Component: 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"]

Requirements

Name	Version
terraform	>= 1.0.0
aws	>= 4.0
cloudinit	>= 2.2

Providers

Name	Version
aws	>= 4.0
cloudinit	>= 2.2

Modules

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

Resources

Name	Type
aws_iam_instance_profile.default	resource
aws_iam_role.default	resource
aws_iam_role_policy.main	resource
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

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
associate_public_ip_address	Whether to associate public IP to the instance.	bool	false	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
availability_zones	AWS Availability Zones in which to deploy multi-AZ resources. If not provided, resources will be provisioned in every private subnet in the VPC.	list(string)	[]	no
container_command	The container command passed in after docker run --rm -it <image> bash -c.	string	"bash"	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
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
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
image_container	The image container to use in container.sh.	string	""	no
image_repository	The image repository to use in container.sh.	string	""	no
instance_type	Bastion instance type	string	"t2.micro"	no
kms_alias_name_ssm	KMS alias name for SSM	string	"alias/aws/ssm"	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)	null	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
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
region	AWS region	string	n/a	yes
security_group_rules	A list of maps of Security Group rules. The values of map is fully complated with aws_security_group_rule resource. To get more info see https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/security_group_rule .	list(any)	[ { "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" } ]	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
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

References

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