Defining cloud services using a declarative approach

1. Introduction to Cloud Service
Definition
By
Naveen Joy
Cloud Architect
@naveenjoy

2. Agenda
• Declarative modeling
• Service definition language
• Real-World scenario
• Template structure
• Conceptual service models
• Service definition details
• Create the stack!! – (Live demo)

3. Declarative Approach
• You describe what should be accomplished
and NOT how to get there
• The service figures out the detailed steps to
make it happen

4. How to describe services?

5. Just enough YAML
• List items using ( “- ” ) or [ ]
• Key-Value mappings using
(“: ”) or { key: value }
• Uses indentation with spaces to define scope

6. Scenario
• A company has deployed OpenStack with
Orchestration (Heat)
• Wants to simplify application deployment

7. Two Key Requirements
• Create a repeatable infrastructure
configuration
• Create unique instantiations of the
configuration in a predictable manner

8. From Requirements to Concepts
Repeatable
infrastructure
configuration
YAML
TEMPLATE
SPECIFICATION
Unique
instantiation of
the configuration
STACK
SET OF RESOURCES
CREATED AND MANAGED
AS ONE UNIT

9. Service Description
• An IGW
• Two inside networks
and subnets
• Router interface on
both inside subnets
• Instance
• Volume
• Volume Attachment
Run Time
Parameters
• Network
Names
• Subnet
CidrBlocks
• SSH Key
• Image
• Flavor
• Volume Size
• VM Network
IGW
Inside networks
External network
Instance
Volume
Virtual Private
Cloud
(VPC)
Instance + Volume
(myApp)
component1
component2

10. YAML Template Structure
heat_template_version:
description:
parameters:
resources:
outputs:
INPUTS TO CUSTOMIZE THE STACK
DESCRIPTION OF THE RESOURCES IN
THE STACK w/ DEPENDENCIES
VALUES TO BE RETURNED AFTER
STACK CREATION

11. VPC Service
Conceptual Model
network1
network2
subnet1
subnet1_interface
subnet2
igw
subnet2_interface
net1_name
RESOURCES
PARAMETERS
(INPUTS) OUTPUTS
net2_name
subnet1_cidrBlock
subnet2_cidrBlock
subnet1_gw_ip
subnet2_gw_ip

12. myApp Service
Conceptual Model
my_instance
my_volume
volume_attachment
RESOURCES
PARAMETERS
(INPUTS) OUTPUTS
volume_size
my_instance_ip
ssh_key_name
image
flavor
vm_network

13. Functions enable
get_resource: References another resource
{ get_resource: <resource_name> }
get_param: References an input parameter
{ get_param: <input parameter name> }
get_attr: References a resource attribute
{ get_attr: [ <resource_name>, <attribute_name> ] }

14. Capturing resource dependencies

15. Demo
Create VPC
[Deploy vpc.yaml]
Create another VPC
[Deploy vpc.yaml with different parameter values]
Deploy App (VM + Volume) to the VPC
[Deploy app.yaml]
STEP1
STEP2
STEP3

16. Thank You
All yaml files, local.conf (to create devstack) and this
deck are available for download at:
https://goo.gl/Hjw0pr