AWS EC2 Service Discovery

Add resource tags to your EC2 instances

Add the following resource tags to:

• EC2 instances, or

• an AWS Auto Scaling Group launch template.

The HAProxy Enterprise Data Plane API will discover tagged instances and populate a backend section with their IP addresses.

The instances may have been created either individually or from a launch template.

For example, in a launch template:

See also

• Auto Scaling Group Launch Template

• AWS security credentials

Enable Service Discovery on HAProxy Enterprise

To enable service discovery, install and configure the HAProxy Data Plane API.

1. Add a section such as the following to the /etc/hapee-extras/dataplaneapi.hcl configuration file.

   service_discovery {
     aws_regions = [
       {
         AccessKeyID                = "KAB[...]2X6"
         Description                = "Production environment"
         Enabled                    = true
         IPV4Address                = "private"
         Name                       = "my-disc"
         Region                     = "eu-west-3"
         RetryTimeout               = 10
         SecretAccessKey            = "qjT[...]uXV"
         ServerSlotsBase            = 10
         ServerSlotsGrowthIncrement = 0
         ServerSlotsGrowthType      = "exponential"
       },
     ]
   }

   HCL configuration directive	JSON directive	Description
   AccessKeyID	access_key_id	AWS Access Key ID
   Description	description	Service discovery description
   Enabled	enabled	true or false. If set to false: The Data Plane API will not update server sections in discovered backend sections. Data can become outdated if: newer EC2 instances launch, or if an existing instance reboots with a new IPv4 address.
   IPV4Address	ipv4_address	private (for the private network, reachable inside the AWS VPC) or public.
   Name	name	Service discovery name
   Region	region	AWS region
   RetryTimeout	retry_timeout	Interval of time in seconds between the reconciliation and the following.
   SecretAccessKey	secret_access_key	AWS Secret Access Key
   ServerSlotsBase	server_slots_base	The minimum amount of server entries per backend section. Defaults to 10.
   ServerSlotsGrowthIncrement	server_slots_growth_increment	The number of additional slots that are allocated for server entries if there are additional entries. Defaults to 0.
   ServerSlotsGrowthType	server_slots_growth_type	Function type to implement when the number of server slots increases: exponential or linear. Defaults to exponential.

2. Restart the service:

   $ sudo systemctl restart hapee-extras-dataplaneapi

3. Check the /etc/hapee-1.6/hapee-lb.cfg file.

   A new backend section displays.

   The name of the new backend comprises the following parts:

   aws-<AWS region>-<Service discovery name>-<HAProxy:Service:Name tag value>-<HAProxy:Service:Port tag value>

   backend aws-eu-west-3-my-disc-MyApp-80
     server SRV_ONGQw 172.31.14.35:80 check weight 128
     server SRV_5hi3l 127.0.0.1:80 disabled weight 128
     server SRV_L2rw7 127.0.0.1:80 disabled weight 128
     server SRV_pG3MX 127.0.0.1:80 disabled weight 128
     server SRV_9WFsc 127.0.0.1:80 disabled weight 128
     server SRV_o2UU2 127.0.0.1:80 disabled weight 128
     server SRV_GMuw1 127.0.0.1:80 disabled weight 128
     server SRV_3Id36 127.0.0.1:80 disabled weight 128
     server SRV_6Ivld 127.0.0.1:80 disabled weight 128
     server SRV_jYF88 127.0.0.1:80 disabled weight 128

   This backend may only have several servers enabled out of the total number of servers specified by the ServerSlotsBase directive.

   When you register more instances of the same service, HAProxy Enterprise fills in disabled server slots. You can thus scale up or down without a reload, in most cases.

4. Edit the new backend as needed.

   For example, you can specify a load-balancing algorithm.

5. Configure a frontend section that routes traffic to this backend pool of servers.

See also

• Data Plane API AWS Service Discovery

• Install HAProxy Enterprise

• Data Plane API installation