Adrian Silva skiold

Clustering: The basics

The trick? pass the file descriptor from a parent process and have the server.listen reuse that descriptor. So multiprocess in their own memory space (but with ENV shared usually)

It does not balance, it leaves it to the kernel.

In the last nodejs > 0.8 there is a cluster module (functional although marked experimental)

http://nodejs.org/api/cluster.html
Simple cluster example:

Falsehoods programmers believe about prices

You can store a price in a floating point variable.
All currencies are subdivided in 1/100th units (like US dollar/cents, euro/eurocents etc.).
All currencies are subdivided in decimal units (like dinar/fils)
All currencies currently in circulation are subdivided in decimal units. (to exclude shillings, pennies) (counter-example: MGA)
All currencies are subdivided. (counter-examples: KRW, COP, JPY... Or subdivisions can be deprecated.)
Prices can't have more precision than the smaller sub-unit of the currency. (e.g. gas prices)
For any currency you can have a price of 1. (ZWL)
Every country has its own currency. (EUR is the best example, but also Franc CFA, etc.)

Embedded Variables

The ngx_http_core_module module supports embedded variables with names matching the Apache Server variables. First of all, these are variables representing client request header fields, such as $http_user_agent, $http_cookie, and so on. Also there are other variables:

$arg_name
argument name in the request line

Running Docker on two hosts, bridged with Open vSwitch

This Gist shows how to use Open vSwitch to bridge Docker containers on two hosts. It is based on this blog post http://goldmann.pl/blog/2014/01/21/connecting-docker-containers-on-multiple-hosts/.

A similar Gist using Tinc instead of Open vSwitch is available: https://gist.github.com/noteed/11031504.

Setup

Running Docker on two hosts, bridged with Tinc

This Gist is similar to https://gist.github.com/noteed/8656989 which uses Open vSwitch instead of Tinc.

Setup

Download the install.sh script and run it:

> https://gist.githubusercontent.com/noteed/11031504/raw/install.sh

	#
	# This config file is a combination of ideas from:
	# http://www.37signals.com/svn/posts/1073-nuts-bolts-haproxy
	# http://www.igvita.com/2008/05/13/load-balancing-qos-with-haproxy/
	# http://wiki.railsmachine.com/HAProxy
	# http://elwoodicious.com/2008/07/15/nginx-haproxy-thin-fastcgi-php5-load-balanced-rails-with-php-support/
	# http://upstream-berlin.com/2008/01/09/using-haproxy-with-multiple-backends-aka-content-switching/
	# http://wiki.railsmachine.com/HAProxy
	# http://gist.github.com/raw/25482/d39fb332edf977602c183194a1cf5e9a0b5264f9
	#

	net.core.somaxconn = 32768
	net.ipv4.conf.all.send_redirects = 1
	net.ipv4.ip_nonlocal_bind = 1
	net.ipv4.tcp_abort_on_overflow = 0
	net.ipv4.tcp_fin_timeout = 10
	net.ipv4.tcp_keepalive_time = 300
	net.ipv4.tcp_max_orphans = 262144
	net.ipv4.tcp_max_syn_backlog = 16384
	net.ipv4.tcp_max_tw_buckets = 262144
	net.ipv4.tcp_mem = 200000 280000 300000

	#!/bin/sh
	#
	# Creates a SmartOS VM in VirtualBox (assuming you alread have VirtualBox installed)
	#
	# This script will:
	# * Download the latest live ISO image of SmartOS
	# * Create a VirtualBox VM, or update an existing VM with the latest ISO
	# * Configure the VM with a zones disk, and boot it!
	#
	#

	#!/bin/bash

	###############################################################################
	# CONFIG

	# AWS config
	export AWS_SECRET_KEY="XXXX"
	export AWS_ACCESS_KEY="XXXX"
	export PATH=$PATH:/usr/local/aws/ec2/bin
	export EC2_HOME=/usr/local/aws/ec2/

	#!/bin/bash
	PUTIO_USERNAME="your put.io username"
	PUTIO_PASSWORD="your put.io password"
	wget --http-user=${PUTIO_USERNAME} --http-password=${PUTIO_PASSWORD} --content-disposition -c $@