terraform-aws-cdr-link

Updated August 10, 2023

WARNING: Pre-release module. Do not rely on any of the inputs/outputs remaining stable here.

Terraform module to deploy the base infrastructure for CDR Link to AWS. The deployment will be optimised for security by default, although some features may be disabled in order to reduce costs. The following groups of resources will be created:

Virtual Private Cloud (VPC)
Key Management Service (KMS) key
PostgreSQL RDS instance
Amazon OpenSearch Domain
EC2 instance

Architecture Overview

Architecture diagram

Virtual Private Cloud (VPC)

A VPC is created to have tight control over the subnets in use. The deployment uses a single AWS region, and a single availability zone (a single subnet is provisioned in a second availability zone due to the requirement that RDS instances are attached to two subnets in different availability zones, but nothing else interacts with that subnet).

The deployment model intends that a zero-trust access solution is used to access the application (e.g. Cloudflare Access) and so all resources containing the application and application data are provisioned into a private subnet. No inbound access is permitted to the subnet. The instance must be managed via AWS Systems Manager (SSM).

A gateway endpoint is provisioned for S3. Interface endpoints are provisioned for EC2, SSM, SSM Messages, CloudWatch, and KMS. Outbound Internet access is facilitated by a NAT gateway.

Key Management Service (KMS) key

A single KMS key is created for the encryption of all storage resources. When archiving the deployment, it is possible to provide the account ID to the archive_account_id variable to permit that account access to the KMS key to decrypt the storage.

PostgreSQL RDS instance

TODO

Amazon OpenSearch Domain

TODO

EC2 instance

Usage

module "link" {
  source = "sr2c/cdr-link/aws"
  # version = "x.x.x"
  namespace   = "eg"
  name        = "link"
  stage       = "dev"
}

Requirements

Name	Version
terraform	>= 1.3.5
aws	>= 4.52.0
cloudinit	>= 2.2.0
random	>= 3.4.3
tls	>= 4.0.4

Providers

Name	Version
aws	4.53.0
cloudinit	2.2.0
random	3.4.3
tls	4.0.4

Modules

Name	Source	Version
dummy_subnet	cloudposse/dynamic-subnets/aws	2.1.0
dynamic_subnet	cloudposse/dynamic-subnets/aws	2.1.0
ec2_security_group	cloudposse/security-group/aws	2.0.0
elasticsearch	cloudposse/elasticsearch/aws	0.35.1
elasticsearch_label	cloudposse/label/null	0.25.0
instance_role_profile	sr2c/ec2-conf-log/aws	0.0.2
kms_key	cloudposse/kms-key/aws	0.12.1
rds	cloudposse/rds/aws	0.40.0
this	cloudposse/label/null	0.25.0
vpc	cloudposse/vpc/aws	2.0.0
vpc_endpoints	cloudposse/vpc/aws//modules/vpc-endpoints	2.0.0

Resources

Name	Type
aws_ebs_volume.data	resource
aws_elasticsearch_domain_policy.default	resource
aws_instance.default	resource
aws_key_pair.default	resource
aws_volume_attachment.default	resource
random_password.metamigo	resource
random_password.metamigo_authenticator	resource
random_password.rds_superuser	resource
random_password.zammad	resource
random_password.zammad_monitoring_token	resource
tls_private_key.default	resource
aws_ami.default	data source
aws_availability_zones.this	data source
aws_caller_identity.this	data source
aws_iam_policy_document.kms	data source
cloudinit_config.this	data source

Inputs

Name	Description	Type	Default	Required
additional_tag_map	Additional key-value pairs to add to each map in `tags_as_list_of_maps`. Not added to `tags` or `id`. This is for some rare cases where resources want additional configuration of tags and therefore take a list of maps with tag key, value, and additional configuration.	`map(string)`	`{}`	no
archive_account_id	The AWS account ID of an account that should have access to the deployment’s KMS key to facilitate archiving the deployment at the end of its lifecycle.	`string`	`null`	no
attributes	ID element. Additional attributes (e.g. `workers` or `cluster`) to add to `id`, in the order they appear in the list. New attributes are appended to the end of the list. The elements of the list are joined by the `delimiter` and treated as a single ID element.	`list(string)`	`[]`	no
context	Single object for setting entire context at once. See description of individual variables for details. Leave string and numeric variables as `null` to use default value. Individual variable settings (non-null) override settings in context object, except for attributes, tags, and additional_tag_map, which are merged.	`any`	{ “additional_tag_map”: {}, “attributes”: [], “delimiter”: null, “descriptor_formats”: {}, “enabled”: true, “environment”: null, “id_length_limit”: null, “label_key_case”: null, “label_order”: [], “label_value_case”: null, “labels_as_tags”: [ “unset” ], “name”: null, “namespace”: null, “regex_replace_chars”: null, “stage”: null, “tags”: {}, “tenant”: null }	no
delimiter	Delimiter to be used between ID elements. Defaults to `-` (hyphen). Set to `""` to use no delimiter at all.	`string`	`null`	no
descriptor_formats	Describe additional descriptors to be output in the `descriptors` output map. Map of maps. Keys are names of descriptors. Values are maps of the form `{<br> format = string<br> labels = list(string)<br>}` (Type is `any` so the map values can later be enhanced to provide additional options.) `format` is a Terraform format string to be passed to the `format()` function. `labels` is a list of labels, in order, to pass to `format()` function. Label values will be normalized before being passed to `format()` so they will be identical to how they appear in `id`. Default is `{}` (`descriptors` output will be empty).	`any`	`{}`	no
ebs_volume_disk_allocation_gb	The amount of storage to allocate for the EBS volume mounted at /var/lib/cdr inside the EC2 instance. If left unset, 10 GB will be allocated.	`number`	`null`	no
ec2_disk_allocation_gb	The amount of storage to allocate for the EC2 instance. If left unset, the amount allocated will depend on the stage of the deployment. If the stage variable is set to “prod”, 100 GB will be allocated, otherwise only 40 GB will be allocated.	`number`	`null`	no
ec2_instance_type	The instance class for the EC2 instance. If left unset, the instance class will depend on the stage of the deployment. If the stage variable is set to “prod”, t3.large will be use, otherwise only t3.medium.	`string`	`null`	no
enabled	Set to false to prevent the module from creating any resources	`bool`	`null`	no
environment	ID element. Usually used for region e.g. ‘uw2’, ‘us-west-2’, OR role ‘prod’, ‘staging’, ‘dev’, ‘UAT’	`string`	`null`	no
es_allocated_disk_gb	The amount of storage to allocate for the Elasticsearch domain. If left unset, 10 GB will be allocated.	`number`	`null`	no
es_enabled	If set to false, no Elasticsearch resources will be created. This option may be used to reduce costs, with either the Elasticsearch server running within the Docker Compose stack on the EC2 instance at the expense of performance and reliability, or forgoing Elasticsearch entirely at the expense of full text search within Zammad.	`bool`	`true`	no
es_instance_type	n/a	`string`	`null`	no
id_length_limit	Limit `id` to this many characters (minimum 6). Set to `0` for unlimited length. Set to `null` for keep the existing setting, which defaults to `0`. Does not affect `id_full`.	`number`	`null`	no
label_key_case	Controls the letter case of the `tags` keys (label names) for tags generated by this module. Does not affect keys of tags passed in via the `tags` input. Possible values: `lower`, `title`, `upper`. Default value: `title`.	`string`	`null`	no
label_order	The order in which the labels (ID elements) appear in the `id`. Defaults to [“namespace”, “environment”, “stage”, “name”, “attributes”]. You can omit any of the 6 labels (“tenant” is the 6th), but at least one must be present.	`list(string)`	[ “namespace”, “name”, “tenant”, “stage”, “attributes” ]	no
label_value_case	Controls the letter case of ID elements (labels) as included in `id`, set as tag values, and output by this module individually. Does not affect values of tags passed in via the `tags` input. Possible values: `lower`, `title`, `upper` and `none` (no transformation). Set this to `title` and set `delimiter` to `""` to yield Pascal Case IDs. Default value: `lower`.	`string`	`null`	no
labels_as_tags	Set of labels (ID elements) to include as tags in the `tags` output. Default is to include all labels. Tags with empty values will not be included in the `tags` output. Set to `[]` to suppress all generated tags. Notes: The value of the `name` tag, if included, will be the `id`, not the `name`. Unlike other `null-label` inputs, the initial setting of `labels_as_tags` cannot be changed in later chained modules. Attempts to change it will be silently ignored.	`set(string)`	[ “default” ]	no
name	ID element. Usually the component or solution name, e.g. ‘app’ or ‘jenkins’. This is the only ID element not also included as a `tag`. The “name” tag is set to the full `id` string. There is no tag with the value of the `name` input.	`string`	`null`	no
namespace	ID element. Usually an abbreviation of your organization name, e.g. ’eg’ or ‘cp’, to help ensure generated IDs are globally unique	`string`	`null`	no
rds_allocated_disk_gb	The amount of storage to allocate for the RDS instance. If left unset, 10 GB will be allocated.	`number`	`null`	no
rds_enabled	If set to false, no RDS related resources will be created. This option may be used to reduce costs at the expense of reliability with the PostgreSQL server running in the Docker Compose stack in the EC2 instance.	`bool`	`true`	no
rds_instance_type	The instance class of the PostgreSQL RDS instance to deploy. If left unset, db.t3.micro will be used.	`string`	`null`	no
regex_replace_chars	Terraform regular expression (regex) string. Characters matching the regex will be removed from the ID elements. If not set, `"/[^a-zA-Z0-9-]/"` is used to remove all characters other than hyphens, letters and digits.	`string`	`null`	no
stage	ID element. Usually used to indicate role, e.g. ‘prod’, ‘staging’, ‘source’, ‘build’, ’test’, ‘deploy’, ‘release’	`string`	`null`	no
tags	Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`). Neither the tag keys nor the tag values will be modified by this module.	`map(string)`	`{}`	no
tenant	ID element _(Rarely used, not included by default)_. A customer identifier, indicating who this instance of a resource is for	`string`	`null`	no

Outputs

Name	Description
es_hostname	n/a
instance_id	n/a
rds_hostname	n/a
rds_metamigo_authenticator_password	n/a
rds_metamigo_password	n/a
rds_port	n/a
rds_superuser_password	n/a
rds_superuser_user	n/a
rds_zammad_password	n/a
zammad_monitoring_token	n/a

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