About a month ago I wrote about how cool was to migrate to HHVM on OpenShift. Custom cartridge for Nginx + HHVM and MariaDB was running fast and I was really excited about the new stack. I was landing on a new, beautiful world.

About a week later I faced some problems because of disk space. Files took only 560MB over 1GB but OpenShift shell gave me an error for 100% disk usage (and a nice blank page on the home because cache couldn’t be written). I wasn’t able to understand why it was giving me that error. It probably depends on log files written by custom cartridge in other position inside of the filesystem. No idea. Anyway I had no time to go deeper so I bought 1 more GB of storage.

The day after I bought the storage blog speed goes down. It was almost impossible to open the blog and CloudFlare gives me timeout for half of the requests. Blog visits started to fall and I have no idea about how to fix that. Some weeks later I discover some troubles with My Corderwall Badges and Simple Sharer Button Adder but, in the OpenShift environment, I had no external caching system useful to handle this kind of problems.

I didn’t want to come back to MySQL and Apache but also trash all my articles wasn’t fun so I choose something I rejected 3 years ago: I took a standalone server.

server-in-datacenter

First choice was Scaleway. It’s trendy and is BareMetal. 3.5€ for a 4 core ARM (very hipster choice), 2 GB RAM, 50 GB SSD server. New interface is cool, better then Linode and Digital Ocean, server and resources are managed easily. Unfortunately HHVM is still experimental on ARM and SSD are on SAN, and they aren’t so fast (100MB/s).

Next choice was OVH. New 2016 VPS SSD (available in Canadian datacenters) are cheap enough (3.5$) and offer a virtual core Xeon with 2 GB RAM and 10 GB SSD. Multicore performances are lower and you have a lot of less storage but is an X86-64 architecture and SSD is faster (250 MB/s). I took this one!

Unfortunately my preferences aren’t changed since my first post. I’m still a developer, not a sysadmin. I’m not a master in Linux configuration and my stack has several running parts and my blog was still unavailable. My beautiful migration on cutting edge technologies became an emergency landing.

Luckily I found several online tutorial which explain how to master the WordPress stack. In the next days I completed the migration and my new stack now runs on: Pound, Varnish, Nginx, HHVM, PHP-FPM and MariaDB. I hope to have enough time in the coming days to publish all the useful stuff I used for configuration.

For the moment I’m proud to share average response time of the home page: 342ms 🙂

bedrock_big_logo During the last couple of weeks I had to work on a PHP project with a custom WordPress stack I have never used before: Bedrock.

The home page says “Bedrock is a modern WordPress stack that gets you started with the best development tools, practices, and project structure.“.

What Bedrock really is

It is a regular WordPress installation with a different folder structure and is integrated with composer for dependencies management and capistrano for deploy. The structure reminds Rails or similar frameworks but contains usual WordPress component and run on the same web stack.

├── composer.json
├── config
│   ├── application.php
│   └── environments
│       ├── development.php
│       ├── staging.php
│       └── production.php
├── vendor
└── web
├── app
│   ├── mu-plugins
│   ├── plugins
│   ├── themes
│   └── uploads
├── wp-config.php
├── index.php
└── wp

Server configuration

The project use to works on Apache with mod_php but I personally don’t like this stack. I’d like to test it on HHVM but at the moment I preferred to run it on nginx with PHP-FPM. Starting with an empty Ubuntu 14.04 installation I set up a LEMP stack with memcached and Redis using apt-get:

apt-get update
apt-get install build-essential tcl8.5 curl screen bootchart git mailutils munin-node vim nmap tcpdump nginx mysql-server mysql-client memcached redis-server php5-fpm php5-curl php5-mysql php5-mcrypt php5-memcache php5-redis php5-gd

Everything works fine except the Redis extension (used for custom function unrelated with WordPress). I don’t know why but the config file wasn’t copied into the configuration directory /etc/php5/fpm/conf.d/. You can find it among the available mods into /etc/php5/mods-available/.

PHP-FPM uses a standard configuration placed into /etc/php5/fpm/pool.d/example.conf. It listen on 127.0.0.1:9000 or unix socket in /var/run/php5-fpm-example.sock (I assume the configured name was “example”).

Memcached should be configured to be used for session sharing among multiple servers. To activate it you need to edit the php.ini configuration file setting the following parameters into /etc/php5/fpm/php.ini

session.save_handler = memcache
session.save_path = 'tcp://192.168.0.1:11211,tcp://192.168.0.2:11211'

nginx configuration is placed into /etc/nginx/sites-available/ and linked into /etc/nginx/sites-enabled/ as usual and forward request to PHP-FPM for PHP files.

server {
listen 80 default deferred;
root /var/www/example/htdocs/current/web/;
index index.html index.htm index.php;
server_name www.example.com;
access_log /var/www/example/logs/access.log;
error_log /var/www/example/logs/error.log;
location / {
try_files $uri $uri/ /index.php?q=$uri&$args;
}
location ~\.php$ {
try_files $uri =404;
# fastcgi_pass 127.0.0.1:9000;
fastcgi_pass unix:/var/run/php5-fpm-example.sock;
fastcgi_index index.php;
fastcgi_buffers 16 16k;
fastcgi_buffer_size 32k;
include fastcgi_params;
}
location ~ /\.ht {
deny all;
}
}

Root directory will be web/ of Bedrock prefixed with current/ to support the capistrano directory structure displayed below.

├── current -> /var/www/example/htdocs/releases/20150120114500/
├── releases
│   ├── 20150080072500
│   ├── 20150090083000
│   ├── 20150100093500
│   ├── 20150110104000
│   └── 20150120114500
├── repo
│   └── <VCS related data>
├── revisions.log
└── shared
└── <linked_files and linked_dirs>

Local configuration

I’m quite familiar with capistrano because of my Ruby recent background. You need a Ruby version greater then 1.9.3 to run it (RVM helps). First step is to download dependencies. Ruby uses Bundler.

# run it to install bundler gem the first time
gem install bundler
# run it to install dependencies
bundle install

Bundler read the Gemfile (and Gemfile.lock) and download all the required gems (Ruby libraries).

Now the technological stack is ready locally and on server 🙂
I’ll probably describe how to run a LEMP stack on OS X in a next post. For the moment I’m assuming you are able to run it locally. Here is useful guides by Jonas Friedmann and rtCamp.

Anyway Bedrock could run over any LAMP/LEMP stack. The only “special” feature is the Composer integration. Composer for PHP is like Bundler for Ruby. Helps developers to manage dependencies in the project. Here is used to manage plugins, themes and WordPress core update.

You can run composer install to install libraries. If you update libraries configuration or you want to force download of them (maybe after a fresh install) run composer update.

Deploy

Capistrano enable user to setup different deploy environment. A global configuration is defined and you need to specify only custom configuration for each environment. An example of /config/deploy/production.rb:

set :application, 'example'
set :stage, :production
set :branch, "master"
server '192.168.0.1', user: 'user', roles: %w{web app db}

Everything else is inherited from global config where are defined all the other deploy properties. Is important to say that deploy script of capistrano on Bedrock only download source code from Git repo and run composer install for main project. If you need to run in on any plugin you new to define a custom capistrano task and run it after the end of deploy. For instance you can add in the global configuration the following lines in order to install dependencies on a specific plugin:

namespace :deploy do
desc 'Rebuild Plugin Libraries'
task :updateplugin do
on roles(:app), in: :sequence, wait: 5 do
execute "cd /var/www/#{fetch(:application)}/htdocs/current/web/app/plugins/anything/ && composer install"
end
end
end
after 'deploy:publishing', 'deploy:updateplugin'

Now you are ready to deploy your Bedrock install on server!
Simply run cap production deploy, restart PHP-FPM (service php5-fpm restart) and enjoy it 😀

Many thanks to Giuseppe, great sysadmin and friend, for support during development and deploy of this @#@?!?@# application.

YouPorn is one of the most visited porn site on the web. I applied for a job as developer in 2009 because of a post who talk about its technological stack.

I heard again about its infrastructure because, about an year ago, @ErikPickupYP spoke about the great switchover at CooFoo and @antirez tweet some details regarding datastore. The development team rewrote the entire site using Redis as primary database.

Original stack was based on Perl and Catalyst and powered the site from 2006 to 2011. After acquisition they rewrote the site using a well designed LAMP stack.

The chosen framework is Symfony2 (which uses Doctrine as ORM) running over nginx with PHP-FPM helped by Varnish (speed up requests, manage cache and check servers status) and HAProxy (load balance and health check of servers). Syslog-ng handle logs. They maintain two pools of servers: a write pool with a fail-over to backup-Master and a read pool will servers except the master.

Datastore is the most interesting part. Initially they used MySQL but more than 200 million of pageviews and 300K query per second are too much to be handled using only MySQL. First try was to add ActiveMQ to enqueue writes but a separate Java infrastructure is too expensive to be maintained. Finally they add Redis in front of MySQL and use it as main datastore.

Now all reads come from Redis. MySQL is used to allow the building new sorted sets as requirements change and it’s highly normalized because it’s not used directly for the site. After the switchover additional Redis nodes were added, not because Redis was overworked, but because the network cards couldn’t keep up with Redis 😀

Lists are stored in a sorted set and MySQL is used as source to rebuild them when needed. Pipelining allows Redis to be faster and Append-only-file (AOF) is an efficient strategy to easily backup data.

In the end YouPorn uses a LAMP stack “on-steroids” which smartly uses Redis and other modern middlewares.

Sources: