Ming-der Wang mingderwang

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?

As I was testing around with https://bitnami.com/stack/kubernetes-sandbox I wanted to remotely access it

First find the token, by getting on the server, which is configured to trust any local user to be cluster admin with kubectl

TOKEN=$(kubectl get secrets -n kube-system | grep default-token | awk '{print $2}')
kubectl describe secret $TOKEN -n kube-system | grep token:

Now give that default user the cluster admin role

kubectl create clusterrolebinding admin-role --clusterrole=cluster-admin --serviceaccount=kube-system:default

Advisory: secret size attack on cross-chain hash lock smart contracts

Dr. Mark B Lundeberg, 2018 Feb 15 bitcoincash:qqy9myvyt7qffgye5a2mn2vn8ry95qm6asy40ptgx2

This security advisory notes a vulnerability in the common construction of cross-chain smart contracts (contracts between distinct cryptocurrencies) through hash locking. I focus on the primary use case in [atomic

	[ req ]
	default_bits = 4096
	default_md = sha256
	default_keyfile = private.key
	distinguished_name = req_distinguished_name
	attributes = req_attributes
	x509_extensions = v3_user_req
	req_extensions = v3_user_req

	[ req_distinguished_name ]

	#!/usr/bin/env python

	##
	# kube-resources.py
	# Collate and report Kubernetes pod usages vs. node limits.
	#
	# Assumes `kubectl` is installed and available.
	#
	# Author: Henry Cooke, [email protected]
	# Version: 20150816

	# in your group vars
	HOST_SUFFIX: "dev.apps"
	SERVICE_LIST:
	- {serviceName: "my_service1", destinationUrl: "http://some-random-dev-machine:5555/"}
	- {serviceName: "admin.my_service1", destinationUrl: "http://some-random-dev-machine:5556/"}
	- {serviceName: "other-service2", destinationUrl: "http://another-machine-another-port:4279/"}

	# in your playbook's yaml
	...
	roles:

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8"/>
	<title>Untitled benchmark #jsbench #jsperf</title>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/benchmark/1.0.0/benchmark.min.js"></script>
	<script src="./suite.js"></script>
	</head>
	<body>
	<h1>Open the console to view the results</h1>

	#
	# INPUT - Logstash listens on port 8514 for these logs.
	#

	input {
	udp {
	port => "8514"
	type => "syslog-cisco"
	}

	Aardvark
	Aardwolf
	African Buffalo
	African Elephant
	African Leopard
	Albatross
	Alligator
	Alpaca
	Alpaca
	American Buffalo (bison)

	---
	- hosts: gluster
	become: true
	vars:
	gluster_mount_dir: /mnt/g1
	gluster_brick_dir: /bricks/brick1
	gluster_brick_name: g1
	tasks:

	- name: Install parted