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List of Linux networking tools

netstat (ss)

Displays contents of /proc/net files. It works with the Linux Network Subsystem, it will tell you what the status of ports are ie. open, closed, waiting, masquerade connections. It will also display various other things. It has many different options. Netstat (Network Statistic) command display connection info, routing table information etc. To displays routing table information use option as -r.

Sample output:

Proto Recv-Q Send-Q  Local Address          Foreign Address        (state)    
tcp4 0 0 127.0.0.1.62132 127.0.0.1.http ESTABLISHED

Better SSH Authorized Keys Management

A seemingly common problem that people encounter is how to handle all of your users authorized_keys file.

People struggle over management, ensuring that users only have specific keys in the authorized_keys file or even a method for expiring keys. A centralized key management system could help provide all of this functionality with a little scripting.

One piece of functionality overlooked in OpenSSH is the AuthorizedKeysCommand configuration keyword. This configuration allows you to specify a command that will run during login to retrieve a users public key file from a remote source and perform validation just as if the authorized_keys file was local.

Here is an example directory structure for a set of users with SSH public keys that can be shared out via a web server:

This document is a list with video playlists from recent conferences on DevOps, WebOps, SRE, Systems administration, Monitoring, Building and Scaling Highly available sytems, apps and websites.

Available

Internet Scale Services Checklist

A checklist for designing and developing internet scale services, inspired by James Hamilton's 2007 paper "On Desgining and Deploying Internet-Scale Services."

http://mvdirona.com/jrh/talksandpapers/jamesrh_lisa.pdf

Basic tenets

Does the design expect failures to happen regularly and handle them gracefully?
Have we kept things as simple as possible?

AWS Certification notes

Those are my personal notes on AWS Solution Architect certification preparation. Hope you find them usefull.

To pass AWS certification, you should have:

Sound knowledge about most of the AWS services ( EC2, VPC, RDS, Cloudfront, S3, Route53 etc,)
Hands on experience with AWS services.

Amazon Web Services (AWS) & Google Cloud Platform (GCP) explained in simple English

This guide is only representative from my point of view and it may not be accurate and you should go on the official AWS & GCP websites for accurate and detailed information. It's initially inspired by AWS in simple English and GCP for AWS professionals. The idea is to compare both services, give simple one-line explanation and examples with other software that might have similiar capabilities. Comment below for suggestions.

Category	Service	AWS	GCP	Description	It's like
Compute	IaaS	Amazon Elastic Compute Cloud (EC2)	Google Compute Engine	Type-1 virtual servers	VMware ESXi, Citrix XenServer
	PaaS	AWS Elastic Beanstalk	Google App Engine	Running your app on a platform

This file contains links to online materials which I find useful for re-reading from time to time. I had started this initiative back in HP when created email list called Arete among my colleagues and spamming it with some useful materials on a regular basis. Since I left I wanted to continue sharing valuable content, here's why I have continued this here. Use the comments, to add more valuable stuff and never stop learning!

Bash academy - an initiative to promote and educate the bash shell language.

How to reset the scmadmin (administrator) password in SCM Manager?

Recently I had some troubles in resetting the SCM Manager admin password and here's simply how to do it.

Look for file users.xml where the users and passwords are stored. Usual locations:

/root/.scm/config/users.xml
/var/scm-server/conf/users.xml
$SCM_INSTALL_OR_HOME_DIR/config/users.xml

	#!/bin/bash
	# Nico Snyman, [email protected], 14/05/2015
	# Change an instance type, while keeping snapshots
	# This script will stop an instance identified by instance ID,
	# take snapshots of all atached volumes, and restart it
	# Use:
	# -i instance ID - REQUIRED - stored in instance_id
	# -t instance new instance type - REQUIRED - stored in instance_type
	# -s if set to 0, no snapshot will be taken, dafault is 1
	# (take snapshot of attached volumes) - stored in snapshot

	#!/bin/env/python
	#
	# Source: http://blog.webhose.io/2015/08/16/dead-simple-for-devs-python-crawler-script-for-extracting-structured-data-from-any-almost-website-into-csv/

	import sys, thread, Queue, re, urllib2, urlparse, time, csv
	### Set the site you want to crawl & the patterns of the fields you want to extract ###
	siteToCrawl = "http://www.amazon.com/"
	fields = {}
	fields["Title"] = '<title>(.*?)</title>'
	fields["Rating"] = 'title="(S+) out of 5 stars"'