Notes: Server Migration and Ubuntu 20.04

May 1, 2020

This is a collection of notes from a server migration.

New Machine Setup

The destination server now runs Ubuntu 20.04. Some initial setup stuff.

# add a sudo user
adduser cooldude
usermod -aG sudo cooldude

# name the machine (instead of editing /etc/hostname)
hostnamectl set-hostname servername

# you should add `servername` to the /etc/hosts file
# (mainly so you can refer to the local machine by name)

# generate an ssh key (I need to ssh in to another machine so)
ssh-keygen -t rsa -b 4096

# enable firewall
ufw allow 22
ufw allow http
ufw allow https
ufw enable

# install updates
apt update
apt upgrade

# HEY! I originally installed OpenLitespeed, but it wasn't going to work
# Here is that setup code and info

## install build tools
#apt install build-essential cmake
#
## checkout litespeed
#git clone https://github.com/litespeedtech/openlitespeed.git
#cd openlitespeed
#
## the build script makes some incorrect assumptions.
## you might need to add a return to the `installCmake` function.
## the build script will attempt to install packages you need.
#sudo ./build.sh

# COOL! We're done with that
# Lets install NginX with PHP instead
sudo add-apt-repository ppa:ondrej/php
sudo add-apt-repository ppa:ondrej/nginx
sudo apt update

sudo apt install nginx php7.4 php7.4-fpm php7.4-mysql php7.4-gd

# Copy files... ?
scp -P 22 [email protected]:/mnt/data .
rsync -azrP -e 'ssh -p 22' [email protected]:/mnt/data .

Notes: The Elements of Style

January 20, 2020

I’ve started reading the ancient little book on writing. I eventually attacked the book with a highlighter, but I know I will forget some of my thought, so I’ve decided to take notes. I shouldn’t have to say it, but if you’re trying to gleen what’s in the book by reading this, don’t bother. Go buy the book. It’s $10 brand new. 1. Form the posessive singular of nouns by adding ’s Cool....

Notes: Creating Live OBS Motion Graphics in HTML5

June 16, 2019

This is early, but here are a collection of thoughts when it comes to creating motion graphics for OBS. OBS Browser source plugin Our ability to make live motion graphics that move and even use live data is made possible thanks to the OBS Browser plugin. The plugin ships with the Windows/Mac version of OBS, but the original repo is an important reference. Windows, Mac: https://github.com/obsproject/obs-browser Linux: https://github.com/bazukas/obs-linuxbrowser I have not done much testing with Linux yet, but in quick tests it was working....

Notes: KCP ARQ Network Protocol

June 14, 2019

This is a deep dive in to the source code for KCP. Despite the project claiming to have good documentation, I disagree. It’s simple, but it doesn’t do a great job explaining itself. The following is a breakdown of the logic of each function. https://github.com/skywind3000/kcp https://github.com/skywind3000/kcp/blob/master/README.en.md ikcp.c The main source file. ikcp_encode8u … ikcp_encode32u, ikcp_decode8u [private] A bunch of functions for byte-swapping. the encode functions write to the pointer, while the decode functions read from it, writing to the input argument....

Notes: KQueue, EPoll, Poll, Select

June 9, 2019

Polling methods on Unix. In generall, all methods provide a way to monitor file descriptors. So in network programming, you’d either make a list of socket FD’s, or use a single one if entirely transmitting over UDP. Select The original. /* According to POSIX.1-2001, POSIX.1-2008 */ #include <sys/select.h> /* According to earlier standards */ #include <sys/time.h>#include <sys/types.h>#include <unistd.h> int select(int nfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, struct timeval *timeout); void FD_CLR(int fd, fd_set *set); int FD_ISSET(int fd, fd_set *set); void FD_SET(int fd, fd_set *set); void FD_ZERO(fd_set *set); In general, Select is the most widely supported (even on Windows), but most limited....

Notes: Gitea (Github-like GIT suite)

April 25, 2019

Generally speaking I followed this guide: https://www.vultr.com/docs/how-to-install-gitea-on-ubuntu-18-04 My earlier attempt at installing Gitea didn’t quite work right, but this went off without a hitch. Notable changes: I installed Gitea on an LXD container (so this works totally-fine) I installed the latest stable version of MariaDB (https://downloads.mariadb.org/mariadb/repositories/) I installed the latest version of Gitea, which at the time of this writing is 1.8.0. I would recommend checking the releases here: https://dl....

Notes: Migrating SVN repos to GIT

April 23, 2019

Generally I don’t have much to add. Be sure you install the GIT-SVN package first. sudo apt install git-svn I followed this guide up to step 3: https://gist.github.com/epicserve/1219858/9f30d5ffca7d6b6e4130c4b9b300b8167c868a5f As well as this one: https://git-scm.com/book/en/v2/Git-and-Other-Systems-Migrating-to-Git I ran in to issues initially because the SVN repository I was trying to port over DIDN’T follow the norm: it had no trunk, tags, or branches folders. The solution was pretty straight forward once I realized this is why it wasn’t working....

Notes: Easy OpenVPN

December 1, 2018

The recommended way of running OpenVPN is incredibly verbose. See here: https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-18-04 That’s a lot of work, with a lot of places to make mistakes. That said, this is still the correct way to run OpenVPN. An easier way is to do it via the easy-openvpn snap. 1. Setting up Easy OpenVPN Installing easy-openvpn is … well, easy. The thing to understand though is Installing openvpn is only half the battle....

Notes: Yet another Linux Server Setup

September 29, 2018

Here we go again! Linux like OpenGL is old, and though finding information how to use it isn’t hard, finding the right information can be. Things have changed and evolved over time, and a “best practice” from years ago might not be best anymore (i.e. every article that still uses apt-get). Sooo, like every other time I do one of these note-posts, I’m trying to make sure I’m doing each step the most current/ideal/recommended way....

Notes: Systemd and systemctl

September 26, 2018

For clarity: there’s lots of references online that say use “upstart” to manage auto-starting applications. Don’t! Upstart was obsoleted, and as of Ubuntu 14.10 it’s no longer available. The ideal way to start applications is with Systemd. Status To check the status of services, do the following: systemctl status This will give you a tree of all the started services. If you see that your state is degraded, this means a service failed to start....