# Virtualization
       
       It is realy easy to virtualize an operating system with OpenBSD thanks to vmd.
       
       > Well, that's nice, but what virtualizing means ?
       
       Instead of installing different OS on different computers, you can install an OS inside your current OS. The virtualizer fake to be a full device and run an OS installed on a disk, which is in this case a simple file.
       
       It is very handy since :
       
       * You can use multiple system simultaneously.
       * Each system is independent. If one is compromised, others should be safe. It's better than a chroot.
       * Backup is really easy: just copy the disk file.
       * It's great to try things.
       
       However, it require more resources.
       
       Before going further, make sure we use the same vocabulary :
       
       * "host" is your server. The host virtualize other systems.
       * "client" are hosted systems.
       
       OpenBSD offer 3 tools for virtualization :
       
       * vmd : a daemon to manage multiple clients.
       * vmctl : To control clients and sending commands to vmd.
       * vmm : To watch over clients.
       
       First of all, check if your hardware can virtualize :
       
       ```
       $ dmesg | egrep '(VMX/EPT|SVM/RVI)'
       ```
       
       If the result isn't empty, it's all good 😊.
       
       Don't forget to upgrade firmwares if needed: # fw_update.
       
       To add a new virtual machine, you will always :
       
       1. Install in a new disk file with vmctl.
       2. Configure vmd to manage this client automatically.
       
       ## How to virtualize OpenBSD ?
       
       Actually, everything is already well documented on OpenBSD's website. This chapter will just focus on a few tips.
       
       You should definitely read OpenBSD's FAQ on this topic 😉.
 (HTM) https://www.openbsd.org/faq/faq16.html
       
       ### Use other installation media
       
       To use img disk (installXX.img or minirootXX.img):
       
       ```
       # vmctl start -c -m 1G -L -i 1 -d installXX.img -d /var/vm/obsdvm.qcow2 openbsdvm
       ```
       
       Or if you don't want to download any file, you still can use the bsd.rd probably already on your system:
       
       ```
       # vmctl start -c -m 1G -L -i 1 -b /bsd.rd -d /var/vm/obsdvm.qcow2 openbsdvm 
       ```
       
       However, such install requires to previously configure a network access for clients.
       
       In /etc/pf.conf:
       
       ```
       # using quad9 DNS
       pass in quick proto { tcp udp } from 100.64.0.0/10 to any port domain \
           rdr-to 9.9.9.9 port domain
       match out on egress from 100.64.0.0/10 to any nat-to (egress)
       ```
       
       Even better, you can use unwind if it is already configured on host, which is an excellent idea 😎 :
       
       ```
       pass in proto { tcp udp } from 100.64.0.0/10 to any port domain \
           rdr-to localhost port domain
       match out on egress from 100.64.0.0/10 to any nat-to (egress)
       ```
       
       In /etc/sysctl.conf:
       
       ```
       net.inet.ip.forwarding=1
       net.inet6.ip6.forwarding=1
       ```
       
       ## Virtualize debian
       
       Like most linux distro, you'll have to set the installer and bootloader to start the client with a serial console at speed 15200.
       
       ```
       # download debian image
       ftp "https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-10.5.0-amd64-netinst.iso"
       # create disk
       vmctl create -s 50G /var/vm/debian.qcow2 
       # start the VM
       vmctl start -c -m 1G -L -i 1 -r debian*.iso -d /var/vm/debian.qcow2 debianvm
       ```
       
       Choose install menu without validating ⚠.
       
       Press TAB then edit the line to change vga and console parameters:
       
       ```
       /install.amd/vmlinuz vga=off initrd=/install.amd/initrd.gz --- quiet console=ttyS0,115200n8 
       ```
       
       Press Enter.
       
       After installing and rebooting on the fresh debian install, edit /etc/default/grub so serial console is still used.
       
       ```
       GRUB_TIMEOUT=1
       GRUB_CMDLINE_LINUX_DEFAULT=""
       GRUB_CMDLINE_LINUX="console=tty1 console=ttyS0,115200"
       GRUB_TERMINAL="console serial"
       GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
       ```
       
       Then reload grub:
       
       ```
       # update-grub
       ```
       
       ## Virtualize Alpine Linux
       
       Alpine Linux is a very light distro.
 (HTM) https://www.alpinelinux.org/
       
       Here again, you need to boot using serial console.
       
       ```
       # vmctl create -s 50G /var/vm/linux.qcow2 
       # vmctl start -c -m 1G -L -i 1 -r image.iso -d /var/vm/linux.qcow2 linux
       ```
       
       When starting virual machine, press "TAB" to see available image (i.e. "lts" or "virt"). Add appropriate parameter to use serial console :
       
       ```
       virt console=ttyS0,115200
       ```
       
       Then press Enter and it's all good.
       
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