Nyimbi Odero nyimbi

STEP 1: First Install HomeBrew, download it from http://brew.sh

$ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

STEP 2: Install Hadoop

$ brew search hadoop
$ brew install hadoop

Buffer DB (using Redis)

Create a buffer DB inbetween the client and the database server that kept common objects in memory (like the whole page and comments section) allowing fast edits (and appends) and only syncing it all to the DB every X seconds or after the object has fallen off the front page and things have slowed down for it.

A incrementing counter would be needed as we would need to sync stuff before it has a DB id? Or we could get a database ID on first save, but still use the buffer DB until things died back down.

Redis could be the sync store since multiple servers could read-write to it in an ATOMIC / ACID way without problems. You cannot ever prevent race conditions (two people making changes to a comment); only race conditions that clober previous updates (two people saving a comment at the same time resulting in a lost comment).

Data structure

Each element of the object which needs CRUD support would need to be a new HASH with the ID stored in a SET (except for the root objec

Redis Guideline

The guideline is tested on centOs 7

Enable redis remote access

Check your /etc/redis.conf, and make sure to change the default:

bind 127.0.0.1

to

	<!DOCTYPE html>
	<html lang="en">

	<head>
	<meta charset="UTF-8">

	<title>Keycloak JS Demo</title>

	<style>
	body {

	[DEFAULT]
	product_ranking_start = 10
	product_ranking_steps_down = 0.2
	cat_ranking_start = 10
	cat_ranking_steps_down = 0.2
	product_recommendations_campaignArn=arn:aws:personalize:us-east-2:11123456:campaign/es-test03-hrnn
	product_rankings_campaignArn=arn:aws:personalize:us-east-2:222789:campaign/es-test03-rank
	property1_recommendations_campaignArn=arn:aws:personalize:us-east-2:3333456:campaign/es-test03-cat-hrnn
	property1_rankings_campaignArn=arn:aws:personalize:us-east-2:444789:campaign/es-test03-cat-rank

	application {
	config {
	baseName gateway,
	packageName com.okta.developer.gateway,
	applicationType gateway,
	authenticationType oauth2,
	prodDatabaseType postgresql,
	searchEngine elasticsearch,
	serviceDiscoveryType eureka,
	testFrameworks [protractor]

	#!/bin/sh
	# Command-line world clock
	# Taken from http://stackoverflow.com/questions/370075/command-line-world-clock

	# .worldclock.zones file looks like:
	# US/Pacific
	# Europe/Berlin
	# Chile/Continental

	: ${WORLDCLOCK_ZONES:=$HOME/.worldclock.zones}

	# Author: Pieter Noordhuis
	# Description: Simple demo to showcase Redis PubSub with EventMachine
	#
	# Update 7 Oct 2010:
	# - This example does not appear to work with Chrome >=6.0. Apparently,
	# the WebSocket protocol implementation in the cramp gem does not work
	# well with Chrome's (newer) WebSocket implementation.
	#
	# Requirements:
	# - rubygems: eventmachine, thin, cramp, sinatra, yajl-ruby

	digraph cloud_platform {
	rankdir=LR
	splines=ortho

	subgraph cluster_1 {
	11 -> 12 -> 13 -> 14
	}

	subgraph cluster_2 {
	21 -> 22 -> 23 -> 24