Manage Backend Mapping

The Backend Mapping tab lists the backend groups behind a load balancer and lets you add, edit, and remove them after creation. A backend group is the pool of servers (or an auto scaling group) that receives traffic, along with its routing policy and health check.

The Backend Mapping tab is available whenever the load balancer is not Creating, Deploying, or Deleting.

For how routing policies and health checks behave, see Choose a Load Balancer.

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What the Tab Shows

The columns differ by load balancer type.

Application Load Balancer (ALB): Backend Group, Backend Type, Routing Policy, Protocol, Health Check, Servers, Socket Timeout, and Actions.

Network Load Balancer (NLB): Backend Group, Routing Policy, LB Listening Port, Servers, and Actions.

Each server appears as a chip showing its name, IP, and port. A server that is DOWN is shown in red. Health is read from the load balancer's monitoring data.

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Add, Edit, and Save

1. For an ALB, select Add Backend Group to create a new group, or the edit (pencil) icon on a row to change one. For an NLB, edit the existing backend.
2. Configure the group in the form (see below).
3. You can add or edit multiple groups before saving. When there are unsaved changes, a Save and Deploy button appears with an info icon next to changed rows.
4. Select Save and Deploy to apply. The load balancer redeploys with the new configuration (about 5–10 minutes).

note

You cannot delete the last backend group on its own. To remove the final backend, delete the entire load balancer instead. Editing and deleting are disabled while the load balancer is Powered off.

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Backend Group Form (ALB)

Field	Type	Details
Backend Group	Text	Required, unique. Letters, digits, hyphen, underscore; up to 64 characters.
Backend Protocol	Select	HTTP (default) or HTTPS — how the load balancer talks to the backends. HTTPS enables TLS to the backend (self-signed or internal-CA certificates are allowed).
Health Check	Checkbox	Enables HTTP health checks. When on, a backend that returns a 2xx or 3xx response on the health-check path is marked UP; otherwise DOWN. The default path is /.
Routing Policy	Select	Source IP Hash (default), Round Robin, or Least Connection.
Backend Type	Select	Node (default) or Auto Scale Group.
Backend Servers	Multi-select	Shown for Node. Select registered servers; use Add Server to add one (see below).
Auto Scaling Group	Select	Shown for Auto Scale Group. Choose an auto scaling group; use Add New to create one.
Scaler Port	Number	Shown for Auto Scale Group. The port used to send and receive traffic (1–65535).
Web Socket Timeout	Number	Optional. 1–100 seconds.

Add Server

The Add Server modal registers a backend server:

Field	Requirement
Server Name	Required. Letters, digits, hyphen, underscore; up to 64 characters.
Server IP	Required. A valid IPv4 address — prefer the private IP if the server is on E2E Cloud.
Server Port	Required. 1–65535.

After you add servers, open the dropdown to review the list for the group.

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Backend Group Form (NLB)

A Network Load Balancer forwards TCP traffic, so its form is simpler — there is no protocol, health-check checkbox, backend type, or WebSocket timeout.

Field	Type	Details
Backend Name	Text	Required. Letters, digits, hyphen, underscore; up to 64 characters.
Routing Policy	Select	Source IP Hash, Round Robin, or Least Connection (Least Connection suits TCP).
LB Listening Port	Number	Required. Must be 80, 443, or 1024–65535. Ports 8080, 10050, and 9101 are reserved and rejected.
Backends	Multi-select	Required. Add servers with Add Server (same fields as above).

note

A Network Load Balancer supports a single TCP backend, and ACL rules cannot be applied to it. For content-based routing across multiple backend groups, use an Application Load Balancer.

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Rules and Limits

• Backend group names must be unique on the load balancer, and none is not allowed as a name.
• At least one backend group is required.
• An NLB allows only one TCP backend; TCP and HTTP backends cannot be mixed.
• ACL rules apply to ALBs only.

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Related Resources

Resource	Use it for
ACL routing rules	Route requests to different backend groups (ALB).
Choose a Load Balancer	Routing policies and health checks explained.
Auto Scaling	Use a dynamic scale group as a backend.
Troubleshoot Load Balancers	Fix backends marked DOWN.