Samuel Walker sfxworks

Getting a shell on each node

I run several K8S cluster on EKS and by default do not setup inbound SSH to the nodes. Sometimes I need to get into each node to check things or run a one-off tool.

Rather than update my terraform, rebuild the launch templates and redeploy brand new nodes, I decided to use kubernetes to access each node directly.

Alternative option

https://github.com/alexei-led/nsenter

Raspberry Pi on Internet via reverse SSH tunnel

HackerNews discussed this with many alternative solutions: https://news.ycombinator.com/item?id=24893615

I already have my own domain name: mydomain.com. I wanted to be able to run some webapps on my Raspberry Pi 4B running perpetually at home in headless mode (just needs 5W power and wireless internet). I wanted to be able to access these apps from public Internet. Dynamic DNS wasn't an option because my ISP blocks all incoming traffic. ngrok would work but the free plan is too restrictive.

I bought a cheap 2GB RAM, 20GB disk VM + a 25GB volume on Hetzner for about 4 EUR/month. Hetzner gave me a static IP for it. I haven't purchased a floating IP yet.

Notes on setting up a Kubernetes cluster on CoreOS (stable) with DigitalOcean's platform.

Partially stolen from this guide by kevashcraft

Spin up VMs

Spin up 4 VMs with CoreOS Stable. One will be the master, the other 3 will be workers
Tag them with k8s:master and k8s:worker respectively, along with a tag for the cluster
Droplets can be created via your DO control panel, or by using doctl. Just change the CLUSTER_NAME, CLUSTER_DOMAIN, and SSHKEY_ID values below to match your own, then save the file to cluster_create.sh, chmod +x cluster_create.sh, then run it ./cluster_create.sh. If you don't already have doctl setup, it will probably be easier to just do this from the DO control panel if you only need to do a one-time setup for development.

Installing Kubernetes on ArchLinux

Packages

pacman -S curl docker ebtables ethtool wget unzip

Also cfssl is needed but available on AUR, using pacaur

pacaur -S cfssl

Downloading Shared Files on Google Drive Using Curl

When the shared files on Google Drive is downloaded, it is necessary to change the download method by the file size. The boundary of file size when the method is changed is about 40MB.

File size < 40MB

CURL

filename="### filename ###"
fileid="### file ID ###"
curl -L -o ${filename} "https://drive.google.com/uc?export=download&amp;id=${fileid}"

How to configure static website using Nginx with MinIO ?

1. Install nginx

2. Install minio

3. Install mc client

4. Create a bucket:

$ mc mb myminio/static
Bucket created successfully ‘myminio/static’.

	import time

	print "..."
	time.sleep(1)
	print "..."
	print "..."
	print "..."
	print "..."
	time.sleep(1)
	print "..."

	# This will use osd.5 as an example
	# ceph commands are expected to be run in the rook-toolbox
	1) disk fails
	2) remove disk from node
	3) mark out osd. `ceph osd out osd.5`
	4) remove from crush map. `ceph osd crush remove osd.5`
	5) delete caps. `ceph auth del osd.5`
	6) remove osd. `ceph osd rm osd.5`
	7) delete the deployment `kubectl delete deployment -n rook-ceph rook-ceph-osd-id-5`
	8) delete osd data dir on node `rm -rf /var/lib/rook/osd5`

	"""Creates a python socket client that will interact with javascript."""
	import socket

	socket_path = '/tmp/node-python-sock'
	# connect to the unix local socket with a stream type
	client = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
	client.connect(socket_path)
	# send an initial message (as bytes)
	client.send(b'python connected')
	# start a loop

	#!/bin/bash
	# This is meant to be executed from packer

	if [ -z "$PACKER_BUILD_NAME" ] && [ -z "$PACKER_BUILDER_TYPE" ]; then
	echo "Do not run by hand, this is run by packer"
	exit 1
	fi

	export DEBIAN_FRONTEND=noninteractive