Jerry Jerry-Fix

System Design Cheatsheet

Picking the right architecture = Picking the right battles + Managing trade-offs

Basic Steps

Clarify and agree on the scope of the system

User cases (description of sequences of events that, taken together, lead to a system doing something useful)
- Who is going to use it?
- How are they going to use it?

Intro

TCL-Expect scripts are an amazingly easy way to script out laborious tasks in the shell when you need to be interactive with the console. Think of them as a "macro" or way to programmaticly step through a process you would run by hand. They are similar to shell scripts but utilize the .tcl extension and a different #! call.

Setup Your Script

The first step, similar to writing a bash script, is to tell the script what it's executing under. For expect we use the following:

#!/usr/bin/expect

	vi /etc/environment

	add these lines...

	LANG=en_US.utf-8
	LC_ALL=en_US.utf-8

	package testjava;

	import java.util.HashMap;
	import java.util.Random;

	/*
	* URL Shortener
	*/
	public class URLShortener {
	// storage for generated keys

	# Output json-esque output for logstash to parse easily.

	http {
	# ...

	log_format logstash_json '{"@timestamp": "$time_iso8601", '
	'"remote_addr": "$remote_addr", '
	'"remote_user": "$remote_user", '
	'"body_bytes_sent": "$body_bytes_sent", '
	'"request_time": "$request_time", '

	#!/usr/bin/python

	# Quick and dirty demonstration of CVE-2014-0160 by Jared Stafford ([email protected])
	# The author disclaims copyright to this source code.

	import sys
	import struct
	import socket
	import time
	import select

	#!/bin/bash
	IPT="/sbin/iptables"

	# Server IP
	SERVER_IP="$(ip addr show eth0 \| grep 'inet ' \| cut -f2 \| awk '{ print $2}')"

	# Your DNS servers you use: cat /etc/resolv.conf
	DNS_SERVER="8.8.4.4 8.8.8.8"

	# Allow connections to this package servers

	Axure RP 7.0注册码
	用户名：axureuser
	序列号：8wFfIX7a8hHq6yAy6T8zCz5R0NBKeVxo9IKu+kgKh79FL6IyPD6lK7G6+tqEV4LG

	1. 7004_A
	开启特性
	feature vpc
	feature lacp
	no ip domain-lookup

	建立 VRF 与 peer-keepalive，将建立的 peer-keepalive 成员端口加入到 VRF 中，与 7004 的路由表隔离
	interface mgmt0
	vrf member management
	ip address 10.1.1.1/24

	# dmidecode -t cache
	# dmidecode 2.9
	SMBIOS 2.6 present.

	Handle 0x0700, DMI type 7, 19 bytes
	Cache Information
	Socket Designation: Not Specified
	Configuration: Enabled, Not Socketed, Level 1
	Operational Mode: Write Back
	Location: Internal