powerbot

powerbot: A Power Control Tool
=================================

powerbot is a tool for turning ports on networked PDUs on and off. Currently it is designed specifically for use in a cluster environment, where every node's hostname is of the form <prefix><number>, such as ccc1 or kn402.

Motivation
----------

After using powerman for some time and attempting to set it up for a new cluster, I became frustrated. Even with debugging turned up, I couldn't see what it was actually sending and receiving. Writing new PDU configurations involved too much guesswork. I also found that powerman does something odd; although power actions are relatively rare, powerman runs a daemon which attempts to maintain a constant connection to each PDU it manages, rather than simply logging in when you issue your (infrequent) commands.

I wanted something that was extensible like powerman, so I could use it with different PDUs, but faster and simpler. I wanted to avoid running a daemon in the background. I liked the configuration style of powerman, so that has largely remained, but the code is entirely original.

Usage
-------

powerbot commands consist of an action (on/off/cycle/status) and a list of nodes for which to perform the action. You can use ranges to specify multiple nodes. Here are some example commands:

	powerbot on ccc1		# Turn on ccc1
	powerbot off ccc[1-10]		# Turn off ccc1 through ccc10
	powerbot cycle ccc[1-3,7,10-12] # Cycle power to nodes 1, 2, 3, 7, 10, 11, and 12
	powerbot status ccc1		# Check the power status of ccc1

Installation & Configuration
-----------------------------

You should have received powerbot as part of the minimega repository. Run "build.bash" at the top level to compile everything, then put bin/powerbot somewhere convenient (/usr/local/bin is usually good).

You'll also need a config file in /etc/powerbot.conf. An example is provided in the src/powerbot directory and is reproduced here:

	# Prefix for your nodes. Sorry, need this for ranges
	prefix	ccc
	
	# device specification
	# device	<name>	<type>	<host>	<port>	<username>	<password>
	device	p1	tripplite	pdu 5214	localadmin	localadmin
	
	# node listing
	# node	<nodename>	<pdu>	<outlet>
	node  ccc1	   p1	 4
	node  ccc2	   p1	 5
	node  ccc3	   p1	 6
	node  ccc4	   p1	 7
	node  ccc5	   p1	 9
	node  ccc6	   p1	 10
	node  ccc7	   p1	 11
	node  ccc8	   p1	 12
	node  ccc9	   p1	 13
	node  ccc10	   p1	 14
	node  ccc11	   p1	 15
	node  ccc12	   p1	 17
	node  ccc13	   p1	 18
	node  ccc14	   p1	 19

The essential components of a config file are:

* Prefix. This line specifies the prefix used in every hostname. In this example the hostnames look like ccc1, ccc2, etc., so our prefix is "ccc".
* Devices. Each "device" line specifies an individual PDU in your system. Here we set up a device called "p1" (this name is internal to powerbot). It is a Tripp Lite PDU, so the device type is given as "tripplite" (see the list at the end of this document for supported PDU types). The device's hostname is "pdu", although this can also be specified as an IP. This device listens for control connections on port 5214. We also specify a username and password to log in to the PDU.
* Nodes. Each "node" line corresponds to a physical machine. We specify a node's name (such as "ccc1"), the PDU it is connected to ("p1"), and then the specific outlet on the PDU to which the node is connected. Different PDU manufacturers use different outlet specifications; Tripp Lite numbers 1-N, but for example Server Tech has names like ".AA1" and ".AB5".

At this time, you can have only one prefix per configuration. If you must control multiple clusters with different prefixes, you can place another configuration file elsewhere and call "powerbot -config /path/to/conf" to use that instead.

Supported PDUs
---------------

* "tripplite": Tripp Lite PDUs with the SNMPWEBCARD interface. Specify the port serving the telnet CLI; this should be 5214 by default.

Adding PDU Types
-----------------

Your PDU may not be supported. To add a PDU, you simply need to define a type which conforms to the PDU interface:

	type PDU interface {
		On(map[string]string) error
		Off(map[string]string) error
		Cycle(map[string]string) error
		Status(map[string]string) error
	}

Each function takes a map of node names (ccc1, etc.) to outlet names, so ccc1 maps to 4 in the example configuration above. You may not need the node names for your implementation, but they can be useful for debugging.

The file tripplite.go contains the implementation for a Tripp Lite PDU using the SNMPWEBCARD as found in many Tripp Lite products. It was specifically written for a PDU3VSR10L2130 model, but should work on others. Our specific device serves a telnet CLI on port 5214.

Add your device code in a separate file, then insert it into the PDUtypes map in powerbot.go. You should now be able to configure devices with your new device type.

Note that since powerbot does not have a daemon process, you will most likely have to log in for every command (see tripplite.go). This is simpler than attempting to keep a long-lived connection alive.

Although this code is focused on networked PDUs, it should be very easy to code up a device that uses something like a serial port by passing other values in the "host" and "port" configuration fields. For instance, if the PDU is accessed via /dev/tty0 and doesn't need authentication, your device configuration line might look like this:

	device	p2	serialpdu	/dev/tty0	nil	nil	nil

We specify that it is a "serialpdu" device on /dev/tty0, and the un-needed port and username/password fields are given dummy values. (Note that no "serialpdu" device is implemented, this is just an example)