Load Balancers

Load balancers improve resource usage, scaling ability, and help with instance availability on Compute Cloud@Customer.

Two major types of load balancers are available on Compute Cloud@Customer:

• Load Balancer as a Service – Provides Layer-7 routing, which sees all headers inserted before the message data, including information in the HTML part of the message.
• Network Load Balancing – Provides Layer-4 pass-through routing, meaning NLB sees only the IP and TCP headers on a packet.

Although the operational layers are the most obvious difference between LBaaS and NLBs, some features are shared while others differ. For example, both types of LBs require a public network load balancer to accept traffic from the internet, and a public LB can't be in a private subnet.

The following table summarizes these major differences.

If a VCN uses network security groups (NSGs), you can associate the load balancer with an NSG. An NSG has a set of security rules that controls allowed types of inbound and outbound traffic. The rules apply only to the resources in the group. An NSG isn't a security list, where the rules apply to all the resources in any subnet that uses the list. See Controlling Traffic with Network Security Groups.

If you prefer to use security lists for the VCN, see Controlling Traffic with Security Lists.

We recommend that you distribute backend servers across all availability domains.

Other differences are of an operational nature, or involved in configuration limits. Many of the NLB limitations are because of the functioning at Layer 4 and no higher. These differences are listed in the following table.

Depending on the type of load balancer you want to use, see one of these sections:

• Load Balancer as a Service
• Network Load Balancing