Heat is an OpenStack template-based orchestration service that allows users to describe infrastructure and applications in text files called Heat Orchestration Templates (HOT) and automate the deployment of multi-component, multi-tier applications across OpenStack and other platforms. Heat provides the ability to define infrastructure resources like servers, networks, routers, and security groups and specify relationships between resources. It comprises several Python applications that work together to provision and manage OpenStack resources through a REST API according to the templates.

1. Openstack Heat
Arun prasath S
Dec 23, 2014

2. What is Heat ?
Template-driven engine
that allows us to describe and
automate the deployment of
infrastructure

3. Use cases
• Infrastructure provisioning using templates
• Version controlling the infrastructure
• Auto scale feature
• Works well with configuration management tools
• Many PaaS applications

4. Orchestration in other
platforms
• AWS – CloudFormation
• CloudStack templates
• Azure PowerShell cmdlets
• Eucalyptus - CloudFormation

5. Heat capabilities
• Provides ability to describe an infrastructure in text file.
• Infrastructure resources include – Servers, network,
router, floating IP, security groups
• We can also specify the relationship between the
resources
• Changes in infrastructure made easy

6. Heat Overview

7. Architecture
• Heat project comprises of number of
python applications
o heat
o heat-api
o heat-api-cfn
o heat-engine

8. Architecture

9. Workflow

10. Implementation
• Create database for Heat
• Create Keystone users and roles
• Create services and endpoints
• Install necessary packages

11. Heat components
Stack
Resource
Resource
…
…
Network
subnet
Router
Subnet – Router
connection
Some other
resources
…
Nested stack

12. HOT Anatomy
Parameters
User defined parameters passed into template from CLI or GUI
Parameters include type, description, default value, hidden, and
constraints
Resources
Resources for Heat to Orchestrate
Consists of Type, Properties, DependsOn
Resources produce global attributes
Outputs
Displayed via CLI/GUI to identify important information of
template

13. HOT Anatomy -
Parameters
heat_template_version: 2013-05-23
parameters:
image:
type: string
description: Image to use for the instance to be created.
default: cirros0.3.2x86_64disk
constraints:
- allowed_values: ['cirros0.3.2x86_64disk','fedora20.x86_64']
volume_size:
type: number
description: Size of volume to attach to instance
default: 1
constraints:
- range: {min: 1, max: 10}

14. HOT Anatomy -
Resources
heat_template_version: 2013-05-23
resources:
heat_network_01:
type: OS::Neutron::Net
properties:
admin_state_up: true
name: heat-network-01
heat_subnet_01:
type: OS::Neutron::Subnet
properties:
name: heat-subnet-01
cidr: 10.10.10.0/24
enable_dhcp: true
network_id: { get_resource: heat_network_01 }

15. HOT Anatomy - Output
outputs:
instance_ip:
description: The IP address of the deployed Web application
value: { get_attr: [web-app-instance, show] }
Connection_details:
description: The IP address of the deployed Web application
value: { get_attr: [web-app-instance, addresses, public, 0] }

16. Hello Heat
heat_template_version: 2013-05-23
resources:
compute_instance: # You can name this whatever you
prefer
type: "OS::Nova::Server"
properties:
flavor: 1GB Standard Instance
image: CentOS 6.5
name: My Compute Instance

17. Ways to run heat
command
• By using python-heatclient
• By using Horizon
Input template
File
Direct text
URL

18. Nested stack example
(my_nested.yaml)
heat_template_version: 2013-05-23
resources:
my_instance:
type: OS::Nova::Server
properties:
flavor: m1.small
image: my_image
(new_stack.yaml)
heat_template_version: 2013-05-23
resources:
my_nested:
type: my_nested.yaml

19. Provider resources
No hard-coded names/paths (in the template)
Staging workflow/testing much simplified
Allows deployer or user to define custom resource types
– /etc/heat/environment.d
– /etc/heat/templates
– Users heat stack-create –environment-file=foo.yaml
-Users can override default environment resources!
resource_registry:
"My::Custom::Server": server.yaml

20. Environments
parameters:
key_name: mykey
resource_registry:
My::Custom::Server : my_server.yaml
OS::Nova::Server : override_nova.yaml
• python-heatclient resolves local files and URLs
• Files associated with environment are passed along with the
stack-create/update API request
• heat stack-create mystack -f template.yaml –e
environment.yaml

21. Provider Resource Example
(my_nested.yaml)
heat_template_version: 20130523
resources:
my_instance:
type: OS::Nova::Server
properties:
flavor: m1.small
image: my_image
(my_stack.yaml)
heat_template_version: 20130523
resources:
my_nested:
type: My::Custom::Server
(environment.yaml)
resource_registry:
My::Custom::Server: my_nested.yaml

22. Demo : Create an instance

23. Demo : Deploy a web
server using HEAT

24. Troubleshooting
• Check if you can reach the endpoints
• heat template-validate
• heat template-show
• Check for resources
• Logs - /var/log/heat/*

25. Important links
• http://docs.openstack.org/developer/heat/template_guide
/hot_guide.html
• http://docs.openstack.org/developer/heat/template_guide
/
• https://github.com/openstack/heat-templates

26. Questions ?