Vlad Borovtsov vladborovtsov

How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

#MongoDB 3.2.x Replica Sets on AWS EC2 A MongoDB replica set provides a mechanism to allow for a reliable database services. The basic replica set consists of three servers, a primary, a secondary and an arbitrator. The primary and secondary both hold a copy of the data. The arbitrator is normally a low spec server which just monitors the other servers and help with the failover process. In production, there can be more than three servers.

To setup mongo as a replica set on Amazon Web Services EC2 you need to first setup a security group with ssh on port 22 and mongodb on port 27017. You then need to create three servers. Select Ubuntu 14.04 LTS x64 and a micro (or bigger depending on your database size, ideally you should have enough memory to match your database size) instance for the primary and secondary and a nano instance for the arbitrator.

##Adjust the File System on each Server The operating system by default will update the last access time on a file. In a high data throughput database application

tmux cheatsheet

As configured in my dotfiles.

start new:

tmux

start new with session name:

	-- ddcavcontrol

	-- v1.2.1

	-- This Hammerspoon script is intended to do the following:
	-- 1) Control External Display Brightness via DDC (utilizing a proper brightness+contrast curve)
	-- 2) Control External Display Volume via DDC
	-- 3) Control Digital AV Volume via Network (currently works with Yamaha AVs)
	-- 4) Use the standard brightness and volume keys of an Apple keyboards
	-- 5) Display the standard MacOS OSD as expected

	//
	// NSImage+OpenCV.h
	//

	#import <AppKit/AppKit.h>

	@interface NSImage (NSImage_OpenCV) {

	}

	[program:mongodb]
	command=/opt/mongodb/bin/mongod --dbpath /storage/mongodb_data --rest
	directory=/opt/mongodb
	user=root
	autostart=false

	# You don't need Fog in Ruby or some other library to upload to S3 -- shell works perfectly fine
	# This is how I upload my new Sol Trader builds (http://soltrader.net)
	# Based on a modified script from here: http://tmont.com/blargh/2014/1/uploading-to-s3-in-bash

	S3KEY="my aws key"
	S3SECRET="my aws secret" # pass these in

	function putS3
	{
	path=$1

	openssl req -new -newkey rsa:2048 -nodes -keyout yourdomain.key -out yourdomain.csr

	http://support.godaddy.com/help/article/3601/generating-a-certificate-signing-request-nginx
	http://support.godaddy.com/help/article/4976/rekeying-an-ssl-certificate

	# Be sure to remember to chain them!
	cat gd_bundle-g2-g1.crt >> yourdomain.crt

	# Move 'em
	sudo mv yourdomain.crt /etc/ssl/certs/yourdomain.crt

	import os
	from PIL import Image


	def extractFrames(inGif, outFolder):
	frame = Image.open(inGif)
	nframes = 0
	while frame:
	frame.save( '%s/%s-%s.gif' % (outFolder, os.path.basename(inGif), nframes ) , 'GIF')
	nframes += 1

	from django.db import connections
	from django.db.models.query import QuerySet
	from __future__ import print_function

	class QuerySetExplainMixin:
	def explain(self, analyze=True):
	cursor = connections[self.db].cursor()
	print(self.query)
	print()
	sql, params = self.query.sql_with_params()