Alex bzz

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

Interdisciplinary Open Source Community Conferences

Criteria

Must be an event that someone involved in open source would be interested in attending
Must be a community oriented event (no corporate owned for-profit events here please)
Can't be about a specific language/framework.

Leave suggestions in the comments below

Generating Flame Graphs for Apache Spark

Flame graphs are a nifty debugging tool to determine where CPU time is being spent. Using the Java Flight recorder, you can do this for Java processes without adding significant runtime overhead.

When are flame graphs useful?

Shivaram Venkataraman and I have found these flame recordings to be useful for diagnosing coarse-grained performance problems. We started using them at the suggestion of Josh Rosen, who quickly made one for the Spark scheduler when we were talking to him about why the scheduler caps out at a throughput of a few thousand tasks per second. Josh generated a graph similar to the one below, which illustrates that a significant amount of time is spent in serialization (if you click in the top right hand corner and search for "serialize", you can see that 78.6% of the sampled CPU time was spent in serialization). We used this insight to spee

Install

Either copy the aliases from the .gitconfig or run the commands in add-pr-alias.sh

Usage

Easily checkout local copies of pull requests from remotes:

git pr 4 - creates local branch pr/4 from the github upstream(if it exists) or origin remote and checks it out
git pr 4 someremote - creates local branch pr/4 from someremote remote and checks it out

Easiest HDFS cluster in the world with kubernetes.

Inspiration from kimoonkim/kubernetes-HDFS

kubectl create -f namenode.yaml
kubectl create -f datanode.yaml

Setup a port-forward to so you can see it is alive:

	{
	"configurations": [
	{
	"global": {
	"nagios_contact": ""
	}
	}
	],
	"host_groups": [
	{

	import java.util.Properties
	import scala.util.control.Breaks._
	import kafka.server.KafkaServer
	import kafka.server.KafkaConfig
	import kafka.producer.ProducerConfig
	import kafka.producer.Producer
	import kafka.message.Message
	import kafka.producer.KeyedMessage
	import kafka.consumer.SimpleConsumer
	import kafka.api.FetchRequest

	#!/bin/bash

	# Install parallel on CentOS 6.
	# Assumes you are root. Prefix w/ sudo if not.

	cd /etc/yum.repos.d/
	wget http://download.opensuse.org/repositories/home:/tange/CentOS_CentOS-6/home:tange.repo
	yum install parallel

	#!/boot/bzImage

	# Linux kernel userspace initialization code, translated to bash
	# (Minus floppy disk handling, because seriously, it's 2017.)
	# Not 100% accurate, but gives you a good idea of how kernel init works
	# GPLv2, Copyright 2017 Hector Martin <marcan@marcan.st>
	# Based on Linux 4.10-rc2.

	# Note: pretend chroot is a builtin and affects the current process
	# Note: kernel actually uses major/minor device numbers instead of device name