Vmware vCloud: My Study Notes

Here are my quick and dirty notes while I was preparing for the VMware vCloud VCA certification.

Cloud Deployment Models

The cloud can be deployed in one of four ways:
  • Private cloud:
    • all the hardware and the software is owned by the organization
    • management and monitoring is the responsibility of the organization (the IT department)
    • builds on top of traditional virtualization technologies (think vSphere)
    • resources are almost always guaranteed
  •  Community Cloud:
    • the cloud is shared by two or more organizations that have similar technical requirements
  • Public Cloud:
    • is hosted on the provider network
    • resource management and monitoring is the responsibility of the cloud provider
    •  resources are transparently shared by customers
    • providers should allow customers to oversubscribe resources, without impacting other customers’ vDC performance
    • providers should enforce security and prevent unauthorized access between Org vDCs
    • providers allow customer to provision resources for future growth
  • Hybrid Cloud:
    • the cloud is hosted on the company’s site and expands to the cloud provider platform
    • useful for companies that:
      • have unpredictable resource usage platforms or testing applications
      • have bursty applications during pre-holiday periods
    • management is the responsibility of the customer

Basic Vmware vCloud Terminology

  • a Customer in vCloud Director is an organization
  • Organization (Org)
    • a unit of administration that has its users and groups
    • contains policies
  • Each Org can have one or more service catalogs 
  • Service ID: identifies a customer that’s doing business with Vmware, through a Vmware Authorized partner
  • VM: Virtual Machine
  • Tenant: an tenant is a VM
  • Multi-tenant environment: each tenant is a VM. 
  • vApp: a group of tenants and their underlying networking software
  • Catalog: a group of vApps, vTemplates and media files
  • vTemplate: created from a vApp. It allows to quickly deploy new vApps without going through the same steps as in the first vApp. It’s a sort of time-saver
  • Resource: a resource can be :
    • a compute resource: CPU or memory
    • a storage resource: disks
    • a networking resource
  • Resource Pool: a vSphere abstraction of physical CPU and memory resources; used by Provider vDCs
  • Cell: a single instance of vCloud Director. 
  • There should be one vCenter instance attached to each cell
  • vShield: old term to designate the virtual Cloud Network and Security software (vCNS)
  • There should be an instance of vCNS attached to each vCenter instance
  • Network Pool: a collection of undifferentiated networks that are destined to be consumed by Org vDCs, for the purpose of communication inside the cloud
  • External Networks: a collection of networks to be used for communications between the cloud and the corporate network, like a VPN or an Internet connection. External networks are not owned by the organizations.
  • Fence vApp: a feature that allows vApps to have identical MAC and IP addresses, without generating conflicts with other vApps

Vmware vCloud Allocation Models and equivalent terms in vSphere world: 
  • Allocation (in vCloud) = Limit (in vSphere)
  • Guarantee (in vCloud) = Reservation (in vSphere) 

vCloud network types

  • Org networks: networks that are owned by the organization and are part of the Org vDC
  • vApp networks: networks that exist only inside a vApp
  • External networks: represent the connection points between the cloud and the rest of the “Internet world”; are attached to vShield Edge appliances

VMware vCloud and Business Challenges 

Vmware vCloud solutions solve the following business challenges:

  • Efficiency
  • Elasticity (aka scalability)
  • Management
  • Availability

    vCloud Automation Center features

    One of VMware vcloud management blocks is the Service Provisioning. Part of the Service Provisioning block is the vCloud Automation Center.
    After briefly exposing cloud service models, I describe now some features of the vCloud Automation Center software.

    Intelligent Resource Governor

    • reclaims unused resources
    • load-balances workloads among available resources
    • enforces organization policies

    Self Service Portals

    • allows to create requests for virtual workloads. (We don’t have to say each time that it’s virtual and not physical, since we’re dealing with virtual datacenters the whole time)

    Lifecycle Management

    Policy-based Provisioning and Governance
    • user-based control
    • allows to create custom workflows
    Workflow Engine
    • provides a customizable set of mini-workflows
    • allows for decommission of workloads

    Vmware vCloud Hybrid Service

    Business Operations

    • Termination:  Vmware deletes all resources and data associated with the customer. However, data is kept for 30 days after the termination date.
    • Suspension and Re-enablement: Vmware suspends all resources associated with the customer, due for example to an infringement of some terms of service. Suspension is maintained until the customer issue is solved.
    • Metered usage: we distinguish here “metered objects”. Metered objects are like excess bandwidth and third-party licenses. Vmware charges the customer on a usage basis, according to the then rates
    • Renewal:
      • manual:the customer is contacted to check whether he still wants to renew the contract. If he wishes to change the Authorized partner associated to his Service ID, he can do so at the term period
      • automatic:the customer has nothing to do to renew the contract. But he can change the renewal method by accessing the portals
      • (termination)

    Classes of Service

    Cloud service providers offer two types of hybrid clouds:

    • Dedicated Cloud: resources are dedicated to the customer. By resources we mean compute, storage and networking. One or more virtual data centers are available to use by the customer.
    • Virtual Private Cloud: resources are virtual and shared among customers. These latters share a single virtual datacenter. Here the provider must ensure security and resource availability.

    Service Objects

    The building blocks of a hybrid cloud service are:
    – vDC: virtual datacenters
    – VMs
    – networks.

    Service Portals

    Customers have two portals with which they manage their allocated resources:
    – the “MyVmware” portal: to manage licenses
    – the ” Console” portal: to manage vCloud features and to link to vCloud Director.

    Provider vDC and Organization vDC

    Provider vDC

    • a Provider vDC is a container of resources that are taken from the vSphere layer and will be consumed by Organizations; These resources serve to create Org vDCs
    • Cloud Providers offer cloud services in the form of Organization vDCs (Org vDCs). They create service catalogs for each Org vDC
    • takes compute resources from the Resource Pool or directly from the DRS cluster
      • if the resources are taken from the Resource Pool, then only the allocated resources are available for the Provider vDC
      • if the resources are taken from the DRS cluster, then all DRS cluster resources are available for the the Provider vDC
    • takes storage resources from Datastores

    Organization vDC (Org vDC)

    • an Org vDC is a logical grouping of resources taken from Provider vDCs
    • an organization can order one or more Org vDCs, from one or more Provider vDCs (in other words, it can order cloud services from one or more Cloud providers)
    • each Org vDC maps to a class of service defined by the Provider vDC. Each class of service corresponds to a specific budget and a set of technical requirements

    vCloud Private Service

    This service is given by Vmware to Cloud providers, allowing them (the cloud providers) to sell cloud services to customers

    Use Cases

    • there are three types of cloud services uses, from a customer perspective, in terms of resource utilization:
      • High elasticity: bursty
      • Transient state: occasional bursty, seasonal, event-based (like pre-holiday periods)
      • Steady state: predictable amount of data and resources, mission-critical data. This is common for most companies
    • With each of these use cases, there’s a service offering and a correspondent Allocation Model

    Private Cloud Service Offerings

    • Basic: customer is charged on VM basis, and per hour of usage
    • Committed: Customer has a guaranteed percentage and a total allocation value. when customer resource usage bursts, it can reach up to the total allocation value but no more. This is only possible if there are available shared resources of course.
    • Dedicated: customer has dedicated resources for his cloud environment, i.e. no other customers shares them with him. Besides, customer has complete control over his resources

    Cloud Consumption/Allocation Models

    Allocation models map to each service offering and to each use case. With each model, the provider creates an allocation threshold (resource usage limit) and a guarantee threshold (resource usage reservation)
    • Allocation Pool
      • customer has a resource reservation set (kind of a minimum guaranteed). If resource utilization exceeds the limit, the customer is charged for that.
      • the vSphere Admission Control feature ensures that, before each VM is started, it has enough resources
    • Pay-as-you-Go (PAYG) model
        • customer is charged only when vApps are deployed to his Org vDC
        •   limits and reservations are set at the VM level only:
            • there can only be reservations for memory,
            • there can be reservations and limits set for CPU
    • Reservation Pool
      • the allocation and the guarantee are set at the resource pool level (think REServation pool > RESource pool)
      • resources are consumed as long as there still are resources in the resource pool
      • the max number of VMs is dictated by the amount of resources in the resource pool of the Org vDC 

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