Colton Dick coltondick

Notes

These instructions were developed for Ubuntu 12.04, but they will work for 12.10 and 13.04 with minor differences noted below.
If you have trouble, see the Errors section at the bottom.

Procedure

Install Apache

apt-get install apache2

Session Management in an Autoscaling Environment

Problem Statement

User sessions in J2EE and LAMP stacks have traditionally been handled in memory by the application server handling the user request. Because of that, load balancers have been configured to use sticky sessions. By sticky sessions we mean that once the user has visited the site, they will be assigned an app server and will return to that server for subsequent requests. The load balancers typically handle that by referencing the users session cookie.

Elastic cloud environments differ from traditional server configurations in that they have a variable number of servers based on traffic loads whereas traditional configurations had a fixed number of servers. When traffic volumes decline it is necessary to vaporize servers. In doing so, we would lose user sessions (essentially forcing a logout) unless we come up with a new strategy for session management.

A new approach

After much research, it is clear that the best

To remove a submodule you need to:

Delete the relevant section from the .gitmodules file.
Stage the .gitmodules changes git add .gitmodules
Delete the relevant section from .git/config.
Run git rm --cached path_to_submodule (no trailing slash).
Run rm -rf .git/modules/path_to_submodule (no trailing slash).
Commit git commit -m "Removed submodule "
Delete the now untracked submodule files rm -rf path_to_submodule

	#!/bin/sh

	REPOSRC=$1
	LOCALREPO=$2

	# We do it this way so that we can abstract if from just git later on
	LOCALREPO_VC_DIR=$LOCALREPO/.git

	if [ ! -d $LOCALREPO_VC_DIR ]
	then

	# Check if X-Forwarded-For header is set and extract the leftmost IP into the variable
	SetEnvIf X-Forwarded-For "^(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})" XFFCLIENTIP=$1
	# Setup a LogFormat with the env variable in it
	LogFormat "%{XFFCLIENTIP}e %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" proxy

	# If X-Forwarded-For don't log, previous rules take care of it
	SetEnvIf X-Forwarded-For ".+" dontlog
	# Filter ELB-HealthChecker
	SetEnvIf User-Agent "^ELB-HealthChecker.*" dontlog

	SELECT s.inst_id,
	s.sid,
	s.serial#,
	p.spid,
	S.Username,
	S.Program,
	'exec rdsadmin.rdsadmin_util.kill('\|\|s.sid\|\|','\|\|s.serial#\|\|');'
	FROM gv$session s
	Join Gv$process P On P.Addr = S.Paddr And P.Inst_Id = S.Inst_Id
	Where S.Type != 'BACKGROUND'

	/* Use WP-CLI instead https://developer.wordpress.org/cli/commands/search-replace/ */

	SET @oldsite='http://oldsite.com';
	SET @newsite='http://newsite.com';
	UPDATE wp_options SET option_value = replace(option_value, @oldsite, @newsite) WHERE option_name = 'home' OR option_name = 'siteurl';
	UPDATE wp_posts SET post_content = replace(post_content, @oldsite, @newsite);
	UPDATE wp_links SET link_url = replace(link_url, @oldsite, @newsite);
	UPDATE wp_postmeta SET meta_value = replace(meta_value, @oldsite, @newsite);

	/* only uncomment next line if you want all your current posts to post to RSS again as new */

	packages:
	yum:
	gcc: []
	libstdc++-devel: []
	gcc-c++: []
	fuse: []
	fuse-devel: []
	libcurl-devel: []
	libxml2-devel: []
	openssl-devel: []

	If you have a huge repository (in size and in history) and want to add a subfolder
	to your project as a submodule you can follow this example to save time and space
	using git's shallow clone and shallow checkout feature. It is a bit more complicated
	in this example because I assume that you want your submodule to track a non-default
	branch, called `mybranch`, instead of the `master` branch. Things could probably get
	a lot simpler when using the default branch. After following the commands in these
	examples you can use `git submodule update` and `git submodule update --remote` as normal.