Lee Jones leejones

If you want to interact with the chef server using the chef gem, you can get an interactive console using knife exec. This can be useful when trying out ideas for automation.

For example, how do I get the IP for a single (random) node for a role (example requires that pry is available):

$> bundle exec knife exec -E "require 'pry'; binding.pry"
[1] pry(#<Object>)> search(:node, 'role:solr-search').shuffle.first.ipaddress
=> "10.45.10.189"

This outline is for a presentation I'm giving at CoderFaire 2014 called Cache Me If You Can on September 21, 2014.

The description that will be listed for the talk:

Using a Content Delivery Network (CDN) can be a great way to improve the performance of your website. In this talk, we will explore the key concepts of HTTP caching and how they are used by a CDN. We will review some of the common challenges and pitfalls in setting up an awesome CDN configuration. To tie it all together, we will walk through how to verify your CDN configuration with automated testing.

intro

me
what is a CDN?

	#!/bin/bash

	# loads a pry console to interact with the chef server
	# (substitute irb if pry is not available)

	bundle exec knife exec -E "require 'pry'; binding.pry"

	# type `ls` to see available methods
	# to perform a node search for example: `nodes.search("roles:web*")`

	#!/bin/bash

	host="$1"
	workspace="/tmp/memcached-keys/$1"

	rm -rf "$workspace"
	mkdir -p "$workspace/items"

	for item in $(echo "stats items" \| nc "$host" 11211 \| grep items \| awk '{print $2}' \| cut -d : -f 2 \| sort -n \| uniq); do
	echo "stats cachedump $item 1000000" \| nc "$host" 11211 > "$workspace/items/$item"

	class DotDot
	def self.dot(starting_text = "Loading", completed_text = "Done!")
	print starting_text
	thread = Thread.new { loop { print '.'; sleep 1 } }
	yield if block_given?
	Thread.kill(thread)
	print "\n"
	puts completed_text
	end
	end

	#!/usr/bin/env ruby

	USAGE = <<-EOS
	Run shell commands from vim in another terminal window.

	Useful for triggering long-running tasks (tests, vagrant, test-kitchen, etc) without
	blocking your vim session.

	## Usage

	#!/bin/sh
	current_datetime=$(date \| date +'%F-%H%M')
	ps aux \| grep current \| grep -v grep \| awk '{print $2}' > /tmp/passengers.$current_datetime.txt
	passenger-status \| grep PID \| awk '{print $2}' >> /tmp/passengers.$current_datetime.txt
	likely_freeloaders=$(uniq -u /tmp/passengers.$current_datetime.txt)
	echo "Passenger doesn't know if these guys should be on the train"
	echo $likely_freeloaders \| xargs ps -o pid,command --no-headers

	class PingMonitor < Scout::Plugin
	OPTIONS =<<-EOS
	destination:
	default: yahoo.com
	name: Desitnation
	notes: The destination address for ping to check.
	EOS

	def build_report
	ping_output = `ping -c 1 #{option(:destination)}`

	require 'chronic'

	class PassengerProcess
	attr_accessor :pid, :uptime

	def initialize(passenger_status_line)
	values = passenger_status_line.match(/PID:\s(\d).Uptime:\s(.)$/)
	@pid = values[1].to_i
	@uptime = values[2]
	end