yeetpy

yeet.py

A yeetifier for C/C++ code.

Usage:

1. Select a C++ file:

// main.cpp
#include<iostream>

AlinaNova21

Kubernetes and Arm

Getting rke and Rancher setup to run kubernetes on arm is interesting. There is no official support yet via rancher, although there is interest and some work done towards those efforts. This is my attempt at getting a cluster of 3 Pis (2 3Bs and 1 3B+) provisioned and registered to a rancher 2 server.

Prep

I've successfully completed this both with Hypriot OS 1.9.0 and the arm64 builds https://github.com/DieterReuter/image-builder-rpi64 Both times I used the same basic cloud-init setup

squidpickles

Multiplatform (amd64 and arm) Kubernetes cluster setup

The official guide for setting up Kubernetes using kubeadm works well for clusters of one architecture. But, the main problem that crops up is the kube-proxy image defaults to the architecture of the master node (where kubeadm was run in the first place).

This causes issues when arm nodes join the cluster, as they will try to execute the amd64 version of kube-proxy, and will fail.

It turns out that the pod running kube-proxy is configured using a DaemonSet. With a small edit to the configuration, it's possible to create multiple DaemonSets—one for each architecture.

Steps

Follow the instructions at https://kubernetes.io/docs/setup/independent/create-cluster-kubeadm/ for setting up the master node. I've been using Weave Net as the network plugin; it see

haavard

This work, excluding the Arch Linux logo, is made available under CC0: https://creativecommons.org/publicdomain/zero/1.0/

jboner

Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

Jach

import sys
import ctypes
pyint_p = ctypes.POINTER(ctypes.c_byte*sys.getsizeof(5))
five = ctypes.cast(id(5), pyint_p)
print(2 + 2 == 5) # False
five.contents[five.contents[:].index(5)] = 4
print(2 + 2 == 5) # True (must be sufficiently large values of 2 there...)