NetBSD as a DomU
c33ris2's gentle guide to installing NetBSD in a prgmr DomU (January 2009)
Note: By June 2010 (or earlier) some of the dom0 hosts have packed the installer files into the /distros collection available to many recovery images. In these cases, the fetching activity is no longer required.
Note: what Xen version is marshall? It also has the issue.
Note: A -current NetBSD kernel is required to run under Xen 4.x. When NetBSD 6 is released, these notes will go away. -current is for EXPERTS ONLY.
Note: Daily binary kernels (and bootable installers) with Xen 4.x compatibility are available at http://nyftp.netbsd.org/pub/NetBSD-daily/netbsd-5/201110240510Z/ and later.
Note: It seems that loadable kernel modules are not supported under Xen. See http://gnats.netbsd.org/43796. Among other things, this renders pf firewalling unusable under the default NetBSD kernel, as loading the pf module
(modload /usr/lkm/pf.o) will cause the kernel to crash; building a new kernel with pf built-in may work.
Installing NetBSD as DomU is easy, but not trivial.
Boot your preconfigured system, in order to discover, and note for later use, YOUR_IP, NETMASK, GATEWAY, and NAMESERVER as follows:
Run 'ifconfig eth0' and note your "inet addr" and "Mask" values. Run 'route' or 'ip route' and note the IP of the default gateway. Run 'cat /etc/resolv.conf' and note the IP of the nameserver
From the control menu on your dom0 host, destroy/shutdown the instance, and restart ("create/start") it, selecting the "rescue" option from the bootloader. Login as 'root'.
Your fixed disk, as known to the linux rescue image, is /dev/xvda. Later, when booted to the NetBSD installer, it is identified as /dev/xbd0.
For NetBSD, this disk must be partitioned, and the NetBSD installer files placed therein.
From within fdisk,
- delete the existing partition, *which will destroy your current OS image and data*
- create a new primary partition #1, with first cylinder at default=1 and last cylinder at +32M
- create a new primary partition #2, directly after partition 1 and last cylinder at end of disk
- change the ID of the new partition #2 to 'a9' (NetBSD)
- write the new parition table to the disk.
- exit fdisk
Success to this point is evidenced by the prseence of /dev/xvda1 which must now be formatted, mounted, and a /boot directory created:
mkfs.ext2 /dev/xvda1 mount -n /dev/xvda1 /mnt mkdir /mnt/boot mkdir /mnt/boot/grub
If the file 'netbsd64.tar.gz' exists in /distros, skip over to #Unpacking the Installer
Note: if you will be using a -current install, then don't bother with /distros
Otherwise you'll have to proceed here with
Fetching the Installer
Substituting actual values observed (above) for YOUR_IP, NETMASK, GATEWAY, and NAMESERVER ...
ifconfig eth0 up YOUR_IP/NETMASK route add default gw GATEWAY eth0 echo "nameserver NAMESERVER" >/etc/resolv.conf
wget and extract to /mnt/boot/ :
cd /mnt/boot wget ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-5.1/amd64/binary/kernel/netbsd-INSTALL_XEN3_DOMU.gz wget ftp://ftp.netbsd.org/pub/NetBSD/NetBSD-5.1/amd64/binary/kernel/netbsd-XEN3_DOMU.gz gunzip netbsd-INSTALL_XEN3_DOMU.gz gunzip netbsd-XEN3_DOMU.gz
Note: if you will be using -current, you must get a current build from NetBSD's releng. (http://releng.netbsd.org). Check for a successful amd64 build in the log data, then determine the corresponding location in the binary snapshots.
Configuring Boot Menu
Create a file boot/grub/menu.lst with this content:
timeout 5 title NetBSD run root (hd0,0) kernel --type=netbsd /boot/netbsd-XEN3_DOMU title NetBSD install root (hd0,0) kernel --type=netbsd /boot/netbsd-INSTALL_XEN3_DOMU
Skip to #Booting the Installer
Unpacking the Installer
This section presumes the presence, in the rescue instance, of /distros/netbsd64.tar.gz
Unpack this into the new boot menu, and shutdown.
tar zxf /distros/netbsd64.tar.gz -C /mnt/boot/ shutdown -h now
Booting the Installer
Returning to the control menu on your dom0 host, change your bootloader selection to 'amd64' instead of 'i386'. Destroy/shutdown your instance if it is running, and create/start it again, this time selecting first the "user bootloader configuration" from the options presented by the dom0, and after that select the installer from your new user bootloader. This should take you to the NetBSD Installer, for which a tutorial exists at netbsd.org
Install onto xbd0
When presented with the option, choose
b: Use existing partition sizes
The next screen should show the existing BSD-disklabel partitions, as follows for a 3G allocation.
Start MB End MB Size MB FS type Newfs Mount Mount point --------- --------- --------- ---------- ----- ----- ----------- a: 0 0 0 unused b: 0 0 0 unused c: 0 3071 3072 NetBSD partition d: 0 3071 3072 Whole disk e: 0 29 30 Linux Ext2 f: 30 3071 3041 4.2BSD Yes Yes / g: 0 0 0 unused
If you're new to NetBSD partitioning, which I am, which is why I'm writing this, refer to this NetBSD Guide section
In order to install NetBSD properly, lets move the root partition to label:a and create swap. Select a:, set the partition type to "FFSv2" instead of "unused", and use 'e' as the start of your partition. Leave space at the end for swap. I used 128 MB, but you may want more depending on your application and VM allocation. Make sure to set Newfs, Mount, and Mount point correctly. Select b: and create swap until the end of the disk (-1).
You can also set the mount point for e:.
Finally, remove (the now obsolete) label:f by setting it to unused.
Here is an example disklabel setup for a 3072M disk with a 30M boot partition:
Start MB End MB Size MB FS type Newfs Mount Mount point --------- --------- --------- ---------- ----- ----- ----------- a: 30 2942 2912 FFSv2 Yes Yes / b: 2943 3071 128 swap c: 0 3071 3072 NetBSD partition d: 0 3071 3072 Whole disk e: 0 29 30 Linux Ext2 Yes /boot f: 0 0 0 unused
Select "accept these sizes" and continue with the installation.
When prompted by the installer, select "use existing bootblocks".
Install by FTP
When prompted by the installer, use the xennet0 device and when it asks for "Network media type" just press enter.
Try to use DHCP. If it doesn't work,
Use the actual values observed (above) for
YOUR_IP, NETMASK, GATEWAY, and NAMESERVER
when prompted by the installer
The installation of NetBSD is now complete. The system should boot from hard disk. Follow the instructions in the INSTALL document about final configuration of your system. The afterboot(8) manpage is another recommended reading; it contains a list of things to be checked after the first complete boot. At a minimum, you should edit /etc/rc.conf to match your needs. See /etc/defaults/rc.conf for the default values.
Mount boot partition in NetBSD domU
Log in as root.
# mkdir /extboot # vi /etc/fstab
find the line in fstab that contains /dev/xbd0e and make it look like this:
/dev/xbd0e /extboot ext2fs rw 0 0
Now it will be readable:
# mount /extboot # cd /extboot/boot/ # ls grub netbsd-INSTALL_XEN3_DOMU netbsd-XEN3_DOMU
As of December 2012, it has been reported that NetBSD can also be installed following these directions, using these images: