Dawid Dziurla dawidd6

Network Namespace

Linux kernal (v5.6) has 8 types of namespaces. Network namespace is one of the feature of linux kernal. Most container technologies use this feature to create isolated network stack in the operating system. We can create virtualized network stack with its interfaces, IP range, routing table etc. We can run application in different network stacks.

VETH devices are virtual ethernet devices. They can act as tunnels between network namespaces to create a bridge to a physical network device in another namespace, but can also be used as standalone network devices. The virtual ethernet device will act as a tunnel between the network namespaces that we will create.

We will go thorugh linux network namespace. We want to learn how two network namespace communicate with each other. Also we will see how a network namespace will communicate with outer world.

Our objectives:

If you'd like to keep up-to-date with Chrome from unstable but otherwise want to run a stable NixOS release you can do the following:

Create a file /etc/nixos/unstable.nix:

{ config, pkgs, ...}:
let
  baseconfig = { allowUnfree = true; };
  unstable = import <nixos-unstable> { config = baseconfig; };
in {

how to leverage oracle's temping offers

free tier limits

The limits of the free tier say that you can create up to 4 instances.

x2 x86 instances (2core/1g)
x2 ampere instances (with 4core/24g spread between them)
200GB total boot volume space across all intances (minimum of 50G per instance)

create your account

Svelte cheatsheet

Doc examples

Running ARM programs under linux (without starting QEMU VM!)

First, cross-compile user programs with GCC-ARM toolchain. Then install qemu-arm-static so that you can run ARM executables directly on linux

If there's no qemu-arm-static in the package list, install qemu-user-static instead

Emulating a Raspberry Pi with QEMU

Goal: Emulate a Raspberry Pi with QEMU in order to run the Raspbian O/S (based on Debian Linux).

The current setup is not ideal. For one thing, the maximum RAM allowed using the "versatile-pb" firmware is 256 Mb. In addition, only the most basic peripherals, a keyboard and mouse, are supported.

A number of articles have been written on this topic. Most are outdated, and the few recent ones are missing key information.

	#!/usr/bin/env bash

	echo
	echo "Arch Linux in QEMU with love from eirikb"
	echo
	set -x

	TARGET=ArchLinuxARM-rpi-armv7-latest.tar.gz

	wget "http://os.archlinuxarm.org/os/$TARGET"

	# Running specific applications through a VPN with network namespaces

	# Initial state
	curl ifconfig.co/city
	sudo ip link list
	sudo ip netns list

	# Disable Uncomplicated Firewall (Ubuntu)
	sudo ufw disable

	// XPath CheatSheet
	// To test XPath in your Chrome Debugger: $x('/html/body')
	// http://www.jittuu.com/2012/2/14/Testing-XPath-In-Chrome/
	// Credit to the original author: https://gist.github.com/LeCoupa/8c305ec8c713aad07b14


	// 0. XPath Examples.
	// More: http://xpath.alephzarro.com/content/cheatsheet.html