Oracle Cloud Infrastructure Developer 2020 Associate

Applications in the Function services
In Oracle Functions, an application is:
1. a logical grouping of functions 2. a common context to store configuration variables that are available to all functions in the application
When you define an application in Oracle Functions, you specify the subnets in which to run the functions in the application.

Pulling Images from Registry during Deployment During the deployment of an application to a Kubernetes cluster, you'll typically want one or more images to be pulled from a Docker registry. In the application's manifest file you specify the images to pull, the registry to pull them from, and the credentials to use when pulling the images. The manifest file is commonly also referred to as a pod spec, or as a deployment.yaml file (although other filenames are allowed). If you want the application to pull images that reside in Oracle Cloud Infrastructure Registry, you have to perform two steps:
- You have to use kubectl to create a Docker registry secret. The secret contains the Oracle Cloud
Infrastructure credentials to use when pulling the image. When creating secrets, Oracle strongly recommends you use the latest version of kubectl
To create a Docker registry secret: 1- If you haven't already done so, follow the steps to set up the cluster's kubeconfig configuration file and (if necessary) set the KUBECONFIG environment variable to point to the file. Note that you must set up your own kubeconfig file. You cannot access a cluster using a kubeconfig file that a different user set up. 2- In a terminal window, enter:
$ kubectl create secret docker-registry <secret-name> --docker-server=<region-key>.ocir.io --docker- username='<tenancy-namespace>/<oci-username>' --docker-password='<oci-auth-token>' --docker-
email='<email-address>' where:
<secret-name> is a name of your choice, that you will use in the manifest file to refer to the secret .
For example, ocirsecret
<region-key> is the key for the Oracle Cloud Infrastructure Registry region you're using. For example, iad.
See Availability by Region. ocir.io is the Oracle Cloud Infrastructure Registry name. <tenancy-namespace> is the auto-generated Object Storage namespace string of the tenancy containing the repository from which the application is to pull the image (as shown on the Tenancy Information page). For example, the namespace of the acme-dev tenancy might be ansh81vru1zp. Note that for some older tenancies, the namespace string might be the same as the tenancy name in all lower-case letters (for example, acme-dev).
<oci-username> is the username to use when pulling the image. The username must have access to the tenancy specified by <tenancy-name>. For example, [email protected] . If your tenancy is federated with
Oracle Identity Cloud Service, use the format oracleidentitycloudservice/<username> <oci-auth-token> is the auth token of the user specified by <oci-username>. For example, k]j64r{1sJSSF-;)K8 <email-address>
is an email address. An email address is required, but it doesn't matter what you specify. For example, [email protected]
- You have to specify the image to pull from Oracle Cloud Infrastructure Registry, including the repository location and the Docker registry secret to use, in the application's manifest file.

Testing using API mocks
Developers are frequently tasked with writing code that integrates with other system components via APIs.
Unfortunately, it might not always be desirable or even possible to actually access those systems during development. There could be security, performance or maintenance issues that make them unavailable ? or they might simply not have been developed yet. This is where mocking comes in: instead of developing code with actual external dependencies in place, a mock of those dependencies is created and used instead. Depending on your development needs this mock is made "intelligent" enough to allow you to make the calls you need and get similar results back as you would from the actual component, thus enabling development to move forward without being hindered by eventual unavailability of external systems you depend on

You can invoke a function that you've deployed to Oracle Functions in different ways: Using the Fn Project CLI.
Using the Oracle Cloud Infrastructure CLI.
Using the Oracle Cloud Infrastructure SDKs.
Making a signed HTTP request to the function's invoke endpoint. Every function has an invoke endpoint.
Each of the above invokes the function via requests to the API. Any request to the API must be authenticated by including a signature and the OCID of the compartment to which the function belongs in the request header. Such a request is referred to as a 'signed' request. The signature includes Oracle Cloud Infrastructure credentials in an encrypted form.

Emits messages to a stream. There's no limit to the number of messages in a request, but the total size of a message or request must be 1 MiB or less. The service calculates the partition ID from the message key and stores messages that share a key on the same partition. If a message does not contain a key or if the key is null, the service generates a message key for you. The partition ID cannot be passed as a parameter.
POST /20180418/streams/<streamId>/messages
Host: streaming-api.us-phoenix-1.oraclecloud.com
<authorization and other headers>
{
"messages":
{
{
"key": null,
"value": "VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cu" },
{
"key": null,
"value": "UGFjayBteSBib3ggd2l0aCBmaXZlIGRvemVuIGxpcXVvciBqdWdzLg==" }
}
}
https://docs.cloud.oracle.com/en-us/iaas/api/#/en/streaming/20180418/Message/PutMessages

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

kubectl explain to List the fields for supported resources
https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#explain

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

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