Sherry

Sherry is a quick, easy-to-use, low-overhead server to deal with a very specific PXE configuration:

• machines always boot from pxe
• pxe server tells machines to boot from disk
• except when told to reimage with a specific image

This approach is especially useful in test and dev environments, with machines that need to be conditionally rebuilt from time to time.

Sherry is designed to retain state for as little time as possible. Store configuration information, mac addresses, OBM IPs, and the like in the calling scripts, rather than the machine which does the reimaging.

For more complicated setups, there's always Cobbler. But forking Sherry might be faster than configuring Cobbler.

Installation

Sherry depends on Flask, gunicorn, dnsmasq, and iPXE. Installing the deb will install the sherry specific dnsmasq boot script, and configure dnsmasq to serve tftp, but you are responsible for making dnsmasq serve dhcp.

You'll need to make sure your /etc/dnsmasq.conf contains this line:

conf-dir=/etc/dnsmasq.d

Sherry installs and configures nginx to serve the sherry app, as well as the image files.

You'll need to enter your IPMI username and password /etc/sherry/sherry.conf.

Usage

Control flow with Sherry is roughly like this:

• Client PXE Boots, gets DHCP from dnsmasq
• Client downloads and boots iPXE
• iPXE downloads /pxe/<mac_address>
• Server sends
  • boot.pxe if the mac is unknown.
  • install.pxe if mac is known. Server removes mac from list.
• Client boots from disk or via provided initrd, kernel, and kernel parameters.

In normal use, clients always get redirected to boot from disk. When a client needs to be reimaged, make a request (GET or POST) to /reimage with these parameters:

• mac_address
• obm_address
• location
• kernel_opts

Sherry will use the obm_address (and configured obm credentials) to reboot the client. When it restarts, it will boot using

• kernel http://{SERVER_NAME}/images/{location}/vmlinuz {kernel_opts}
• initrd http://{SERVER_NAME}/images/{location}/initrd.img

Security

Sherry deliberately has no security mechanisms. Don't expose it to a public network.

Sherry Cobbler

• 4 oz dry Sherry
• 3 slices orange
• 2 bar-spoons sugar

Shake all ingredients hard with ice and pour, unstrained, in to a tall glass. Garnish with fresh berries then add a straw.