What is thecommunication method between different Cloud native applications services?

• A.Complex and asynchronous
• B.Basic and synchronous
• C.Complex and synchronous
• D.Basic and asynchronous

Correct Answer: D

Explanation
What Is Cloud Native?
Cloud native technologies arecharacterized by the use of containers, microservices, serverless functions, development pipelines, infrastructure expressed as code, event-driven applications, and Application Programming Interfaces (APIs). Cloud native enables faster software developmentand the ability to build applications that are resilient, manageable, observable, and dynamically scalable to global enterprise levels.
When constructing a cloud-native application, you'll want to be sensitive to how back-end services communicate with each other. Ideally, the less inter-service communication, the better. However, avoidance isn't always possible as back-end services often rely on one another to complete an operation.
While direct HTTP calls between microservices are relatively simple to implement, care should be taken to minimize this practice. To start, these calls are always synchronous and will block the operation until a result is returned or the request times outs. What were once self-contained, independent services, able to evolve independently and deploy frequently, now become coupled to each other. As coupling among microservices increase, their architectural benefits diminish.
Executing an infrequent request that makes a single direct HTTP call to another microservice might be acceptable for some systems. However, high-volume calls that invoke direct HTTP calls to multiple microservices aren't advisable. They can increase latency and negatively impact the performance, scalability, and availability of your system. Even worse, a longseries of direct HTTP communication can lead to deep and complex chains of synchronous microservices calls, shown in Figure 4-9:

A message queue is an intermediary construct through which a producer and consumer pass a message.
Queues implement an asynchronous, point-to-point messaging pattern.
Events
Message queuing is an effective way to implement communication where a producer can asynchronously send a consumer a message.
References:
https://www.xenonstack.com/blog/cloud-native-architecture/
https://www.oracle.com/sa/cloud/cloud-native/
https://www.oracle.com/technetwork/topics/entarch/cloud-native-app-development-wp-3664668.pdf

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You are working on a cloud native e-commerce application on Oracle Cloud Infrastructure (OCI). Your application architecture has multiple OCI services, including Oracle Functions. You need to trigger these functions directly from other OCI services, without having to run custom code.
Which OCI service cannot trigger your functions directly?

• A.OCI Events Service
• B.OCI Registry
• C.OCI API Gateway
• D.Oracle Integration

Correct Answer: B

Explanation
Overview of Functions:
Oracle Functions is a fully managed, multi-tenant, highly scalable, on-demand, Functions-as-a-Service platform. It is built on enterprise-gradeOracle Cloud Infrastructure and powered by the Fn Project open source engine. Use Oracle Functions (sometimes abbreviated to just Functions) when you want 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. With Oracle Functions, you can write code in Java, Python, Node, Go, and Ruby (and for advanced use cases, bring your own Dockerfile, and Graal VM).
You can invoke a function that you'vedeployed to Oracle Functions from:
- The Fn Project CLI.
- The Oracle Cloud Infrastructure SDKs.
- Signed HTTP requests to the function's invoke endpoint. Every function has an invoke endpoint.
- Other Oracle Cloud services (for example, triggered by an event in the Events service) or from external services.
so You can then deploy your code, call it directly or trigger it in response to events, and get billed only for the resources consumed during the execution.
Invoking Oracle Functions from Other OracleCloud Infrastructure Services:
You can invoke functions in Oracle Functions from other Oracle Cloud Infrastructure services. Typically, you'll want an event in another service to trigger a request to invoke a function defined in Oracle Functions.
This functionality is currently available in:
A:The Events service. For more information, see Overview of Events.
B:The Notifications service. For more information, see Notifications Overview. For a scenario, see Scenario A: Automatically Resize VMs.
C:The API Gateway service. For more information, see Adding a Function in Oracle Functions as an API Gateway Back End.
D:The Oracle Integration service, using the OCI Signature Version 1 security policy. For more information, see Configure Oracle Integration to CallOracle Cloud Infrastructure Functions with the REST Adapter in Using the REST Adapter with Oracle Integration.

so OCI Registry services cannot trigger yourfunctions directly
References:
https://docs.cloud.oracle.com/en-us/iaas/Content/Functions/Tasks/functionsintegratingwithother.htm
https://docs.cloud.oracle.com/en-us/iaas/Content/Functions/Concepts/functionsoverview.htm
https://blogs.oracle.com/cloud-infrastructure/announcing-notifications-triggers-for-serverless-functions

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Given a service deployed on Oracle Cloud infrastructure Container Engine for Kubernetes (OKE), which annotation should you add in the sample manifest file to specify a 400 Mbps load balancer?

• A.service.beta, kubernetes. lo/oci-load-balancer-kind: 400Mbps
• B.service, beta, kubernetes. lo/oci-load-balancer-value: 4 00Mbps
• C.service . beta. kubernetes . lo/oci-load-balancer-shape: 400Mbps
• D.service . beta . kubernetes . lo/oci-load-balancer-size: 400Mbps

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What is one of the differences between a microservice and a serverless function?

• A.Microservices are used for long running operations and serverless functions for short running operations.
• B.Microservices always use a data storeand serverless functions never use a data store.
• C.Microservices are stateless and serverless functions are stateful.
• D.Microservices are triggered by events and serverless functions are not.

Correct Answer: A

Explanation
microservice is larger and can do more than a function. A function is a relatively small bit of code that performs only one action in response to an event.
Many microservices can run on several servers, and different instances of a specific microservice can run on several servers.
In many cases, microservices can be decomposed into a number of smaller stateless functions. The difference between microservices and functions is not simply the size. Functions are stateless, and they require no knowledge about or configuration of the underlying server-hence, the term serverless.
Microservices are best suited for long-running, complex applications that have significant resource and management requirements. You can migrate an existing monolithic application to microservices, which makes it easier to modularly develop features for the application and deploy it in the cloud. Microservices are also a good choice for building e-commerce sites, as they can retain information throughout a transaction and meet the needs of a 24/7 customer base.
On the other hand, serverless functions only execute when needed. Once the execution is over, the computing instance that runs the code decommissions itself. Serverless aligns with applications that are event driven, especially when the events are sporadic and the event processingis not resource-intensive. Serverless is a good choice when developers need to deploy fast and there are minimal application scaling concerns. For example, a good use of serverless computing is a scheduled task that needs to perform some data aggregation and will execute for just a few seconds.

References:
https://www.cloudflare.com/learning/serverless/glossary/serverless-microservice/
https://developer.oracle.com/java/fn-project-introduction.html
https://searchapparchitecture.techtarget.com/answer/When-should-I-choose-between-serverless-and-microservice

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Which one of the following is NOT a valid backend-type supported by Oracle Cloud Infrastructure (OCI) API Gateway?

• A.STOCK_RESPONSE_BACKEND
• B.ORACLE_FUNCTIONS_BACKEND
• C.ORACLE_STREAMS_BACKEND
• D.HTTP_BACKEND

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