OpenStack Compute Instance Terraform Module

This Terraform module creates and configures OpenStack compute instances with optional attached storage volumes and networking configurations.

Copyright and License

Copyright © EUMETSAT 2025.

The provided code and instructions are licensed under the MIT license. They are intended to automate the setup of an environment that includes third-party software components. The usage and distribution terms of the resulting environment are subject to the individual licenses of those third-party libraries.

Users are responsible for reviewing and complying with the licenses of all third-party components included in the environment.

Contact EUMETSAT for details on the usage and distribution terms.

Features

• Create OpenStack compute instances with customizable configurations
• Optionally boot from volume with configurable size
• Support for attaching additional volumes
• Floating IP assignment for public access
• Security group configuration
• Integration with cloud-init for instance initialization
• Flexible networking options
• Resource tagging support with automatic app_name tagging

Authentication

Before proceeding, if you lack OpenStack Application Credentials or do not know how to make them available to Ansible in your development environment, make sure to check out the EWC documentation.

Usage

module "web_server" {
  source = "path/to/openstack-compute"

  app_name       = "web"
  instance_name  = "server"
  instance_index = 1
  image_id       = "your-image-id"
  flavor_id      = "your-flavor-id"
  keypair_name   = "your-keypair-name"
  
  networks = ["internal"]
  
  instance_has_fip = true
  
  os_volume = {
    enable = true
    size   = 80
  }
  
  extra_volume      = true
  extra_volume_size = 100
  
  security_groups = ["default", "web"]
  
  instance_metadata = {
    environment = "production"
    role        = "web"
  }
  
  tags = {
    environment = "production"
    project     = "website"
    owner       = "team-alpha"
  }
}

Inputs

Name	Description	Type	Default	Required
app_name	Application name, used as prefix in the full instance name	string	n/a	yes
instance_name	Name of the instance, used in the full instance name	string	n/a	yes
instance_index	Index or identifier for the instance, used as suffix in the full instance name	number	n/a	yes
image_id	(Optional; Required if image_name is empty and not booting from a volume. Do not specify if booting from a volume.) The image ID to use for the instance	string	n/a	no
flavor_id	(Optional; Required if flavor_name is empty) The flavor ID to use for the instance	string	n/a	no
image_name	(Optional; Required if image_id is empty and not booting from a volume. Do not specify if booting from a volume.) The name of the image to use for the instance	string	n/a	no
flavor_name	(Optional; Required if flavor_id is empty) The name the flavor to use for the instance	string	n/a	no
keypair_name	Name of the keypair to use for SSH access to the instance	string	n/a	yes
networks	List of network names to attach the instance to	list(string)	n/a	yes
security_groups	List of security group names to apply to the instance	list(string)	["default"]	no
instance_has_fip	Whether to assign a floating IP to the instance	bool	false	no
os_volume	Configuration for the primary OS volume	object({enable = bool, size = number})	{enable = false, size = 50}	no
extra_volume	Whether to attach an additional volume to the instance	bool	false	no
extra_volume_size	Size in GB of the additional volume	number	1	no
extra_volume2	Whether to attach a second additional volume to the instance	bool	false	no
extra_volume2_size	Size in GB of the second additional volume	number	1	no
cloudinit_userdata	User data for cloud-init to be passed to the instance	string	null	no
instance_metadata	Metadata to associate with the instance (key-value pairs)	map(string)	null	no
add_sfs_network	Shared File System network to add (if needed)	string	null	no
external_network_name	Name of the external network for floating IPs	string	"external"	no
tags	A map of tags to assign to all resources that support it	map(string)	{}	no

SW Bill of Materials (SBoM)

Third-party components used in the working environment.

The following components will be included in the working environment:

Component	Version	License	Home URL
terraform-provider-openstack	1.53.0	MPL-2.0	https://github.com/terraform-provider-openstack/terraform-provider-openstack

Outputs

Name	Description
instance-data	Comprehensive information about the created instance
volumes	Information about the attached volumes

Instance Output Structure

{
  name           = "app-name-instance-name-01"
  id             = "instance-id"
  internal_ip    = "192.168.1.10"
  floating_ip    = "203.0.113.10"
  networks       = [/* Network details */]
  flavor_id      = "flavor-id"
  volumes        = ["volume-id-1", "volume-id-2"]
  access_address = "203.0.113.10"  # or internal IP if no floating IP
}

Volumes Output Structure

{
  primary  = "volume-id-primary"  # if os_volume.enable = true
  volume_1 = {
    id   = "volume-id-1"
    name = "app_name_instance_name_01_volume"
    size = 100
  }
  volume_2 = {
    id   = "volume-id-2"
    name = "app_name_instance_name_01_volume2"
    size = 50
  }
}

Best Practices

1. Always specify appropriate security groups for your instances
2. Use unique and descriptive names for instances to aid in identification
3. Consider using OS volumes for production instances for improved performance and resilience
4. Implement proper key management for your keypair_name
5. Use cloud-init userdata for consistent instance initialization

Resource Tagging

This module supports tagging of OpenStack resources using the tags variable. Additionally, the module automatically adds the app_name as a tag to all resources that support tagging. This provides consistent identification across your OpenStack environment.

Tag Implementation Details

• Compute Instance: Tags are implemented as metadata key-value pairs
• Volumes: Tags are implemented as a list of string tags
• Floating IPs: Tags are implemented as a list of string tags

Example of how tags are applied:

tags = {
  environment = "production"
  project     = "web-app"
}

The above will result in:

• Compute instance metadata containing: app_name, environment, and project keys
• Volumes and floating IPs tagged with: app_name, environment, and project tags

This tagging approach makes it easier to filter, identify, and manage resources in your OpenStack environment.

Changelog

All notable changes (i.e. fixes, features and breaking changes) are documented in the CHANGELOG.md.

Contributing

Thanks for taking the time to join our community and start contributing! Please make sure to:

• Familiarize yourself with our Code of Conduct before contributing.
• See CONTRIBUTING.md for instructions on how to request or submit changes.

Authors

European Weather Cloud <support@europeanweather.cloud>