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--- computing:preseed [2024/02/17 17:42] – created oemb1905
+++ computing:preseed [2024/02/17 17:50] – oemb1905
@@ Line 1: / Line 1: @@
+-------------------------------------------
+  * **preseed**
+  * **Jonathan Haack**
+  * **Haack's Networking**
+  * **webmaster@haacksnetworking.org**
+-------------------------------------------
+//preseed//
+-------------------------------------------
 I created my own virtualization stack which is complete with version control, file backups, full image backups and more. Additionally, because my client base and use-case does not require that I spin up VMs too often, it was very easy to just keep a few VMs pre-configured generically and then virt-clone them upon need and then tweak a few settings. However, my use-cases and needs are expanding and so I wanted to be able to spin up a new VM with a shell script and have a super minimal and clean copy of Debian installed on it, with absolutely no network configuration, extra packages, etc. So, I decided to dig deeper into both qemu and libvirt to see if there was something that could be developed. After working on qemu options for a bit, I decided that libvirt fit my needs better. After studying forums, I saw that Debian had an "auto-installer" feature and that you could pass configs to it through virsh by adding a few xml lines. After a little trial and error with using a remote site for the config vs. localhost, I developed the following recipe:
-virt-install --name=domain.org.qcow2 \
+  virt-install --name=domain.org.qcow2 \
---os-variant=debian11 \
+   --os-variant=debian11 \
---vcpu=2 \
+   --vcpu=2 \
---ram=4096 \
+   --ram=4096 \
---disk path=/mnt/vms/production/domain.org.qcow2 \
+   --disk path=/mnt/vms/production/domain.org.qcow2 \
---check path_in_use=off \
+   --check path_in_use=off \
---graphics spice \
+   --graphics spice \
---location=/mnt/vms/isos/debian-12.4.0-amd64-netinst.iso \
+   --location=/mnt/vms/isos/debian-12.4.0-amd64-netinst.iso \
---network bridge:br0 \
+   --network bridge:br0 \
---initrd-inject /mnt/vms/cfgs/preseed.cfg
+   --initrd-inject /mnt/vms/cfgs/preseed.cfg
 Other resources online insisted that I needed to add something like --extra-args="ks=file:/mnt/vms/cfgs/preseed.cfg console=tty0 console=ttyS0,115200" to the recipe as well, but I found that was unnecessary through trial and error. I think that syntax is required for those desiring kickstarter and/or if they are not using standard X passthrough for the shell. I'm not sure though. After I got the installer to recognize configuration file, I then began making a list as to which options worked automatically and which did not. One by one, I checked the stock configuration file here and adjusted my config until everything worked. Below, I've linked the stock configuration file I used as a jumping off point, and the one I developed for my use-case.
-Stock Configuration
+  * [[https://www.debian.org/releases/stable/example-preseed.txt|Stock Configuration]]
+  * [[https://repo.haacksnetworking.org/haacknet/haackingclub/-/blob/main/scripts/preseeds/external/preseed.cfg?ref_type=heads|My Use-Case]]
-My Use-Case
 After getting the virt-install recipe and config to perform the desired Debian install, my next task was to automate all of this with a simple script that would create a virtual hard disk of any desired size and a libvirt entry with my desired naming convention in my production VM directory. Here's what I came up with:
-echo -n "Please enter the fully qualified hostname:"
+  echo -n "Please enter the fully qualified hostname:"
-read hostname
+  read hostname
-echo -n "How large (in GB) would you like the virtual hard disk to be?"
+  echo -n "How large (in GB) would you like the virtual hard disk to be?"
-read size
+  read size
-qemu-img create -f qcow2 /mnt/vms/production/${hostname}.qcow2 ${size}G
+  qemu-img create -f qcow2 /mnt/vms/production/${hostname}.qcow2 ${size}G
-sleep 2s
+  sleep 2s
+  echo "Okay, I am now creating the preseed.cfg file for your host …"
-echo "Okay, I am now creating the preseed.cfg file for your host …"
+  mkdir /mnt/vms/cfgs/${hostname}
-mkdir /mnt/vms/cfgs/${hostname}
+  cp -ar /mnt/vms/cfgs/preseed.cfg /mnt/vms/cfgs/${hostname}/preseed.cfg
-cp -ar /mnt/vms/cfgs/preseed.cfg /mnt/vms/cfgs/${hostname}/preseed.cfg
+  rpl -w "unassigned-hostname" "$hostname" /mnt/vms/cfgs/${hostname}/preseed.cfg
-rpl -w "unassigned-hostname" "$hostname" /mnt/vms/cfgs/${hostname}/preseed.cfg
+  rpl -w "unassigned-domain" "$hostname" /mnt/vms/cfgs/${hostname}/preseed.cfg
-rpl -w "unassigned-domain" "$hostname" /mnt/vms/cfgs/${hostname}/preseed.cfg
+  sleep 2s
-sleep 2s
+  echo "Alright, I am opening up virt-installer and building your host …"
-echo "Alright, I am opening up virt-installer and building your host …"
+  virt-install --name=${hostname}.qcow2 \
+   --os-variant=debian11 \
+   --vcpu=2 \
+   --ram=4096 \
+   --disk path=/mnt/pathtovms/${hostname}.qcow2 \
+   --check path_in_use=off \
+   --graphics spice \
+   --location=/mnt/vms/isos/debian-12.4.0-amd64-netinst.iso \
+   --network bridge:br0 \
+   --initrd-inject /mnt/pathtovms/${hostname}/preseed.cfg
-virt-install --name=${hostname}.qcow2 \
+For now, I just need really simple Debian VMs as quickly as possible. However, as I wrote this, I began to realize that I could easily expand this script to meet the needs of a variety of different use cases, could add conditionals to it, validation and more. Down the road, I plan to do that, and you can stay up to date with how I expand this script's functionality on the Hacking Club repository:
---os-variant=debian11 \
---vcpu=2 \
---ram=4096 \
---disk path=/mnt/pathtovms/${hostname}.qcow2 \
---check path_in_use=off \
---graphics spice \
---location=/mnt/vms/isos/debian-12.4.0-amd64-netinst.iso \
---network bridge:br0 \
---initrd-inject /mnt/pathtovms/${hostname}/preseed.cfg
-For now, I just need really simple Debian VMs as quickly as possible. However, as I wrote this, I began to realize that I could easily expand this script to meet the needs of a variety of different use cases, could add conditionals to it, validation and more. Down the road, I plan to do that, and you can stay up to date with how I expand this script's functionality on the repository. Well, after all that, I deleted everything and ran the script fresh from top to bottom and tested that everything worked. No more waiting for the jenky X passthrough feedback or putting in details that never/rarely change. It's all hot and ready!
+  * [[https://repo.haacksnetworking.org/haacknet/haackingclub/-/tree/main/scripts/preseeds?ref_type=heads|Preseed Project]]
-Happy Hacking
+ --- //[[jonathan@haacksnetworking.org|oemb1905]] 2024/02/17 17:42//
-@oemb1905

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