kiba islander

WAL-G PITR

This gist summarises a way to simulate point-in-time recovery (PITR) using WAL-G. Most of the material is adapted from Creston's tutorial.

Setup

First we initialize a database cluster

pg_ctl init -D cluster

systemd-nspawn container architecture

This short document will show how to turn systemd-nspawn into a usable containeration system.

Those instructions here should work under Arch Linux and Debian 10 (Buster)

Host requirements

systemd-nspawn and machinectl (systemd-container package under Debian)
dnsmasq
debootstrap

Thinkfan setup

Note: I configured this thinkfan setup for my old Thinkpad w520 on Ubuntu 17.10.

1. Install necessary programs

Install lm-sensors and thinkfan.

sudo apt-get install lm-sensors thinkfan

Story: Writing Scripts with Go

This is a story about how I tried to use Go for scripting. In this story, I’ll discuss the need for a Go script, how we would expect it to behave and the possible implementations; During the discussion I’ll deep dive to scripts, shells, and shebangs. Finally, we’ll discuss solutions that will make Go scripts work.

Why Go is good for scripting?

While python and bash are popular scripting languages, C, C++ and Java are not used for scripts at all, and some languages are somewhere in between.

Docker compose as a systemd unit

Create file /etc/systemd/system/[email protected]. SystemD calling binaries using an absolute path. In my case is prefixed by /usr/local/bin, you should use paths specific for your environment.

[Unit]
Description=%i service with docker compose
PartOf=docker.service
After=docker.service

On master and nodes

Pull images form internet access laptop

docker pull gcr.io/google_containers/kube-apiserver-amd64:v1.5.0
docker pull gcr.io/google_containers/kube-controller-manager-amd64:v1.5.0
docker pull gcr.io/google_containers/kube-proxy-amd64:v1.5.0
docker pull gcr.io/google_containers/kube-scheduler-amd64:v1.5.0
docker pull weaveworks/weave-npc:1.8.2
docker pull weaveworks/weave-kube:1.8.2

	function logColor(color, args) {
	console.log(`%c ${args.join(' ')}`, `color: ${color}`);
	}

	const log = {
	aliceblue: (...args) => { logColor('aliceblue', args)},
	antiquewhite: (...args) => { logColor('antiquewhite', args)},
	aqua: (...args) => { logColor('aqua', args)},
	aquamarine: (...args) => { logColor('aquamarine', args)},
	azure: (...args) => { logColor('azure', args)},

	#!/usr/bin/python3
	#
	# usage: python3 docker_descendants.py <image_id> ...

	import sys
	from subprocess import check_output


	def main(images):
	image_ids = set(images)

	import sys
	import base64
	from Crypto.Cipher import AES


	class AESCipher(object):
	def __init__(self, key):
	self.bs = 16
	self.cipher = AES.new(key, AES.MODE_ECB)

	#!/bin/bash
	#
	# Reboot a Cisco SPA112 using its web ui.
	# Tested on firmware v1.4.1 (002).
	#
	# Written by Ian Wilson <[email protected]> on 2017-03-07

	DEVICE_IP=192.168.1.42
	USER=admin
	PASSWORD=hunter2