Lukas W wojukasz

A Brief Introduction to Fabric

Fabric is a deployment management framework written in Python which makes remotely managing multiple servers incredibly easy. If you've ever had to issue a change to a group servers, this should look pretty familiar:

for s in $(cat servers.txt); do ssh $s service httpd graceful; done

Fabric improves on this process by providing a suite of functions to run commands on the servers, as well as a number of other features which just aren't possible in a simple for loop. While a working knowledge of Python is helpful when using Fabric, it certainly isn't necessary. This tutorial will cover the steps necessary to get started with the framework and introduce how it can be used to improve on administering groups of servers.

tmux shortcuts & cheatsheet

start new:

tmux

start new with session name:

tmux new -s myname

1: Generate CSR

openssl req -new -newkey rsa:2048 -nodes -keyout server-cert.key -out server-cert-sign-req.csr

# Country Name (2 letter code) [AU]:US
# State or Province Name (full name) [Some-State]:California
# Locality Name (eg, city) []:
# Organization Name (eg, company) [Internet Widgits Pty Ltd]:Flutterby Labs, Inc.
# Organizational Unit Name (eg, section) []:
# Common Name (eg, YOUR name) []:www.dogo.co

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

Initialize

gitflow	git
`git flow init`	`git init`
	`git commit --allow-empty -m "Initial commit"`
	`git checkout -b develop master`

Connect to the remote repository

Session Management in an Autoscaling Environment

Problem Statement

User sessions in J2EE and LAMP stacks have traditionally been handled in memory by the application server handling the user request. Because of that, load balancers have been configured to use sticky sessions. By sticky sessions we mean that once the user has visited the site, they will be assigned an app server and will return to that server for subsequent requests. The load balancers typically handle that by referencing the users session cookie.

Elastic cloud environments differ from traditional server configurations in that they have a variable number of servers based on traffic loads whereas traditional configurations had a fixed number of servers. When traffic volumes decline it is necessary to vaporize servers. In doing so, we would lose user sessions (essentially forcing a logout) unless we come up with a new strategy for session management.

A new approach

After much research, it is clear that the best

###Some don't work yet.

Get the top request methods

varnishtop -i RxRequest

Top urls that missed the cache.

varnishtop -i TxURL

	#!/usr/bin/env python
	import optparse
	import sys

	from boto.s3.connection import S3Connection

	def sign(bucket, path, access_key, secret_key, https, expiry):
	c = S3Connection(access_key, secret_key)
	return c.generate_url(
	expires_in=long(expiry),

	# Install ARCH Linux with encrypted file-system and UEFI
	# The official installation guide (https://wiki.archlinux.org/index.php/Installation_Guide) contains a more verbose description.

	# Download the archiso image from https://www.archlinux.org/
	# Copy to a usb-drive
	dd if=archlinux.img of=/dev/sdX bs=16M && sync # on linux

	# Boot from the usb. If the usb fails to boot, make sure that secure boot is disabled in the BIOS configuration.

	# Set swedish keymap

	# Ask for the user password
	# Script only works if sudo caches the password for a few minutes
	sudo true

	# Install kernel extra's to enable docker aufs support
	# sudo apt-get -y install linux-image-extra-$(uname -r)

	# Add Docker PPA and install latest version
	# sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9
	# sudo sh -c "echo deb https://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list"