DavidWittman

settings = {
   logfile = "/var/log/lsyncd/lsyncd.log",
   statusFile = "/var/log/lsyncd/lsyncd-status.log",
   statusInterval = 20
}

servers = {
    "web02",
    "web03"
}

DavidWittman

Nested list comprehensions in Python

For some reason or another, I'm always second guessing myself when writing nested list comprehensions. Here's a quick example to clarify what's going behind the scenes:

>>> words = ["foo", "bar", "baz"]
>>> [letter for word in words for letter in word]
['f', 'o', 'o', 'b', 'a', 'r', 'b', 'a', 'z']

DavidWittman

iptables n'at

Source NAT

Source NAT changes the source address in IP header of a packet. It may also change the source port in the TCP/UDP headers. The typical usage is to change the a private (rfc1918) address/port into a public address/port for packets leaving your network. Available only in the POSTROUTING chain in iptables.

Syntax

iptables -t nat -A POSTROUTING -i eth1 -j SNAT --to-source 1.2.3.4[:port]

Example

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Notes from the DBA Exam (Part 1)

Note: for questions where you can select multiple answers, it will tell you how many to choose.

Overview

• Lots of InnoDB and transactional stuff
• Understand everything about locking

Specific questions

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OpenStack Summit Images Talk

Who we are

Rackspace Private Cloud. We install and operate Openstack clusters, both locally in our datacenters, and remotely in customer datacenters.

Reference Alamo v3?

What are we talking about?

Automating base image builds for OpenStack private clouds.

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#!/usr/bin/env python

import json
import os
import time

import clouddns

USERNAME = ''
APIKEY   = ''

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Packet Analysis with Wireshark

Links

• Capture files
• CloudShark

Common filters

Source IP is 192.168.1.1

ip.src == 192.168.1.1

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USE keystone
-- This needs to be set in the my.cnf to persist
SET GLOBAL event_scheduler = 1;
DELIMITER $$
CREATE EVENT tokenreaper
ON SCHEDULE EVERY 1 WEEK
DO BEGIN
    DELETE FROM `token` WHERE expires <= DATE_SUB(NOW(), INTERVAL 1 WEEK);
END $$
DELIMITER ;

DavidWittman

Automated DevStack deployments on Rackspace with salt-cloud

Preparation

Install salt-master and salt-cloud

These instructions will install salt-master and salt-cloud on recent Ubuntu releases. Consult the SaltStack Installation Documentation should you require instructions for other distributions.

echo deb http://ppa.launchpad.net/saltstack/salt/ubuntu `lsb_release -sc` main | sudo tee /etc/apt/sources.list.d/saltstack.list

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#!/bin/bash

# neutron-scope
# 
# Run a command in the network namespace of an OpenStack server
#
# Pro-tip: The string _IP_ is replaced with the first IP address of the server
#          e.g. neutron-scope my-server ssh root@_IP_

set -e