Running a Cloud in a VM

Use the cloud to build the cloud! Use your cloud to launch new versions of OpenStack in about 5 minutes. When you break it, start over! The VMs launched in the cloud will be slow as they are running in QEMU (emulation), but their primary use is testing OpenStack development and operation. Speed not required.

Virtual Machine

DevStack should run in any virtual machine running a supported Linux release. It will perform best with 2Gb or more of RAM.

OpenStack Deployment & cloud-init

If the cloud service has an image with cloud-init pre-installed, use it. You can get one from Ubuntu's Daily Build site if necessary. This will enable you to launch VMs with userdata that installs everything at boot time. The userdata script below will install and run DevStack with a minimal configuration. The use of cloud-init is outside the scope of this document, refer to the cloud-init docs for more information.

If you are directly using a hypervisor like Xen, kvm or VirtualBox you can manually kick off the script below as a non-root user in a bare-bones server installation.

Launching With Cloud-Init

This cloud config grabs the latest version of DevStack via git, creates a minimal local.conf file and kicks off stack.sh. It should be passed as the user-data file when booting the VM.

#cloud-config

users:
  - default
  - name: stack
    lock_passwd: False
    sudo: ["ALL=(ALL) NOPASSWD:ALL\nDefaults:stack !requiretty"]
    shell: /bin/bash

write_files:
  - content: |
        #!/bin/sh
        DEBIAN_FRONTEND=noninteractive sudo apt-get -qqy update || sudo yum update -qy
        DEBIAN_FRONTEND=noninteractive sudo apt-get install -qqy git || sudo yum install -qy git
        sudo chown stack:stack /home/stack
        cd /home/stack
        git clone https://github.com/openstack-dev/devstack.git
        cd devstack
        echo '[[local|localrc]]' > local.conf
        echo ADMIN_PASSWORD=password >> local.conf
        echo MYSQL_PASSWORD=password >> local.conf
        echo RABBIT_PASSWORD=password >> local.conf
        echo SERVICE_PASSWORD=password >> local.conf
        echo SERVICE_TOKEN=tokentoken >> local.conf
        ./stack.sh
    path: /home/stack/start.sh
    permissions: 0755

runcmd:
  - su -l stack ./start.sh

As DevStack will refuse to run as root, this configures cloud-init to create a non-root user and run the start.sh script as that user.

Launching By Hand

Using a hypervisor directly, launch the VM and either manually perform the steps in the embedded shell script above or copy it into the VM.

Using OpenStack

At this point you should be able to access the dashboard. Launch VMs and if you give them floating IPs access those VMs from other machines on your network.

One interesting use case is for developers working on a VM on their laptop. Once stack.sh has completed once, all of the pre-requisite packages are installed in the VM and the source trees checked out. Setting OFFLINE=True in local.conf enables stack.sh to run multiple times without an Internet connection. DevStack, making hacking at the lake possible since 2012!