| Select Listener Protocol |
Select the protocol of the listener.
In this example, TCP is selected.
|
| Listening Port |
Set the listening port used to receive requests and forward them to backend servers.
Valid values: 1 to 65535.
Note You can apply for the permissions to set the same port for TCP and UDP listeners in the same SLB instance on the Quota Management page. This feature is in public preview and is supported in the following regions.
In other cases, the listening ports must be unique.
- UAE (Dubai)
- Australia (Sydney)
- UAE (Dubai)
- UK (London)
- Germany (Frankfurt)
- US (Silicon Valley)
- US (Virginia)
- Indonesia (Jakarta)
- Japan (Tokyo)
- India (Mumbai)
- Singapore (Singapore)
- Malaysia (Kuala Lumpur)
- China (Hong Kong)
- China (Shenzhen)
- China (Hohhot)
- China (Qingdao)
- China (Chengdu)
- China (Zhangjiakou)
- China (Shanghai)
- China (Beijing)
- China (Hangzhou)
|
| Advanced |
| Scheduling Algorithm |
SLB supports the following scheduling algorithms: RR, WRR, WLC, and CH.
- Weighted Round-Robin (WRR): Backend servers with a higher weight receive more requests than those with a lower
weight.
- Round-Robin (RR): Requests are sequentially distributed to backend servers.
- Weighted Least Connections (WLC): Requests are distributed based on the combination of the weights and active connections
of backend servers. If two backend servers have the same weight, the backend server
with fewer connections is expected to receive more requests.
- Consistent Hash (CH):
- Source IP: the source IP address hash. Requests from the same source IP address are scheduled
to the same backend server.
- Tuple: a quadruple hash that consists of the source IP address, destination IP address,
source port number, and destination port number. Requests with the same quadruple
are scheduled to the same backend server.
Note The CH algorithm can be used only by guaranteed-performance instances.
|
| Enable Session Persistence |
Specify whether to enable session persistence.
After session persistence is enabled, the listener forwards all requests from the
same client to a specific backend server for the duration of a session.
For TCP listeners, session persistence is implemented based on IP addresses. Requests
from the same IP address are forwarded to the same backend server.
|
| Enable Access Control |
Specify whether to enable access control. |
| Access Control Method |
Select an access control method after you enable access control.
- Whitelist: Only the requests from the IP addresses or CIDR blocks in the specified access control
list (ACL) are forwarded. You can use the whitelist feature when you want to allow
access from specified IP addresses.
Using the whitelist feature may pose risks to your services. After the whitelist is
enabled, only the IP addresses in the ACL can access the SLB listener. If the whitelist
is enabled without any IP addresses specified, the SLB listener does not forward any
requests.
- Blacklist: Requests from the IP addresses or CIDR blocks in the specified ACL are not forwarded.
You can use the blacklist feature when you want to deny access from specified IP addresses.
If the blacklist is enabled without any IP addresses specified, the SLB listener forwards
all requests.
|
| Access Control List |
Select an ACL that is used as the whitelist or blacklist of the listener.
Note IPv6 instances can be associated only with IPv6 ACLs, while IPv4 instances can be
associated only with IPv4 ACLs. For more information, see Create an access control list.
|
| Enable Connection Draining |
When connection draining is enabled, connections to the backend server can function
as expected for a specific time period after they are removed or fail the health check.
|
| Connection Draining Timeout |
After you enable connection draining, you can specify the maximum timeout period to
keep connections alive before a backend server is removed from an SLB server group.
After the backend server is removed or remains unhealthy for the specified time period,
SLB terminates the connections to the backend server.
Value values: 10 to 900.
Unit: seconds.
|
| Enable Peak Bandwidth Limit |
Specify whether to set a bandwidth limit for the listener.
For a pay-by-bandwidth SLB instance, you can set different maximum bandwidth values
for different listeners to limit listener traffic. The sum of maximum bandwidth values
of all listeners that belong to the same SLB instance cannot exceed the bandwidth
of this SLB instance.
By default, the bandwidth limit is disabled and all listeners share the bandwidth
of the SLB instance.
Note A pay-by-data-transfer SLB instance does not impose limits on its maximum bandwidth.
|
| Idle Timeout |
Specify the idle timeout for TCP connections. Unit: seconds. Valid values: 10 to 900. |
| Listener Name |
Enter a name for the listener. |
| Obtain Client Source IP Address |
For Layer 4 listeners, backend servers can directly obtain the actual IP addresses
of clients.
|
| Automatically Enable Listener After Creation |
Specify whether to start the listener immediately after it is configured. By default,
the listener is started after it is configured.
|
