This post describes Xen DomU setup procedures from the early 2010s. While Xen remains critical infrastructure for cloud providers like AWS EC2 and Citrix Hypervisor, it’s rarely deployed for new on-premises virtualization projects. For modern Linux virtualization, consider: KVM/QEMU: The default hypervisor in most Linux distributions, better community support, and tighter kernel integration Proxmox VE…
IPv6 is enabled by default on most Linux distributions. While IPv6adoption has grown, many environments still rely primarily on IPv4, and disabling IPv6 can simplify networking configurations or resolve compatibility issues. Quick Method: Disable via modprobe The most straightforward approach is to prevent the IPv6 kernel module from loading: echo “options ipv6 disable=1” >> /etc/modprobe.d/disable-ipv6.conf…
Running 32-bit Firefox on a 64-bit Linux system is less common than it used to be, but there are still valid reasons: testing web compatibility across architectures, supporting legacy plugins, or working with older systems. This guide covers Fedora and RHEL-based systems, though the core approach applies to other distributions. Prerequisites Ensure you have multilib…
Mistakes happen during development. Git provides several commands to undo changes at different stages—before committing, after committing, or in specific files. Understanding which tool to use depends on where you are in the workflow. Revert the entire working tree before committing If you’ve made changes to multiple files and want to discard everything back to…
The uptime command is the quickest way to check how long your system has been running: $ uptime 22:19:29 up 10 days, 22:26, 5 users, load average: 0.00, 0.00, 0.01 This output shows: Current time: 22:19:29 System running for: 10 days, 22 hours, 26 minutes Active user sessions: 5 Load averages: 1-minute, 5-minute, and 15-minute…
PuTTY remains a solid choice for SSH access from Windows. It’s lightweight, portable (no installation required), and handles key-based authentication well. Download the .exe version for portability. For a more modern terminal experience, Git Bash (included with Git for Windows) gives you native OpenSSH on Windows. If you’re on Windows 10+, the built-in OpenSSH client…
pgrep and pkill are essential tools for finding and signaling processes by name and attributes. They’re far more precise than grepping ps output and should be your go-to for process management scripts and one-liners. pgrep: Find Process IDs pgrep searches running processes and outputs matching PIDs. All selection criteria must match unless you use alternatives…
LVM (Logical Volume Manager) lets you combine multiple physical disks into flexible storage pools. This guide covers creating a volume group from multiple disk partitions—a common setup for servers that need flexible storage allocation across Xen guests, databases, or other demanding workloads. Prerequisites This assumes you have two or more unformatted disk devices available. In…
LVM snapshots provide an efficient way to duplicate virtual machines in seconds rather than minutes. Instead of copying an entire filesystem, snapshots leverage copy-on-write semantics—physical blocks are only duplicated when the source or snapshot is modified. This approach works well for any LVM-backed virtualization platform, though Xen is used here as an example. Note: Xen…
LVM snapshots provide a fast, efficient way to duplicate virtual machines across servers. This technique applies to any LVM-backed hypervisor including Xen, KVM, and Proxmox. The process uses LVM snapshots on the source server, then transfers the snapshot image to the destination using standard Unix tools. Scenario Source server: 10.0.0.10 with VM stored in /dev/vg_xen/vm-10.0.0.123…
Building and maintaining Linux clusters requires coordinated management of user accounts, storage, networking, and services across multiple machines. This guide covers practical approaches to common clustering challenges, from unified authentication to network isolation. Account and Storage Management Unified Authentication and Home Directories Centralizing user management across cluster nodes eliminates the overhead of maintaining individual user…
The firmware (BIOS/UEFI) on your system contains critical hardware settings and boot information. Knowing your firmware version is essential for updates, compatibility checks, and troubleshooting. Here’s how to find it. Using dmidecode dmidecode is the standard tool for reading the Desktop Management Interface (DMI) table, which stores hardware and firmware metadata. Most distributions include it,…
Xen remains a production-grade hypervisor used in enterprise environments (AWS EC2, Citrix Hypervisor), though KVM has become the default for most Linux distributions. This guide covers building a stable Xen Dom0 on current Fedora releases using modern kernel sources. Hardware Considerations This guide assumes server-class hardware with: Intel or AMD processor with virtualization extensions (VT-x…
GNOME has hidden a few playful easter eggs in its desktop environment over the years. Two of the most well-known are “Free the Fish” and “Wanda the Fish” — small animated features that surprise unsuspecting users. Free the Fish (GNOME 2) In GNOME 2, pressing Alt+F2 and running this command: free the fish releases a…
A Fedora Live USB lets you boot directly into a Fedora environment without modifying your hard drive. You can use it to test Fedora, troubleshoot your system, or perform a fresh installation. This guide covers modern tools and workflows for creating bootable USB media. Back up any data on your USB stick first — the…
Xen remains relevant in production environments (AWS EC2, Citrix Hypervisor), though KVM has become the default for most Linux distributions. This guide covers frequent installation and configuration issues specific to Fedora Dom0 setups, with many tips applicable to other Linux platforms. BIOS Configuration If Xen fails with “I/O virtualization disabled,” you need to enable virtualization…
To find all available versions of a package in your repository, use the –showduplicates flag: dnf list –showduplicates kernel Or for other packages: dnf list –showduplicates <package-name> The output shows both installed and available versions with their release tags. For example: Installed Packages kernel.x86_64 6.8.1-1.fc39 @updates Available Packages kernel.x86_64 6.7.12-200.fc39 updates kernel.x86_64 6.6.25-1.fc39 updates kernel.x86_64…
Linux provides multiple ways to query network configuration. While the underlying concepts remain consistent, modern tools have evolved from the older net-tools utilities. IP Address, MAC Address, and Netmask The modern replacement for ifconfig is ip addr: $ ip addr show This displays all network interfaces with their IPv4 and IPv6 addresses, MAC addresses, and…
Xen remains production-grade virtualization for specific use cases (AWS EC2, Citrix Hypervisor), but most Linux distributions default to KVM. This guide covers Xen DomU setup using modern tools and practices. For new deployments, evaluate KVM/libvirt or container solutions like Podman/Kubernetes first. Storage Setup Create a file-backed virtual block device (VBD) for your DomU. File-backed storage…
When using KDE Plasma with GTK applications, you’ll notice the mouse cursor switches to a default style when moving from the desktop to applications like Firefox or GIMP. This happens because GTK and Qt use separate cursor theme configurations by default. Quick Fix The easiest solution is to explicitly configure GTK to use your chosen…