As of writing, the newest version of Vagrant is 1.4.3.
I recently started looking into ways that I could improve my current deployment workflow. Since my server doesn't have much RAM, I currently build the binaries locally in a Virtual Machine (VM from here on out) and then send them to the server using scp.
Although I can't do much about the server part (except buying a bigger server), I can do something about what I do locally. I set out to check what possibilities I had, and ended up looking at Vagrant.
While it doesn't cut hugely from the local part of my deployment hassles, it could atleast streamline it a bit, and help remove the cabal hell that I'd sometimes run into with my current setup (having multiple applications that I deploy from the same VM).
A quick overview of the article:
- What is Vagrant?
- Getting started with Vagrant
- Replicating your server
- Rolling your own Vagrant box
- Setting up the VM
- Exporting the VM box
- But how do we use it?
- Concluding thoughts
What is Vagrant?
Vagrant basically manages your VMs in a manner that is local to each project you use it in (although you can use it in a more general way). As standard it uses VirtualBox, but you can also use it with other providers, such as VMWare.
That said, for the purpose of being convenient to most people, I'm going to assume VirtualBox throughout this article, since that is the free alternative of the two I mentioned.
Getting started with Vagrant
Vagrant has a nice getting started series that you should follow if you want to understand Vagrant better (I highly recommend it, it's not that long). I'm going to try and give a quick explanation of how it works though.
Vagrant uses something called a
box. These serve as the basis for the Vagrant setups you create, and are in essence just VMs with the bare minimum installed. To add a box you do,
vagrant box add precise64 http://files.vagrantup.com/precise64.box
which will add a VM with a 64-bit version of Ubuntu 12.04 (Precise Pangolin). It will from then on be under the name
precise64, stored on your computer. You can change the url with any other url or a local filepath, and the name with what you want your box to be refferred to as.
You can try and search around if you can find a box that matches your needs, but if you want to customize it completely, I recommend creating your own.
Replicating your server
Before we start creating our Vagrant box, we need to know what our server looks like, so we can get the correct distro image.
On Debian, and most likely others, you can check out what version you're using with, cat /etc/*-release. This will output something like,
PRETTY_NAME="Debian GNU/Linux jessie/sid" NAME="Debian GNU/Linux" ID=debian ANSI_COLOR="1;31" HOME_URL="http://www.debian.org/" SUPPORT_URL="http://www.debian.org/support/" BUG_REPORT_URL="http://bugs.debian.org/"
which tells us we're dealing with Debian Jessie (testing).
Next up, is the architecture, and we get that by running, uname -r, which may look like,
amd64 telling us it's 64 bit and built for amd. You should also try and match the kernel version as best you can though (the
Rolling your own Vagrant box
First off, you need to install VirtualBox, and then go and download the installer image for the distro you want. Since my server uses the amd64 version of Debian Jessie, I'm going to go ahead and download the amd64 netinst CD image.
After downloading it you launch it in VirtualBox and install it as you normally would a Virtual Machine. Following Vagrant's guidelines for creating a base box, I set the following properties (with some altercations of my own):
40GBdynamically resizing drive
2GBRAM (they recommend 360MB, but compiling is quite memory intensive, and my laptop has 8GB of memory already)
- Audio disabled (we will only ssh into it)
- USB disabled
- NAT networking
And as recommended, I set the following values:
- Root password:
- Main account login:
- Main account password:
- Uncheck all software, to get the bare minimum
Now that you have the VM up and running, it's time to set it up as a Vagrant box.
Setting up the VM
Vagrant assumes sudo access without password, since that allows Vagrant to do a lot of neat thigns without our intervention (installing packages, setting up network folders etc).
First we change to root, and then,
apt-get install sudo
followed by editing the sudoers file with visudo. Here we add,
# /etc/sudoers Defaults env_keep="SSH_AUTH_SOCK" %admin ALL=(ALL:ALL) ALL %admin ALL=NOPASSWD: ALL
which allows users in the admin group to use sudo without a password.
After that, we need to add the vagrant user to the admin group,
groupadd admin usermod -a -G admin vagrant
Installing VirtualBox's Guest Additions
While still logged in as root, we need to uninstall VirtualBox packages and install linux headers so we can install the tools VirtualBox uses,
apt-get autoremove virtualbox-ose-guest-dkms virtualbox-ose-guest-utils virtualbox-ose-guest-x11 apt-get install linux-headers-$(uname -r) build-essential
note that there might not be able to find any of the packages we tried to remove, and that is fine, but sometimes they get installed automatically depending on the distro etc.
After that, we mount the Guest Additions CD, which is located in the
Devices menu and then something like
Insert Guest Additions CD Image.... We then run,
mount /dev/cdrom /media/cdrom sh /media/cdrom/VBoxLinuxAdditions.run
The last thing we need to do as root is installing the packages that we need,
apt-get install ruby rubygems puppet openssh-server openssh-client
depending on what distro you use, rubygems might fail to install. On debian Jessie, gems was included in the ruby package. After this, we need to set SSH to not use DNS. This will give a small speedup when SSH'ing to the VM,
echo 'UseDNS no' >> /etc/ssh/sshd_config
I intentionally didn't include
chef here, since I don't personally need it, and the install process is also a tad more bothersome than puppet's. You would just add it here if you need it though.
This step is a bit more personalized, whereas the rest is for creating a general Vagrant box. Since I intend to use this box for deploying and testing my Haskell packages, it's relevant for me to install the
haskell-platform and an updated version of
cabal to save some time when I create the VM with vagrant up later on.
You can also do these steps automatically on the creation of a box, by adding a shell script with the comamnds inside the
VagrantFile in your project, sorta like the example with automatically setting up Apache.
That said, I did the following,
apt-get install haskell-platform cabal update cabal install cabal-install
This will save me a bit of time compiling things (especially
cabal-install) over and over again.
Finally, you can now jump back to the vagrant user with exit, since the last bit needs to be done in the home folder of the vagrant user. We need to setup the authorized SSH keys for the vagrant user so vagrant ssh works easily using their standard insecure key pair,
mkdir .ssh wget --no-check-certificate -O .ssh/authorized_keys https://raw.github.com/mitchellh/vagrant/master/keys/vagrant.pub chmod 700 .ssh chmod 600 .ssh/authorized_keys
Now we just need to cleanup the VM and shut it down,
sudo apt-get clean sudo shutdown -h now
Exporting the VM box
The final step is to export the VM as a vagrant box and add it. Vagrant neatly picks up the VMs that VirtualBox manages (assuming you use the default location), so you can simply do,
vagrant package --base Jessie64
Jessie64 is the name I gave the VM inside VirtualBox. It will create a file named
package.box at the location you ran the command.
Now you can add the box to Vagrant just like any other box,
vagrant box add jessie64 ~/package.box
But how do we use it?
I'm going to give a little example of how I would set up and use Vagrant in one of my projects.
First I create the VagrantFile inside my project, using the box I just created,
vagrant init jessie64
After this, I create a small script that serves to setup my project with the packages that it needs. The content of the script should be self-explanatory. I name this
bootstrap.sh and it contains the following,
#!/usr/bin/env bash cd /vagrant /home/vagrant/.cabal/bin/cabal update && \ /home/vagrant/.cabal/bin/cabal sandbox init && \ /home/vagrant/.cabal/bin/cabal install
/vagrant folder is a folder that Vagrant keeps in sync with the host filesystem. It is the folder that Vagrant is running in, which in this case is my project folder.
I then add a line,
config.vm.provision :shell, :path => "bootstrap.sh"
VagrantFile inside the
Vagrant.configure(VAGRANTFILE_API_VERSION) do |config| section.
After this I can do, vagrant up and my project will get completely bootstrapped and ready for me to compile it and deploy. This usually means doing vagrant ssh and then two simple commands,
cd /vagrant yesod keter
with this, I've now build my binary, packaged it up and sent it to my server.
If there is some trouble with some packages I can simply do, vagrant destroy. This will destroy the VM in my project (it still keeps the box we created before, don't worry).
You can change destroy with halt to shut down the VM or suspend to simply suspend it. There is some information about the pros and cons to the three options in the Vagrant documentation.
Vagrant has greatly made me more comfortable messing around with my local VMs, since it's so easy to just destroy one and spin up an exact replica.
It also allows me to easily sandbox my projects completely by having VagrantFile's in each of them, with exactly what they need. Since Vagrant syncs the project folder, I can make changes using my preferred tools and the VM keeps the folders in sync.
As to what comes after this; I'm looking into puppet at the moment, since I would like to make setting up my server completely automatic. This will be a future article for itself though.