Reference:
https://docs.microsoft.com/en-us/graph/api/resources/approle

Explanation

Box 1: Deployment
To deploy Azure Functions to Kubernetes use the func kubernetes deploy command has several attributes that directly control how our app scales, once it is deployed to Kubernetes.
Box 2: ScaledObject
With --polling-interval, we can control the interval used by KEDA to check Azure Service Bus Queue for messages.
Example of ScaledObject with polling interval
apiVersion: keda.k8s.io/v1alpha1
kind: ScaledObject
metadata:
name: transformer-fn
namespace: tt
labels:
deploymentName: transformer-fn
spec:
scaleTargetRef:
deploymentName: transformer-fn
pollingInterval: 5
minReplicaCount: 0
maxReplicaCount: 100
Box 3: Secret
Store connection strings in Kubernetes Secrets.
Example: to create the Secret in our demo Namespace:
# create the k8s demo namespace
kubectl create namespace tt
# grab connection string from Azure Service Bus
KEDA_SCALER_CONNECTION_STRING=$(az servicebus queue authorization-rule keys list \
-g $RG_NAME \
--namespace-name $SBN_NAME \
--queue-name inbound \
-n keda-scaler \
--query "primaryConnectionString" \
-o tsv)
# create the kubernetes secret
kubectl create secret generic tt-keda-auth \
--from-literal KedaScaler=$KEDA_SCALER_CONNECTION_STRING \
--namespace tt
Reference:
https://www.thinktecture.com/en/kubernetes/serverless-workloads-with-keda/

Explanation
Graphical user interface, application Description automatically generated

Box 1: The monitored container
The monitored container has the data from which the change feed is generated. Any inserts and updates to the monitored container are reflected in the change feed of the container.
Box 2: The lease container
The lease container acts as a state storage and coordinates processing the change feed across multiple workers.
The lease container can be stored in the same account as the monitored container or in a separate account.
Box 3: The host: A host is an application instance that uses the change feed processor to listen for changes.
Multiple instances with the same lease configuration can run in parallel, but each instance should have a different instance name.
Box 4: The delegate
The delegate is the code that defines what you, the developer, want to do with each batch of changes that the change feed processor reads.
Reference:
https://docs.microsoft.com/en-us/azure/cosmos-db/change-feed-processor

Explanation
The session state provider for Azure Cache for Redis enables you to share session information between different instances of an ASP.NET web application.
The same connection can be used by multiple concurrent threads.
Redis supports both read and write operations.
The output cache provider for Azure Cache for Redis enables you to save the HTTP responses generated by an ASP.NET web application.
Note: Using the Azure portal, you can also configure the eviction policy of the cache, and control access to the cache by adding users to the roles provided. These roles, which define the operations that members can perform, include Owner, Contributor, and Reader. For example, members of the Owner role have complete control over the cache (including security) and its contents, members of the Contributor role can read and write information in the cache, and members of the Reader role can only retrieve data from the cache.
Reference:
https://docs.microsoft.com/en-us/azure/architecture/best-practices/caching

Box 1: compositeIndexes
You can order by multiple properties. A query that orders by multiple properties requires a composite index.
Box 2: descending
Example: Composite index defined for (name ASC, age ASC):
It is optional to specify the order. If not specified, the order is ascending.
{
"automatic":true,
"indexingMode":"Consistent",
"includedPaths":[
{
"path":"/*"
}
],
"excludedPaths":[],
"compositeIndexes":[
[
{
"path":"/name",
},
{
"path":"/age",
}
]
]
}