- Details
- admin
- Redhat / CentOS
Apache Bench is a useful little tool for testing the response time of a webservice, and thus the performance of the webserver. We can specify the number of requests to send, the target URL, set up concurrency, just to name a few of this tool's settings.
While such simulated workloads will not result exactly the same data that real world traffic will do, it is always a good idea to test before going to production. Maybe before deploying a new version of the application, we could run the tests on the new version, and compare the results with the previous test data to see if our application will serve slower, or faster than the last version. With well-planned testing, this tool can show the possible bottlenecks of the application, and may provide points of interest where we should look into our code for possible optimization.
In this tutorial we will install Apache Bench on Red Hat Enterprise Linux 8, as well as an Apache Webserver to run some tests against.
In this tutorial you will learn:- How to install Apache Bench
- How to install httpd webserver, and add some basic content
- How to run simple tests against the webserver
- Details
- admin
- Redhat / CentOS
Apache Cassandra is an open-source NoSQL database. One of it's main features is it's decentralized nature that gives unique fault tolerance. Having our data replicated across datacenters means our production will not suffer from the loss of one of our sites, something all sysadmins dream of (or really happy to have such setup).
In this tutorial we will install Cassandra on Red Hat Enterprise Linux 8 by adding the Cassandra repository, install the software, and set up all else needed to have our service up and running and easy to manage.
In this tutorial you will learn:- How to add Cassandra repository
- How to install needed packages
- How to repair systemd unit file
- How to test Cassandra with cqlsh
- Details
- admin
- Redhat / CentOS
Apache Kafka is a distributed streaming platform. With it's rich API (Application Programming Interface) set, we can connect mostly anything to Kafka as source of data, and on the other end, we can set up a large number of consumers that will receive the steam of records for processing. Kafka is highly scaleable, and stores the streams of data in a reliable and fault-tolerant way. From the connectivity perspective, Kafka can serve as a bridge between many heterogeneous systems, which in turn can rely on it's capabilities to transfer and persist the data provided.
In this tutorial we will install Apache Kafka on a Red Hat Enterprise Linux 8, create the systemd unit files for ease of management, and test the functionality with the shipped command line tools.
- How to install Apache Kafka
- How to create systemd services for Kafka and Zookeeper
- How to test Kafka with command line clients
- Details
- Lubos Rendek
- Redhat / CentOS
userdel command.
In this tutorial you will learn:
- How to delete user on RHEL 8 / CentOS 8.
- How to force user deletion.
- How to delete user as well as its home directory.
- Details
- admin
- Redhat / CentOS
In this tutorial we will install gdb on RHEL 8, and test how it is working with a simple C application.
In this tutorial you will learn:- How to install gdb
- How to compile a simple C application with debug symbols
- How to set breakpoints in the running application with gdb
- How to print actual values of given variables within the application
- Details
- Lubos Rendek
- Redhat / CentOS
In this tutorial you will learn:
- How to Install LAMP Stack on RHEL 8.
- How to configure MariaDB database.
- How to install Matomo (Piwik) on RHEL 8.
- How to open HTTP and HTTPS firewall ports.
- Details
- Lubos Rendek
- Redhat / CentOS
ddrescue command hence creating a bootable RHEL 8 USB flashdrive.
In this tutorial you will learn:
- How to create bootable RHEL 8 USB flash drive.
- How to access boot menu.
- How to access BIOS/UEFI.
- Details
- Lubos Rendek
- Redhat / CentOS
bash command after stopping the GUI and disabling the nouveau driver by modifying the GRUB boot menu.To install Nvidia driver on other Linux distributions, follow our Nvidia Linux Driver guide.
- Details
- Sandip Bhowmik
- Redhat / CentOS
In this tutorial you will learn:
- Ansible Overview
- Install and Configure Python
- Set Password-less SSH
- Install Ansible
- Testing and Managing the Ansible
- Details
- Nick Congleton
- Redhat / CentOS
There are a ton of ways that you can install RHEL 8 on a virtual machine. This guide will cover using KVM with and without virt-manager as well as VirtualBox.
In this tutorial you will learn:
- How to Install RHEL 8 on KVM With Virt-Manager
- How to Set Up Your VM in Virt-Manager
- How to Install RHEL 8
- How to Install RHEL 8 on KVM Via the CLI
- How to Create Your VM
- How to Connect to Your VM Over VNC
- How to Install RHEL 8 on VirtualBox
- How to Set Up Your VM on VirtualBox
- How to Install RHEL 8
- Details
- Răzvan T. Coloja
- Redhat / CentOS
But what you have to keep in mind is that this is a commercial Linux distribution and thus you will get access not only to technical support but also commercial software, unavailable otherwise in fully open-source Linux distributions based on Red Hat Linux.
In this tutorial you will learn:
- How to subscribe to software channels in Red Hat Enterprise Linux 8
- How to install software in Red Hat Enterprise Linux 8 with the help of Red Hat repositories
- How to install standalone RPM packages
- How to compile software for RHEL yourself
- How to convert between DEB packages to RPM
- Details
- Thomas Sandmann
- Redhat / CentOS
As part of the RHCSA exam preparation, we already learned how to manage partitions on disk. Partitions are useful to separate disk space (for example, separating database-related files from webserver-related files), but we have a much more flexible solution that can separate or aggregate storage space.
This solution is called LVM, the Logical Volume Manager. LVM allows us to see multiple disks as one filesystem, thus overcoming the limitations of a physical disk's site. We can also create software mirroring on disks to protect or data written to the filesystem. In this tutorial we'll cover the basics: we'll manage the three layers of LVM, physical volumes, volume groups and logical volumes.
- How to create and remove physical volumes
- How to assign physical volumes to volume groups
- How to create and delete logical volumes
- Details
- Thomas Sandmann
- Redhat / CentOS
While in the desktop world we rarely change our hard drive - and that mostly indicated by hardware failure - in the server world it isn't uncommon for the underlying storage environment to change over time.
In a SAN (Storage Area Network) environment, for High Availability, a server can reach it's storage trough many paths, in reality distributed and mirrored to multiple disks in the storage network. If some paths change, the server needs to identify the "disk" again. That's why it is recommended to use special identifiers set on the device, and mount by these identifiers, not by device name which may change. In this part of RHCSA exam preparation tutorial, we'll add a new disk to our test machine, and configure mounting by UUID (Universally Unique IDentifier) and by label.
- How to get UUID of a given device
- How to get and set label of a device
- How to mount device by UUID
- How to mount device by label
- Details
- Lubos Rendek
- Redhat / CentOS
ERROR: Unable to find the kernel source tree for the currently running kernel. Please make sure you have installed the kernel
source files for your kernel and that they are properly configured; on Red Hat Linux systems, for example, be sure you have
the 'kernel-source' or 'kernel-devel' RPM installed. If you know the correct kernel source files are installed, you may
specify the kernel source path with the '--kernel-source-path' command line option.
In this tutorial you will learn:
- How to install kernel-headers
- How to install kernel-devel
- How to check kernel version
- How to check for installed kernel-devel version
- Details
- Thomas Sandmann
- Redhat / CentOS
Disk partitions are the basis of storing our data on disks. To be able to handle partitions, in this part of RHCSA exam preparation tutorial we will add an empty disk to our test RHEL 8 system, and create, list, and delete a new partition on it. First we will use the classic MBR (Master Boot Record) setup, then we'll do the same on GPT (GUID Partitioning Table) setup. GPT is a more advanced partitioning technique that allows large partitions, whereas MBR is limited to 2 TB disk space per partition. So if that doesn't seem like a very limiting size at the moment, think of the trend of disk usage, which may be not that much from the end user perspective, but certainly it is from the Linux system administration job perspective.
In this tutorial you will learn:- How to create a new MBR partition using fdisk
- How to list classic partitions using fdisk
- How to delete partition using fdisk
- How to create GPT partition using gdisk
- How to list GPT partitions
- How to delete GPT partitions
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