Introduction We have the host machine with the OS Ubuntu 22.04. On this PC or server, we will create two virtual machine guests: myubuntu2204test01 having static IP of 192.168.122.146 myubuntu2204test02 having static IP of 192.168.122.147 The guest VMs will use the default network created by libvirt. The gateway IP for the default network is 192.168.122.1. We will achieve automation using libvirt, qemu and cloud-init. To go through the article and exercise, you should have a rudimentary understanding of Linux system administration and networking.

So, you have an SSH key pair. The public key has been added on to the server. On the client, ie your laptop/desktop you have your private key. For some reason, your private key has not been loaded into memory. All you have to do is start the ssh-agent and then load the key into memory via ssh-add. Step 1: Start the agent eval $(ssh-agent) Step 2: load the key into memory

Using Linux KVM, Expose Virtual Guests On The LAN Audience: The blog post is for beginner to intermediary Linux system administrators. You should have a thorough understanding of the shell commands and be comfortable on the command line be able to install and configure packages, etc. be able to start and stop services using systemd be familiar with Linux configuration files be able to set Linux kernel parameters using sysctl be able to enable and disable Kernel modules be comfortable installing and using guest VMs using libvirt You should have a rudimentary understanding of networking concepts and tooling such as

Ansible Prerequisites Before jumping on to learning Ansible, have a firm grounding in Linux system administration and shell scripting. You can use Ansible for a lot of automation projects. The primary target audience for this blog post are DevOps engineers, IT infrastructure engineers and system administrators who create and manage IT infrastructure to run workloads. A good understanding of YAML is required before starting to write Ansible playbooks. A background in at least one programming language helps.

KVM (Kernel-based Virtual Machine), libvirt, and QEMU are three components that work together to provide a virtualization solution on Linux systems. KVM is a virtualization infrastructure built into the Linux kernel that allows it to run multiple virtual machines (VMs) on a single physical host. It provides the underlying virtualization technology, such as hardware acceleration for virtualized CPU and memory, and device emulation. libvirt is an open-source API, daemon, and management tool for virtualization environments, it provides a common, stable, and simple interface for managing virtualization technologies such as KVM, QEMU, and others.

NFS Server To run your own NFS (Network File System) server, you’ll need to first install Linux on your server. I’d go with Debian, Ubuntu or CentOS distributions. Once you’ve done that, you can install the NFS server software, which is typically included with most Linux distributions. After the NFS server software is installed, you’ll need to configure it to specify which directories on the server should be shared with NFS clients, and what type of access they should have.

syslog Syslog is a standard for logging system events on Unix and Linux systems. It is typically used to collect and store log messages from various applications and system components, such as the kernel, system libraries, and applications. Syslog uses a client-server model, where each client application sends log messages to a central syslog server, which then stores the messages in a log file. The syslog server can also forward the log messages to other syslog servers or send them to a log management system for further analysis.

There are many tools and software programs that can be used for monitoring and performance analysis on Linux systems. Some popular options include: top - This is a command-line utility that shows real-time information about the processes running on a Linux system, such as their CPU and memory usage. htop - This is a more advanced version of top that provides a more user-friendly interface and additional features, such as the ability to sort processes by different metrics and to kill processes.

Introduction If you have chosen the DevOps engineering path for your career, Linux system administration skills are a must. Companies run their workloads on Linux on-premise as well as in the cloud. Many developers write software on their Linux laptops and workstations. In this post, I will lay out a plan to master Linux system administration skills. The journey begins with you becoming a Linux desktop user. Gradually, you start using your laptop as a Linux server.

Introduction The Linux Kernel parameters are settings that can be configured to control the behavior of the Linux kernel. They are typically used to fine-tune system performance or to enable/disable certain features. Some examples of kernel parameters include: Memory-related parameters: These parameters control how the kernel manages system memory, including how much memory is allocated to user processes and how aggressively the kernel caches data. Processor-related parameters: These parameters control how the kernel interacts with the system’s processors, including how it schedules processes and how it handles interrupts.

Using Git with SSH is a common practice among software developers. The convenience of not having to remember passwords is a huge productivity boost in software development workflows. In a previous blog post, I wrote about managing SSH keys. Having many SSH keys can cause few issues: ssh-agent doesn’t work well with too many keys. Can’t always map SSH keys to servers in SSH client configuration. Both personal and company projects Git can be hosted on the same server or third-party service such as Github.

What is SSH Key Management? The blog post is intended towards someone new to SSH key management. Do you have just one SSH key pair? Do you have multiple key pairs? What are some pros and cons of having single or multiple key pairs? The post answers such questions about SSH key usage in practice. The Premise So, someone walked up to you or in a video call asked for your SSH public key?

Introduction The article explains how to run your own OpenVPN server. We will create a Certificate Authority Server and an OpenVPN server. We will also generate certificates for the clients. We will also learn how to manage revocation of client certificates using the Ansible roles. Use the Ansible roles gavika.openvpn and gavika.easy_rsa to install and configure your OpenVPN server. You can install the OpenVPN server on any public cloud or hosting provider or on-premise servers.

We are pleased to announce gavika.administrators. The Ansible role provides a declarative method to create Linux user accounts with administrative privileges. In other words, these users have sudo access without password and are empowered to run all commands on the system. You might be wondering why you would need a role when you can write a couple tasks yourselves in an Ansible playbook. The reason is, Do Not Repeat Yourself(DRY). Instead of writing such tasks over and over, use the abstraction provided by the role.

Yesterday, we announced the launch of Ansible role to install and configure AWS CloudWatch Agent. You might have seen my other open source Ansible roles on Ansible Galaxy and Github. In the same spirit, the company, Gavika Information Technologies Pvt. Ltd. Bangalore, has started publishing open source projects on Github. Ansible role to install and configure AWS CloudWatch Agent is the first project. Expect more projects in the future. These are some guidelines for the Ansible role projects that Gavika follows:

Ansible comes with a vault feature. It is meant to be used in the context of configuration management. But you can also use it as a standalone simple password vault for your personal or organization’s use. Initial setup of password vault: Create or clone a Git or another SCM repository git init Create the password vault ansible-vault create myvault.secret Type the new master password and confirm, ansible-vault will open your text editor.

In this tutorial, I will provide step-by-step process to implement MySQL replication. We will create one master and one slave. We will use two CentOS 6 servers - one for master and the other for slave. This following steps have been tested on two virtual machines. Our master server will have IP address 192.168.122.10. Our slave server will have IP address 192.168.122.12. You might want to run SELinux in permissive mode.

Moving around You can use the arrow keys on keyboard to move around in the command line. Bash also provides convenient keyboard shortcuts to navigate effectively. Try them out and see for yourself. To become a Bash pro user you have to get yourself familiar with the keyboard shortcuts. Once you do, you’ll find yourself productive. Shortcut Description CTRL+b move backward one character CTRL+f move forward one character ESC+b move one word backward ESC+f move one word forward CTRL+a move to beginning of line CTRL+e move to end of line CTRL+p move to previous line CTRL+n move to next line ESC+< move to first line of history list ESC+> move to last line of history list Moving around words using ESC+f and ESC+b are my favourites in this list.