Nedumaran Rajagopal neduma

On Tue Oct 27, 2015, history.state.gov began buckling under load, intermittently issuing 500 errors. Nginx's error log was sprinkled with the following errors:

2015/10/27 21:48:36 [crit] 2475#0: accept4() failed (24: Too many open files)

2015/10/27 21:48:36 [alert] 2475#0: *7163915 socket() failed (24: Too many open files) while connecting to upstream...

An article at http://www.cyberciti.biz/faq/linux-unix-nginx-too-many-open-files/ provided directions that mostly worked. Below are the steps we followed. The steps that diverged from the article's directions are marked with an *.

* Instead of using su to run ulimit on the nginx account, use ps aux | grep nginx to locate nginx's process IDs. Then query each process's file handle limits using cat /proc/pid/limits (where pid is the process id retrieved from ps). (Note: sudo may be necessary on your system for the cat command here, depending on your system.)
Added fs.file-max = 70000 to /etc/sysctl.conf

Erlang for beginners

Bash string manipulation cheatsheet

Assignment
Assign `value` to `variable` if `variable` is not already set, `value` is returned. Combine with a `:` no-op to discard/ignore return `value`.	`${variable="value"}` `: ${variable="value"}`

Option 1: Command-line download extension as zip and extract

extension_id=jifpbeccnghkjeaalbbjmodiffmgedin   # change this ID
curl -L -o "$extension_id.zip" "https://clients2.google.com/service/update2/crx?response=redirect&os=mac&arch=x86-64&nacl_arch=x86-64&prod=chromecrx&prodchannel=stable&prodversion=44.0.2403.130&x=id%3D$extension_id%26uc" 
unzip -d "$extension_id-source" "$extension_id.zip"

Thx to crxviewer for the magic download URL.

	#!/bin/bash

	# set up some variables

	NOW_DATE=$(date '+%Y-%m-%d-%H-%M')
	RESTORE_FROM_INSTANCE_ID=<source name>
	TARGET_INSTANCE_ID=<target name>
	TARGET_INSTANCE_CLASS=db.m4.large
	VPC_ID=<vpc subnet id>
	NEW_MASTER_PASS=<root password>

	#!/bin/sh

	# Make sure to:
	# 1) Name this file `backup.sh` and place it in /home/ubuntu
	# 2) Run sudo apt-get install awscli to install the AWSCLI
	# 3) Run aws configure (enter s3-authorized IAM user and specify region)
	# 4) Fill in DB host + name
	# 5) Create S3 bucket for the backups and fill it in below (set a lifecycle rule to expire files older than X days in the bucket)
	# 6) Run chmod +x backup.sh
	# 7) Test it out via ./backup.sh

	---

	hosts: all
	tasks:
	- name: add github ssh key
	copy: >
	src=files/id_rsa.github
	dest=/root/.ssh/id_rsa.github
	owner=root
	group=root

	import groovy.sql.Sql
	import java.util.Date
	import java.text.SimpleDateFormat

	/*
	* THIS IS AN EXAMPLE SNIPPET. FOR MORE DETAILS SEE THE FOLLOWING BLOG ARTICLE:
	* https://blog.codecentric.de/en/?p=30502
	*
	* This Jenkins Job DSL Groovy Script creates Continuous Integration (CI) Jobs
	* for all Maven & Ant projects that exist on a GitLab Server.

	\n
	============= HOST: ==========\n
	\n
	local_ip: %{local_ip}\n
	local_port: %{local_port}\n
	remote_ip: %{remote_ip}\n
	remote_port: %{remote_port}\n
	\n
	======= CONNECTION: ==========\n
	\n

	#!/usr/bin/env python

	import sys
	import argparse
	import ansible.constants as C
	import ansible.inventory
	import subprocess


	def get_inventory(subset_pattern):