Testing Multi-Domain Subject Alternative Names Certificates
by Ramses Soto-Navarro ramses@sotosystems.com, 3/2/2023
Overview
Setup Apache
Certificate Script
Create Certificate
Second Virtual Host
Overview
Brief notes on how to create and verify multi-domain SSL certificates using the subject alternative names extension. Useful for Apache web URLs that require many different subdomains, while using one certificate. The same technique can be used for OpenSSL self-signed test certificates or official certificate signing requests, which service multiple domains with one certificate. Here we will use a Linux Red Hat 9 test scenario. The audience is experienced Linux administrators.
SUSE 15 OS Updates via GRUB
by Ramses Soto-Navarro ramses@sotosystems.com, 10/26/2022
Overview
Copy Kernel
Modify GRUB
GRUB Boot Parameters
Erase GRUB Boot Entry
Troubleshooting
Overview
Brief notes on how to update SUSE 15 SP3 to SP4 via GRUB boot, without using the virtual guest CDROM. Perform an offline OS upgrade using the server’s own hard disk without a need to attach any devices (like USB drive or DVD ISO); use a local network source mounted repository for the installation media. The audience is experienced Linux administrators.
SUSE 15 SP4 Mini CD ISO
by Ramses Soto-Navarro ramses@sotosystems.com, 9/12/2022
Overview
Download and Mount ISO
Mount ISO Repo
Copy ISO Files
Create Custom Mini ISO
Boot to the Upgrade
Overview
Brief notes on how to create a 130MB mini CD or ISO, in order to run a release upgrade, from SUSE 15 SP3 to SP4, via a custom web mounted repository. This is a much better alternative than using the 13GB DVD ISO for a release upgrade, especially for VM machines. All previous repositories will be deleted. This steps were created using a Debian workstation. Audience is experienced Linux administrators.
Upgrade Oracle Linux 7 to 8 Using Leapp
by Ramses Soto-Navarro ramses@sotosystems.com, 7/27/2022
Overview
Pre-install Steps
Run Leapp Pre-upgrade
Verify Version 8 Local Repo
Run Leapp Upgrade
Verify New OS
Remove Old Kernels
Overview
Brief notes on how to run an online upgrade of Oracle Linux 7 to 8 using Leapp. Audience is experienced Linux administrators.
UEFI Recovery for Oracle Linux 7
by Ramses Soto-Navarro ramses@sotosystems.com, 7/26/2022
Overview
Create KVM Guest
Start SSH
Partition for UEFI
Format Partitions
Mount and Chroot
Reinstall UEFI Grub2
Initialize UEFI GRUB2
Rebuild the Boot Ramdisk
Last Tasks
Overview
Brief notes on P2V physical to virtual and back, Oracle Linux 7 migration, with UEFI secure boot included; useful for rescue or recovery of physical Linux servers that require UEFI. Here we migrate a physical Linux server to a virtual guest under Linux KVM. The same can be done with Linux version 8. The audience is experienced Linux administrators.