At the last meetup of the Berlin PHP Usergroup, Christoph gave a talk about Vagrant.
Good enough of a reason to write down or re-cap some things I’ve learned with or about Vagrant over the last two years.
Base boxes
There are lots of base boxes available, but don’t be tempted to rely on them (e.g. via config.vm.box_url).
- Vagrantbox.es doesn’t actually mirror images and that is a huge pain.
- Available base boxes tend to be outdated. (Think kernel, packages, etc.) Running updates each time you provision is painful.
- Available base boxes use U.S. mirrors only/mostly/always — because we all live in the U.S. of A..
- Your VirtualBox guest additions may not match with your system and this may create random issues.
Your best bet is to create your own base box and establish a workflow e.g. using veewee or bento.
At EasyBib, we use bento and we created a definition which replaces the sources with Ubuntu’s nifty mirror syntax (since we’re pretty distributed at times, everyone appreciates this) and upgrades the base system. Either one of these tools introduce more Ruby into your organization and you may think “WTF — why do I need this?!”, but the clear advantage is that no one has to write down a lot of steps how to recreate these boxes and anyone can do it.
In bento’s case, the requirement is Ruby 1.9.1+ (getting this installed is IMO the hardest) and bundler. bundle install in your bento-clone gets you everything needed and then the three commands require build, validate and export a box which is ready to use. Ensure to put whatever you need into the definition — for example in the update.sh. Avoid too many manual steps before you export because the next person will have to know and repeat them. Bento serves as documentation as well.
I version our boxes with like easybib-something-10.04.4_vbox-4.1.8_0.1.box and upload them to an S3 bucket. The first number is the Ubuntu release and the second is the version of the VirtualBox guest additions. Simple. The third version is our internal iteration — typically a base box isn’t perfect from the beginning while e.g. the Ubuntu and VirtualBox part are settled, there might be other improvements. With an extra version you avoid conflicts and extra work like vagrant box delete etc. and ensure the latest box is always used.
Also — in case the software stack is very different across your projects, it also helps to to create different boxes which come with different software pre-installed.
Standardize on versions
Vagrant and VirtualBox have frequent releases. I suggest to standardize on one so members of your team don’t have random issues at hand and fires to fight.
Even for a small team of up to ten developers this makes a lot of sense. Because people tend to add a lot of randomness anyway — different hardware, operating systems and so on. Fight only the battles you want to fight, and deploy otherwise.
Vagrant also recently went from being a rubygem to providing installers. I haven’t had the time to roll this out yet, but I expect this to help as well since at least as far as ruby is concerned all the dependencies are bundled.
This of course still implies that testing is required so you and your team don’t walk into a stupid little regression and waste away the day trying to figure out what went wrong. And of course even if Vagrant is smoother, it still leaves you with VirtualBox and tools like bento and plenty of potential breakage.
Chef Versions
On a side-note — Chef 10 and 11 may also introduce a lot of breakage in recipes. It helps to roll your base box with a specific version as well. With bento the work-around was pretty straight forward: I replaced the chef-client.sh and installed Chef 10 (instead of 11 — or whatever the latest is).
VirtualBox and guest additions
In theory, it’s alright to run with different guest additions in a box than the version of VirtualBox you have installed on the host. It should at least match the main release — for example: 4.1.8 guest additions and 4.1.12 VirtualBox should do fine. That’s a big should though, because it also may cause random issues like crashes and hangs.
If you don’t want or cannot rebuild the base box for some reason, you can also use vbguest which is a Vagrant plugin to update the guest additions when you start the virtual machine. Keep in mind that this adds a couple minutes to the bootstrapping.
Learn some Ruby
There are little things where it helps to know a little Ruby. And by Ruby, I don’t mean Rails. A Vagrantfile itself is Ruby code — this implies that it is fully customizable.
An example of something we as a team couldn’t agree on is the location of where projects (and essentially cookbooks) are located on your local disk. Every other team member has a different preference:
It’s as simple as that.
Another example — setting VirtualBox options for everyone but a certain user:
Bonus tip: Once you made changes, make sure to at least re-provision. Commit and push after!
Learn Chef or Puppet
I often see projects where developers end up writing a lot of shell script to bootstrap VMs, but learning Chef or Puppet is not really that hard.
I find it harder to validate exit codes (again and again and again) in bash than using a DSL (which is what Chef and Puppet essentially are). The code in your cookbooks (Chef) or manifests (Puppet) is certainly not faster than a shell script but a lot easier to read and more maintainable in the end.
Bash-scripting is not hard either, but in order to produce a set of scripts which can be ran again and again (not just to bootstrap a fresh VM but e.g. also to run updates on one that is running), defensive coding is paramount. And while that is certainly not impossible, it’s often a waste of time when frameworks like Chef or Puppet have that covered.
But let’s skip on the benefits of using identical tools to bootstrap Vagrant, staging and production because I find them more than obvious.
Learn some Linux
Every once in a while you will run into weird issues with the VMs. These may include one of your VMs losing connectivity (sudo restart networking to the rescue) or weird behavior like assets not refreshing (sendfile off; in nginx). Take it as an opportunity to learn some about the system that is run in production.
In the end all required configuration changes will go back into your provisioning and make sure to share your experience with at least the people on your team.
Backup everything
Whatever you find and use — make a copy of it and put it on Amazon S3 or the local network. With larger teams even a local Ubuntu mirror (or whatever you use) can come in handy.
This includes base boxes, packages, etc.. Nothing is more annoying than waking up and not being able to bootstrap your VMs because someone decided to remove something in order to force you to upgrade.
Don’t dumb it down!
Typically, PHP applications are developed on a single host — Apache, PHP and MySQL on localhost. With Vagrant it becomes surprisingly easy to mimic production.
Not to say that I have to run 20 virtual machines to copy my cluster of application servers, but it’s perfectly acceptable to set up an environment with four VMs where one is a loadbalancer, two are application servers and then a database server.
Networking and port forwards
Unless you regulary let others use your VMs, don’t add port forwards — or at least install a firewall.
For networking, I suggest you either use static IPs (and keep track of them in a sheet) or DHCP. I prefer static IPs though since that makes configuration (e.g. of an application to connect to the database) easier.
It also doesn’t hurt to assign names, so you know which VM you’re dealing with when GUI is enabled:
Hardware
It doesn’t hurt to have lots of CPU and RAM, but also configure the VMs accordingly. I run up to four virtual machines on a Macbook Air — usually configured with 256 to 512 MB. I imagine this would go smoother with VMWare Fusion, but since our team contains Mac and Linux as well, we haven’t moved on this.
Here’s an example how to give 512 MB RAM to a virtual machine:
Fin
That’s all I can think of right now. Happy development!