MuleSoft MCIA-Level-1 - MuleSoft Certified Integration Architect - Level 1

Explanation

CloudHub supports updating your applications at runtime so end users of your HTTP APIs experience zero downtime. While your application update is deploying, CloudHub keeps the old version of your application running. Your domain points to the old version of your application until the newly uploaded version is fully started. This allows you to keep servicing requests from your old application while the new version of your application is starting.

Explanation

* Resilience testing is a type of software testing that observes how applications act under stress. It's meant to ensure the product's ability to perform in chaotic conditions without a loss of core functions or data; it ensures a quick recovery after unforeseen, uncontrollable events.

* In case an API invocation fails — even after a certain number of retries — it might be adequate to invoke a different API as a fallback. A fallback API, by definition, will never be ideal for the purpose of the API client, otherwise it would be the primary API.

* Here are some examples for fallback APIs:

- An old, deprecated version of the same API.

- An alternative endpoint of the same API and version (e.g. API in another CloudHub region).

- An API doing more than required, and therefore not as performant as the primary API.

- An API doing less than required and therefore forcing the API Client to offer a degraded service, which is still better than no service at all.

* API clients implemented as Mule applications offer the ‘Until Successful Scope and Exception’ strategies at their disposal, which together allow configuring fallback actions such as a fallback API invocation.

* All HTTP response status codes within the 3xx category are considered redirection messages. These codes indicate to the user agent (i.e. your web browser) that an additional action is required in order to complete the request and access the desired resource

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Hence correct answer is Redirect client requests through an HTTP 303 temporary redirect status code to the fallback API whenever the Order API is unavailable

A core pillar of the MuleSoft Catalyst delivery approach is focusing on business outcomes. This approach ensures that the integration and API strategies are aligned with the organization’s overall business objectives. By emphasizing business outcomes, MuleSoft Catalyst helps organizations realize measurable benefits such as increased efficiency, faster time to market, and improved customer experiences. This outcome-driven methodology ensures that IT initiatives deliver tangible value to the business.

References:

MuleSoft Catalyst: Methodology Overview

Business Outcomes with MuleSof

Explanation

* If your API implementation involves putting a load balancer in front of your APIkit application, configure the load balancer to redirect URLs that reference the baseUri of the application directly. If the load balancer does not redirect URLs, any calls that reach the load balancer looking for the application do not reach their destination.

* When you receive incoming traffic through the load balancer, the responses will go out the same way. However, traffic that is originating from your instance will not pass through the load balancer. Instead, it is sent directly from the public IP address of your instance out to the Internet. The ELB is not involved in that scenario.

* The question says “each API is deployed to multiple redundant Mule runtimes”, that seems to be a hint for self hosted Mule runtime cluster. Set Inbound allowed for the LB, outbound allowed for runtime to request out.

* Hence correct way is to enable communication from each API’s Mule Runtimes and Network zone to the load balancer of the other API. Because communication is asynchronous one

Explanation

Correct answer is Client Management

* Anypoint Platform acts as a client provider by default, but you can also configure external client providers to authorize client applications.

* As an API owner, you can apply an OAuth 2.0 policy to authorize client applications that try to access your API. You need an OAuth 2.0 provider to use an OAuth 2.0 policy.

* You can configure more than one client provider and associate the client providers with different environments. If you configure multiple client providers after you have already created environments, you can associate the new client providers with the environment.

* You should review the existing client configuration before reassigning client providers to avoid any downtime with existing assets or APIs.

* When you delete a client provider from your master organization, the client provider is no longer available in environments that used it.

* Also, assets or APIs that used the client provider can no longer authorize users who want to access them.

-------------------------------------------------------------------------------------------------------------MuleSoft Reference: https://docs.mulesoft.com/access-management/managing-api-clients

https://www.folkstalk.com/2019/11/mulesoft-integration-and-platform.html

Explanation

* If we store Correlation id value in step 1 as Mule event variables/attributes, the values will be cleared after server restart and we want system to be fault tolerant.

* The Correlation ID value in Step 1 should be stored in a persistent object store.

* We don't need to store Correlation ID value in Step 3 to persistent object store. We can store it but as we also need to make application performant. We can avoid this step of accessing persistent object store.

*  Accessing persistent object stores slow down the performance as persistent object stores are by default stored in shared file systems.

*  As the SOAP service is idempotent in nature. In case of any failures , using this Correlation ID saved in first step we can make call to SOAP service and validate the Correlation ID.

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Additional Information:

* Competing Consumers are multiple consumers that are all created to receive messages from a single Point-to-Point Channel. When the channel delivers a message, any of the consumers could potentially receive it. The messaging system's implementation determines which consumer actually receives the message, but in effect the consumers compete with each other to be the receiver. Once a consumer receives a message, it can delegate to the rest of its application to help process the message.

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* In case you are unaware about term idempotent re is more info:

Idempotent operations means their result will always same no matter how many times these operations are invoked.

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Timeout Attribute:

The timeout attribute in the JMS connector specifies the maximum time allowed for a transaction to be completed. If the transaction does not complete within this specified time, it will be considered a timeout.

Transaction Management:

In the context of an Extended Architecture (XA) transaction, this timeout ensures that if the transaction is not explicitly ended within the defined time, the transaction is rolled back to maintain data consistency.

Implications of Timeout:

If the timeout is exceeded, the JMS message processing is considered unsuccessful, and all operations within the transaction are undone, which helps in avoiding partial updates and maintaining a reliable state.

References:

MuleSoft Documentation on JMS Connector

Understanding XA Transactions

Explanation

Correct answer is EACH item VM message is processed AT LEAST ONCE by ONE ARBITRARY CloudHub worker. Each of the four CloudHub workers can be expected to process some item VM messages In Cloudhub, each persistent VM queue is listened on by every CloudHub worker - But each message is read and processed at least once by only one CloudHub worker and the duplicate processing is possible - If the CloudHub worker fails , the message can be read by another worker to prevent loss of messages and this can lead to duplicate processing - By default , every CloudHub worker's VM Listener receives different messages from VM Queue Referenece: https://dzone.com/articles/deploying-mulesoft-application-on-1-worker-vs-mult

Anypoint Runtime Fabric is the appropriate choice for deploying Mule applications in an isolated Mule runtime within Docker containers on an Azure Kubernetes Service (AKS) infrastructure. This solution provides a containerized and orchestrated environment managed from the MuleSoft-hosted control plane. It enhances the availability, scalability, and robustness of Mule applications by allowing fine-grained control over deployments and providing built-in support for high availability and fault tolerance.

References:

Anypoint Runtime Fabric Overview

Deploying Mule Applications to Kubernetes