Background:
Without slow start, APISIX proxies requests to additional upstream
nodes at a certain rate.
For applications that rely on caching, as well as JVM-based
applications, warming up without slow start may cause the freshly
started service to be overwhelmed by a large number of requests,
resulting in request timeouts, data loss, and poor user experience.
Design:
The weight updating will be done by the Control Plane master (elected via etcd).
A new field slow_start will be added to the node configuration.
Example:
{
"host":"127.0.0.1",
"port":1980,
"weight":1,
"slow_start":{
"target_weight":10,
"window":300,
"weight_update_interval": 5,
"start_timestamp":1673490556
}
}
The unit of window and weight_update_interval is second.
When the start_timestamp + window < current_timestamp, the slow start is done.
Admin API:
- We need to handle route, service, and upstream resources.
- It only works for node configuration in the hash table.
- Add node
- weight is set to 1 as an initial value
- Initialize start_timestamp to the current timestamp value
- Modify node
- Delete slow_start (would trigger the CP master to stop the slow
start processing)
- reset the weight to the target_weightif not specified
- Modify slow_start (would trigger the CP master to restart the slow
start processing)
- reset start_timestamp to the current timestamp value
