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The Problem

We have a few packages we like to install through Amazon Linux Extras repo, but we discovered that this doesn't work right:

execute 'Enable java 11 via amazon-linux-extras' do
  command 'amazon-linux-extras enable java-openjdk11'
end

package 'java-11-openjdk'

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Problem

I wanted to create a jumpbox where the default shell was zsh, but I couldn't actually change the default shell of the users that would be connecting to the box. I also wanted to manage some symlinks in the user profile dynamically with Dotbot.

My initial idea was to add a script to /etc/profile.d that would just dump users into /bin/zsh, but this had several different problems, including the all-important question of "But what if I want to run Bash on purpose?"

Solution

Through a little bit of trial and error, I settled on this script located at /etc/profile.d/dotbot.sh

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#!/bin/bash

which jq > /dev/null 2>&1
if [ "$?" -ne 0 ]; then
  >&2 echo Error: this script requires jq; exit 1
fi

which aws > /dev/null 2>&1
if [ "$?" -ne 0 ]; then
  >&2 echo Error: this script requires awscli; exit 1

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#!/bin/bash

if [ -f /etc/os-release ]; then
    # freedesktop.org and systemd
    . /etc/os-release
    OS=$NAME
    VER=$VERSION_ID
elif type lsb_release >/dev/null 2>&1; then
    # linuxbase.org
    OS=$(lsb_release -si)

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import random

shuffle_key = "QRUzaKNB4V5pparzJWTa"

# Imagine we have a list of images that's 200k items long
frame_list = [*range(1,200000)]

# Shuffle the frame list with the key
random.Random(shuffle_key).shuffle(frame_list)

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# Install python3 and OVS
sudo apt install python3-pip openvswitch-switch -y
# Install os-net-config
sudo pip3 install os-net-config

# Create os-net-config file
sudo mkdir -p /etc/os-net-config
sudo touch /etc/os-net-config/config.yaml

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DNS SRV with Terraform (On AWS Route53)

DNS SRV records are a little cryptic. Even when you create them, it's not particularly obvious what the information in the SRV record actaully means.

When creating the records with Terraform, you can for_each the resource to supply one or more maps that contain better descriptors of the SRV record's constituent components. See the example in the terraform snippet below. Refer here for a longer explanation.

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Amazon Linux 2 on Lightsail, Bare Minimum Setup

The idea here is to give a set of "common sense" defaults for running Amazon Linux 2 on Lightsail. These defaults include:

• Automatic Updates
• Live Kernel Patching
• Automatic Reboots when Required by Updates

Usage

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Installing pfSense on KVM in CentOS 8

We download the latest release of pfSense as a gzipped ISO, then extract it and pass it to virt-install to get the VM up and running. Interactive portions of setup are done with virt-install's native console redirection. This guide assumes you've already installed and configured KVM, and that you've created network bridges already.

Instructions

Find the latest release here.

Download the gzipped memstick-serial image from a mirror into a directory that KVM can access, then unzip it:

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Use the minified code inside of a bookmarklet. You can test it directly in your browser console on any YouTube video page. It ought to work anywhere but was only tested in Chrome 83.

When you're on a YouTube page, click the bookmarklet and it'll take you to the embedded version of the player that fills the entire window without requiring you to go to full screen mode. This is particularly useful if you have a 16:10 monitor.

The non-minified code is included as a reference to show how it works. There are other window-filling bookmarklets out there. I made this one because I wanted to write it.