Libvirt on A Random Walk Down Tech Street

virt-install: boot from specific kernel/initrd just for install

Thu, 30 Jan 2020 00:00:00 +0000

Introduction

For some time now with virt-install (developed under virt-manager) you have been able to specify a kernel and initial ramdisk to start a VM with. The only problem is that the VM will always start with that kernel/initrd (unless you change the definition manually). If you are rapidly testing operating system installations this can be problematic.

On the one hand, providing the kernel/initrd allows one to automate the install process from a Linux terminal, or even a script, by specifying the kernel/initrd and also the kernel command line options. However, it only gives us half the picture, because you’d then have to hand edit the libvirt definition of the machine to see if the installed machine was viable, OR you’d be lazy and just throw away the installed machine and assume it was good because the installation process finished without error; BAD.

Update on Easy PXE boot testing post: minus PXELINUX

Fri, 13 Sep 2019 00:00:00 +0000

Introduction

This is an update to my previous post about easily testing PXE booting by using libvirt + iPXE.

Several people have notified me (thanks Lukas Zapletal and others) that instead of leveraging PXELINUX that I could just use an iPXE script to do the same thing. I hadn’t used iPXE much so here’s an update on how to achieve the same goal using an iPXE script instead of a PXELINUX binary+config.

Easy PXE boot testing with only HTTP using iPXE and libvirt

Fri, 04 Jan 2019 00:00:00 +0000

Update: A future post explains how to do this even easier without PXELINUX.

Introduction

Occasionally I have a need to test out a PXE install workflow. All of this is super easy if you have a permanent PXE infrastructure you maintain which traditionally has consisted of DHCP, TFTP and HTTP/FTP servers. What if I just have my laptop and want to test something in a VM? It turns out it’s pretty easy to do using libvirt and a simple http server.