Explanation
Invoking Functions
You can invoke a functionthat you've deployed to Oracle Functions in different ways:
1. Using the Fn Project CLI.
2. Using the Oracle Cloud Infrastructure CLI.
3. Using the Oracle Cloud Infrastructure SDKs.
4. Making a signed HTTP request to the function's invoke endpoint. Every function has an invoke endpoint.
Using the Fn Project CLI to Invoke Functions
To invoke a function deployed to Oracle Functions using the Fn Project CLI:
Log in to your development environment as a functions developer.
In a terminal window, enter:
$ fn invoke <app-name> <function-name>
Using SDKs to Invoke Functions:
If you're writing a program to invoke a function in a language for which an Oracle Cloud Infrastructure SDK exists, Oracle recommends you use that SDK to send API requests to invoke thefunction. Among other things, the SDK will facilitate Oracle Cloud Infrastructure authentication.
References:
https://docs.cloud.oracle.com/en-us/iaas/Content/Functions/Tasks/functionsinvokingfunctions.htm

Explanation
Implement resilient applications:
Resiliency is the ability to (recover) from failures and continue to function. It isn't about avoiding failures but accepting the fact that failures will happen and responding to them in a way that avoids downtime or data loss. The goal of resiliency is to return the application to a fully functioning state after a failure.
References:
https://docs.microsoft.com/en-us/dotnet/architecture/microservices/implement-resilient-applications/

Explanation
https://docs.cloud.oracle.com/en-us/iaas/Content/ContEng/Tasks/contengcreatingloadbalancer.htm?TocPath=Ser Creating Internal Load Balancers in Public and Pr You can create Oracle Cloud Infrastructure load balancers to control access to services running on a cluster:
When you create a 'custom' cluster, you select an existing VCN that contains the network resources to be used by the new cluster. Ifyou want to use load balancers to control traffic into the VCN, you select existing public or private subnets in that VCN to host the load balancers.
When you create a 'quick cluster', the VCN that's automatically created contains a public regional subnetto host a load balancer. If you want to host load balancers in private subnets, you can add private subnets to the VCN later.
Alternatively, you can create an internal load balancer service in a cluster to enable other programs running in the same VCN asthe cluster to access services in the cluster. You can host internal load balancers in public subnets and private subnets.
To create an internal load balancer hosted on a public subnet, add the following annotation in the metadata section of the manifest file:
service.beta.kubernetes.io/oci-load-balancer-internal: "true"
To create an internal load balancer hosted on a private subnet, add both following annotations in the metadata section of the manifest file:
service.beta.kubernetes.io/oci-load-balancer-internal: "true"
service.beta.kubernetes.io/oci-load-balancer-subnet1: "ocid1.subnet.oc1..aaaaaa....vdfw" where ocid1.subnet.oc1..aaaaaa....vdfw is the OCID of the private subnet.

Explanation
In the API Gateway service, a back end is the means by which a gateway routes requests to the back-end services that implement APIs. If you add a private endpoint back end to an API gateway, you give the API gateway access to the VCN associated with that private endpoint.
You can also grant an API gateway access to other Oracle Cloud Infrastructure services as back ends. For example, you could grant an API gateway access to Oracle Functions, so you can create and deploy an API that is backed by a serverless function.
API Gateway service to create an API gateway, you can create an API deployment to access HTTP and HTTPS URLs.
https://docs.cloud.oracle.com/en-us/iaas/Content/APIGateway/Tasks/apigatewayusinghttpbackend.htm API Gateway service to create an API gateway,you can create an API deployment that invokes serverless functions defined in Oracle Functions.
https://docs.cloud.oracle.com/en-us/iaas/Content/APIGateway/Tasks/apigatewayusingfunctionsbackend.htm API Gateway service, you can define a path to a stock response back end
https://docs.cloud.oracle.com/en-us/iaas/Content/APIGateway/Tasks/apigatewayaddingstockresponses.htm

Explanation
Oracle Functions is a fully managed,multi-tenant, highly scalable, on-demand, Functions-as-a-Service platform. It is built on enterprise-grade Oracle Cloud Infrastructure and powered by the Fn Project open source engine. Use Oracle Functions (sometimes abbreviated to just Functions) when youwant to focus on writing code to meet business needs.
The serverless and elastic architecture of Oracle Functions means there's no infrastructure administration or software administration for you to perform. You don't provision or maintain compute instances, and operating system software patches and upgrades are applied automatically. Oracle Functions simply ensures your app is highly-available, scalable, secure, and monitored Applications built with a serverless infrastructure will scale automatically asthe user base grows or usage increases. If a function needs to be run in multiple instances, the vendor's servers will start up, run, and end them as they are needed.
Oracle Functions is based on Fn Project. Fn Project is an open source, container native,serverless platform that can be run anywhere - any cloud or on-premises.
Serverless architectures are not built for long-running processes. This limits the kinds of applications that can cost-effectively run in a serverless architecture. Because serverlessproviders charge for the amount of time code is running, it may cost more to run an application with long-running processes in a serverless infrastructure compared to a traditional one.
https://docs.cloud.oracle.com/en-us/iaas/Content/Functions/Concepts/functionsconcepts.htm
https://www.cloudflare.com/learning/serverless/why-use-serverless/