Load Balancing
Load Balancing mechanism used for WAF
Overview
Load balancing across multiple application instances is a commonly used technique for optimizing resource utilization, maximizing throughput, reducing latency, and ensuring fault‑tolerant configurations.
Load Balancing Algorithms
This field specifies the load balancing algorithm according to the configured website.
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ROUND ROBIN: This algorithm is a smart approach to distribute client requests across an array of servers. It forwards the client request to each server in turn. Also, assigns a weight to each server as per current load and idle capacity.
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LEAST CONNECTIONS: This algorithm is a dynamic load balancing algorithm. It forwards client requests to the server, which has the least no. of active connections on the server.
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LEAST LISTENER CONNECTIONS: This algorithm is a dynamic load balancing algorithm. It forwards client requests to the server, which has the least no. of active connections to the backend server.
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LEAST RESPONSE TIME: This algorithm is a dynamic load balancing algorithm. It forwards client requests to the server, which have a small response time in order to serve requests.
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LEAST REQUEST: This algorithm is a dynamic load balancing algorithm. It forwards client requests to the server, which have served the minimum amount of requests.
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IP HASH: This algorithm takes the client's and server's source and destination IP address to generate a unique hash key. This key is used to assign the client to a specific server. In the case of a broken session, the key can be regenerated, and the client can be directed to the same server.
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PERSIST HASH: This algorithm takes the user input location within the current request to generate a user-defined custom unique hash key. This key is used to assign the client to a specific server. In the case of a broken session, the key can be regenerated, and the client can be directed to the same server.
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COOKIE HASH: This algorithm takes the cookie name specified by the user in param input field to generate a unique hash key. This key is used to assign the client to a specific server. In the case of a broken session, the key can be regenerated, and the client can be directed to the same server.
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HEADER HASH: This algorithm takes the header name specified by the user in param input field to generate a unique hash key. This key is used to assign the client to a specific server. In the case of a broken session, the key can be regenerated, and the client can be directed to the same server.
Note: In hashing-based load balancing, if a specified value does not exists then the request is served on the basis of client's IP address.
How to Use:
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Go to WAF > Zones > Listeners > Server Groups > Load Balancing
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Set the configurations and Save Changes.
| PARAMETERS | ACCEPTED VALUES | DEFAULT |
|---|---|---|
| Web Socket Enabled | Enabled/Disabled | False |
| Keep-Alive Enabled | Enabled/Disabled | False |
| Keep-Alive Timeout | Integer | 3600 |
| Connection Pool Size | Integer | 32 |
| Max Keep-Alive Requests | Integer | 100 |
| Upstream Retries | Integer | 1 |
| Failover Threshold | Integer | 50 |
| Algorithm | Dropdown | Round Robin |
| Param | String | None |
| Add Location | String & Integer | None & Src IP |
Description
Web Socket Enabled
This toggle button allows you to enable the Websocket support for servers in the server group.
Keep-Alive Enabled
This toggle button allows you to enable keep-alive connections with servers in the server group.
Keep-Alive Timeout
This field specifies upstream keep-alive connection timeout in seconds. By default, the value is set to 3600 seconds.
Connection Pool Size
This field specifies the connection pool size. By default, the value is set to 32.
Max Keep-Alive Requests
This field specifies the max allowed requests per keep-alive connection. By default, the value is set to 100 requests.
Upstream Retries
This field specifies the upstream retries. By default, the value is set to 1.
Failover Threshold
This field specifies the failover threshold in percentage of (active/total) primary servers for switching to backup servers. By default, the value is set to 50%.
Algorithm
This dropdown specifies the algorithm used by the server group. By default, the value is selected as Round Robin.
Param
This field specifies the parameters for the location. Location will be specified with its Priority and Location like IP, Cookie, Port, Session, etc.