Correct Answer: D

After a new version of Kubernetes has been released and when Container Engine for Kubernetes supports the new version, you can use Container Engine for Kubernetes to upgrade master nodes running older versions of Kubernetes. Because Container Engine for Kubernetes distributes the Kubernetes Control Plane on multiple Oracle-managed master nodes (distributed across different availability domains in a region where supported) to ensure high availability, you're able to upgrade the Kubernetes version running on master nodes with zero downtime. Having upgraded master nodes to a new version of Kubernetes, you can subsequently create new node pools running the newer version. Alternatively, you can continue to create new node pools that will run older versions of Kubernetes (providing those older versions are compatible with the Kubernetes version running on the master nodes). Note that you upgrade master nodes by performing an `in-place' upgrade, but you upgrade worker nodes by performing an `out-of-place' upgrade. To upgrade the version of Kubernetes running on worker nodes in a node pool, you replace the original node pool with a new node pool that has new worker nodes running the appropriate Kubernetes version. Having 'drained' existing worker nodes in the original node pool to prevent new pods starting and to delete existing pods, you can then delete the original node pool.

Correct Answer: C

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

Correct Answer: B

Blue-green deployment is a technique that reduces downtime and risk by running two identical production environments called Blue and Green. At any time, only one of the environments is live, with the live environment serving all production traffic. For this example, Blue is currently live and Green is idle. https://docs.cloudfoundry.org/devguide/deploy-apps/blue-green.html Canary deployments are a pattern for rolling out releases to a subset of users or servers. The idea is to first deploy the change to a small subset of servers, test it, and then roll the change out to the rest of the servers. ... Canaries were once regularly used in coal mining as an early warning system. https://octopus.com/docs/deployment-patterns/canary-deployments

Correct Answer: C

Correct Answer: C

A cascading failure is a failure that grows over time as a result of positive feedback. It can occur when a portion of an overall system fails, increasing the probability that other portions of the system fail. the circuit breaker pattern prevents the service from performing an operation that is likely to fail. For example, a client service can use a circuit breaker to prevent further remote calls over the network when a downstream service is not functioning properly. This can also prevent the network from becoming congested by a sudden spike in failed retries by one service to another, and it can also prevent cascading failures. Self-healing circuit breakers check the downstream service at regular intervals and reset the circuit breaker when the downstream service starts functioning properly. https://blogs.oracle.com/developers/gettingstarted-with-microservices-part-three