5V0-23.20 VMware vSphere with Tanzu Specialist Questions and Answers

External HTTP(S) Load Balancing is a proxy-based Layer 7 load balancer that enables you to run and scale your services behind a single external IP address.

A user can have permissions on multiple namespaces. The kubectl commands are typically actioned against the current active namespace.

View the list of available namespaces:

kubectl config get-contexts

Change the current active namespace:

kubectl config use-context

• The HAProxy virtual IP range where external services and DevOps users connect. In this configuration, HAProxy is deployed with two virtual NICs (Default configuration), one connected to the management network, and a second one connected to the Primary Workload Network. You must plan for allocating Virtual IPs on a separate subnet from the Primary Workload Network.

https://docs.vmware.com/en/VMware-vSphere/7.0/vmware-vsphere-with-tanzu/GUID-1F885AAE-92FF-41E6-BF04-0F0FD4173BD9.html

Print the client and server version information.

Synopsis

Print the client and server version information.

• kubectl version

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A vSphere Pod is a VM with a small footprint that runs one or more Linux containers. With vSphere Pods, workloads have the following capabilities:

• Strong isolation from a Linux kernel based on Photon OS

• Resource management using DRS

• Same level of resource isolation as VMs

• Open Container Initiative (OCI) compatible

• Equivalent to a Kubernetes Container Host

vSphere Pods are not compatible with vSphere vMotion. When an ESXi host is placed into maintenance mode, running vSphere Pods are drained and redeployed on another ESXi host, but only if the vSphere Pod is part of a ReplicaSet.

VMware Harbor Registry

VMware Harbor Registry is an enterprise-class registry server that stores and distributes container images. Harbor allows you to store and manage images for use with VMware Tanzu Kubernetes Grid Integrated Edition (TKGI).

Overview

Harbor extends the open source Docker Distribution by adding the functionalities usually required by an enterprise, such as security, identity, and management. As an enterprise private registry, Harbor offers enhanced performance and security. Deploying a registry alongside the TKGI environment improves image management efficiency.

When using vSphere with Tanzu with vDS networking, HAProxy provides load balancing for developers accessing the Tanzu Kubernetes control plane, and for Kubernetes Services of Type Load Balancer. Review the possible topologies that you can implement for the HAProxy load balancer.

https://docs.vmware.com/en/VMware-vSphere/7.0/vmware-vsphere-with-tanzu/GUID-1F885AAE-92FF-41E6-BF04-0F0FD4173BD9.html

The HAProxy appliance is an open-source solution developed by HAProxy Technologies and chosen by VMware as the first supported open-source load balancer for use with vSphere with Tanzu. With the HAProxy, external network traffic is routed to Kubernetes pods running in the vSphere with Tanzu environment.

A virtual machine class is a request for resource reservations for processing power on the virtual machine (VM), including CPU and memory (RAM). For example, the VM class type named "guaranteed-large" reserves 4 CPU and 16 GB RAM. See Default Virtual Machine Classes for a list of default VM classes and their corresponding CPU and RAM reservations.

The VM disk size is set by the OVA template, not the VM class definition. For Tanzu Kubernetes releases, the disk size is 16GB. See About Tanzu Kubernetes release Distributions.

There are two reservation types for VM classes: guaranteed and best effort. The guaranteed class fully reserves its configured resources. This means that for a given cluster the spec.policies.resources.requests matches the spec.hardware settings. The best effort class allows resources to be overcommitted. For production workloads it is recommended that you use the guaranteed VM class type.

Certain Kubernetes workloads require persistent storage to store data permanently. To provision persistent storage for Kubernetes workloads, vSphere with Tanzu integrates with Cloud Native Storage (CNS), a vCenter Server component that manages persistent volumes.

Persistent storage is used by vSphere Pods, Tanzu Kubernetes clusters, and VMs. The following example illustrates how persistent storage is used by a vSphere Pod.

vSphere Pods use different types of storage depending on the objects that are stored. The types of storage are ephemeral virtual machine disks (VMDKs), persistent volume VMDKs, and containers image VMDKs:

• Storage policies for container image and ephemeral disks are defined at the cluster level.

• Storage policies for persistent volumes are defined at the namespace level.

• Networking for vSphere Pods uses the topology provided by NSX.

Spherelet is a kubelet that is ported natively to ESXi. It allows the ESXi host to become part of a Kubernetes cluster. Spherelet performs the following functions:

• Communicates with the control plane VMs

• Manages node configuration

• Starts vSphere Pods

• Monitors vSphere Pods

For a Supervisor Cluster that is configured with the vSphere networking stack, you can provide Layer 2 isolation for your Kubernetes workloads by creating Workload Networks and assigning them to namespaces. Workload Networks provide connectivity to Tanzu Kubernetes clusters in the namespace and are backed by distributed port groups on the switch that is connected to the hosts in the Supervisor Cluster.

For some parts of your application (for example, frontends) you may want to expose a Service onto an external IP address, that's outside of your cluster.

Kubernetes ServiceTypes allow you to specify what kind of Service you want. The default is ClusterIP.

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The vSphere administrator defines and assigns VM storage policies to a namespace:

• VM storage policies are translated into Kubernetes storage classes.

• Developers can access all assigned VM storage policies in the form of storage classes.

• Developers cannot manage storage classes.

Storage class names are created in the following way:

• Spaces in VM Storage Policy names are replaced with hyphens (-).

• Special characters are replaced with a digit. A VM Storage Policy called My Gold Policy $ is called my-gold-policy-0 as a storage class.

If you want to control traffic flow at the IP address or port level (OSI layer 3 or 4), then you might consider using Kubernetes NetworkPolicies for particular applications in your cluster. NetworkPolicies are an application-centric construct which allow you to specify how a pod is allowed to communicate with various network "entities" (we use the word "entity" here to avoid overloading the more common terms such as "endpoints" and "services", which have specific Kubernetes connotations) over the network. NetworkPolicies apply to a connection with a pod on one or both ends, and are not relevant to other connections.