An Ingress Controller is a Kubernetes resource that provides advanced routing and load balancing for your applications running on a Kubernetes cluster1.An Ingress Controller allows you to define rules that specify how to route traffic to different services in your cluster based on the host name or path of the incoming request1.By deploying an Ingress Controller and using it to expose multiple application endpoints, you can achieve the following benefits1:

Cost-effectiveness: You only need to create one load balancer instance per cluster, instead of one per service, which reduces the cost of exposing your applications.

Simplicity: You only need to manage one set of routing rules for all your services, instead of configuring each service separately, which simplifies the application deployment and maintenance.

Flexibility: You can use different types of Ingress Controllers, such as NGINX or Traefik, that offer various features and customization options for your routing needs.

The correct answer is: Microservices are used for long running operations while serverless functions are used for short running operations. One of the key differences between microservices and serverless functions is the duration of their execution. Microservices are typically designed to handle long-running operations and may continuously run and process requests as part of a larger system. They are often deployed and managed as long-lived services. On the other hand, serverless functions are designed to handle short-lived operations or tasks that execute in response to specific events or triggers. They are event-driven and execute only when invoked, providing a lightweight and ephemeral computing model. Serverless functions are often used for executing small, isolated pieces of code without the need for managing infrastructure or scaling concerns. While both microservices and serverless functions can be stateless or stateful depending on the specific implementation, the key distinction lies in the typical duration and execution pattern of these components within an application architecture.

A pod is the smallest and simplest unit in the Kubernetes object model that you create or deploy2. A pod represents a single instance of a running process in your cluster. Pods contain one or more containers, such as Docker containers. When you create a pod, you define how much CPU and memory (RAM) each container needs.A pod can also include storage volumes, IP addresses, options that govern how the container(s) should run, and more2.Pods are the basic building blocks of larger Kubernetes constructs such as deployments, replica sets, and services2.

The correct answer is: 'read only.' The layers of a Docker image are read-only. Once a layer is created, it cannot be modified. Each layer represents a Dockerfile instruction, and it is stacked on top of the previous layer, forming a stack of immutable layers. These layers are designed to be read-only to ensure consistency and integrity of the image. When a Docker image is built, each instruction in the Dockerfile creates a new layer. Each layer represents the changes made by that instruction relative to the previous layer. The layers are stacked on top of each other to form the complete image. This layer-based approach allows for efficient storage and distribution of Docker images. Because the layers are read-only, any changes or modifications to the image result in the creation of new layers rather than modifying the existing ones. This immutability ensures that each layer remains intact and preserves the integrity of the image. It also enables Docker's caching mechanism, where previously built layers can be reused if the corresponding instructions haven't changed, speeding up the image build process. The other options mentioned, such as 'write only,' 'write once,' 'movable,' and 'read mostly,' do not accurately describe the permission associated with Docker image layers. Docker image layers are specifically designed to be read-only.

An action is a response that you define for the rule to perform when the filter finds a matching event1.The action type specifies the service that you want to invoke by delivering the event message1.The following action types are available in OCI Events rule definition1:

Streaming: Send to a stream from Oracle Streaming Service.

Notifications: Send to an Oracle Notification Service topic.

Functions: Send to an Oracle Functions Service endpoint. Email is not a valid action type for OCI Events rule definition.To send an email as an action, you need to use the Notifications service and subscribe to a topic with an email protocol2.