Overview

This analysis is to see the possibility of scaling the CPS-NCMP component horizontally to respond well to increased load.

CPS-786 - Getting issue details... STATUS

Scenario

Load scenario: (model)sync 10,000 cm handles with the same schema-set: imagine this is done by firing 1000 requests of (batches of) 10 cm handles registration to a pool of cps-ncmp instances

Issues and Resolutions

Issue	Description	Resolution
Pod Instances readiness check	the current CPS deployment contains 'livenessProbe' and 'readinessProbe' to determine if containers are
HTTP keep-alive

CPS Deployment in ONAP

Currently, CPS in ONAP deployment has the following configuration shown in the table below.

**Resources listed below is only relevant for this study

Resource name	Description	Notes
cps-and-ncmp deployment	creates instances of pods (set of containers) that run cps application default pod replica count is set to 1 (i.e. creates 1 pod) has 3 associated volumes	replica count can be changed to the number of pods desired to be added through values.yaml file of the cps-core component the value 'replicaCount' is used by the deployment object configured in the manifest deployment.yaml deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: {{- include "common.resourceMetadata" . \| nindent 2 }} spec: replicas: {{ .Values.replicaCount }} . . . if the replica count is 2, the deployment object will create and k8s controller ensures that the number of running pods is always 2, the load is also distributed among the replicas this method has been tested to create 3 instances of cps-ncmp by specifying replicaCount in values.yaml values.yaml . . . # Resource Limit flavor -By Default using small flavor: small # default number of instances replicaCount: 3 # Segregation for Different environment (Small and Large) resources: . . .
postgres deployment	creates instances of pods that run Postgres default pod replica count is set to 1 (i.e. creates 1 pod) utilizes persistent volumes
cps-core service	enables network access to pods running cps application uses the default service type 'ClusterIP' which exposes CPS's multiple ports to allow only internal access to pods this service is also exposed by an Ingress which exposes HTTP and HTTPS routes from outside operates with an Ingress resource wherein the traffic rules are stated allows the service to be reachable via URL allows multiple services to be mapped to a single port	Other service types are NodePort, LoadBalancer, and ExternalName ClusterIp service type uses round-robin/random to load balance
postgres Service	uses the default service type ClusterIP ingress is not enabled for this service therefore it is only accessible within the Kubernetes cluster

Load Balancing Options

Load balancing option	Description	Issues	Possible solution
Increasing pod/replica count	Replica count is changed from the default number to the number of pods desired to be added through values.yaml file Defined in the manifest deployment.yaml which means the deployment object created will own and manage the replicaSet this is the recommended way to use replicaSets	Burst propagation eviction of one replica results in the load being redirected to another replica CPU in the node can be/will be fully used up	adding Horizontal Pod Autoscaler (HPA) allows the automatic deployment of pods to satisfy the stated configuration wherein the number of pods depends on the load i.e. the workload resource will be scaled back down if the load decreases and the number of pods are above the configured minimum. HPA can be defined with multiple and custom metrics. HPA scales up and distributes workload efficiently over the replicas with the linearly increasing workload but takes time to scale up or down with bursty workloads
		Database Bottleneck	Vertical Scaling more resources such as CPU and memory are added if all user is in the same deployment then maybe multiple instances of the database but the synchronization will be complex Sharding? Different databases for different dataspaces** there is only one dataspace for cps-ncmp so it is
		Rolling out Kubernetes by default removes 1 pod at a time and adds a new one after which means we lose 100/Number of pods % ability to server end-users request	Changing the 'maxUnavailable' in the specification of the deployment object to be '0' will ensure that Kubernetes will first deploy a pod and ensure it is running before removing an old one
		Readiness Establish a connection with the database before ensuring the pod is ready to accept requests
		HTTP Protocol if the application has 'HTTP keep-alive' this means that once a connection is established it stays and keeps that connection open