Linux routing tables exist in kernel memory during runtime. To persist routes across reboots, you need to store them on disk and have them reloaded during system startup. The mechanism varies depending on your network management setup. systemd-networkd and netplan (modern systems) On contemporary distributions using systemd-networkd or netplan, define routes in YAML configuration files….
If you need to restart GNOME while keeping your applications open, you have several options depending on your GNOME version and setup. Quick restart with Alt+F2 The fastest method is to use GNOME’s run dialog: Press Alt + F2 Type r and press Enter This restarts the GNOME shell while preserving your running applications and…
Controlling a GNOME desktop remotely—locking the display, activating the screensaver, or blanking the screen—requires you to interact with the running GNOME session. The approach depends on your GNOME version and what you’re trying to accomplish. Using systemd User Sessions and D-Bus Modern GNOME (3.30+) uses systemd user sessions and D-Bus for session management. The older…
MySQL Cluster uses NDB (Network Database) storage engine to provide high availability and data redundancy across multiple nodes. This guide covers installation and configuration on modern RHEL-compatible systems. Prerequisites Three or more servers (minimum: one management node, two data nodes, one SQL node) Rocky Linux 9 or AlmaLinux 9 Root or sudo access Static IP…
To disable all active swap spaces on Linux, run: swapoff -a The -a flag targets all currently enabled swap devices and files. This forces the kernel and applications to rely entirely on physical RAM. When You’d Do This Disabling swap is useful for: Performance testing: Eliminating swap I/O variance to get consistent benchmarks Latency-sensitive workloads:…
GNOME Keyring stores encrypted credentials, SSH keys, and secrets for applications. If you need to disable it or start fresh after forgetting the password, you can remove the keyring database. Keyring Storage Locations The location of keyrings depends on your GNOME version and configuration: GNOME 3.0+: ~/.local/share/gnome-keyring/ or ~/.local/share/evolution/calendar/ Older GNOME: ~/.gnome2/keyrings/ XDG Base Directory…
No-IP provides dynamic DNS service for systems that don’t have static IP addresses. The noip2 client daemon monitors your system’s IP and automatically updates your No-IP domain when changes occur. Here’s how to set it up properly. Prerequisites You’ll need: A No-IP account with at least one hostname configured Root or sudo access A Linux…
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NFSv4 significantly simplifies network exposure compared to NFSv3. Where NFSv3 requires managing multiple dynamic ports (mountd, statd, lockd), NFSv4 uses only port 111 (rpcbind) and port 2049 (NFS). This makes firewall configuration and port forwarding straightforward. For production environments, consider implementing Kerberos authentication (krb5, krb5i, or krb5p) instead of relying solely on network-based access control….
The Secondary NameNode periodically merges the fsimage and edits log files to keep the edits log manageable and consolidate metadata. When this checkpointing fails, you’ll see errors like: ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Exception in doCheckpoint java.io.IOException: Inconsistent checkpoint fields. This typically indicates a mismatch between the NameNode and Secondary NameNode metadata states, often from unclean shutdowns or…
The Linux kernel provides the taskstats API to monitor detailed per-task statistics, including I/O wait time, CPU scheduling delays, and memory reclamation waits. Understanding how these metrics are collected at the kernel level is essential for diagnosing performance issues and understanding process behavior. How the Kernel Records I/O Delays The kernel records I/O wait delays…
Picking your first programming language matters, but it’s not the career-defining decision some make it out to be. What matters more is that you pick something reasonable and start building. That said, some choices will save you months of frustration. Know What You’re Optimizing For Before evaluating languages, answer these questions honestly: What do you…
Systemd replaced traditional init on most modern Linux distributions, shifting terminology from “runlevels” to “targets.” If you’re migrating from older systems, here’s the mapping: Runlevel Systemd Target Purpose 0 poweroff.target Shutdown 1 rescue.target Single-user mode 2, 3, 4 multi-user.target Multi-user, no GUI 5 graphical.target Multi-user with GUI 6 reboot.target Reboot The two targets you’ll use…
Running commands across multiple servers is fundamental to cluster management and infrastructure automation. While orchestration tools like Ansible and Terraform dominate modern deployments, sometimes you need lightweight solutions that work without dependencies—or you’re already invested in SSH-based infrastructure. When managing clusters, you typically work in two modes: serial execution (one node at a time) and…
The /etc/fstab file defines how Linux mounts filesystems at boot and controls mounting behavior for both the system and individual users. Understanding its format and options is essential for reliable storage management. File Format and Fields Each line in /etc/fstab represents one filesystem. Fields are separated by whitespace (tabs or spaces), and lines beginning with…
You’re using a Linux-based OS right now, either directly or indirectly. But what do you actually call it? The naming question matters more than it seems — different distributions frame themselves differently, and understanding the terminology affects how you talk about infrastructure, apply for jobs, and read documentation. How Major Distributions Identify Themselves Red Hat…
Emacs keybindings rely heavily on Ctrl because the editor was designed for Lisp machines in the 1970s—machines where Ctrl sat near the spacebar. Modern PC keyboards moved it to the corner, making constant reaches painful. Once millions of users built muscle memory around these bindings, changing them became impractical. If modern keyboard ergonomics matter to…
Xen remains a production-grade hypervisor used by major cloud providers like AWS and Citrix, though KVM has become the default for most Linux distributions. This guide covers setting up Xen Domain-0 (the privileged management domain) on modern Fedora systems. Installing Xen Packages Install the required Xen packages: sudo dnf install xen xen-libs xen-runtime xen-dom0-tools Modern…
VNC provides graphical remote access to Linux servers. For security, tunnel VNC traffic through SSH rather than expose it directly to the network. This guide covers Windows client setup with SSH tunneling. Prerequisites Windows client: SSH client: Native OpenSSH (built into Windows 10/11) or PuTTY VNC viewer: RealVNC Viewer, TigerVNC Viewer, or TightVNC Viewer Linux…