We discussed the OpenStack orchestration engine in Chapter 2, Exploring AWS Cloud. To recap, OpenStack provides an orchestration engine that can process a template and deploy the specified resources. The template is written in the YAML format.
A basic template that deploys a single VM using the key-pair named test-key
and the image cirros
is as follows:
heat_template_version:2015-04-30description:Simple template that deploys a VMresources:my_instance:type:OS::Nova::Serverproperties:key_name: test-key image: cirros
A typical HOT template has three sections: template version
, description
, and resources
. The description is optional, however, it is a good practice to specify the details about a template that you write.
The set of resources that a template deploys together is called a stack.
Let's now discuss a complex scenario where we want to deploy two VM instances in a specific order. We want VM1 to be started and booted successfully, before VM2 attempts...