It’s all about eXperience

Gaetano Giunta

Symfony LiveSept 2016

Designing a Docker Stack for Symfony apps:

lessons learned

If you have never heard of used Docker

A.I am living under a rock

B.I am living on the moon01

What is it, in one phraseDefinition according to Me™

"just like a VM, but lighter"

Getting started is easyGetting off the hook on the other hand…

"just like a VM, but lighter"

all it takes to get started:

docker run -ti ubuntu:15.10 bash

Where the magic stops

• how to share application data with the container?

• how to access the apps in the container (map container ports to the host)?

• how to start multiple containers together and connect them?

• how to access the log files from the application?

Then things get tricky

• mapping of user ids to properly handle filesystem permissions

• linking containers when there are circular dependencies (solved with recent Docker versions)

• applying security updates to existing containers

• and more…

• for some more of the fine details, see f.e. this blog post: http://blog.kaliop.com/en/blog/2015/05/27/docker-in-real-life-the-tricky-parts/

Docker Compose to the rescue!

• a single file describes multiple containers

• a single command to start/stop them all together

• permits further automation (via eg. introduction of variables)

A Docker stack for Symfony apps

A.Source code?

B.https://github.com/kaliop-uk/websummercamp2016

02

Introducing the stack

• apache• mysql• memcached• solr• php cli• varnish• nginxplus• control panels for all of the above• phpmyadmin• maildev (an smtp server for development purposes)• dockerui (a container monitoring the whole container stack [Inception!])

In 1000 wordsAscii art rocks!

How it worksAll the things someone else has figured out for you

• configuration of the applications is mounted as volume, not copied into the image

a simple service restart is sufficient to take changes into account• application source code is kept on the host computer

no risk of losing changes when rebuilding containersno need to have containers running GUI or IDEs

• all log files accessible from the host, in one place• use ssh-agent to avoid developers storing their own private keys inside

the containers

How it works, IIAll the things someone else has figured out for you

• allow developers to change some variables, while providing good defaults• a configuration file is provided, which has all the variables that developers can customize

• a 2nd configuration file has to be created with local changes (empty is fine)

• ex: id of the user account on the host computer, or github credentials

• the config file with local changes is not committed to git

• not tied to a specific projectcan be quickly converted for usage of Drupal / eZPublish / etc…

• two of them can be run in parallel

How it works, IIIAll the things someone else has figured out for you

• the containers have to replicate as much as possible a production environment

the base images used are Debian or Ubuntu (the platforms we generally deploy on)

• the applications are started using service start and service stop commands

• cronjob tasks definitions are kept as part of the sources of the stack

• developers can access 2 Symfony environments using one stack• one via http (ie. DEV), one via https + Varnish (ie. UAT)

Demo timeAt last!

I’ll be here all night

THANK YOU

https://github.com/kaliop-uk/websummercamp2016

• @gggeek• www.kaliop.co.uk