Load Balancer

What is a Load Balancer?

Load Balancers are highly available and fully managed instances which distribute the workload among your servers. They ensure the scaling of applications while securing their continuous availability. They are commonly used to improve the performance and reliability of web sites, applications, databases, and other services by distributing the workload across multiple servers.


How am I billed for a Load Balancer?

The Load Balancer is billed €0.018 per hour or €8.99 per month.


How can a Load Balancer increase the availability of my applications?

A Load Balancer can monitor the availability of your backend servers, detect if a server fails and rebalance the load between the rest of the servers, making your applications highly available for users.


Are Load Balancers compatible with Dedibox Dedicated Servers?

Yes, a Load Balancer can be used as frontend, both for Scaleway Cloud Servers as well as for Dedibox Dedicated Servers.


What is a Highly Available IP address?

A Highly Available IP address is the IP, the frontend listens to. It provides a special configuration and is by default routed to the primary Load Balancer instance. In case of a failure of the primary Load Balancer instance, this address is automatically rerouted to the replicated one. This is done automatically, by the Load Balancer control subsystems.

By default, each Load Balancer is created automatically with a Highly Available IP. When you delete a Load Balancer, you can keep the HA IP allocated to your account for 1€ a month and reuse it later. HA IP is not compatible with Compute instances, as well as you can’t use an IP address, earlier allocated for a compute instance, for a Load Balancer.


Can I have more than one public IP address for a Load Balancer?

Each Load Balancer comes with one highly available IP address. Currently, it is not possible to assign more than one IP to each Load Balancer.


Is TLS/SSL termination supported?

Currently, TLS/SSL termination is not possible. You can use TCP mode to balance HTTPS sessions.


Do Load Balancers support external IPv6 connections?

Each Load Balancer provides external connectivity via an IPv4 address. IPv6 is not yet supported for external connections, but it can be used to communicate between the Load Balancer and your backend servers.


What are Primary and Replica Load Balancers?

Each Load Balancer consists of two instances: Primary and Replica. These instances are deployed identically on different hardware clusters to ensure that they don’t share physical resources to minimize the risk of simultaneous failure.

In case the primary Load Balancer fails, the highly available IP address is automatically re-routed to the replica Load Balancer to handle the traffic.

Important: There is no stateful connection synchronization between primary and replica and all long-living sessions must be reestablished in case of a switchover.


What are the performance characteristics of a Load Balancer?

The current benchmarks of the Load Balancer instances:

  • 3500 new sessions per second
  • 50000 packets per second
  • 40000 total concurrent sessions

These values may vary depending on a particular use-case, type of payload, policies, and the number of backend servers.


Do backend servers require a public IP address?

No, it’s not strictly required. You can use private Scaleway IPs on your backend servers if they are hosted in the same region as the Load Balancer.


Are Load Balancers manageable by an API?

Yes. You can manage your Load Balancers via REST API.


Is there a limitation on which TCP ports can I load balance?

No, there is no restriction. You can balance any TCP port (1-65535).


Can I use a Load Balancer for UDP traffic?

A Load Balancer can handle only TCP traffic at the moment.


Can I have multiple backends within one Load Balancer?

Yes, you can define multiple backend endpoints for your Load Balancer.


Which operating systems are supported for the backend servers?

You can use any operating system on your backend servers.


How many servers can be added as backend?

It is possible to add as many servers to your backends as your needs require. This allows scaling your applications on demand, e. g. increase the capacity of a website for high-usage periods and decrease it when your customers are on vacation.