kyklos kyklos

Collection of sysctl networking notes

List & reloading changes
Summary details of each connection status
Settings tweaking in /etc/sysctl.conf
- Detailed setting notes
- Control TIME_WAIT and connection tracking timeouts
Miscellaneous
- Nginx Plus additions
Further reading

The fastest remote directory rsync over ssh archival I can muster (40MB/s over 1gb NICs)

This creates an archive that does the following:

rsync (Everyone seems to like -z, but it is much slower for me)

a: archive mode - rescursive, preserves owner, preserves permissions, preserves modification times, preserves group, copies symlinks as symlinks, preserves device files.
H: preserves hard-links
A: preserves ACLs

How to setup your own CA with OpenSSL

For educational reasons I've decided to create my own CA. Here is what I learned.

First things first

Lets get some context first.

Easy Kubernetes Installation on CoreOS

At Timeline Labs, we are continuously looking at new technologies to see what fits our needs. We are especially excited about Kubernetes from Google to manage our services atop Docker and CoreOS.

This process for installing Kubernetes on CoreOS uses Flannel for Kubernetes networking and should be cloud provider agnostic. To deploy the Kubernetes master functionality into the cluster, it uses fleetctl.

Thanks to Kelsey Hightower and his blog posts! They served as a great starting point for this process.

How do I get this running?

Add the cloud config below to your own and bring up your cluster using a CoreOS version with Docker 1.3 (currently v472.0.0 in alpha). During that initial boot, the download-kubernetes and download-flannel units will download binaries from the latest project release and use those.

Overview

The goal of this document to cover all aspects of Kubernetes management, including how resources are expressed, constrained and accounted for. This started a way to ensure that alternate container runtime implementation like Kata containers will behave from a resource accounting and consumption point of view in the same manner as runc.

Location of the latest version of this document: https://gist.github.com/mcastelino/b8ce9a70b00ee56036dadd70ded53e9f

If you do not understand cgroups please refer to a quick primer at the bottom of this document. This will help you understand how the resource enforcement actually works.

Kubernetes Resource Management

	var EventEmitter = require("events").EventEmitter,
	redis = require("redis"),
	dateformat = require("dateformat");

	function population32(x)
	{
	x -= ((x >> 1) & 0x55555555);
	x = (((x >> 2) & 0x33333333) + (x & 0x33333333));
	x = (((x >> 4) + x) & 0x0f0f0f0f);
	x += (x >> 8);

	#!/bin/bash

	NODE_NAME=$1
	ROLLOUT_CMD=$2

	if [[ "$NODE_NAME" == "" ]]; then
	echo "
	USAGE: ./drain.sh <NODE_NAME>

	Drains a node from its Deployments/Stateful set pods.

	# recursive search for keys containing "string" stripping empty results
	jq '.. \| objects \| with_entries(select(.key \| contains("ftp"))) \| select(. != {})'

	# same, but output propper array
	jq '[ .. \| objects \| with_entries(select(.key \| contains("ftp"))) \| select(. != {}) ]'
	# or
	jq 'map( .. \| objects \| with_entries(select(.key \| contains("ftp"))) \| select(. != {}) )'

	# transform input from {type: a, amount: 1} to {a: 1} and sum all values by type
	jq '[ .[] \| {(.type): .amount} ] \| map(to_entries) \| add \| group_by(.key) \| map({key: .[0].key, value: map(.value) \| add}) \| from_entries'

	# For recent versions of Ubuntu:
	- https://www.pugetsystems.com/labs/hpc/ubuntu-22-04-server-autoinstall-iso/

	# Docs:
	- https://wiki.ubuntu.com/FoundationsTeam/AutomatedServerInstalls
	- https://wiki.ubuntu.com/FoundationsTeam/AutomatedServerInstalls/ConfigReference
	- https://cloudinit.readthedocs.io/en/latest/topics/datasources/nocloud.html
	- https://discourse.ubuntu.com/t/please-test-autoinstalls-for-20-04/15250/53

	# Download ISO Installer: