James Francis tcotav

Install a docker registry in a k3s kubernetes cluster

k3s doesn't have a builtin plugin for a local registry, so this is how to install the docker registry. The registry will be exposed via the default traefik ingress (on port 80 and 443).

Assumptions

resolvectl query registry.localhost returns 127.0.0.1 - on most Linux distros it does. If not, enable and configure systemd-resolved
K3s comes with traefik ingress controller by default, so the ingress for the registry service is configured for that.

$ docker run --privileged --pid=host -it alpine:3.8 \
nsenter -t 1 -m -u -n -i sh

--rm : removes the container after it is stopped
-ti (or -t -i) : adds a tty and leaves the standard input opened
--privileged : grants additional permissions to the container, it allows the container to gain access to the devices of the host (/dev)
--pid=host : use the host's Process ID Namespace. Allows the container to use the process tree of the Docker host (the machine in which the Docker daemon is running)

Get boot2docker working with nfs instead of vboxsf.

Tested on:

- Boot2Docker-cli version: v1.6.0
  Git commit: 9894ae9
- Boot2Docker-cli version: v1.6.2
  Git commit: cb2c3bc

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!

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tmux cheat sheet

(C-x means ctrl+x, M-x means alt+x)

Prefix key

The default prefix is C-b. If you (or your muscle memory) prefer C-a, you need to add this to ~/.tmux.conf:

remap prefix to Control + a

	FROM mirror-hub.docker.tech.lastmile.com/alpine:3.5

	RUN apk add --no-cache curl jq

	RUN curl -o /usr/local/bin/kubectl https://storage.googleapis.com/kubernetes-release/release/v1.5.3/bin/linux/amd64/kubectl && chmod +x /usr/local/bin/kubectl

	COPY rmpeers /

	CMD ["/rmpeers"]

	#!/bin/sh
	if [ "$#" -eq 1 ]; then stdinmsg=$(cat); fi
	exec <"$0" \|\| exit; read v; read v; read v; exec /usr/bin/osascript - "$@" "$stdinmsg"; exit

	-- another way of waiting until an app is running
	on waitUntilRunning(appname, delaytime)
	repeat until my appIsRunning(appname)
	tell application "Messages" to close window 1
	delay delaytime
	end repeat

	#!/bin/bash
	# bash generate random alphanumeric string
	#

	# bash generate random 32 character alphanumeric string (upper and lowercase) and
	NEW_UUID=$(cat /dev/urandom \| tr -dc 'a-zA-Z0-9' \| fold -w 32 \| head -n 1)

	# bash generate random 32 character alphanumeric string (lowercase only)
	cat /dev/urandom \| tr -dc 'a-z0-9' \| fold -w 32 \| head -n 1

	terraform {
	required_version = ">=0.12, <0.13"
	}

	A warning occurred (42 apples)
	An error occurred