Config knob to Increase maximum number of API connections per second passed to Avi Controller cluster

Products

• VMware Avi Load Balancer

Issue/Introduction

• In a default config, there's limit to the number of concurrent requests passed to Avi Controller cluster, on an average it's 32 req/sec.
• We can modify this config knob to specify a limit on the  average number of requests passed per second and the excess requests will be delayed.
• There is also a burst parameter that can restrict the number of delayed requests. On reaching the burst limit, the requests are dropped with 429 Too Many Requests. This limit is enforced independently for each client IP.

Resolution

Note: Do not set this value too high, as too many requests at once have been seen to overwhelm the uWSGI process, which can impact cluster performance.

Below is the config knob to increase the rate limit for number of requests passed to Avi Controller cluster

[admin:10-x-x-x]: controllerproperties> configure controller properties
[admin:10-x-x-x]: controllerproperties> portal_request_rate_limit 128
[admin:10-x-x-x]: controllerproperties> portal_request_burst_limit 129
[admin:10-x-x-x]: controllerproperties> save

where,

portal_request_rate_limit: "Maximum average number of requests allowed per second" ("0 to disable")

portal_request_burst_limit: "Burst limit on number of incoming requests" ("0 to disable")