Managing the Boot Procedure

Understanding the Boot Procedure The computer is powered on and runs a POST The computer refers to its own BIOS/UEFI to choose which disk to boot from The GRUB boot loader is loaded, which then loads the Kernel The Kernel is loaded along side initramfs, which contains a temporary root directory (chroot) and all necessary […]

Basic Kernel Management

Understanding the Linux Kernel The Kernel is the heart of the operating system and it communicates with the system’s hardware Linux drivers are implemented as kernel modules initramfs is the initial ram drive that is loaded during boot. It contains drivers that gave been compiled during its installation systemdudevd is used to recognize hot-plug hardware, […]

Managing Advanced Storage

Understanding LVM, Stratis, and VDO LVM Logical Volumes Used during default installation of RHEL Adds flexibility to storage (resize, snapshots, etc.) Statis Next generation Volume Managing Filesystem that uses thing provisioning by default Implemented in the user space, which makes API access possible Virtual Data Optimizer Focused on storing files in the most efficient way […]

Managing Storage

Understanding Disk Layout Disks are stored in /dev There are two different types of disk systems: BIOS: Uses MBR partitions, which only allow four partitions per disk UEFI: Uses GPT, which allows up to 128 partitions Logical and Extended volumes may be used to create more partitions within a single partition lsblk: Lists block devices […]

Configuring Logging

Understanding RHEL 8 Logging Options rsyslogd writes logs to /var/log systemd-journald keeps information from services that are managed by systemd journalctl accesses information stored by systemd-journald systemd-journald is not persistent, but can be configured to connect to rsyslogd via /dev/log systemd-journald can also become persistent by creating the /var/log/journal directory and restarting the systemd-journald service […]

Scheduling Tasks

Understanding cron and at cron is a daemon that triggers jobs on a regular basis Works with different configuration files that specify when a job should be started Should be used for regular re-occurring jobs Does not have STDOUT at is used for tasks that need to be started once Understanding cron Scheduling Options crontab […]

Working with Systemd

Understanding Systemd Units Systemd is the manager of everything after the start of the Linux kernel, and items managed by Systemd are called units systemctl: Management interface to work with Systemd systemctl -t help: Lists available unit types systemctl list-unit-files: Lists all available unit files and their states systemctl-list-units: Lists the statuses of the running […]

Managing Software

Setting up Repository Access The following will create a local repository from the OS Installation Disk ISO Image Create an ISO Image: Create directory /repo: Edit the /etc/fstab and add the following line to the end: Mount the ISO Create the files /etc/yum.repos.d/appstream.repo and /etc/yum.repos.d/base.repo with the following contents: Verify with yum repolist Managing Packages […]

Managing Processes

Managing Shell Jobs [command] &: Will start the command in the background The terminal will provide a Job ID and a PID To move a job to the background: Stop the command using Ctrl+Z Type bg to move the command to the background jobs: Will display all running jobs fg [job_id]: Will bring specified jon […]

Configure Networking

Understanding IPv4 Networking Each node needs its own IP Address, written in dotted decimal notation (192.168.4.200/24) Each IP Address must be indicated with the subnet mask behind it, which defines which part of the network address indicates the network and which part indicates the node The default router, or gateway, specifies which server to forward […]