#Roll your own PaaS

This is a demo combining docker, dokku-alt, and travis CI to create a foolproof push to deploy system.

##Installation

Currently dokku is only really supported on Ubuntu 14.04. Gotta live life on the edge!

###On the server:

There's a bootstrap script in the dokku-alt repo but it defaults to a web based configuration. Generally this just won't work(TM) on an AWS server, so let's do it manually.

Log into root:

sudo su

Add the docker and dokku-alt sources:

echo deb https://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list
echo deb https://dokku-alt.github.io/dokku-alt / > /etc/apt/sources.list.d/dokku-alt.list

Add the relevant keys and update:

apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9
apt-key adv --keyserver keys.gnupg.net --recv-keys EAD883AF
apt-get update -y

Install dokku and docker:

apt-get install -y dokku-alt

If it asks you to modify local files, keep the local ones.

Check whether docker works

dokku access:list

If this gives you an "unable to resolve hostname" congrats, AWS broke your instance!

You'll need to add a host to /etc/hosts as specified here

Then reboot

sudo reboot

And try again

dokku access:list

##Configuration

###On your local machine:

Generate a new key pair

ssh-keygen

This will prompt for a two things, namely:

• The output path (use /home/<username>/.ssh/<project>)
• A passphrase (leave it empty)

Now copy the key to the server

cat ~/.ssh/<project>.pub | ssh [-i <pem file>] <server> sudo dokku access:add

Now we can test pushing a project

Since we're not using the default key pair. We'll have to do a bit of local configuration.

Add the following to ~/.ssh/config

Host <server address>
    IdentityFile ~/.ssh/<project>

Note that we're using the private key not <project>.pub

Add a remote to the project

git remote add <name> dokku@<server address>:tweet

Then push

git push <name> master

###On the server

Note: You'll need a domain to play around with. Deploying to a port doesn't work in dokku

echo <hostname> | sudo tee /home/dokku/VHOST

Testing and Travis

###On your local machine

Install the travis gem

gem install travis

Create a travis directory

mkdir .travis

Create a pem file

openssl rsa -in ~/.ssh/<project> -outform pem > .travis/<project>.pem

Hide it from git

echo .travis/<project>.pem >> .gitignore

Create a .travis.yml file according to this guide

Log into travis

travis login

Encrypt the key

travis encrypt-file .travis/<project>.pem --add

For some reason travis adds the encrypted key to the root directory lets move that

mv <project>.pem.enc .travis

Edit the .travis.yml file to reflect the move. Change -in <project>.pem.enc to -in .travis/<project>.pem.enc

Add a after_success: section like so

- chmod 600 .travis/<project>.pem
- mkdir -p ~/.ssh
- cp .travis/<project>.pem ~/.ssh
- cat .travis/host >> ~/.ssh/config
- git remote add production dokku@<server address>:<project>
- test $TRAVIS_PULL_REQUEST == "false" && test $TRAVIS_BRANCH == "master" && git push <name> master

Then create a .travis/host to make travis use the correct key:

Host <server address>
    StrictHostKeyChecking no
    IdentityFile ~/.ssh/<project>.pem

Then register your project on travis-ci.org and push away.

Adding Complexity

Add on a database

On the server

Create the database

dokku postgresql:create <db>

And link it

dokku postgresql:link <project> <db>

Then you can get the full url

dokku config <project>