Optimizing Keepalive Probes for Enhanced Network Performance

how do I tune keepalive probes

Tuning keepalive probes in HAProxy involves setting various parameters on both the client and server sides to manage the TCP keepalive behavior. Here’s how you can configure these settings:

1. Enabling TCP Keepalive

You can enable TCP keepalive probes with the following options:

• Client Side Keepalive: Use option clitcpka to enable the emission of TCP keepalive probes from HAProxy to the clients. More details on this can be found in the Proxies - Alphabetically sorted keywords reference.

• Server Side Keepalive: Use option srvtcpka to enable the emission of TCP keepalive probes from HAProxy to the backend servers. More information is available in the Proxies - Alphabetically sorted keywords reference.

2. Configuring Keepalive Parameters

After enabling TCP keepalive, you can set specific parameters to control its behavior:

• Client Side Configuration:

  • clitcpka-idle <timeout>: Time in seconds that the connection must be idle before starting to send keepalive probes. Details here.
  • clitcpka-intvl <timeout>: Time in seconds between individual keepalive probes. More information.
  • clitcpka-cnt <count>: Maximum number of keepalive probes to send before considering the connection dead. Documentation link.

• Server Side Configuration:

  • srvtcpka-idle <timeout>: Time in seconds that the connection must be idle before HAProxy begins sending keepalive probes to the server. Reference here.
  • srvtcpka-intvl <timeout>: Interval in seconds between keepalive probes. Documentation link.
  • srvtcpka-cnt <count>: Maximum number of keepalive probes HAProxy sends before dropping the connection. Details here.

3. Example Configuration

Here’s an example of how you might configure these options in a HAProxy configuration file:

defaults
    option clitcpka
    option srvtcpka

frontend main
    bind *:80
    default_backend servers

backend servers
    server server1 192.168.0.1:80 check
    clitcpka-idle 30
    clitcpka-intvl 10
    clitcpka-cnt 5
    srvtcpka-idle 30
    srvtcpka-intvl 10
    srvtcpka-cnt 5

In this configuration, both client and server side TCP keepalives are enabled with specific idle times, intervals, and probe counts, helping to maintain persistent connections effectively.

Adjust these values according to your network characteristics and traffic patterns to optimize the keepalive behavior and resource utilization in your HAProxy setup.