Magento 2 deployment without the downtime

2 SeptemberSep, 2016
Robert Egginton

We recently did a blog post on deploying Magento 2 for production. Since then we’ve refined this process in order to minimise downtime and we wanted to explain these changes in a new blog as the last one was already long enough!

Move compilation to RC

The primary change that we made was to move static and DI compilation out of the live environment and into the build environment (RC) so that this work is done offline in the release candidate.

There are two wrinkles to this:

  1. These compilation steps require a link to the Magento database
  2. Update scripts may then require re-compilation of these steps.

The first of these issues of needing a database link is easy to solve – copy env.php into the relevant RC folder.

The second issue of needing to run setup scripts before compilation is trickier, as you do not want to run these on the live database before the lengthy process of static compilation and/or code updates as you’ll end up with code and data out of sync. Instead we take a copy of the live database in these cases and run the upgrade scripts on these before static and DI compilation in RC. After rsync when we run the setup upgrade on the live server, we can use –keep-generated to ensure that our updated static and DI files are not replaced.

Updated deployment summary

Here are the general steps of this updated process. There is less detail here than in the last post, so if you are trying to set this up then please check that post for reference.

1. Update RC files via git

Update RC files via git
No change here other than to ensure that env.php is available in app/etc on RC.

2. If running setup scripts, make a copy of the live database and run scripts

make a copy of the live database
For speedy duplication we create duplicate database tables using CREATE TABLE new LIKE old and copy the data using INSERT INTO new SELECT * FROM old. Obviously this is a simplification. Our class to perform the duplication is available on github.

3. Static and DI compilation on RC database (if exists) or live database

Static and DI compilation
Depending on whether we’ve duplicated the live database we will either use the live or RC database. This is done by modifying the env.php file – easily done as it’s a PHP array definition that can be loaded in by $envData = include('env.php') and written out by file_put_contents('env.php', "<?php\nreturn " . var_export($envData, true) . ";");

4. Rsync file differences including static and DI generation files

Rsync files
The same as before, except that we sync the pub/static files and var/generation files. A slight issue is that bundled javascript files in pub/static/_cache will be deleted and only recreated on the fly if the full page cache is cleared.

5. Run live setup scripts in maintenance mode if needed

Run live setup scripts
This reduces downtime from the order of 20 minutes to 20 seconds for scripts to run.

That’s it! Much improved in terms of down-time, and seems solid as we’ve been using this on production for a while now.

ABOUT THE AUTHOR

Robert Egginton

As our chief problem-solver and systems architect, Rob is involved in every aspect of our development processes. Rob is partial to a bit of improvisational theatre, and setting up a smart home on a budget.