginx on RHEL 8 / CentOS 8.
  • How to start Nginx.
  • How to enable Nginx to start after reboot.
  • How to open HTTP and HTTPS ports.
  • How to run Nginx encrypted with HTTPS.
  • How to create self-signed SSL certificate for Nginx.

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Python package management system (pip) on Red Hat Enterprise Linux 8.

How to install pip in RHEL 8 / CentOS 8

Pip is a package management system used to install and manage software packages written in Python. RHEL 8 / CentOS 8 repository allows access to both pip versions for Python 2 as well as Python 3 interpreter. The pip command may be missing on your default RHEL 8 / CentOS 8 system installation.

The pip python package management tool can be easily installed by using the dnf command. Both, python 2 and 3 version can coexists on the same system and are accessible via pip2 and pip3 commands respectively.

In this tutorial you will learn:

  • How to install pip on RHEL 8 / CentOS 8 for python version 2.
  • How to install pip on RHEL 8 / CentOS 8 for python version 3.

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List of packages within the

Install development tools on RHEL 8 / CentOS 8

The development tools group acts as a transitional package for installation of multiple development, compilation and debugging tools. Most notably these include Automake, Autoconf, Gcc (C/C++) as well as various Perl & Python macros and debuggers.

See below list for a complete list of packages available as part of the development tools group. The entire development tools group can be easily installed on RHEL 8 / CentOS 8 Linux by using the dnf command.

In this tutorial you will learn:

  • How to list the content of the development tools group on RHEL 8 / CentOS 8
  • How to install the development tools group on RHEL 8 / CentOS 8
  • How to remove the development tools group from RHEL 8 / CentOS 8

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Checking version of installed AWS CLI tools on RHEL 8

Install aws cli on RHEL 8 / CentOS 8

The AWS Command Line Interface (CLI) is a all-in-one tool to manage services available on AWS cloud. On RHEL 8 / CentOS 8 the AWS CLI can be installed by using the python package management system PIP.

In this tutorial you will learn:

  • How to install AWS CLI tools on RHEL 8 / CentOS 8
  • How to configure AWS CLI tools on RHEL 8 / CentOS 8
  • How to remove AWS CLI tools on RHEL 8 / CentOS 8

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Java on RHEL 8

How to Install Java on RHEL 8 / CentOS 8 Linux

Java is incredibly popular on servers, and if you plan on using RHEL 8 / CentOS 8, you’ll need to install it. There are a couple of ways to install Java on RHEL, both from the open source OpenJDK packages and directly from Oracle.

In this tutorial you will learn:

  • How to Install OpenJDK 8
  • How to Install OpenJDK 11
  • How to Install Oracle Java 8 JRE
  • How to Install Oracle Java 8 JDK
  • How to Switch Java Versions

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NRPE - Nagios Remote Plugin Executor

How to setup NRPE for client side monitoring

Nrpe, or Nagios Remote Plugin Executor, is the client side service of a monitoring setup. The monitoring server will send commands to the client, which listens passively when got no work to do. Upon incoming command, the nrpe checks it’s local configuration, and executes the plugin configured with the command, then sends back the results to the server for processing. You can read more about the server side installation in the Nagios installation guide, while this guide will focus on the client side.

In this tutorial you will learn:

  • How to install NRPE on Debian/Red Hat based distributions
  • How to configure NRPE to accept commands from the server
  • How to configure a custom check on the server and client side

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JSch example execution

Executing commands on a remote machine from Java with JSch

SSH is an every-day tool of any Linux System Administration job. It is an easy and secure way to access remote machines on the network, transfer data and execute remote commands. Apart from interactive mode, there are many tools exist that enable automation of remote tasks that also rely on the existing ssh server/client architecture. For one such tool, you can read about ansible on Ubuntu for example. You can also find many implementations of the ssh client, but what about accessing the abilities ssh provides from code?

JSch is a project that implements the ssh protocol in Java. With it’s help, you can build applications that are capable to connect to and interact with a remote or local SSH Server. This way your application is capable of managing any aspect of the target machine that you could complete with your native ssh client, which gives yet another powerful addition to the already vast Java toolset.

In this article we will import JSch into our Java project, and develop the minimal necessary code pieces to create an application that can log in to a remote machine’s ssh server, execute some commands in the remote interactive shell, closes the session, then presents the output. This application will be minimal, however, it may give a hint of the power it provides.

In this tutorial you will learn:

  • How to import JSch into your Java project
  • How to setup the test environment
  • How to implement the UserInfo interface in a custom class
  • How to write an application that initiates interactive ssh session

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Debian package

Easy way to create a Debian package and local package repository

This article describes a simple way to create a home made debian package and include it into a local package repository. Although we could use an existing Debian/Ubuntu package, we will start from scratch by creating and packaging our own trivial application. Once our package is ready, we will include it into our local package repository. This article illustrates a very simplistic approach, however it may serve as a template in many different scenarios.

In this tutorial you will learn:

  • How to create a trivial debian package
  • How to create a local debian repository
  • How to add the repository to the list of software sources

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generate rndc and bind configuration - centos

Configure RNDC Key for Bind DNS server on CentOS 7

Objective

In order to administer DNS server (bind) from a command line, the RNDC utility needs to be correctly configured to avoid error message such as “rndc connect failed 127.0.0.1 connection refused“. The objective is to configure RNDC for Bind DNS server on CentOS 7 Linux.

Operating System and Software Versions

  • Operating System: – CentOS Linux release 7.4.1708 (Core) Linux
  • Software: – Bind 9

Requirements

Privileged access to your Ubuntu System as root or via sudo command is required.

Difficulty

EASY

Conventions

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