Aviatrix with High Availability

Goals

• Ensure that Aviatrix Controller and CoPilot are always deployed with high availability
• Optionally support a hot standby Controller instance which reduces Controller switchover time to under a minute

Description

For HA deployments, this Terraform module will create the following:

• An Auto Scaling Group (ASG) for Aviatrix Controller
  • The Controller will be initialized to the specified version (latest by default) and Controller backups will be configured.
• An Auto Scaling Group (ASG) for Aviatrix CoPilot
• An AWS load balancer with the Controller and CoPilot instances as targets
• An Elastic Container Service (ECS) cluster and task definition. ECS handles Controller and CoPilot failover events and restores the configuration from the latest backup automatically on new instances.
• An Amazon EventBridge event rule that monitors events from the ASGs and invokes ECS.
• An Amazon Simple Notification Service (SNS) topic that receives events from the ASGs.
• An Amazon Simple Queue Service (SQS) queue that is subscribed to the SNS topic. When EventBridge triggers ECS, ECS reads messages from the SQS queue and takes the appropriate actions.
• Additional roles for the resources above with corresponding role policies with required permissions
• If ha_distribution is set to "inter-region":
  • The resources listed above will also be deployed in a second region
  • A Route 53 record specified by record_name will be created in the zone specified by zone_name

Controller Version Support

Aviatrix Platform HA supports controllers running version 7.0 and later

Prerequisites

The following resources should be created before running Terraform. The module will not create these resources.

• The admin password required to initilaize the Controller should be set in the AWS Systems Manager parameter store at /aviatrix/controller/password in us-east-1.

  aws ssm put-parameter --type "SecureString" --name "/aviatrix/controller/password" --value "XXXXXXXXX" --region="us-east-1"

  For non-production deployments, the password can be specified by avx_password. This is not recommended for production because the password will be viewable in the container's environment variables.

• The customer ID required to license the Controller should be set in the AWS Systems Manager parameter store at /aviatrix/controller/customer_id in us-east-1.

  aws ssm put-parameter --type "SecureString" --name "/aviatrix/controller/customer_id" --value "XXXXXXXXX" --region="us-east-1"

  For non-production deployments, the customer ID can be specified by avx_customer_id. This is not recommended for production because the customer ID will be viewable in the container's environment variables.

• For CoPilot initialization, if a specific service account is used, and the copilot_username and copilot_email variables are provided, then the service account password should be set in the AWS Systems Manager parameter store. The path for the password may be provided via the avx_copilot_password_ssm_path variable, or the default path /aviatrix/copilot/password will be checked. The password should be stored in the region defined in the avx_password_ssm_region variable. Otherwise, the default region of us-east-1 will be checked. If service account information is not provided via the copilot_username and the copilot_email variables, then the default admin account on the controller will be used as the service account to initialize the CoPilot.

  aws ssm put-parameter --type "SecureString" --name "/aviatrix/copilot/password" --value "XXXXXXXXX" --region="us-east-1"

  For non-production deployments, if the copilot_username and the copilot_email variables are provided for the service account, the password for the service account can be specified by avx_copilot_password. This is not recommended for production because the password will be viewable in the container's environment variables.

• If ha_distribution is set to "inter-region", the hosted zone specified by zone_name must already exist in Route 53.

• Boto3 should be installed and authentication for AWS should be configured so that helper Python scripts can run on terraform destroy. The following privileges are required to run the scripts:

  • ecs:ListTasks
  • ecs:StopTask
  • ec2:DescribeSecurityGroups
  • ec2:DeleteSecurityGroup

Usage Example

Basic

module "basic" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  avx_password                = <password>
  avx_customer_id             = <customer_id>
}

Single-AZ

module "single_az" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "single-az"
}

Inter-AZ

module "inter_az" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "inter-az"
}

Inter-Region

module "inter_region" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "inter-region"
  zone_name                   = "example.com"
  record_name                 = "controller.example.com"
  inter_region_backup_enabled = true
}

China Deployment

module "china" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "inter-az"
  region                      = "cn-north-1"
  dr_region                   = "cn-northwest-1" //dr region in china must be specified, either in single-az or inter-az case
  avx_customer_id_ssm_region  = "cn-north-1"
  avx_password_ssm_region     = "cn-north-1"
}

Health Checks

The Auto Scaling Groups use both EC2 and Elastic Load Balancing health checks to check whether the Controller and CoPilot instances are healthy.

• For EC2 health checks, the instance is considered unhealthy if it is in any state other than running. This includes when the instance has any of the following states:
  • stopping
  • stopped
  • shutting-down
  • terminated
• For Elastic Load Balancing health checks, the instance is considered unhealthy when the following health check fails:
  • Protocol: TCP
  • Port: 443
  • Unhealthy threshold: 2
  • Timeout: 10 seconds
  • Interval: 30 seconds

Interactions Between Components

• When the Auto Scaling Group (ASG) determines that an EC2 instance is unhealthy, the ASG launches a new replacement instance and terminates the unhealthy instance.
• A Simple Notification Service (SNS) topic is configured as the notification target of the ASG. When there is a new EC2 instance launched, SNS is notified of this event. There are two subscriptions to this SNS topic:
  • The email address specified in asg_notif_email - The user will be notified by email when there is an instance launched.
  • A Simple Queue Service (SQS) queue - The event will be stored as a message in the SQS queue to be retrieved when the container launches and the HA code is run.
• An EventBridge rule looks for EC2_INSTANCE_LAUNCHING events from the Controller and CoPilot Auto Scaling Groups. If there is a matching event, the Elastic Container Service (ECS) target is notified to take action.
• The ECS cluster runs a task that launches a container using the latest image from the container registry. The HA code in the container reads the message from the SQS queue and takes the appropriate action depending on what the event is (e.g. upgrades the Controller and restores the latest backup).

Brownfield Deployment

Aviatrix Controller

To deploy Aviatrix Platform HA with an existing Controller, perform the following steps:

1. Perform a Controller backup.
2. In AWS, go to the S3 bucket where the backup was saved to and sort the files by the date last modified. There will be two recent files with a .enc extension. Note the filename for the file with the date/time stamp in it (e.g. CloudN_10.0.0.39_save_cloudx_config_20230706164329.enc)
3. Deploy the new Aviatrix Platform HA solution.
4. If the previous HA solution was used, disable Controller High Availability by deleting the CloudFormation stack.
5. Terminate the previous Controller instance.
6. Perform a Controller restore using the file noted in step 2.

Aviatrix CoPilot

1. Perform a CoPilot Configuration Backup. This will store the CoPilot configuration on the current, active controller.
2. Optionally, perform a CoPilot Index Data Backup
3. Deploy the new Aviatrix Platform HA solution, and restore the controller configuration as described in the previous section. This will restore the controller configuration from the previously active controller (with the saved CoPilot configuration), into the new active controller, managed by the AWS Platform HA solution.
4. Manually trigger an HA event for the new CoPilot instance launched by AWS Platform HA, by stopping the VM. A new CoPilot VM will be launched, and its configuration will be restored from the saved CoPilot configuration on the controller

Logging and Email Notifications

• Logs can be viewed in CloudWatch in the /aws/ecs/avx_platform_ha log group.
• Email alerts from the Aviatrix Controller will be sent to the address specified in admin_email.
• Auto Scaling group events will be sent to the address specified in asg_notif_email only if you confirm the subscription. Upon terraform apply, AWS will send an email asking to confirm the subscription. If deploying inter-region, you will need to confirm both emails that are received.

Variables

Key	Default Value	Description
access_account_name	aws_admin	A friendly name mapping to your AWS account ID
admin_email		The administrator's email address. This email address will be used for password recovery as well as for notifications from the Controller.
alb_cert_arn	""	The ARN of the ACM certificate to use with the application load balancer in the primary region. Required if load_balancer_type is application.
asg_notif_email	admin_email	The email address for Controller failover notifications. This will default to admin_email if not specified.
app_role_max_session_duration	43200 seconds (12 hours)	The max session duration for the Aviatrix App role
app_role_name	aviatrix-role-app	The name of the Aviatrix App role
avx_copilot_password		The Aviatrix Copilot service account password. WARNING: The password will be visible in the container's environment variables. See above note for more information.
avx_copilot_password_ssm_path	/aviatrix/copilot/password	The path to the Aviatrix CoPilot password
avx_customer_id		The Aviatrix customer ID. WARNING: The Customer ID will be viewable in the container's environment variables. It is recommended to store the customer ID in an SSM parameter and to not use avx_customer_id for production deployments.
avx_customer_id_ssm_path	/aviatrix/controller/customer_id	The path to the Aviatrix customer ID. Only applicable if avx_customer_id is not specified.
avx_customer_id_ssm_region	us-east-1	The region the customer ID parameter is in. Only applicable if avx_customer_id is not specified.
avx_password		The Aviatrix Controller admin password. WARNING: The password will be viewable in the container's environment variables. It is recommended to store the password in an SSM parameter and to not use avx_password for production deployments.
avx_password_ssm_path	/aviatrix/controller/password	The path to the Aviatrix password. Only applicable if avx_password is not specified.
avx_password_ssm_region	us-east-1	The region the password parameter is in. Only applicable if avx_password is not specified.
cft_stack_name	aviatrix-controlplane	The name of the CloudFormation stack. Only applies when ha_distribution is "basic".
configure_waf	false	Whether AWS WAF is enabled for the Controller access.
controller_ami_id	""	The Aviatrix Controller AMI ID
controller_ha_enabled	true	Whether HA is enabled for the Controller. Set to false to temporarily disable HA
controller_name		Name of Controller.
controller_version	"latest"	The initial version of the Aviatrix Controller at launch
copilot_ami_id	""	The Aviatrix Copilot AMI ID
copilot_default_data_volume_size	8GB	Default data volume disk size for CoPilot
copilot_default_data_volume_type	gp3	Default data volume type for CoPilot
copilot_deployment	simple	The CoPilot deployment type. Valid values are simple and fault-tolerant. fault-tolerant is only supported if ha_distribution is single-az or inter-az.
copilot_email		CoPilot account email. See Prerequisites above for more information
copilot_ha_enabled	true	Whether HA is enabled for CoPilot. Set to false to temporarily disable HA.
copilot_incoming_https_cidr	incoming_ssl_cidr	CoPilot allowed CIDRs for HTTPS acccess. This will default to incoming_ssl_cidr if not specified.
copilot_incoming_netflow_cidr	CoPilot Netflow (UDP port 31283) access	CoPilot allowed CIDRs for Netflow acccess
copilot_incoming_syslog_cidr	CoPilot Syslog (UDP port 5000) access	CoPilot allowed CIDRs for Syslog acccess
copilot_instance_type	t3.2xlarge	CoPilot instance size
copilot_name		Name of CoPilot
copilot_root_volume_size	30GB	Root volume disk size for CoPilot
copilot_root_volume_type	gp3	Root volume type for CoPilot
copilot_type	Copilot	Type of billing, can be 'Copilot' or 'CopilotARM'
copilot_username		CoPilot account username. See Prerequisites above for more information
create_iam_roles	true	Whether to create the IAM roles used to grant AWS API permissions to the Aviatrix Controller
dr_alb_cert_arn	""	The ARN of the ACM certificate to use with the application load balancer in the DR region. Required if load_balancer_type is application.
dr_controller_ami_id	""	The DR Aviatrix Controller AMI ID
dr_copilot_ami_id	""	The DR Aviatrix Copilot AMI ID
dr_keypair	""	Key pair which should be used by DR Controller. Only applicable if ha_distribution is "inter-region".
dr_region	"us-east-2"	Region to deploy the DR Controller. Only applicable if ha_distribution is "inter-region".
dr_subnet_ids		The list of existing subnets to deploy the Controller in. Only applicable if use_existing_vpc is true.
dr_vpc	""	VPC to deploy DR Controlller. Only applicable if use_existing_vpc is true. Only applicable if ha_distribution is "inter-region".
dr_vpc_cidr	10.0.0.0/24	The CIDR for the VPC to create for the DR Controller. Only applicable if ha_distribution is "inter-region" and use_existing_vpc is false.
dr_vpc_name	""	The name for the VPC to create for the DR Controller. Only applicable if ha_distribution is "inter-region" and use_existing_vpc is false.
ebs_optimized	false	Whether EBS optimization is enabled. Applies to both the Controller and CoPilot.
ec2_role_name	aviatrix-role-ec2	The name of the Aviatrix EC2 role
ecs_role_name	aviatrix-role-ecs	The name of the ECS role
ecs_policy_name	aviatrix-ecs-policy	The name of the ECS policy
ecs_task_execution_role_name	aviatrix-role-ecs-task-exec	The name of the ECS task execution role
eventbridge_role_name	aviatrix-role-eventbridge	The name of the EventBridge role
eventbridge_policy_name	aviatrix-eventbridge-policy	The name of the EventBridge policy
existing_copilot_dr_eip	""	The existing EIP to use for the DR CoPilot. The EIP must already be allocated in the AWS account. Only applicable if use_existing_copilot_eip is true.
existing_copilot_eip	""	The existing EIP to use for CoPilot. The EIP must already be allocated in the AWS account. Only applicable if use_existing_copilot_eip is true.
existing_dr_eip	""	The existing EIP to use for the DR Controller. The EIP must already be allocated in the AWS account. Only applicable if use_existing_eip is true.
existing_eip	""	The existing EIP to use for the Controller. The EIP must already be allocated in the AWS account. Only applicable if use_existing_eip is true.
ha_distribution	basic	Desired Controller high availability distribution. Valid values are 'basic', 'single-az', 'inter-az', and 'inter-region'.
incoming_ssl_cidr		Incoming CIDR for security group used by Controller
instance_type	t3.xlarge	Controller instance size
inter_region_backup_enabled	false	Whether to enable backups on the primary controller. Only applicable if ha_distribution is "inter-region".
keypair	aviatrix-ha-keypair	Key pair which should be used. They key pair will be created unless use_existing_keypair is true.
license_type	BYOL	Type of billing, can be 'MeteredPlatinum', 'BYOL' or 'Custom'
load_balancer_type	network	Type of load balancer, can be network or application
monitoring	false	Whether detailed monitoring is enabled. Applies both to the Controller and CoPilot.
name_prefix	avx	Additional name prefix for resources created by this module
private_zone	false	Set to true if Route 53 zone is private type
record_name	true	The record name to be created under the exisitng route 53 zone specified by zone_name. Required if ha_distribution is 'inter-region'.
region	"us-east-1"	Region to deploy the Controller and CoPilot
root_volume_size	64	Root volume disk size for Controller
root_volume_type	gp3	Root volume type for Controller
s3_backup_bucket	aviatrix-ha-	If use_existing_s3 is false, a new S3 bucket will be created with the prefix specified by s3_backup_bucket. If use_existing_s3 is true, the S3 bucket must already be created.
s3_backup_region	us-east-1	The region the S3 backup bucket is in
standby_instance_state	Running	Instance state in Warm Pool of AWS autoscaling group. Valid values are Running and Stopped
subnet_ids		The list of existing subnets to deploy the Controller in. Only applicable if use_existing_vpc is true.
subnet_name	Aviatrix-Public-Subnet	The subnet name to create for the Controller. Only applicable if use_existing_vpc is false.
tags	{}	Map of common tags which should be used for module resources. Example: { key1 = "value1", key2 = "value2" }
termination_protection	true	Whether to enable termination protection on the Controller and CoPilot instances
use_existing_copilot_eip	false	Set to true to use the EIP(s) specified by existing_copilot_eip (and existing_copilot_dr_eip) for the Aviatrix CoPilot(s) rather than allocating new EIPs
use_existing_eip	false	Set to true to use the EIP(s) specified by existing_eip (and existing_dr_eip) for the Aviatrix Controller(s) rather than allocating new EIPs
use_existing_keypair	false	If use_existing_keypair is false, a new keypair will be created with the name specified by keypair. If use_existing_keypair is true, they keypair must already be created.
use_existing_s3	false	Whether to use an existing S3 bucket
use_existing_vpc	false	Set to true to deploy Controller and CoPilot to existing VPCs specified by vpc and dr_vpc.
vpc	""	VPC to deploy Controlller and CoPilot in. Only applicable if use_existing_vpc is true.
vpc_cidr	10.0.0.0/24	The CIDR for the VPC to create for the Controller. Only applicable if use_existing_vpc is false.
vpc_name	Aviatrix-VPC	The name for the VPC to create for the Controller. Only applicable if use_existing_vpc is false.
waf_managed_rules	Various free AWS Managed Rules	Managed rules to apply to WAF. Only applicable if configure_waf is true
zone_name	true	The existing Route 53 zone to create a record in. Required if ha_distribution is 'inter-region'.

Outputs

Output	Description
cft_output	The output from the underlying CloudFormation template when doing a basic deployment
controller_name	The name of the Controller
controller_public_ip	The public IP of the Controller in the primary region
copilot_name	The name of CoPilot
copilot_public_ip	The public IP of CoPilot in the primary region
dr_controller_public_ip	The public IP of the DR Controller
dr_copilot_public_ip	The public IP of the DR CoPilot
dr_lb_arn	The ARN of the LB in the DR region
dr_lb_dns_name	The DNS name of the LB in the DR region
dr_region	The DR region
dr_waf_arn	The ARN of the WAF in the DR region
ha_distribution	They type of deployment
lb_arn	The ARN of the LB in the primary region
lb_dns_name	The DNS name of the LB in the primary region
log_group_name	The CloudWatch log group that logs are sent to
region	The region
s3_backup_bucket	The S3 bucket used for backups
s3_backup_region	The region the S3 backup bucket is in
waf_arn	The ARN of the WAF in the primary region
record_name	The record name to be created under the existing route 53 zone specified by zone_name
zone_name	The Route 53 zone that record_name is created in

Additional Information

When an SNS HA event is triggered there are 3 scenarios depending on what autoscaling_source and autoscaling_destination are set to:

1. When autoscaling_source = EC2 and autoscaling_destination = AutoScalingGroup:

   • Assigns the EIP created through terraform to the new Controller.
   • Run initial setup and boot to latest version.
   • Set admin email and password.
   • Create primary AWS account.
   • Setup S3 backup.
   • Update environment variables in Lambda which will be used by next event.

2. When autoscaling_source = EC2 and autoscaling_destination = WarmPool:

   • Update Name tag to indicate standby Controller.
   • Run initial setup and boot to specific version parsed from DB backup.

3. When autoscaling_source = WarmPool and autoscaling_destination = AutoScalingGroup:

   • Update Name tag to indicate standby instance is now active.
   • Assign the EIP to the new Controller.
   • Login and create temp AWS account.
   • Restore configuration from backup.
   • Update environment variables in Lambda.

CloudFormation

Description

Aviatrix Platform HA for AWS is also available via CloudFormation. Users can create, update, and delete the Platform HA infrastructure using the provided . All of the functionalities available via Terraform are similarly available via CloudFormation.

Flow

The CloudFormation stack will gather the input parameters from the user, and then provision the HA infrastructure using a Codebuild instance, which is managed by a Lambda function. Along with a Codebuild project, a Lambda function, the CloudFormation stack will also create an S3 bucket, several SSM parameters to save output values, as well as necessary IAM roles and policies.

Deployment

To create the HA infrastructure using CloudFormation:

1. Create a stack using the provided
2. Provide the required inputs, as required by the selected HA deployment
3. Review the inputs, and create the stack

Troubleshooting and inspection

There are several different resources avaiable for deeper inspection of the CloudFormation deployment status

• CloudFormation stack Events tab will have information regarding the CloudFormation resources, and the stack status
• Cloudwatch will have the following Log streams:
  • Log stream for the Lambda function
  • Log stream for the Codebuild project (sourced from the Codebuild project)
  • Log stream for the Aviatrix Platform HA (assuming provisioning is able to start correctly)
• Along with its own logs (which are also shown in the corresponding Log stream), the Codebuild project will also have details regarding the different variables used to provision the Aviatrix Platform HA

Caveats

• In inter-az and inter-region deployments, if there is an HA event on the primary Controller, it will successfully failover to the standby Controller. A new standby Controller is deployed and will take approximately 15 minutes to initialize. If there is another HA event with the new primary Controller during this 15 minute window, the subsequent failover will not succeed because the new standby Controller has not been fully initialized.

HA in an inter-region deplyoment - Controller ONLY

• In the case of an HA event occurring only for the Controller in an inter-region HA deployment, the CoPilot does NOT automatically switch over to the secondary region. The CoPilot uses its associated Controller to authenticate all requests, and currently, there is no way change the Controller IP that is used for authentication. In an inter-region HA event for the Controller, the Controller IP will change, between the primary and the secondary Controllers. However, the CoPilot will continue to reach out to the primary Controller IP. Currently, the only way to resolve this is to force a CoPilot failover manually. A log message will be printed to show that a Controller HA event has occurred, but the CoPilot has not been restarted recently, and users are asked to verify the connectivity. Users will have 1 hour after the Controller HA event to trigger CoPilot HA.
• In summary, in the case where only the Controller HA event occurs in an inter-region HA deployment, customers wlll have to manually trigger CoPilot HA within 1 hour by stopping the CoPilot VM from the AWS Console.

HA in an inter-region deplyoment - CoPilot ONLY

• In the case of an HA event occurring only for the CoPilot in an inter-region HA deployment, neither the Controller nor the CoPilot automatically switches over to the secondary region. Since CoPilot is currently mostly used for monitoring and the Controller is used for management, we did not want to force an unneeded Controller failover. So, in this case, a log message will be printed to show that a CoPilot HA event was detected an inter-region deployment, but the Controller was not restarted recently. The new CoPilot will be initialized in the same region.
• In summary, in the case where only the CoPilot HA event occurs in an inter-region HA deployment, the new CoPilot will be initialized in the same region as the working Controller.

HA in an inter-region deplyoment - Controller AND CoPilot

• In this case of an HA event occurring for both the Controller and the CoPilot in an inter-region HA deployment, both the Controller and the CoPilot will restored in the DR region. This case assumes a regional outage, because both the Controller and the CoPilot have an HA event.

Private Mode Support

• Private-mode with controller HA is supported 7.1 onwards.
• Inter-region HA is not supported with private-mode.
• Controller has to be launched with a public IP address.

Basic Deployment

• A basic deployment of the Aviatrix control plane leverages a CloudFormation template to launch the Controller and CoPilot instances. The various AWS services required to provide high availability (ECS/EventBridge/etc...) are not deployed.
• Only a subset of the variables allowed in Terraform are exposed in the CloudFormation template:
  • admin_email
  • avx_customer_id
  • avx_password
  • controller_version
  • copilot_default_data_volume_size
  • copilot_instance_type
  • instance_type
  • region
  • vpc_cidr
• avx_customer_id and avx_password are required for basic deployments.
• incoming_ssl_cidr expects a list of CIDRs. The CloudFormation template supports a single CIDR so only the first CIDR from the list will be used.

Temporarily Disabling HA

HA can be temporarily disabled if needed. This can be done via Terraform or by directly modifying the Auto Scaling Groups.

Disable HA using Terraform:

• Set controller_ha_enabled and/or copilot_ha_enabled to false.
• Run terraform apply.

Enable HA using Terraform:

• Set controller_ha_enabled and/or copilot_ha_enabled to true.
• Run terraform apply.

Disable HA by updating the Auto Scaling Group(s):

• Go to EC2 -> Auto Scaling -> Auto Scaling Groups.
• Select the Auto Scaling Group (avtx_controller or avtx_copilot).
• Go to Advanced configurations -> Edit.
• Click on Suspended processes and check the following processes:
  • Launch
  • Terminate
  • HealthCheck
  • Replace Unhealthy
• Click on Update to save the changes.
• Repeat this process for the other Auto Scaling Group if necessary.

Enable HA by updating the Auto Scaling Group(s):

• Go to EC2 -> Auto Scaling -> Auto Scaling Groups.
• Select the Auto Scaling Group (avtx_controller or avtx_copilot).
• Go to Advanced configurations -> Edit.
• Under Suspended processes, remove the following processes:
  • Launch
  • Terminate
  • HealthCheck
  • Replace Unhealthy
• Click on Update to save the changes.
• Repeat this process for the other Auto Scaling Group if necessary.

Warm Pool instance state of AWS Autoscaling Group

The instance state in the AWS ASG Warm Pool is configurable, but it is only supported in the Inter-AZ use case. If the instance state is modified after deployment, the new change will only be effective after a failover.

WAF Support for Aviatrix Controller

A web application firewall (WAF) can be enabled for additional protection for the Aviatrix Controller. The requirements to use WAF are:

• The load balancer type must be an application load balancer. Network load balancers are not supported. load_balancer_type should be set to application
• A signed certificate in AWS Certificate Manager is required for ALB. Ensure that the certificate's status is Issued in AWS Certificate Manager.

There are 2 main WAF deployment scenarios:

• Default WAF rules
• Customized WAF rules

Using the Default WAF Rules

If configure_waf is set to true, the following AWS Managed Rules are enabled:

• AWS Managed Rules - Common Ruleset
• AWS Managed Rules - Known Bad Inputs Ruleset
• AWS Managed Rules - Amazon IP Reputation List
• AWS Managed Rules - Anonymous IP List
• AWS Managed Rules - SQLite Ruleset
• AWS Managed Rules - Linux Ruleset
• AWS Managed Rules - Unix Ruleset

Configure waf_managed_rules to customize the list of managed rules to implement.

WAF deployment with basic rules

module "waf_basic_rules" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "inter-az"
  load_balancer_type          = "application"
  alb_cert_arn                = "arn:aws:acm:us-east-1:111111111111:certificate/aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
  configure_waf               = true
}

Customized WAF use case

By default, the module will implement the set of AWS Managed Rules listed above. Further customization is possible.

WAF deployment with basic rules and extended rules

If you want to add additional rules to the AWS Managed Rules:

• Refer the module's output parameter alb_arn.
• Create additional aws_wafv2_web_acl resources.
• Associate the aws_wafv2_web_acl with the alb_arn using a aws_wafv2_web_acl_association resource.

module "waf_extended_rules" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "inter-az"
  load_balancer_type          = "application"
  alb_cert_arn                = "arn:aws:acm:us-east-1:111111111111:certificate/aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
  configure_waf               = true
}

resource "aws_wafv2_web_acl" "example" {
  name        = "example-acl"
  description = "Example ACL"
  scope       = "REGIONAL" # Use CLOUDFRONT for CloudFront distributions
  --- rules omitted ---
}

resource "aws_wafv2_web_acl_association" "associate_alb" {
  resource_arn = module.aws_controller_ha.lb_arn
  web_acl_arn  = aws_wafv2_web_acl.example.arn
}

WAF deployment with basic rules disabled

If you don't want to use the AWS Managed Rules and would like to fully customize the WAF rules:

• Set configure_waf to false.
• Refer the module's output parameter alb_arn.
• Create additional aws_wafv2_web_acl resources.
• Associate the aws_wafv2_web_acl resources with the alb_arn using a aws_wafv2_web_acl_association resource.

module "waf_basic_rules_disabled" {
  source                      = "github.com/aviatrix/terraform-aviatrix-aws-controlplane"
  incoming_ssl_cidr           = ["x.x.x.x/32"]
  admin_email                 = "admin@example.com"
  ha_distribution             = "inter-az"
  load_balancer_type          = "application"
  alb_cert_arn                = "arn:aws:acm:us-east-1:111111111111:certificate/aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
  configure_waf               = false
}

resource "aws_wafv2_web_acl" "example" {
  name        = "example-acl"
  description = "Example ACL"
  scope       = "REGIONAL" # Use CLOUDFRONT for CloudFront distributions
  --- rules omitted ---
}

resource "aws_wafv2_web_acl_association" "associate_alb" {
  resource_arn = module.aws_controller_ha.lb_arn
  web_acl_arn  = aws_wafv2_web_acl.example.arn
}