Simon Oakes soakes

Using strace and lsof to debug blocked processes

You can use strace on a specific pid to figure out what a specific process is doing, e.g.:

strace -fp <pid>

You might see something like:

select(9, [3 5 8], [], [], {0, 999999}) = 0 (Timeout)

Backup MySQL to Amazon S3

This is a simple way to backup your MySQL tables to Amazon S3 for a nightly backup - this is all to be done on your server :-)

Sister Document - Restore MySQL from Amazon S3 - read that next

1 - Install s3cmd

this is for Centos 5.6, see http://s3tools.org/repositories for other systems like ubuntu etc

#launchd Usage

I have a bash script called foo.sh that takes one command line argument, bar. I want it to run every 60 seconds and load at startup.

an XML plist is Apple Property List
com.mydomain.foo.plist Name of launchd plist file should be a reverse fqdn, like (this may not be required, but convention)
com.mydomain.foo.plist lives in $HOME/Library/LaunchAgents and is ran as that user.
com.mydomain.foo.plist can also live /Library/LaunchDaemons or /Library/LaunchAgents, have requirements, ran as root
Load plist with launchctl load com.mydomain.foo.plist
Unload plist with lauchctl unload com.mydomain.foo.plist

Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

Concept

People talk about two servers: a web server (e.g. Nginx, Apache, etc.) and a app server (e.g. Language specific servers like Unicorn, Node.js, Tomcat, Http-Kit, etc.). There are exceptions where app servers not required at all (as web server itself provides preprocessors for handling), but let's not talk about now.
Web servers are really fast and supports lot of standard and commonly used MIME-type requests. Concept of serving a file is -- forming and sending a response of bytes of data and labeling it with requested MIME-type by a client (e.g. web browser).
Every response format (in layman's language, a file) is recognized by it's MIME-type, for e.g. a PNG image file has "image/png" MIME-type. JavaScript file has "text/javascript". HTML responses (or files) has "text/html". Plain text files have "text/plain".
Modern Browsers supports a lot of standard MIME-types. Images, videos, text files (XML, HTML, SVG, JS), and they better know how to visualize it. Browser also knows unrec

Typing vagrant from the command line will display a list of all available commands.

Be sure that you are in the same directory as the Vagrantfile when running these commands!

Creating a VM

vagrant init -- Initialize Vagrant with a Vagrantfile and ./.vagrant directory, using no specified base image. Before you can do vagrant up, you'll need to specify a base image in the Vagrantfile.
vagrant init <boxpath> -- Initialize Vagrant with a specific box. To find a box, go to the public Vagrant box catalog. When you find one you like, just replace it's name with boxpath. For example, vagrant init ubuntu/trusty64.

Starting a VM

vagrant up -- starts vagrant environment (also provisions only on the FIRST vagrant up)

	#!/usr/bin/env python

	'''
	Send an multipart email with HTML and plain text alternatives. The message
	should be constructed as a plain-text file of the following format:

	From: Your Name <your@email.com>
	To: Recipient One <recipient@to.com>
	Subject: Your subject line
	---

	##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### ##### #####

	### Shell script to download Oracle JDK / JRE / Java binaries from Oracle website using terminal / command / shell prompt using wget.
	### You can download all the binaries one-shot by just giving the BASE_URL.
	### Script might be useful if you need Oracle JDK on Amazon EC2 env.
	### Script is updated for every JDK release.

	### Features:-
	# 1. Resumes a broken / interrupted [previous] download, if any.
	# 2. Renames the file to a proper name with including platform info.

	#!/bin/sh

	docker events --filter 'event=start' --filter 'event=stop' \| while read event

	do

	container_id=`echo $event \| sed 's/.Z\ \(.\):\ .*/\1/'`

	echo $container_id

	{
	"check": {
	"id": "check-disk",
	"name": "check-disk",
	"script": "/usr/lib/nagios/plugins/check_disk -w 30% -c 5%",
	"interval": "1m"
	}
	}