Discovery - HashiCorp Consul

Objective

This document provides instructions on how to discover service endpoints using HashiCorp Consul. Service discovery enables you to find the endpoints where a given service is available. To learn more about service discovery, see Service Discovery.

Using the instructions provided in this guide, you can create a discovery object and endpoint for a service using the service name and the location where the service is available.

Note: The service name is obtained from HashiCorp Consul.

Prerequisites

An F5® Distributed Cloud Services Account. If you do not have an account, see Create an Account.
Consul with a service or application reachable from a Distributed Cloud Services Site. Install the Node or Cluster Image in your cloud or edge location.

Configuration

Distributed Cloud Services enable you to discover existing service endpoints using multiple methods, including the HashiCorp Consul. This document covers service discovery on sites, virtual sites, or virtual networks using Consul.

The following figure shows the configuration workflow for service discovery with Consul:

Figure: Setting Up Service Discovery with Consul

Configuration Sequence

Discovering services using the Consul service information requires performing the following sequence of actions:

Phase	Description
Create Discovery for Consul Cluster	Create a service discovery object of type Consul.
Verify Discovered Services	Verify that the service discovery object was created and successfully discovering services.
Use Discovered Services	Configure an endpoint with K8s as the discovery type and associate sites with it.

Note: The site of the discovery object and the endpoint must be the same.

Create Discovery for Consul Cluster

Step 1: Start discovery object creation.

Log into F5® Distributed Cloud Console (Console).
Click Multi-Cloud App Connect.

Figure: Console Homepage

Click Manage > Service Discoveries.
Click Add Discovery.

Figure: Navigate to Service Discovery

Step 2: Enter metadata.

In the Name field, enter a name for the service discovery object.
Optionally, add labels and a description.

Step 3: Set discovery location.

In the Where section, perform the following:
- From the Virtual-Site or Site or Network menu, select Site or Virtual Site.
- Accordingly, select an appropriate object from the Reference menu.
- From the Network Type menu, select the network type for the object.

Step 4: Configure Consul settings for discovery.

In the Discovery Method section, perform the following:
- From the Select Discovery Method menu, select Consul Discovery Configuration.
- Click Configure.
- Enter the API server IP address and port number for your Consul server.

Figure: API Host and Port

Note: If authentication is HTTP based, skip Step 5 and proceed to Step 6.

Step 5: Configure TLS parameters.

If the authentication method for Consul is TLS-based, click Configure.
In the Server Parameters section, enter the Server Name Indication (SNI) name and enter the Server CA certificate in ASCII or base64(binary) formats.

Figure: Consul Server Parameters

In the Client Parameters section, enter the client certificate in ASCII or base64(binary) formats.
Under Client Private Key, click Configure.
Choose Blindfold Secret or Clear Secret from the Secret Info menu.
Provide the key in one of the formats available. If you have ASCII text and must blindfold, click Blindfold.
Click Apply.

Step 6: Configure HTTP authentication.

If authentication is HTTP parameters-based for the Consul server, configure the settings in the HTTP Authentication Parameters field.

In the User Name field, enter the username for the Consul server.
Click Configure.
Choose Blindfold Secret or Clear Secret from the Secret Info menu.
Provide the key in one of the formats available. If you have ASCII text and must blindfold, click Blindfold.
Click Apply.

Step 7: Set VIP publishing.

In the VIP Publishing Configuration section, perform the following:
- From the Enable/Disable VIP Publishing menu, select Publish domain to VIP mapping.
- Click Apply.
- Click Save and Exit.

Verify Discovered Services

Verify that the service discovery object was created and discovering services.

Step 1: Navigate to service discovery in Console.

Click Manage > Service Discoveries.
Verify that the service discovery object is present and that the Services field displays the number of services discovered.

Step 2: Verify the discovered services.

Click on the value displayed in the Services field. This displays the list of discovered services.
Note down the service to use from the Service Name field.

Use Discovered Services

After the service discovery object is created and the services are discovered, you can use them in configuration, such as the following:

Origin Pools: The origin pools are a way to declare the origin servers for your service in the load balancer configuration. You can create origin pools as part of HTTP load balancer creation or individually create and apply to an HTTP load balancer later.
Endpoints: The endpoint objects are for advanced configuration for using in the virtual host configuration.

Configure Origin Pool with Consul Service Information

This chapter shows the origin pool creation with Consul service name for the origin server specification.

Step 1: Start creating origin pool.

In Console, click Multi-Cloud App Connect.
Change to your application namespace.
Click Manage > Load Balancers > Origin Pools.
Click Add Origin Pool.

Step 2: Set Consul as the type of origin.

Enter a name in the Metadata section.
In the Basic Configuration section, click Add Item.
From the Select Type of Origin Server menu, select Consul Service Name of Origin Server on given Sites.

Step 3: Set the service name.

Obtain the service name using the instructions in the Verify Discovered Services chapter.
Enter the service name in the Service Name field.

Step 4: Specify the location for the origin pool.

Select Site or Virtual Site from the Select Site or Virtual Site menu.
Select a site or virtual site accordingly.
Select a network from the Select Network on the site menu.
Click Apply.

Step 5: Set port.

From the Port menu, enter a port number.

Figure: Set Port

To complete the configuration, see the Origin Pools guide.
Click Save and Exit.

Create Endpoint with K8s Service Information

Step 1: Navigate to your application namespace in Console.

Select the namespace from the namespace selector or create a new namespace.

Step 2: Start creating endpoint.

Select Manage > Virtual Host > Endpoints.
Click Add endpoint.
In the Metadata section, perform the following:
- Add a name.
- Optionally, add labels and a description.

Step 3: Obtain Consul service information.

Obtain the Consul service information using the instructions in the Verify Discovered Services chapter.

Step 4: Configure the endpoint address.

Configure where the endpoint should be discovered.

From the Endpoint Specifier menu, select Service Selector Info. This option requires you to use a service name or label selector to reach the endpoint.
From the Discovery menu, select HashiCorp Consul.
From the Service menu, select Service Name.
Enter your service name in the Service Name field. Use the <servicename> format.

Note: Obtain the service name from Step 3.

Step 5: Configure the network.

From the Virtual-Site or Site or Network menu, select an option. This site or virtual site must be the same as that of the discovery object created.
From the Reference menu, select the object.

Note: Any reference object (site, virtual site, and virtual network) needs to be created and listed before configuring this field. The available object list is displayed on a cascading menu, where you can select one or more objects.

From the Network Type menu, select an option.

Step 6: Set port and protocol.

Enter a port number and a protocol value for the Port and Protocol fields, respectively.

Figure: Set Port and Protocol

Note: The port must be the service port of the Consul service and not the node port.

Step 7: Optionally, set a health check port.

In the Port used for health check, enter a port number to use as an alternative port number for a health check on the endpoint.

Step 8: Complete creating an endpoint.

Click Save and Exit.

With the steps above, you can discover a service endpoint from Consul using Service Info on a location specified using the selector. Once the service is discovered, the object can be used with other configuration objects on the Distributed Cloud Services platform. For example, you can advertise it across sites in the cloud or edge.

Concepts

API References

Discovery