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Service Catalog Version 0.78.1

OpenVPN Server

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Overview​

This service deploys an OpenVPN Server.

OpenVPN server architectureOpenVPN server architecture

This server acts as the entrypoint to the VPC in which it is deployed. You must connect to it with an OpenVPN client before you can connect to any of your other servers, which are in private subnets. This way, you minimize the surface area you expose to attackers, and can focus all your efforts on locking down just a single server.

Features​

  • An AMI to run on the OpenVPN Server
  • An Auto Scaling Group of size 1 (for fault tolerance)
  • An Elastic IP Address (EIP)
  • IAM Role and IAM instance profile
  • Security group.
  • A DNS record
  • Harden the OS by installing fail2ban, ntp, auto-update, ip-lockdown, and more
  • Send all logs and metrics to CloudWatch
  • Configure alerts in CloudWatch for CPU, memory, and disk space usage
  • Manage SSH access with IAM groups using ssh-grunt

Under the hood, this is all implemented using Terraform modules from the Gruntwork terraform-aws-openvpn repo.

Learn​

note

This repo is a part of the Gruntwork Service Catalog, a collection of reusable, battle-tested, production ready infrastructure code. If you’ve never used the Service Catalog before, make sure to read How to use the Gruntwork Service Catalog!

Core concepts​

To understand core concepts like why you should use an OpenVPN server, how to connect to the vpn, how to use the VPN server to connect to other systems on the AWS VPC, see the openvpn-server documentation documentation in the package-openvpn repo.

Deploy​

Non-production deployment (quick start for learning)​

If you just want to try this repo out for experimenting and learning, check out the following resources:

  • examples/for-learning-and-testing folder: The examples/for-learning-and-testing folder contains standalone sample code optimized for learning, experimenting, and testing (but not direct production usage).

Production deployment​

If you want to deploy this repo in production, check out the following resources:

  • examples/for-production folder: The examples/for-production folder contains sample code optimized for direct usage in production. This is code from the Gruntwork Reference Architecture, and it shows you how we build an end-to-end, integrated tech stack on top of the Gruntwork Service Catalog, configure CI / CD for your apps and infrastructure.

Reference​

  • alarms_sns_topic_arn — The ARNs of SNS topics where CloudWatch alarms (e.g., for CPU, memory, and disk space usage) should send notifications.
  • allow_manage_key_permissions_with_iam — If true, both the CMK's Key Policy and IAM Policies (permissions) can be used to grant permissions on the CMK. If false, only the CMK's Key Policy can be used to grant permissions on the CMK. False is more secure (and generally preferred), but true is more flexible and convenient.
  • allow_ssh_from_cidr_list — The IP address ranges in CIDR format from which to allow incoming SSH requests to the OpenVPN server.
  • allow_vpn_from_cidr_list — A list of IP address ranges in CIDR format from which VPN access will be permitted. Attempts to access the OpenVPN Server from all other IP addresses will be blocked.
  • ami — The AMI to run on the OpenVPN Server. This should be built from the Packer template under openvpn-server.json. One of var.ami or ami_filters is required. Set to null if looking up the ami with filters.
  • ami_filters — Properties on the AMI that can be used to lookup a prebuilt AMI for use with the OpenVPN server. You can build the AMI using the Packer template openvpn-server.json. Only used if var.ami is null. One of var.ami or ami_filters is required. Set to null if passing the ami ID directly.
  • backup_bucket_name — The name of the S3 bucket that will be used to backup PKI secrets. This is a required variable because bucket names must be globally unique across all AWS customers.
  • base_domain_name — The base domain name to use for the OpenVPN server. Used to lookup the Hosted Zone ID to use for creating the Route 53 domain entry. Only used if create_route53_entry is true.
  • ca_cert_fields — An object with fields for the country, state, locality, organization, organizational unit, and email address to use with the OpenVPN CA certificate.
  • cloudwatch_log_group_tags — Tags to apply on the CloudWatch Log Group, encoded as a map where the keys are tag keys and values are tag values.
  • cmk_administrator_iam_arns — A list of IAM ARNs for users who should be given administrator access to this CMK (e.g. arn:aws:iam::<aws-account-id>:user/<iam-user-arn>). If this list is empty, and kms_key_arn is null, the ARN of the current user will be used.
  • cmk_external_user_iam_arns — A list of IAM ARNs for users from external AWS accounts who should be given permissions to use this CMK (e.g. arn:aws:iam::<aws-account-id>:root).
  • cmk_user_iam_arns — A list of IAM ARNs for users who should be given permissions to use this KMS Master Key (e.g. arn:aws:iam::1234567890:user/foo).
  • default_user — The default OS user for the OpenVPN AMI. For AWS Ubuntu AMIs, which is what the Packer template in openvpn-server.json uses, the default OS user is 'ubuntu'.
  • enable_cloudwatch_alarms — Set to true to enable several basic CloudWatch alarms around CPU usage, memory usage, and disk space usage. If set to true, make sure to specify SNS topics to send notifications to using alarms_sns_topic_arn.
  • enable_fail2ban — Enable fail2ban to block brute force log in attempts. Defaults to true.
  • enable_ip_lockdown — Enable ip-lockdown to block access to the instance metadata. Defaults to true.
  • external_account_arns — The ARNs of external AWS accounts where your IAM users are defined. This module will create IAM roles that users in those accounts will be able to assume to get access to the request/revocation SQS queues.
  • external_account_ssh_grunt_role_arn — Since our IAM users are defined in a separate AWS account, this variable is used to specify the ARN of an IAM role that allows ssh-grunt to retrieve IAM group and public SSH key info from that account.
  • force_destroy — When a terraform destroy is run, should the backup s3 bucket be destroyed even if it contains files. Should only be set to true for testing/development
  • instance_type — The type of instance to run for the OpenVPN Server
  • keypair_name — The name of a Key Pair that can be used to SSH to this instance. Leave blank if you don't want to enable Key Pair auth.
  • name — The name of the OpenVPN Server and the other resources created by these templates
  • request_queue_name — The name of the sqs queue that will be used to receive new certificate requests.
  • revocation_queue_name — The name of the sqs queue that will be used to receive certification revocation requests. Note that the queue name will be automatically prefixed with 'openvpn-requests-'.
  • should_create_cloudwatch_log_group — When true, precreate the CloudWatch Log Group to use for log aggregation from the EC2 instances. This is useful if you wish to customize the CloudWatch Log Group with various settings such as retention periods and KMS encryption. When false, the CloudWatch agent will automatically create a basic log group to use.
  • ssh_grunt_iam_group — If you are using ssh-grunt, this is the name of the IAM group from which users will be allowed to SSH to this OpenVPN server. This value is only used if enable_ssh_grunt=true.
  • ssh_grunt_iam_group_sudo — If you are using ssh-grunt, this is the name of the IAM group from which users will be allowed to SSH to this OpenVPN server with sudo permissions. This value is only used if enable_ssh_grunt=true.
  • subnet_ids — The ids of the subnets where this server should be deployed.
  • tenancy — The tenancy of this server. Must be one of: default, dedicated, or host.
  • use_strong_prime — When true, generate Diffie-Hellman parameters using strong primes. Note that while stronger primes make the keys more cryptographically secure, the effective security gains are known to be insignificant in practice.
  • vpc_id — The ID of the VPC in which to deploy the OpenVPN server.
  • vpn_search_domains — A list of domains to push down to the client to resolve over VPN. This will configure the OpenVPN server to pass through domains that should be resolved over the VPN connection (as opposed to the locally configured resolver) to the client. Note that for each domain, all subdomains will be resolved as well. E.g., if you pass in 'mydomain.local', subdomains such as 'hello.world.mydomain.local' and 'example.mydomain.local' will also be forwarded to through the VPN server.
  • vpn_subnet — The subnet IP and mask vpn clients will be assigned addresses from. For example, 172.16.1.0 255.255.255.0. This is a non-routed network that only exists between the VPN server and the client. Therefore, it should NOT overlap with VPC addressing, or the client won't be able to access any of the VPC IPs. In general, we recommend using internal, non-RFC 1918 IP addresses, such as 172.16.xx.yy.