shamil

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

sivel

Better SSH Authorized Keys Management

A seemingly common problem that people encounter is how to handle all of your users authorized_keys file.

People struggle over management, ensuring that users only have specific keys in the authorized_keys file or even a method for expiring keys. A centralized key management system could help provide all of this functionality with a little scripting.

One piece of functionality overlooked in OpenSSH is the AuthorizedKeysCommand configuration keyword. This configuration allows you to specify a command that will run during login to retrieve a users public key file from a remote source and perform validation just as if the authorized_keys file was local.

Here is an example directory structure for a set of users with SSH public keys that can be shared out via a web server:

kenjij

# Download the legacy format for NGINX compatibility
wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCountry/GeoIP.dat.gz
wget http://geolite.maxmind.com/download/geoip/database/GeoLiteCity.dat.gz
# Unzip
gunzip Geo*.gz
# Copy to /usr/share/GeoIP/
cp Geo*.dat /usr/share/GeoIP/

pablitoc

##Install AWS CLI Tools##

1. Install AWS CLI Tools. You can also use the EC2 API Tool if you are more comfortable with them. But this write-up uses the EC2 CLI.
2. Create a user via Amazon IAM or download the security accessID and securitykey you will need it to query Amazon CLI.
3. using Terminal cd into .aws directory cd ~/.aws edit or create new file named config paste the following contents inside.
   `[default]`
   `aws_access_key_id = ACCESS_ID`
   `aws_secret_access_key = SECRET_ID`
   `output = json OR bson OR text`
   `region = PREFERRED_AWS_REGION`

Save the file as "config"

wendelb

#
# This background job automatically locks your Workstation after a specified amount of
# time. It will come in handy if you cannot access the screensaver settings due to policy
# restriction but want to lock your screen after a idle timeout. Or you could just
# press [Win]+[L] everytime you leave your desk ;) .
#
# start with
# 	powershell.exe -windowstyle hidden -executionpolicy Unrestricted P:\ATH\TO\logoff.ps1
#
# `-windowstyle hidden` will make your PowerShell disappear/run in background

olivermt

package com.mtdevelopment.loadbalancer;


import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.DatagramPacket;

import java.net.InetSocketAddress;
import java.util.Random;

P7h

tmux vs. screen commands

---

Action	tmux	screen
start a new session	tmux tmux new tmux new-session	screen
start a new session with a name	tmux new -s name	screen -S name
re-attach a detached session	tmux attach tmux attach-session	screen -r
re-attach a detached session with a name	tmux attach -t name tmux a -t name	screen -r name
re-attach an attached session (detaching it from elsewhere)	tmux attach -dtmux attach-session -d	screen -dr

jareware

⇐ back to the gist-blog at jrw.fi

Simple, semi-anonymous backups with S3 and curl

Backing stuff up is a bit of a hassle, to set up and to maintain. While full-blown backup suites such as duplicity or CrashPlan will do all kinds of clever things for you (and I'd recommend either for more complex setups), sometimes you just want to put that daily database dump somewhere off-site and be done with it. This is what I've done, with an Amazon S3 bucket and curl. Hold onto your hats, there's some Bucket Policy acrobatics ahead.

There's also a tl;dr at the very end if you just want the delicious copy-pasta.

Bucket setup

platan

#!/bin/bash
window_ids=$(wmctrl -l | cut -f1 -d " ")
for window_id in $window_ids
do
    wmctrl -i -r "$window_id" -b add,maximized_vert,maximized_horz
done

niun

#!/bin/sh
#
#  Read-only Root-FS for Raspian
#
#  Modified 2015 by Pascal Rosin to work on raspian-ua-netinst with
#  overlayfs integrated in Linux Kernel >= 3.18.
#
#  Originally written by Axel Heider (Copyright 2012) for Ubuntu 11.10.
#  This version can be found here:
#  https://help.ubuntu.com/community/aufsRootFileSystemOnUsbFlash#Overlayfs