1z0-1084-22 Oracle Cloud Infrastructure 2022 Developer Professional Questions and Answers

Service Choreography

Service choreography is a global description of the participating services, which is defined by exchange of messages, rules of interactionand agreements between two or more endpoints. Choreography employs a decentralized approach for service composition. the decision logic is distributed, with no centralized point.

Choreography, in contrast, does not rely on a central coordinator. and all participants in the choreography need to be aware of the business process, operations to execute, messages to exchange, and the timing of message exchanges.

References:

https://stackoverflow.com/questions/4127241/orchestration-vs-choreography/33316988

Overview ofEvents

Oracle Cloud Infrastructure Events enables you to create automation based on the state changes of resources throughout your tenancy. Use Events to allow your development teams to automatically respond when a resource changes its state.

Event Rules must also specify an action to trigger when the filter finds a matching event. Actions are responses you define for event matches. You set up select Oracle Cloud Infrastructure services that the Events service has established as actions. The resources forthese services act as destinations for matching events. When the filter in the rule finds a match, the Events service delivers the matching event to one or more of the destinations you identified in the rule. The destination service that receives the eventthen processes the event in whatever manner you defined. This delivery provides the automation in your environment.

You can only deliver events to certain Oracle Cloud Infrastructure services with a rule. Use the following services to create actions:

Notifications

Streaming

Functions

References:

https://docs.cloud.oracle.com/en-us/iaas /Content/Events/Concepts/eventsoverview.htm

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-microservices

Overviewof Functions:

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 softwarepatches 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, bringyour own Dockerfile, and Graal VM). 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.

References:

https://docs.cloud.oracle.com/en-us/iaas/Content/Functions/Concepts/functionsoverview.htm

Specifying Alternative Load Balancer Shapes

The shape of an Oracle Cloud Infrastructure load balancer specifies its maximum total bandwidth (that is, ingress plus egress). By default, load balancers are created with a shape of 100Mbps. Other shapes are available, including 400Mbps and 8000Mbps.

SHAPE

A template that determines the load balancer's total pre-provisioned maximum capacity (bandwidth) for ingress plus egress traffic. Available shapes include 10Mbps, 100 Mbps, 400 Mbps, and 8000 Mbps.

References:

https://docs.cloud.oracle.com/en-us/iaas/Content/ContEng/Tasks/contengcreatingloadbalancer.htm

https://docs.cloud.oracle.com/en-us/iaas/Content/Balance/Concepts/balanceoverview.htm

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

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

distributed systems of native-cloud like functions that have a lot of benefit like

Resiliency and availability

Resiliency and availability refers to the ability of asystem to continue operating, despite the failure or sub-optimal performance of some of its components.

In the case of Oracle Functions:

The control plane is a set of components that manages function definitions.

The data plane is a set of components thatexecutes functions in response to invocation requests.

For resiliency and high availability, both the control plane and data plane components are distributed across different availability domains and fault domains in a region. If one of the domains ceasesto be available, the components in the remaining domains take over to ensure that function definition management and execution are not disrupted.

When functions are invoked, they run in the subnets specified for the application to which the functions belong. For resiliency and high availability, best practice is to specify a regional subnet for an application (or alternatively, multiple AD-specific subnets in different availability domains). If an availability domain specified for an application ceases to be available, Oracle Functions runs functions in an alternative availability domain.

Concurrency and Scalability

Concurrency refers to the ability of a system to run multiple operations in parallel using shared resources. Scalability refers to the ability of the system to scale capacity (both up and down) to meet demand.

In the case of Functions, when a function is invoked for the first time, the function's image is run as a container on an instance in a subnet associated with the application to which thefunction belongs. When the function is executing inside the container, the function can read from and write to other shared resources and services running in the same subnet (for example, Database as a Service). The function can also read from and write toother shared resources (for example, Object Storage), and other Oracle Cloud Services.

If Oracle Functions receives multiple calls to a function that is currently executing inside a running container, Oracle Functions automatically and seamlessly scales horizontally to serve all the incoming requests. Oracle Functions starts multiple Docker containers, up to the limit specified for your tenancy. The default limit is 30 GB of RAM reserved for function execution per availability domain, although you can request an increase to this limit. Provided the limit is not exceeded, there is no difference in response time (latency) between functions executing on the different containers.