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A network service gives a workload’s Instances on one network a stable name and named ports. Datum keeps the service’s membership current as Instances start, stop, and move between locations, and sends each request to the nearest location that has a ready Instance. Datum’s Application Load Balancer reaches a workload through a network service.
Galactic VPC is in preview, and the networking.datumapis.com/v1alpha API can change.

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How network services work

A network service is a NetworkService resource with two parts:
  • A selector: labels that an Instance’s network interface must carry to belong to the service. Every Instance of a workload carries the workload’s name as a label, so a service usually selects one workload.
  • Ports: the ports the Instances listen on, each with a name, such as http on port 8080. A load balancer refers to a port by its name, not its number.
Keep the following points in mind:
  • One network: A service covers Instances on one network. If the selector matches Instances on more than one network, the service serves none of them.
  • Ready Instances only: A service sends traffic only to Instances that report themselves ready. An Instance that is starting, failing, or shutting down doesn’t receive traffic.
  • Nearest location first: Each request goes to the nearest location with a ready Instance. If that location has none, the request goes to the next nearest.
  • Created before the workload: You can create a service before its workload exists. The service starts serving when matching Instances are ready.
When you publish a workload with datumctl compute deploy --http-port, the command creates a network service named after the workload. For more information, see Serve public traffic with ALB.

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Before you begin

  • Install datumctl, log in, and select a project. For more information, see the datumctl quickstart.
  • Install the network plugin. For more information, see Manage networks with datumctl.
  • To create, change, or delete network services, you need the Network Admin role in the project.

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Create a network service

To create a network service for a workload, run the following command:
Replace the following:
  • SERVICE_NAME: a name for the service. You can’t change the name later.
  • WORKLOAD_NAME: the name of the workload whose Instances answer for the service.
  • PORT_NAME: a name for the port, such as http. Use lowercase letters, numbers, and hyphens.
  • PORT_NUMBER: the port that your Instances listen on, such as 8080.
To add more ports, repeat --port. A service takes up to 16 ports, and each name and number must be unique. To select Instances by label instead of by workload, use --selector, such as --selector app=web. The labels must be on the Instances’ network interfaces, not only on the workload.

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Send load balancer traffic to a network service

To send a load balancer’s traffic to a network service, name the service and one of its port names:
For more information, see ALB quickstart.

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Check a network service

To see what a service selects, its ports, and where it’s serving, run the following command:
The output ends with a diagnosis. If the service isn’t serving, the output also lists the Instances that aren’t ready and what each one reports. The following table describes the most common reasons that a service isn’t serving:

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Change a network service

To change which workload a service selects, run the following command:
To change a service’s ports, run the following command:
--port replaces the whole port list, so name every port that the service should keep. A load balancer that refers to a port name that you remove stops reaching the service.

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Delete a network service

To delete a network service, run the following command:
Before it asks you to confirm, the command lists the load balancers that send traffic to the service. Those load balancers stop reaching anything on that route.

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What’s next

Last modified on October 13, 2026