How to Manage Load Balancing Algorithms on a Vultr Load Balancer

Updated on April 7, 2025

A Load Balancing algorithm determines how a Vultr Load Balancer distributes incoming traffic to linked instances. Vultr Load Balancers support the Least Connections and Round Robin algorithms that manage the distribution of traffic to instances depending on your application needs.

Follow this guide to manage load balancing algorithms on a Vultr Load Balancer using the Vultr Customer Portal, API, or CLI.

Vultr Customer Portal
Vultr API
Vultr CLI

Navigate to Products and click Load Balancers.
Click your target Load Balancer to open its management page.
Click Configuration.
Click Load Balancer in the left navigation menu.
Click the Algorithm drop-down and select a Load Balancing algorithm from the list of options.
- Round Robin: Distributes traffic evenly across all linked instances in a circular order.
- Least Connections: Forwards traffic to the instance with the lowest number of active connections.
Click Save changes to apply the Load Balancing algorithm.

Send a GET request to the List Load Balancers endpoint and note the target Load Balancer's ID.

                            console
                            
                        
$ curl "https://api.vultr.com/v2/load-balancers" \
    -X GET \
    -H "Authorization: Bearer ${VULTR_API_KEY}"

Send a PATCH request to the Update Load Balancer endpoint to update the target Load Balancer's algorithm.

                            console
                            
                        
$ curl "https://api.vultr.com/v2/load-balancers/{load-balancer-id}" \
    -X PATCH \
    -H "Authorization: Bearer ${VULTR_API_KEY}" \
    -H "Content-Type: application/json" \
    --data '{                           
        "balancing_algorithm": "{roundrobin_or_leastconn}"
    }'

Send a GET request to the Get Load Balancer endpoint to fetch the details of the target Load Balancer.

                            console
                            
                        
$ curl "https://api.vultr.com/v2/load-balancers/{load-balancer-id}" \
    -X GET \
    -H "Authorization: Bearer ${VULTR_API_KEY}"

List all available instances and note the target Load Balancer's ID.
console
```
$ vultr-cli load-balancer list
```

Update the target Load Balancer's algorithm.

                            console
                            
$ vultr-cli load-balancer update <load-balancer-id> --balancing-algorithm "<roundrobin_or_leastconn>"