Compute: Containers

Question 1

Azure Container Instances: Container Group

Answer 1

The top-level resource in Azure Container Instances.

• a collection of containers that get scheduled on the same host machine
• containers in a container group share a lifecycle, resources, local network, and storage volumes

Question 2

Docker Container:

Answer 2

Container is an instance of a Docker image. It represents the execution of a single application, process, or service. It consists of the contents of a Docker image, an execution environment, and a standard set of instructions.

Question 3

Docker Container Image:

Answer 3

refers to a package with all the dependencies and information required to create a container. The dependencies include frameworks and the deployment and execution configuration that a container runtime uses

Question 4

Container Build

Answer 4

refers to the action of building a container image based on the information and context provided by the Dockerfile. The build also includes any other files that are needed.

Question 5

Docker Pull

Answer 5

Pull refers to the process of downloading a container image from a container registry.

Question 6

Docker Push

Answer 6

Push refers to the process of uploading a container image to a container registry.

Question 7

Dockerfile

Answer 7

refers to a text file that contains instructions on how to build a Docker image. The Dockerfile is like a batch script. The first line identifies the base image. The rest of the file includes the build actions.

Question 8

AKS: Pools

Answer 8

Pools are groups of nodes with identical configurations.

Question 9

AKS Nodes

Answer 9

Nodes are individual virtual machines running containerized applications.

Question 10

AKS Pods

Answer 10

Pods are a single instance of an application. A pod can contain multiple containers.

Question 11

AKS: Container

Answer 11

is a lightweight and portable executable image that contains software and all of its dependencies.

Question 12

AKS Deployment

Answer 12

Deployment has one or more identical pods managed by Kubernetes.

Question 13

AKS Manifest

Answer 13

Manifest is the YAML file describing a deployment.

Question 14

AKS Kubernetes cluster is divided into two components:

Answer 14

Azure-managed nodes, which provide the core Kubernetes services and orchestration of application workloads.

Customer-managed nodes that run your application workloads.

Question 15

AKS: Kubelet

Answer 15

the Kubernetes agent that processes the orchestration requests from the Azure-managed node, and scheduling of running the requested containers.

Question 16

AKS: kube-proxy

Answer 16

Virtual networking is handled by the kube-proxy on each node. The proxy routes network traffic and manages IP addressing for services and pods.

Question 17

AKS: Container Runtime

Answer 17

The container runtime is the component that allows containerized applications to run and interact with additional resources such as the virtual network and storage.

Question 18

AKS Networking: Cluster IP

Answer 18

an internal IP address for use within the AKS cluster. Good for internal-only applications that support other workloads within the cluster

Question 19

AKS Networking: NodePort

Answer 19

Creates a port mapping on the underlying node that allows the application to be accessed directly with the node IP address and port.

Question 20

AKS LoadBalancer

Answer 20

Creates an Azure load balancer resource, configures an external IP address, and connects the requested pods to the load balancer backend pool. To allow customers traffic to reach the application, load-balancing rules are created on the desired ports.

Question 21

AKS ExternalName

Answer 21

ExternalName - Creates a specific DNS entry for easier application access.

Question 22

AKS Storage: Volumes

Answer 22

A volume represents a way to store, retrieve, and persist data across pods and through the application lifecycle.

Azure Disks can be used to created a Kubernetes DataDisk resource.

Azure Files can be used to mount an SMB 3.0 share backed by Azure Storage account to pods.

Question 23

AKS Storage persistent volumes

Answer 23

A persistent volume (PV) is a storage resource created and managed by the Kubernetes API that can exist beyond the lifetime of an individual pod

Question 24

AKS Storage classes

Answer 24

To define different tiers of storage, such as Premium and Standard, you can create a StorageClass.

The StorageClass also defines the reclaimPolicy.

This reclaimPolicy controls the behavior of the underlying Azure storage resource when the pod is deleted and the persistent volume may no longer be required.

Question 25

AKS Storage: Persistent Volume Claims

Answer 25

A PersistentVolumeClaim requests either Disk or File storage of a particular StorageClass, access mode, and size.

A PersistentVolume is bound to a PersistentVolumeClaim once an available storage resource has been assigned to the pod requesting it. There is a 1:1 mapping of persistent volumes to claims.

Question 26

AKS Scaling (HPA)

Answer 26

Kubernetes uses the horizontal pod autoscaler (HPA) to monitor the resource demand and automatically scale the number of replicas.

By default, the horizontal pod autoscaler checks the Metrics API every 30 seconds for any required changes in replica count.

When changes are required, the number of replicas is increased or decreased accordingly. Horizontal pod autoscaler works with AKS clusters that have deployed the Metrics Server for Kubernetes 1.8+.

Question 27

AKS Cluster autoscaler

Answer 27

To respond to changing pod demands, Kubernetes has a cluster autoscaler that adjusts the number of nodes based on the requested compute resources in the node pool.

Question 28

The local configuration manager (LCM) - Push mode:

Answer 28

Push mode: An administrator manually sends, or pushes, the configurations to one or more nodes. The LCM makes sure that the state on each node matches what the configuration specifies.