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WordPress is a powerful blogging platform written in PHP. This charm aims to deploy WordPress in a fashion that will allow anyone to scale and grow out
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This charm is available in the Juju Charm Store, to deploy you'll need at a minimum: a cloud environment, a working Juju installation,
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and a successful bootstrap. Please refer to the [Juju Getting Started](https://juju.ubuntu.com/docs/getting-started.html) documentation before continuing.
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Once bootstrapped, deploy the MySQL charm then this WordPress charm:
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Add a relation between the two of them
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juju add-relation wordpress mysql
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Expose the WordPress installation
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## Scaled Down Usage for Personal Use
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If you're just looking to run a personal blog and want to save money you can run all of this on a single node, here's an entire single node installation from scratch:
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juju deploy --to 0 wordpress
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juju deploy --to 0 mysql
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juju add-relation wordpress mysql
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This will run everything on one node, however we still have the flexibility to grow horizontally. If your blog gets more traffic and you need to scale:
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juju add-unit wordpress
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Since we're omitting the `--to` command Juju will fire up a new dedicated machine for Wordpress and relate it. You can also `remove-unit` when the surge is over and go back to a cheaper one node set up.
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You can deploy a memcached server and relate it to your WordPress service to add memcache caching. This will
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automagically install [WP-FFPC](http://wordpress.org/extend/plugins/wp-ffpc/) (regardless of your tuning settings) and configure it to cache
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rendered pages to the memcache server. In addition to this layer of caching, Nginx will pull directly from memcached bypassing PHP altogether.
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You could theoretically then turn off php5-fpm on all of your servers and just have Nginx serve static content via memcached (though, you
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wouldn't be able to access the admin panel or any uncached pages - it's just a potential scenario).
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juju add-relation memcached wordpress
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This setup will also synchronize the flushing of cache across all WordPress nodes, making it ideal to avoid stale caches.
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A small note, when using the Apache2 engine and memcache, all request will still be sent to WordPress via Apache where typical caching
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procedures will take place and wp-ffpc will render the memcached page.
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This WordPress charm comes with several tuning levels designed to encompass the different styles in which this charm will be used.
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A use case for each tuning style is outlined below:
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The Bare configuration option is meant for those who wish to run the stock WordPress setup with no caching, no manipulation of data,
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and no additional scale out features enabled. This is ideal if you intend to install additional plugins to deal with coordinating
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WordPress units or simply wish to test drive WordPress as it is out of the box. This will still create a load-balancer when an additional
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unit is created, though everything else will be turned off (WordPress caching, APC OpCode caching, and NFS file sharing).
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To run this WordPress charm under a bare tuning level execute the following:
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juju set wordpress tuning=bare
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When running in Single mode, this charm will make every attempt to provide a solid base for your WordPress install. By running in single
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the following will be enabled: Nginx microcache, APC OpCode caching, WordPress caching module, and the ability to sync files via NFS.
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While Single mode is designed to allow for scaling out, it's meant to only scale out for temporary relief; say in the event of a large
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traffic in-flux. It's recommended for long running scaled out versions that optimized is used. The removal of the file share speeds up
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the site and servers ensuring that the most efficient set up is provided.
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To run this WordPress charm under a single tuning level execute the following:
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juju set wordpress tuning=single
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If you need to run WordPress on more than one instance constantly, or require scaling out and in on a regular basis, then Optimized is the
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recommended configuration. When you run WordPress under an Optimized tuning level, the ability to install, edit, and upgrade themes and plugins
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is disabled. By doing this the charm can drop the need for an NFS mount which is inefficient and serve everything from it's local disk.
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Everything else provided in Single level is available. In order to install or modify plugins with this setup you'll need to edit and commit
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them to a forked version of the charm in the files/wordpress/ directory.
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To run this WordPress charm under an optimized tuning level execute the following:
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juju set wordpress tuning=optimized
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### Handling wp-content
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In order to allow for custom WordPress content within the Juju charm a separate configuration option exists for pointing to any Git or Bzr
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repository. An example of a valid formed wp-content repository can be found on the [Juju Tools Github page](https://github.com/jujutools/wordpress-site).
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To set the wp-content directive to a git repository, use one of the following formats making sure to replace items like `host`, `path`, and `repo` with their
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juju set wordpress wp-content=git@host:path/repo.git
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juju set wordpress wp-content=http://host/path/repo.git
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juju set wordpress wp-content=git://host/path/repo.git
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If you wish to use a bzr repository, then apply one of the following schemes replacing items like `host`, `username`, `path`, and `repo` with their respective values:
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For LaunchPad hosted repostiories:
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juju set wordpress wp-content=lp:~username/path/repo
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For other Bzr repositories:
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juju set wordpress wp-content=bzr://host/path/repo
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juju set wordpress wp-content=bzr+ssh://host/path/repo
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Setting the wp-content option to an empty string ("") will result in no further updates being pulled from that repository; however, the last pull will remain
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on the system and will not be removed.
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This option will create a directory `_debug` at the root of each unit (`http://unit-address/_debug`). In this directory are two scripts: info.php (`/_debug/info.php`)
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and apc.php (`/_debug/apc.php`). info.php is a simple phpinfo script that will outline exactly how the environment is configured. apc.php is the APC admin portal which
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provides APC caching details in addition to several administrative functions like clearing the APC cache. This should never be set to "yes" in production as it exposes
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detailed information about the environments and may provide a way for an intruder to DDoS the machine.
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juju set wordpress debug=yes
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to disable debugging:
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juju set wordpress debug=no
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The debugging is disabled by default.
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By default the WordPress charm will install nginx and php5-fpm to serve pages. In the event you do not wish to use nginx - for whatever reason - you can switch to Apache2.
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This will provide a near identical workflow as if you were using nginx with one key difference: memcached. In nginx, the cached pages are served from memcached prior to
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hitting the php contents, this isn't possible with apache2. As such memcached support still works, since it falls back to the WordPress caching engine, but it's not as robust.
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Otherwise, Apache2 will still perform balancing and everything else mentioned above. You can switch between engines at will with the following:
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juju set wordpress engine=apache2
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juju set wordpress engine=nginx
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Any other value will result in the default (nginx) being used.
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# Known Limitations and Issues
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At this time WordPress + Memcached don't work on HP Cloud's standard.xsmall. To get around this deploy the WordPress charm with the
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charm to at least a `standard.small`, to do this:
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juju deploy --constraints "instance-type=standard.small" wordpress
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This only is a problem when attempting to relate memcached to WordPress, otherwise an xsmall is _okay_ though it's really not the best
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sized platform for running a stable WordPress install.
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## Single mode and the scale-out
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If you're in Single mode and you want to/need to scale out, but you've been upgrading, modifying, and installing plugins + themes like
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a normal WordPress user on a normal install; you can still scale out but you'll need to deploy a shared-fs charm first. At the time of
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this writing only the NFS charm will work, but as more shared-fs charms come out (gluster, ceph, etc) that provide a shared-fs/mount
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interface those should all work as well. In this example we'll use NFS:
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juju add-relation nfs wordpress:nfs
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By doing so, everything in the wp-contents directory is moved to this NFS mount and then shared to all future WordPress units. It's strongly
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recommended that you first deploy the nfs mount, _then_ scale WordPress out. Failure to do so may result in data loss. Once nfs is deployed,
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running, and related you can scale out the WordPress unit using the following command:
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juju add-unit wordpress
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In the event you want more than one unit at a time (and do not wish to run the add-unit command multiple times) you can supply a `-n` number
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of units to add, so to add three more units:
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juju add-unit -n3 wordpress
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# Contact Information
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## WordPress Contact Information
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- [WordPress Homepage](http://www.wordpress.org)
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- [Reporting bugs](http://codex.wordpress.org/Reporting_Bugs) on WordPress itself
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