bastion

This component is responsible for provisioning a generic Bastion host within an ASG with parameterized user_data and support for AWS SSM Session Manager for remote access with IAM authentication.

If a special container.sh script is desired to run, set container_enabled to true, and set the image_repository and image_container variables.

By default, this component acts as an "SSM Bastion", which is deployed to a private subnet and has SSM Enabled, allowing access via the AWS Console, AWS CLI, or SSM Session tools such as aws-gate. Alternatively, this component can be used as a regular SSH Bastion, deployed to a public subnet with Security Group Rules allowing inbound traffic over port 22.

Usage

Stack Level: Regional

By default, this component can be used as an "SSM Bastion" (deployed to a private subnet, accessed via SSM):

components:
  terraform:
    bastion:
      vars:
        enabled: true
        name: bastion-ssm
        # Your choice of availability zones. If not specified, all private subnets are used.
        availability_zones: ["us-east-1a", "us-east-1b", "us-east-1c"]
        instance_type: t3.micro
        image_container: infrastructure:latest
        image_repository: "111111111111.dkr.ecr.us-east-1.amazonaws.com/example/infrastructure"

The following is an example snippet for how to use this component as a traditional bastion:

components:
  terraform:
    bastion:
      vars:
        enabled: true
        name: bastion-traditional
        image_container: infrastructure:latest
        image_repository: "111111111111.dkr.ecr.us-east-1.amazonaws.com/example/infrastructure"
        associate_public_ip_address: true # deploy to public subnet and associate public IP with instance
        custom_bastion_hostname: bastion
        vanity_domain: example.com
        security_group_rules:
          - type: "ingress"
            from_port: 22
            to_port: 22
            protocol: tcp
            cidr_blocks: ["1.2.3.4/32"]
          - type: "egress"
            from_port: 0
            to_port: 0
            protocol: -1
            cidr_blocks: ["0.0.0.0/0"]

Variables

Required Variables

region (string) required: AWS region

Optional Variables

associate_public_ip_address (bool) optional

Whether to associate public IP to the instance.

Default value: false

availability_zones (list(string)) optional

AWS Availability Zones in which to deploy multi-AZ resources.
If not provided, resources will be provisioned in every private subnet in the VPC.

Default value: [ ]

container_command (string) optional

The container command passed in after docker run --rm -it <image> bash -c.

Default value: "bash"

image_container (string) optional

The image container to use in container.sh.

Default value: ""

image_repository (string) optional

The image repository to use in container.sh.

Default value: ""

instance_type (string) optional

Bastion instance type

Default value: "t2.micro"

kms_alias_name_ssm (string) optional

KMS alias name for SSM

Default value: "alias/aws/ssm"

security_group_rules (list(any)) optional

A list of maps of Security Group rules.
The values of map is fully completed with aws_security_group_rule resource.
To get more info see https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule .

Default value:

[
  {
    "cidr_blocks": [
      "0.0.0.0/0"
    ],
    "from_port": 0,
    "protocol": -1,
    "to_port": 0,
    "type": "egress"
  },
  {
    "cidr_blocks": [
      "0.0.0.0/0"
    ],
    "from_port": 22,
    "protocol": "tcp",
    "to_port": 22,
    "type": "ingress"
  }
]

Context Variables

The following variables are defined in the context.tf file of this module and part of the terraform-null-label pattern.

additional_tag_map (map(string)) optional

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.

Required: No

Default value: { }

attributes (list(string)) optional

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.

Required: No

Default value: [ ]

context (any) optional

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.

Required: No

Default value:

{
  "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
}

delimiter (string) optional

Delimiter to be used between ID elements.
Defaults to - (hyphen). Set to "" to use no delimiter at all.

Required: No

Default value: null

descriptor_formats (any) optional

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).

Required: No

Default value: { }

enabled (bool) optional

Set to false to prevent the module from creating any resources
Required: No

Default value: null

environment (string) optional

ID element. Usually used for region e.g. 'uw2', 'us-west-2', OR role 'prod', 'staging', 'dev', 'UAT'
Required: No

Default value: null

id_length_limit (number) optional

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.

Required: No

Default value: null

label_key_case (string) optional

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.

Required: No

Default value: null

label_order (list(string)) optional

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.

Required: No

Default value: null

label_value_case (string) optional

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.

Required: No

Default value: null

labels_as_tags (set(string)) optional

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.

Required: No

Default value:

[
  "default"
]

name (string) optional

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.

Required: No

Default value: null

namespace (string) optional

ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique
Required: No

Default value: null

regex_replace_chars (string) optional

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.

Required: No

Default value: null

stage (string) optional

ID element. Usually used to indicate role, e.g. 'prod', 'staging', 'source', 'build', 'test', 'deploy', 'release'
Required: No

Default value: null

tags (map(string)) optional

Additional tags (e.g. {'BusinessUnit': 'XYZ'}).
Neither the tag keys nor the tag values will be modified by this module.

Required: No

Default value: { }

tenant (string) optional

ID element (Rarely used, not included by default). A customer identifier, indicating who this instance of a resource is for
Required: No

Default value: null

Outputs

autoscaling_group_id: The AutoScaling Group ID
iam_instance_profile: Name of AWS IAM Instance Profile
security_group_id: ID on the AWS Security Group associated with the ASG

Dependencies

Requirements

terraform, version: >= 1.0.0
aws, version: >= 4.0
cloudinit, version: >= 2.2

Providers

aws, version: >= 4.0
cloudinit, version: >= 2.2

Modules

Name	Version	Source	Description
`bastion_autoscale_group`	0.35.1	`cloudposse/ec2-autoscale-group/aws`	n/a
`iam_roles`	latest	`../account-map/modules/iam-roles`	n/a
`sg`	2.2.0	`cloudposse/security-group/aws`	n/a
`ssm_tls_ssh_key_pair`	0.10.2	`cloudposse/ssm-tls-ssh-key-pair/aws`	n/a
`this`	0.25.0	`cloudposse/label/null`	n/a
`vpc`	1.5.0	`cloudposse/stack-config/yaml//modules/remote-state`	n/a

Resources

The following resources are used by this module:

aws_iam_instance_profile.default (resource)
aws_iam_role.default (resource)
aws_iam_role_policy.main (resource)

Data Sources

The following data sources are used by this module:

aws_ami.bastion_image (data source)
aws_iam_policy_document.default (data source)
aws_iam_policy_document.main (data source)
cloudinit_config.config (data source)

References

cloudposse/terraform-aws-components - Cloud Posse's upstream component

Usage​

Variables​

Required Variables​

Optional Variables​

Context Variables​

Outputs​

Dependencies​

Requirements​

Providers​

Modules​

Resources​

Data Sources​

References​

Usage

Variables

Required Variables

Optional Variables

Context Variables

Outputs

Dependencies

Requirements

Providers

Modules

Resources

Data Sources

References