Immut

Overview

This project is a work in progress automating the creation of immutable infrastructure.

Goals

1. Automate as much of the infrastructure setup as possible.
2. Provide auditable configuration files.
3. Store all infrastructure definitions and configuration in git.
4. Automate tests for the infrastructure

Prerequisites

1. Packer (https://github.com/mitchellh/packer)
2. Virtual Box and/or Qemu

Build

Currently the project consists of a project atomic virtual machine image with SSSD running on the host.

SSSD provides authentication to running docker containers. The build depends on the creation of an Ostree repository creation to perform an update of the Atomic host and to use for the Docker containers.

We recommend that you do not build this in a virtual environment, as nested virtualization will be slow.

First of all you need to build an Ostree repository. Go to the immut/packer directory and run:

packer build rpmostree-update.json

Now you have an Ostree repository in compressed in immut/packer/files/repo.zip with all the filesystems needed to make the system work.

To build the VM, cd into the immut/packer directory (if you are not already there from the previous step) and run:

sudo unzip files/repo.zip -d files
packer build fedora-atomic-24.json

Note: This will output all images we currently support. In order to build only one of them see below:

In order to build a single image use the -only packer argument, eg:

• to build only a VirtualBox image (output image file in immut/packer/output-virtualbox):

  packer build -only virtualbox fedora-atomic-24.json
  

• to build only a Qemu image (output image file in immut/packer/output-qemu):

  Add "headless": "true", to the qemu config in fedora-atomic-24.json This will be the default in the future; it is not the default yet as it is harder to develop in headless mode.

  packer build -only qemu fedora-atomic-24.json
  

Next, to make the Qemu image testable in VirtualBox, cd into the output-qemu directory and convert it using:

qemu-img convert -f qcow2 packer-qemu -O vdi packer-qemu.vdi

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Set Up

Once you have an image, cd into the immut/cloud-init-iso directory and run the script:

./create-iso.sh

This will create an iso that will include the cloud config configuration files meta-data and user-data in the same folder. These configuration file specifies what services need to run (in containers)and for what projects.

Now, create a virtual machine. If using the qemu build, do things the usual way and use the image you created with packer for the hard disk file. If using the VirtualBox build, you should instead import the ovf file to create the VM:

In VirtualBox:

• file > import appliance
• select the .ovf from the immut/packer/output-virtualbox directory
• click 'import'

That should create a VM.

Attach the iso to the optical drive (and make sure it's not treated as a live CD).

Add a VirtualBox host-only network to your VM:

• file > preferences > network

• (add it)

• click the screwdriver

• go to the DCHP server tab:

  • change server address to match adapter address, but with 2 at the end instead of 1

  • change server mask to 255.255.255.0

  • change lower address to match the adapter address but with 110 at the end instead of 1

  • change upper adress to match the adapter address but with 200 at the end instead of 1

• right click your vm > settings > network

• enable adapter 2 and attach it to a host-only adapter

This will ensure the VM has a visible IPV4 address.

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Run

Start the VM! Use the Fedora 24 default, with login username 'root' with password 'atomic'.

Once you are logged in, running docker ps should return some information.

On the VM, create a new user, eg:

adduser immutuser
passwd immutuser (then set a password)

Add your new user to the example project group:

usermod -a -G p1 immutuser

On the VM, run ip addr to get its IP address. There will be a few; the relevant one should have a name like 'enp0s8' and look fairly standard (ie: start with 192.168...)

Now, on your host, you can now run something like:

git clone http://gitserver.p1.$VM-IP-ADDRESS.xip.io/git/foo

to get a repo from your new git server. You should be able to add, commit and push changes. If you browse to:

http://gitserver.p1.$VM-IP-ADDRESS.xip.io/cgit/

You should be able to see a cgit instance, containing your changes.

Test

There are yarn scenario tests in the 'tests' directory. These will be installed in /home/tests inside the VM.

To run them, you must be logged into the VM as root, or as another user that can execute docker containers. Then you can run the following:

sudo $HOME/tests/run.sh

This will currently create a haproxy and gitserver container, along with a container to run the yarns in, and run the yarns.

If the user desires, they can import a different version of the tests into the VM (the best option currently is to scp the directory containing the tests from the host to the VM). Once the tests are in the VM, the user can run them via the run.sh wrapper, with ./run.sh.

Yarn is part of the cmdtest package. There is an overview of yarn here:

http://blog.liw.fi/posts/yarn/

and the source is over here:

http://git.liw.fi/cgi-bin/cgit/cgit.cgi/cmdtest/tree/