Overview
An orchestration template is a YAML document that declaratively describes a set of
cloud resources and their relationships. The Orchestration engine reads the template,
resolves dependencies between resources, and provisions them in the correct order.
Templates are reusable — parameterized values allow the same template to deploy
different environments without modification.
Prerequisites
- Familiarity with YAML syntax
- Access to the Xloud Orchestration service in your project
xloud CLI installed for template validation
Template Structure
Every orchestration template has up to six top-level sections:
xloud_template_version: "2025-10-15" # Required — template format version
description: > # Optional — human-readable description
Brief summary of what this template deploys.
parameter_groups: # Optional — group parameters for the UI
- label: Instance Settings
parameters: [instance_name, flavor]
parameters: # Optional — runtime variables
instance_name:
type: string
default: my-instance
conditions: # Optional — conditional resource creation
create_extra_volume:
equals: [{ get_param: env }, production]
resources: # Required — cloud objects to create
my_instance:
type: Xloud::Compute::Server
properties:
name: { get_param: instance_name }
outputs: # Optional — values returned after creation
server_ip:
description: The instance IP address
value: { get_attr: [my_instance, first_address] }
| Section | Required | Purpose |
|---|
xloud_template_version | Yes | Specifies the template format version |
description | No | Human-readable summary shown in the Dashboard |
parameter_groups | No | Groups parameters into labeled sections in the Dashboard UI |
parameters | No | Defines input variables that customize the template at runtime |
conditions | No | Named boolean expressions controlling conditional resource creation |
resources | Yes | The cloud resources to create, update, or delete |
outputs | No | Values extracted from created resources and returned to the caller |
Parameters
Parameters make templates reusable across different environments and projects.
Parameter Types
| Type | Description | Example Value |
|---|
string | Arbitrary text value | "m1.large" |
number | Integer or float | 3 |
boolean | true or false | true |
json | Arbitrary JSON object or array | {"key": "value"} |
comma_delimited_list | CSV string interpreted as a list | "az1,az2,az3" |
Parameter Definition Reference
parameters-reference.yaml
parameters:
flavor:
type: string
label: Instance Flavor
description: The compute flavor (vCPU and RAM profile) for the instance
default: m1.small
constraints:
- allowed_values: [m1.small, m1.medium, m1.large]
description: Must be a supported flavor
instance_count:
type: number
label: Instance Count
description: Number of instances to launch in the scaling group
default: 2
constraints:
- range: { min: 1, max: 20 }
description: Between 1 and 20 instances
enable_monitoring:
type: boolean
label: Enable Monitoring
description: Whether to install the monitoring agent on boot
default: false
tags:
type: json
label: Instance Tags
description: Key-value metadata to attach to each instance
default: { "env": "dev", "team": "platform" }
Validate parameters before deploying: run openstack orchestration template validate -t your-template.yaml
to catch type mismatches and constraint violations before the stack is submitted.
Resources
Resources are the core of every template. Each resource has a logical name, a type,
and a set of properties.
resources:
web_server:
type: Xloud::Compute::Server
depends_on: [web_network_port] # Explicit dependency
deletion_policy: Retain # Retain | Snapshot | Delete (default)
update_policy:
rolling_update:
max_batch_size: 1
pause_time: PT30S
properties:
name: web-server-01
image: { get_param: image }
flavor: { get_param: flavor }
key_name: { get_param: key_name }
networks:
- port: { get_resource: web_network_port }
user_data: |
#!/bin/bash
apt-get install -y nginx
Intrinsic Functions
Intrinsic functions allow template sections to reference other parts of the template
dynamically at runtime.
| Function | Syntax | Description |
|---|
get_param | { get_param: param_name } | Returns the value of a template parameter |
get_resource | { get_resource: resource_name } | Returns the ID of another resource in the stack |
get_attr | { get_attr: [resource_name, attribute] } | Returns a specific attribute of a resource |
str_replace | { str_replace: { template: "...", params: {...} } } | Performs string substitution |
list_join | { list_join: [",", [value1, value2]] } | Joins a list of values with a delimiter |
if | { if: [condition_name, true_value, false_value] } | Returns one of two values based on a condition |
equals | { equals: [value_a, value_b] } | Returns true if both values are equal |
not | { not: condition } | Negates a condition |
and | { and: [condition_a, condition_b] } | Returns true if all conditions are true |
or | { or: [condition_a, condition_b] } | Returns true if any condition is true |
Function Examples
intrinsic-function-examples.yaml
resources:
# get_param — retrieve a parameter value
my_instance:
type: Xloud::Compute::Server
properties:
flavor: { get_param: flavor }
# get_resource — reference another resource's ID
volume_attachment:
type: Xloud::BlockStorage::VolumeAttachment
properties:
instance_uuid: { get_resource: my_instance }
volume_id: { get_resource: my_volume }
# get_attr — retrieve a resource attribute
floating_ip_assoc:
type: Xloud::Networking::FloatingIPAssociation
properties:
floatingip_id: { get_resource: my_floating_ip }
port_id: { get_attr: [my_instance, addresses, default, 0, port] }
# str_replace — build a user_data script from parameters
bootstrap_instance:
type: Xloud::Compute::Server
properties:
user_data:
str_replace:
template: |
#!/bin/bash
echo "Deploying to $ENV_NAME" > /etc/motd
params:
$ENV_NAME: { get_param: environment }
Conditions
Conditions enable selective resource creation based on parameter values. Define a
condition by name, then reference it in resource definitions with condition:.
parameters:
environment:
type: string
default: dev
constraints:
- allowed_values: [dev, staging, production]
conditions:
is_production:
equals: [{ get_param: environment }, production]
resources:
# Always created
app_server:
type: Xloud::Compute::Server
properties:
flavor: { if: [is_production, m1.large, m1.small] }
image: { get_param: image }
# Only created in production
monitoring_agent:
type: Xloud::Compute::Server
condition: is_production
properties:
flavor: m1.small
image: { get_param: image }
Outputs
Outputs expose values from created resources back to the caller. They are visible in
the Dashboard stack detail view and retrievable via CLI.
outputs:
instance_id:
description: UUID of the compute instance
value: { get_resource: my_instance }
instance_ip:
description: Primary fixed IP address
value: { get_attr: [my_instance, first_address] }
public_url:
description: Publicly accessible application URL
value:
str_replace:
template: "https://$IP/app"
params:
$IP: { get_attr: [my_floating_ip, floating_ip_address] }
Next Steps
Resource Types
Full reference for all supported resource types and their properties
Getting Started
Deploy your first stack using a complete example template
Auto-Scaling
Use scaling groups and alarm policies in templates
Manage Stacks
Update and manage stacks through their full lifecycle
