Saturday, November 14, 2009

Creative Server Installs - WAN Boot on Solaris (SPARC)

Sun's SPARC servers have the ability to boot a kernel and run an installer across a routed network using only HTTP or HTTPS. On SPARC platforms, the (BIOS|Firmware|Boot PROM) can download a bootable kernel and mini root file system via HTTP/HTTPS, boot from the mini root, and then download and install Solaris. This allows booting a server across a local or wide area network without having any bootable media attached to the chassis. All you need is a serial console, a network connection, an IP address, a default gateway and a web server that's accessible from the bare SPARC server. You set a few variables, then tell it to boot. Yep, it's cool.

From the Boot PROM prompt (the SPARC equivalent of the BIOS)
OK> setenv network-boot-arguments host-ip=client-IP,
router-ip=router-ip,subnet-mask=mask-value,
hostname=client-name,http-proxy=proxy-ip:port,
file=wanbootCGI-URL

OK> boot net -v install

Our base Solaris install is fairly small - on the order of a few hundred megabytes - so booting across a WAN through a proxy or an SSH tunnel works pretty well. We usually build a temporary SSH tunnel from our management  infrastructure out to another server in the same security container and point the new server at the tunnel end point.

PXE is an attempt to provide similar functionality. It's got a dependency on having DHCP available on the deployed subnet, something which I'm absolutely do not want to enable on non-desktop networks, and it's based on UDP, which makes it slightly less suitable for booting across WAN's where packet loss might be an issue. In any case, we've had enough issues with network boots on x86/x64 platforms that we've pretty much defaulted to using bootable USB's or CD/DVD's for remote installs. That makes an x86/x64 deploy significantly more work effort, as we have to arrange for a bootable USB or CD/DVD's to be delivered on site, or we need to leave bootable media installed in production servers.

Linux has 'BKO', but as far as I can tell, it's still dependent on having either bootable media or PXE.

SPARC's Wan boot is pretty slick, but not as slick as Cisco's AutoInstall. AutoInstall allows you to drop ship an unconfigured router to a remote site. The router will learn it's IP address from it's upstream router via either SLARP or BootP,  automatically download a configuration file, and re-boot with a valid configuration.

A couple of closing thoughts:
  • If the SPARC platform ever goes away, I'll miss it.
  • If router engineers ever decide to build application servers, they'd probably come up with radically new ways of solving old problems. 

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