Load Balancing

A load balancing group is a group of Key Manager servers the client can connect to. Load balancing is a mechanism to equally distribute the connection load across the Key Managers when there are concurrent requests. To add multiple key managers, refer to Add Multiple Key Managers.

CADP for Java also allows you to create multiple levels of load balancing groups., called as tiers. For details, refer to Multi-Tier Load Balancing

How it works

The following steps describe what happens when the client attempts to connect to the load balancing group for the first time:

1. The client creates a session. This in turn creates a new load balancer. The load balancer stores the NAE_IP, NAE_Port, KMIP_Port, Protocol, Connection_Timeout, Connection_Retry_Interval, and Unreachable_Server_Retry_Period` parameters.

   If persistent connections are enabled, the load balancer also creates a new connection pool for each server in the load balancing group. else, the connection pool is not created.

   Tip

   It is recommended to enable persistent connection.

2. The client requests a connection from the load balancer. For the first connection request, the load balancer chooses one of the available Key Managers at random and creates a connection. For future requests, the load balancer will apply the Load_Balancing_Algorithm to decide which Key Manager to use.

3. The client waits the duration of Connection_Timeout for a server response.

4. If server 1 does not respond within the timeout period. The client ignores server 1 for the duration of the Connection_Retry_Interval.

5. The client attempts to connect to server 2.

6. The client obtains the connection.

7. The client uses the connection to send a cryptographic request to server 2.

8. Server 2 sends the response.

9. The load balancer keeps the connection in the connection pool, if persistent connections are enabled. Otherwise, the connection is closed.

Related parameters

• NAE_IP

• NAE_Port

• KMIP_Port

• Protocol

• Load_Balancing_Algorithm

• Connection_Timeout

• Connection_Retry_Interval

• Unreachable_Server_Retry_Period

For more information about these parameters, refer to Connection Parameters.

Examples

The defaults

The CADP_for_JAVA.properties uses the following default values:

• Connection_Timeout=1m

• Connection_Read_Timeout=7000

• Connection_Retry_Interval=600000

• Unreachable_Server_Retry_Period=60000

• Maximum_Server_Retry_Period=0

Let's understand the impact of these parameters on load balancing:

Setting Unreachable_Server_Retry_Period

We’ll still use NAE_IP.1=alpha:beta:gamma, but for this example, we’ll configure new values for Connection_Timeout and Unreachable_Server_Retry_Period parameters. The values of Connection_Read_Timeout, Connection_Retry_Interval, and Maximum_Server_Retry are unchanged (default).

• Connection_Timeout=2000

• Connection_Read_Timeout=7000

• Connection_Retry_Interval=600000

• Unreachable_Server_Retry_Period=840000

• Maximum_Server_Retry_Period=0

The following table highlights the impact of these parameters on load balancing:

Setting Maximum_Server_Retry_Period

Now we’ll set Unreachable_Server_Retry_Period to the infinite retry period. We’ll counter this by setting Maximum_Server_Retry_Period.

• Connection_Timeout=2000

• Connection_Read_Timeout=7000

• Connection_Retry_Interval=600000

• Unreachable_Server_Retry_Period=-1

• Maximum_Server_Retry_Period=1200000

The following table highlights the impact of these parameters on load balancing: