Skip to content

PXE Booting SmartOS

While USB and DVD installation are useful for small or non-production deployments, SmartOS is fundamentally designed as a netboot operating system. Advantages of netbooting include:

  • Scalability: Media (USB or CD/DVD) is not required for each node
  • Speed: Boot times on a 1Gb/s network (100MB/s) are much faster than USB 2.0 (10-30MB/s depending on USB key) or optical media
  • Versatility & Safety: Clients can be upgraded easily by simply changing the boot target to the new image and rebooting at your leasure into the new image, rather than re-flashing a USB key in place which could leave you stranded on a bad upgrade. This applies equally to upgrades and downgrades.

The NetBoot Environment

Adding SmartOS Images to an Existing PXE Environment

If you already have a DHCP/TFTP environment in place for netbooting, you can simply download the latest platform release and unpack it into your TFTP directory.

There are 2 files of importance, the kernel (unix) and the boot archive (boot_archive). The paths to these files are significant and should not be omitted. They should be:

  • (prefix)/platform/i86pc/kernel/amd64/unix
  • (prefix)/platform/i86pc/amd64/boot_archive

The prefix may be anything you wish (a common prefix would be "/tftpboot/smartos/20121004T212912Z/") but the path after the prefix must be in the form above. If you do not the OS will fail to boot with an error saying "krtld: error during initial load/link phase"; in this case the image make sure your path is in the proper form. The important point being, don't just untar the latest platform image into your TFTP directory and boot it, you'll have problems unless you change the typical "platform_20121004T212912Z/" to simply "platform/".

For details on the boot parameters you may wish to pass to the kernel, see below.

Building an iPXE Boot Infrastructure

Want to create a netboot environment from scratch? No problem! Which OS you use isn't very important, you can use SmartOS is you really want to, but any Linux distro will do, we might even suggest considering OmniOS as a general purpose server to supply your networks various needs. What is important is that your boot server have the following:

  • A DHCP Server. We recommend ISC DHCP.
  • A TFTP Server.
  • iPXE. (If you wish to use PXEGRUB directly see the appropriate section below.)

We will not discuss each of these indepth, nor how to install them on your selected platform. We'll focus on the important points of using each for booting SmartOS.

Before we get into the guts, lets just recap for those new to netbooting. Remove bootp and all those other protocols you won't notice. When you boot your server and tell it to PXE/Network boot, it will send a DHCP request which the server will answer and it will include two special things: a "next-server" and filename. The "next-server" is your TFTP server and filename is the file your server will download and run. That file is usually a bootloader such as Syslinux or GRUB (more correctly, the PXE variations of them: pxelinux or pxegrub). In our case the file will be the iPXE program named "undionly.kpxe". iPXE can execute scripts and do other net things your normal PXE client on your network card can't. We will use it to actually boot SmartOS which will involve downloading and booting the SmartOS kernel and archive from the TFTP/HTTP server.

ISC DHCP

There are many tutorials on the net about configuring ISC DHCP, but the important part is allowing it to execute iPXE correctly. You'll want to create a DHCP pool that looks similar to the following:

subnet 10.99.99.0 netmask 255.255.255.0 {
 pool {
  range 10.99.99.210 10.99.99.219;
  next-server 10.99.99.250;
  if exists user-class and option user-class = "iPXE" {
        filename "menu.ipxe";
  } else {
        filename "undionly.kpxe";
  }
 }
}

The above example we're giving out addresses on the 10.99.99.0/24 subnet. The TFTP server is also located on the same host as our DHCP server so we specify it as the "next-server". The conditional here is to ensure that the client first boots iPXE. Once iPXE is running it will DHCP again and this time the user-class will be set as "iPXE", in which case we instead set our filename to an IPXE script which will take over.

DHCP support requires special NIC configuration as documented inĀ Managing NICs - DHCPSupport.

TFTP

Again, there are many TFTP tutorials on the net for various platforms. We'll assume that your TFTP root directory is /tftpboot. Within that directory, install iPXE and create a "smartos/" directory.

You can download a binary distribution of iPXE here: undionly.kpxe. To use it, copy to /tftpboot.

To install a SmartOS release:

  1. Download the latest "platform-*" build
  2. Unpack it in /tftboot/smartos/
  3. Rename the "platform-(buildnumber)" directory to just the build number
  4. Enter the build directory from the previous step, mkdir platform and mv i86pc platform.

When the above is done properly your kernel will be in (for example) /tftpboot/smartos/20121004T212912Z/platform/i86pc/kernel/amd64/unix and your boot archive will be in /tftpboot/smartos/20121004T212912Z/platform/i86pc/amd64/boot_archive. This is very important; the kernel and archive must contain the path "/platform/i86pc/kernel/amd64/unix", if you don't the PXE boot will fail with an ugly error message saying "krtld: error during initial load/link phase"

iPXE

iPXE is the all powerful open source PXE client. It can download images from HTTP as well as TFTP, it can boot from iSCSI, FCoE, and AoE, over wireless, WAN, and infiniband networks, but most importantly it can execute scripts and act as its own bootloader which is what we'll use it for. If you've never heard of iPXE before, it began life as the Etherboot project, then became gPXE and after a squabble it was forked to become iPXE. The idea of using PXE to load a PXE client might seem odd at first, but the PXE client burned into your NIC is small and dumb, iPXE is very smart. It can be burned into your NIC's ROM, loaded from USB or ISO, etc, but we'll use our servers native PXE to load iPXE and then let it do the heavy lifting.

In previous steps we put iPXE ("undionly.kpxe") in our /tftpboot directory, added a SmartOS image and configured DHCP to use it. Now we simply create the iPXE script we referenced earlier to actually boot it.

The simplest possible iPXE script would look like this:

#!ipxe

kernel /smartos/20121004T212912Z/platform/i86pc/kernel/amd64/unix -B smartos=true
initrd /smartos/20121004T212912Z/platform/i86pc/amd64/boot_archive
boot

... but this is iPXE and SmartOS, so lets make it more interesting by using a boot menu!

#!ipxe

set smartos-build 20121004T212912Z

######## MAIN MENU ###################
:start
menu Welcome to iPXE's Boot Menu
item
item --gap -- ------------------------- Operating systems ------------------------------
item smartos    Boot SmartOS (${smartos-build})
item --gap -- ------------------------------ Utilities ---------------------------------
item shell      Enter iPXE shell
item reboot     Reboot
item
item exit       Exit (boot local disk)
choose --default smartos --timeout 30000 target && goto ${target}


########## UTILITY ITEMS ####################
:shell
echo Type exit to get the back to the menu
shell
set menu-timeout 0
goto start

:reboot
reboot

:exit
exit

########## MENU ITEMS #######################
# SmartOS Root shadow is "root"
:smartos
kernel /smartos/${smartos-build}/platform/i86pc/kernel/amd64/unix -B smartos=true,root_shadow='$5$2HOHRnK3$NvLlm.1KQBbB0WjoP7xcIwGnllhzp2HnT.mDO7DpxYA'
initrd /smartos/${smartos-build}/platform/i86pc/amd64/boot_archive
boot
goto start

The configuration above is just a taste of what you can do here. You could add variations of SmartOS that use ttya or ttyb for serial redirection, load KMDB, etc. Learn more about iPXE menus in the iPXE Command Documentation, and learn about the various kernel options below.

As a side benefit, you now have an excellent platform for netbooting a variety of OS's in a variety of configurations. If you want maximum l337 points, use iPXE SAN Boot to boot a SmartOS ISO on iSCSI served up by a COMSTAR iSCSI target on ZFS!

Kernel Boot Options

Several parameters can and should be passed to the "unix" kernel. These would be comma-delimited following "-B", as seen in examples above.

  • smartos=: If set true and /usbkey/shadow is present, it will use the root password within /usbkey/shadow
  • root_shadow=: A root password hash as would be found in /etc/shadow. If present, and "smartos=" is not present, this will override the default platform password in /usbkey/shadow
  • hostname=: Set the hostname
  • noimport=true: Don't import the Zpool
  • standalone=true: Used only by Smart Data Center
  • headnode=true: Used only by Smart Data Center

Other options to know about are:

  • console=ttya,ttya-mode="115200,8,n,1,-": Console redirection to ttya (COM1)
  • console=ttyb,ttyb-mode="115200,8,n,1,-": Console redirection to ttyb (COM2)
  • console=text: Console is directed to local keyboard and monitoring. This is the default behavior.
  • -kd: Enable the Kernel Debugger (KMDB); this is typically only used for debugging drivers
  • -v: Verbose boot

Alternatives

Stripped down dnsmasq, tftp-hpa, pxegrub

The example code in this section uses a very old image and hasn't been tes ted in a while. If you end up using this section as a guide, try using a modern image. If you succeed, please update the image_uuid.

Motivation

So you have a machine running SmartOS from a USB stick or CD. Wouldn't it be nice to be able to use that machine to PXE boot a whole additional rack of machines? Here's how to set up a simple PXE server in a SmartOS zone that will serve up... SmartOS!

This section assumes some basics covered in other wiki pages.

Zone Configuration

{
  "alias": "pxe-server",
  "hostname": "pxe-server",
  "brand": "joyent",
  "max_physical_memory": 64,
  "quota": 2,
  "image_uuid": "f9e4be48-9466-11e1-bc41-9f993f5dff36",
  "nics": [
    {
      "nic_tag": "admin",
      "ip": "172.16.0.2",
      "netmask": "255.255.255.0",
      "gateway": "172.16.0.1",
      "dhcp_server": "1"
    }
  ]
}

It's up to you to get the networking right, and not to run multiple DHCP s ervers on your network in a way that breaks things. BE CAREFUL!

Setting up TFTP

Use zlogin to log into the zone:

zlogin <uuid>

In the zone:

pkgin -y install tftp-hpa
mkdir /tftpboot
echo "tftp dgram udp wait root /opt/local/sbin/in.tftpd in.tftpd -s /tft
pboot" > /tmp/tftp.inetd
svcadm enable inetd
inetconv -i /tmp/tftp.inetd -o /tmp
svccfg import /tmp/tftp-udp.xml
svcadm restart tftp/udp

The last two commands are probably extraneous.

Setting up DHCP (using Dnsmasq)

pkgin -y install dnsmasq

Hereis an example /opt/local/etc/dnsmasq.conf. It's up to you to get the networking right, and not to run multiple DHCP servers on your network in a way that breaks things. BE CAREFUL!

#Lease File to track leases
dhcp-leasefile=/etc/dnsmasq.leases
# Give out addresses in the 172.16.0.1/24 subnet
dhcp-range=172.16.0.10,172.16.0.50,2h
# The name of the boot file is pxegrub
dhcp-boot=pxegrub

Then enable the service.

svcadm enable dnsmasq

Setting up the tftpboot directory

(Use the pkgsrc wget which can actually validate certificates)

pkgin -y install wget
hash -r
cd /tftpboot
wget https://download.joyent.com/pub/iso/latest.iso
LOFI=$(lofiadm -a latest.iso)
mount -F hsfs $LOFI /mnt
rsync -av /mnt/ .
umount /mnt
lofiadm -d $LOFI
wget -O pxegrub http://aszeszo.googlepages.com/pxegrub

Integrating SmartOS into an existing PXELINUX environment

The critical detail to know about booting SmartOS from PXELINUX (or SYSLINUX) is that you must use mboot.c32 to get them to load the kernel and boot_archive using the multiboot specification. See here for further details about that.

Recent versions of SYSLINUX require libcom32.c32 and ldlinux.c32 to be present to use mboot.c32

Instructions:

  1. Download the image
  2. Extract the entire platform subtree from the ISO.
  3. Download a tarball of syslinux and get the mboot.c32, libcom32.c32, and ldlinux.c32 files out of it.
  4. In the tftp root directory, create a directory named smartos
  5. Copy the platform directory you got from the ISO into the smartos directory
  6. Copy the the mboot.c32, libcom32.c32, and ldlinux.c32 files into the smartos directory
  7. Update your pxelinux.cfg/default file with this content:
    default smartos
    prompt 1
    timeout 50

    label smartos
    kernel smartos/mboot.c32
    append smartos/platform/i86pc/kernel/amd64/unix -B smartos=true,console=text,root_shadow='$5$2HOHRnK3$NvLlm.1KQBbB0WjoP7xcIwGnllhzp2HnT.mDO7DpxYA' --- smartos/platform/i86pc/amd64/boot_archive

    label smartosrescue
    kernel smartos/mboot.c32
    append smartos/platform/i86pc/kernel/amd64/unix -B smartos=true,console=text,standalone=true,noimport=true,root_shadow='$5$2HOHRnK3$NvLlm.1KQBbB0WjoP7xcIwGnllhzp2HnT.mDO7DpxYA' --- smartos/platform/i86pc/amd64/boot_archive