How to Implement Load Balancing in SAP CAP Node.js on BTP?

[fabi2295]

What are the steps to implement load balancing for a Node.js application using SAP Cloud Application Programming (CAP) on SAP BTP to ensure high availability and avoid service downtime during high traffic flows, so that no service becomes unavailable or overloaded?

[Beyhan · Accepted solution]

yes, the Cloud Foundry platform has a routing component which distributes the requests to an app instances by default in round robin algorithm. Additionally, I would recommend you to check the High Availability at Platform and Application Level section in the SAP BTP help portal. 

[fabi2295 · Accepted solution]

Incredible, I got it. I ran some tests, and it's indeed balancing automatically. I also enabled the autoscaler with the CPU configuration so that when it reaches 5%, it adds another instance.

Test: I triggered a script that makes 4 * 10,000 calls to the service, and it automatically added or removed instances based on CPU usage.

Config:

{
	"instance_min_count": 1,
	"instance_max_count": 5,
	"scaling_rules": [
		{
			"metric_type": "cpuutil",
			"breach_duration_secs": 60,
			"threshold": 5,
			"operator": ">",
			"adjustment": "+1"
		},
		{
			"metric_type": "cpuutil",
			"breach_duration_secs": 60,
			"threshold": 5,
			"operator": "<",
			"adjustment": "-1"
		}
	]
}

3 CPU's