Troy Melhase natural

Google Compute Engine NFS Container VM

This script creates a Container VM on Google Compute Engine running a NFS V4 server exposed on Port 2049 with the /exports directory mounted to a persistent disk. This means:

If the NFS VM Crashes, the persistent disk will still hold the NFS Files
The persistent disk can be snapshotted to backup NFS Files

To run:

(:identity req) is auth backend independent way to access user data
login and logout implementation depends on auth backend
:current-user doesn't imply that authentication is required, route should also have :auth-rules if authentication is required

Clojure Destructuring Tutorial and Cheat Sheet

(Related blog post)

Simply put, destructuring in Clojure is a way extract values from a datastructure and bind them to symbols, without having to explicitly traverse the datstructure. It allows for elegant and concise Clojure code.

Vectors and Sequences

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

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

General Background and Overview

Probabilistic Data Structures for Web Analytics and Data Mining : A great overview of the space of probabilistic data structures and how they are used in approximation algorithm implementation.
Models and Issues in Data Stream Systems
Philippe Flajolet’s contribution to streaming algorithms : A presentation by Jérémie Lumbroso that visits some of the hostorical perspectives and how it all began with Flajolet
Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
[Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep=rep1&t

Backend Architectures

Twitter

ror, scala, jetty, erlang, thrift, mongrel, comet server, my-sql, memchached, varnish, kestrel(mq), starling, gizzard, cassandra, hadoop, vertica, munin, nagios, awstats

Introduce Gizzard of Twitter - 트위터의 새로운 분산 관리 라이브러리 Gizzard를 소개합니다.
The Architecture Twitter Uses to Deal with 150M Active Users, 300K QPS, a 22 MB/S Firehose, and Send Tweets in Under 5 Seconds
Scaling Twitter: Making Twitter 10000 Percent Faster

Sometimes I use this automagically from a script... Just toss in the -kfile flag.

Decrypt:

#!/bin/bash
openssl enc -aes-256-cbc -d -kfile /path/to/passwd_in_file.txt -in $1 -out `echo $1 | sed s/.enc//`

Encrypt:

#!/bin/bash

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

	#!/bin/bash
	killall Xcode
	xcrun -k
	xcodebuild -alltargets clean
	rm -rf "$(getconf DARWIN_USER_CACHE_DIR)/org.llvm.clang/ModuleCache"
	rm -rf "$(getconf DARWIN_USER_CACHE_DIR)/org.llvm.clang.$(whoami)/ModuleCache"
	rm -rf ~/Library/Developer/Xcode/DerivedData/*
	rm -rf ~/Library/Caches/com.apple.dt.Xcode/*
	open /Applications/Xcode.app