Deploy an Application with OpenStack Heat

This guide deploys a composite application (made up of more than a single instance) on the cloud infrastructure. This also involves launch-time customization of the VMs. This guide makes some assumptions:

  • OpenStack, including Heat have been deployed, using either RDO Havana or RDO Grizzly instructions
  • OpenStack is deployed on RHEL 6.4 or Fedora 19

Get the demo files

It is time now to launch your first multi-instance cloud application! There are a number of sample templates available in the heat-templates git repo.

First, download the composed Wordpress example with::

$ wget

Next, register a pre-built cfntools image with glance. Note the command automatically downloads the image. For reference, pre-built Fedora images are available from:

$ glance image-create --name Fedora-Cloud-Base-20141203-21.x86_64 --disk-format qcow2 --container-format bare --is-public True --copy-from

Upload your public key in nova to make sure you'll be able to login on the VMs using SSH::

  $ nova keypair-add --pub_key ~/.ssh/ userkey

Some templates require the instances to be able to connect to the heat CFN API, so it would be a good idea to add a chain to iptables to accept connection to 8000 and 8003 ports so that the guests can communicate with the heat-api-cfn server and heat-api-cloudwatch server. You can append to your /etc/sysconfig/iptables ::

  $ -A INPUT -i br100 -p tcp --dport 8000 -j ACCEPT
  $ -A INPUT -i br100 -p tcp --dport 8003 -j ACCEPT

where br100 is the interface of the bridge that your instances are using.


It is time for the real fun now, launch your first composed application with::

  $ heat stack-create wordpress --template-file=WordPress_Composed_Instances.template --parameters="DBUsername=wp;DBPassword=wp;KeyName=userkey;LinuxDistribution=F17"

More parameters could have passed, note for instance the LinuxDistribution parameter discussed above. Now the interesting stuff:

  $ heat stack-list
  $ heat event-list wordpress

After the VMs are launched, the mysql/httpd/wordpress installation and configuration begins, the process is driven by the cfntools, installed in the VMs images. It will take quite some time, despite the event-list reporting completion for the WordPress install too early (there is signaling, via cfn-signal, only in the MySQL template). You can login on the instances and check the logs or just use ps to see how things are going. After some minutes the setup should be finished:

  $ heat stack-show wordpress
  $ wget ${WebsiteURL} # that is an URL from the previous command!

If anything goes wrong, check the logs at /var/log/heat/engine.log or look at the scripts passed as UserData to the instances, these should be found in /var/lib/cloud/data/. Time to hack your very own template and delete the test deployment! :)

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