Openstack Heat

Arun prasath SDec 23, 2014

What is Heat ?

Template-driven engine

that allows us to describe and

automate the deployment of

infrastructure

Use cases

• Infrastructure provisioning using templates

• Version controlling the infrastructure

• Auto scale feature

• Works well with configuration management tools

• Many PaaS applications

Orchestration in other platforms

• AWS – CloudFormation

• CloudStack templates

• Azure PowerShell cmdlets

• Eucalyptus - CloudFormation

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

Heat Overview

Architecture• Heat project comprises of number of

python applicationso heat

o heat-api

o heat-api-cfn

o heat-engine

Architecture

Workflow

Implementation

• Create database for Heat

• Create Keystone users and roles

• Create services and endpoints

• Install necessary packages

Heat components

Stack

Resource

Resource

…

…

Network subnet

Router

Subnet – Router connection

Some other resources

…

Nested stack

HOT AnatomyParameters

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

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}

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 }

HOT Anatomy - Outputoutputs:

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] }

Hello Heatheat_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

Ways to run heat command

• By using python-heatclient

• By using Horizon

Input template

File

Direct text

URL

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

Provider resourcesNo 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

Environmentsparameters:

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

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

Demo : Create an instance

Demo : Deploy a web server using HEAT

Troubleshooting

• Check if you can reach the endpoints

• heat template-validate

• heat template-show

• Check for resources

• Logs - /var/log/heat/*

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

Questions ?