Tim Bart pims

Minecraft on Raspberry Pi cluster with metrics

Ever wanted to put your Rapsberry Pi cluster to great use? Our team is working remotely, so we started to play Minecraft. I decided I would host the Minecraft server on my Raspberry Pi cluster. This gist will guide you through the steps I took to get a k3s cluster up with k3sup and later installed Minecraft as well as metrics exporter and Prometheus Operator

Why?

Quoniam Possumus - Because we can

You'll need

3 Ways to design the lightmap API

The purpose of the module is to create and update path-traced 2D lightmaps. For example, to create interesting dynamic top-down lighting in a 2D game.

Option 1: Trace on lightmap

lm := lightmap.New(image.Rect(0, 0, 100, 100))
light := lightmap.Light{

Create Bridge interface on the host and give internet access

sudo ip link add name br0 type bridge
sudo ip addr add 172.20.0.1/24 dev br0
sudo ip link set dev br0 up
sudo sysctl -w net.ipv4.ip_forward=1
sudo iptables --table nat --append POSTROUTING --out-interface enp3s0 -j MASQUERADE
sudo iptables --insert FORWARD --in-interface br0 -j ACCEPT

Create a tap device and link to the bridge

You can use CodePipeline and CodeBuild to create a continuous deployment/integration pipeline for serverless applications build on AWS Lambda and Amazon API Gateway. This sample application is written in Go with the Gin framework and uses the eawsy API Gateway proxy shim: https://github.com/eawsy/aws-lambda-go-net

We initially detailed our methodology in this blog post: https://aws.amazon.com/blogs/compute/continuous-deployment-for-serverless-applications/

We have used the shim technology created by eawsy to run Golang applications inside AWS Lambda (https://github.com/eawsy/aws-lambda-go-shim) and created a container that can be used with CodeBuild as part of our original pipeline template.

The container is available on DockerHub and is called sapessi/aws-lambda-go18-codebuild:latest. To use this container, simply change the Image property of the CodeBuild project environment.

The pipeline template, sample app, buildspec and SAM files are attached to this gist.

security and hardening options for systemd service units

A common and reliable pattern in service unit files is thus:

NoNewPrivileges=yes
PrivateTmp=yes
PrivateDevices=yes
DevicePolicy=closed
ProtectSystem=strict

	/*
	Code to perform L1, L2 cache locality experiments
	https://kaushikghose.wordpress.com/2020/01/27/profiling-and-improving-cache-performance/
	*/
	#include <iostream>
	#include <vector>

	const size_t N = 1200;

	class Matrix {

	/* ext2scan:
	* Scans an input stream, sector by sector, for something that looks like an ext{2,3,4} partition.
	* It does this by looking for a magic WORD, 0xEF53, at a known offset into the sector.
	* For random data, this will occur by chance around once per 32MB of data, so we also
	* check whether the first two sectors are all zeros, which is commonly true for ext partitions.
	*
	* Compile with:
	* gcc ./ext2scan.c -o ./ext2scan
	*
	* Example usage:

	from __future__ import division
	from random import random
	import numpy as np
	import pandas as pd

	'''
	Use regret-matching algorithm to play Scissors-Rock-Paper.
	'''

	class RPS:

	In [1]: %paste
	from sklearn.datasets import load_iris
	from sklearn import tree
	import coremltools

	iris = load_iris()
	clf = tree.DecisionTreeClassifier()
	clf = clf.fit(iris.data, iris.target)

	## -- End pasted text --

	var https = require('https');
	var util = require('util');

	exports.handler = function(event, context) {
	console.log(JSON.stringify(event, null, 2));
	console.log('From SNS:', event.Records[0].Sns.Message);

	var subject = event.Records[0].Sns.Subject;
	var message = JSON.parse(event.Records[0].Sns.Message);