README.md

AWS Bastion Terraform module

Terraform module which creates a secure SSH bastion on AWS.

Mainly inspired by Securely Connect to Linux Instances Running in a Private Amazon VPC

Features

This module will create an SSH bastion to securely connect in SSH to your private instances. All SSH commands are logged on an S3 bucket for security compliance, in the /logs path.

SSH users are managed by their public key, simply drop the SSH key of the user in the /public-keys path of the bucket. Keys should be named like 'username.pub', this will create the user 'username' on the bastion server.

Then after you'll be able to connect to the server with :

ssh [-i path_to_the_private_key] username@bastion-dns-name

From this bastion server, you'll able to connect to all instances on the private subnet.

If there is a missing feature or a bug - open an issue.

Usage

module "bastion" {
  "source" = "terraform-aws-modules/bastion/aws"
  "bucket_name" = "my_famous_bucket_name"
  "region" = "eu-west-1"
  "vpc_id" = "my_vpc_id"
  "is_lb_private" = "true|false"
  "bastion_host_key_pair" = "my_key_pair"
  "hosted_zone_id" = "my.hosted.zone.name."
  "bastion_record_name" = "bastion.my.hosted.zone.name."
  "elb_subnets" = [
    "subnet-id1a",
    "subnet-id1b"
  ]
  "auto_scaling_group_subnets" = [
    "subnet-id1a",
    "subnet-id1b"
  ]
  tags = {
    "name" = "my_bastion_name",
    "description" = "my_bastion_description"
  }
}

Inputs

Name	Description	Type	Default	Required
auto_scaling_group_subnets	List of subnet were the Auto Scalling Group will deploy the instances	list	-	yes
allow_ssh_commands	Allows the SSH user to execute one-off commands. Pass 'True' to enable. Warning: These commands are not logged and increase the vulnerability of the system. Use at your own discretion.	string	""	no
bastion_host_key_pair	Select the key pair to use to launch the bastion host	string	-	yes
bastion_instance_count	Count of bastion instance created on VPC	string	1	no
bastion_launch_configuration_name	Bastion Launch configuration Name, will also be used for the ASG	string	lc	no
bastion_ami	The AMI that the Bastion Host will use. If not supplied, the latest Amazon2 AMI will be used.	string	``	no
bastion_record_name	DNS record name to use for the bastion	string	``	no
bucket_name	Bucket name were the bastion will store the logs	string	-	yes
bucket_force_destroy	On destroy, bucket and all objects should be destroyed when using true	string	false	no
bucket_versioning	Enable bucket versioning or not	string	true	no
cidrs	List of CIDRs than can access to the bastion. Default : 0.0.0.0/0	list	<list>	no
create_dns_record	Choose if you want to create a record name for the bastion (LB). If true 'hosted_zone_id' and 'bastion_record_name' are mandatory	integer	-	yes
elb_subnets	List of subnet were the ELB will be deployed	list	-	yes
extra_user_data_content	Additional scripting to pass to the bastion host. For example, this can include installing postgresql for the psql command.	string	""	no
hosted_zone_id	Name of the hosted zone were we'll register the bastion DNS name	string	``	no
is_lb_private	If TRUE the load balancer scheme will be "internal" else "internet-facing"	string	-	yes
log_auto_clean	Enable or not the lifecycle	string	false	no
log_expiry_days	Number of days before logs expiration	string	90	no
log_glacier_days	Number of days before moving logs to Glacier	string	60	no
log_standard_ia_days	Number of days before moving logs to IA Storage	string	30	no
private_ssh_port	Set the SSH port to use between the bastion and private instance	string	22	no
public_ssh_port	Set the SSH port to use from desktop to the bastion	string	22	no
region		string	-	yes
tags	A mapping of tags to assign	map	<map>	no
vpc_id	VPC id were we'll deploy the bastion	string	-	yes

Outputs

Name	Description
bucket_name
bucket_name	The name of the bucket where logs are sent
elb_ip	The ELB DNS Name for the Bastion Host instances
bastion_host_security_group_id	The security group ID of the Bastion Host
private_instances_security_group	The security group ID of the the private instances that allow Bastion SSH ingress

Known issues

Tags are not applied to the instances generated by the auto scaling group do to known terraform issue : hashicorp/terraform-provider-aws#290

Authors

Module managed by Guimove.

License

Apache 2 Licensed. See LICENSE for full details.