Sunday, June 22, 2014

Engineered Systems VS. NIST Definition of Cloud Computing

According to the NIST,
Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model is composed of five essential characteristics, three service models, and four deployment models.(

In this blog, I will examine how each of the five essential characteristics defined by NIST (in bold/italics) applies to the engineered systems - Exalogic, Exadata, and Exalytics.

On-Demand Self-Service:  

A consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider.
This refers to the ability of cloud services consumers to configure and maintain the landscape presented to them. This allows for distributed administration capabilities. While the centralized team concentrates on managing the infrastructure tasks like initial setup, capacity planning and resource quota allocation, backup, disaster recovery, patching, libraries of Virtual Machine (VM) templates, middleware code, etc., the application-level administration is delegated to the consumers. They can create VMs from the template library and extend them according to their needs.

To enable the consumers to do this, several administration consoles are provided by the Cloud Infrastructure to allow for GUI, Command Line Interface (CLI) or scripted interaction with the system.

Oracle’s engineered systems provide the following self-service capabilities:
 •  Cloud admin account access
Enterprise Manager Operations Center (EMOC) access 
Virtual Data Center (vDC) Management tab with access to pre-built Virtual Machine templates for frequently used functions
Base VM templates to build upon
Command Line Interfaces (CLI and dCLI) access to most of these tasks for automation and one-touch unilateral provisioning

Broad Network Access:  

Capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, tablets, laptops, and workstations).
Oracle’s engineered systems are generally used for private cloud offerings within secured corporate or public sector settings. Therefore, access to these is not required on a mobile device. The systems provide the access over SSL/SSH using the following: 

  • Browser-based interfaces (EMOC/VM Manager/ZFSManager)
  • CLI interface over SSH

Resource Pooling:  
The provider’s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand. There is a sense of location independence in that the customer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Examples of resources include storage,  processing, memory, and network bandwidth.
This, I believe, is the most important characteristic of a cloud offering. With commodity servers running independently, we have seen that there is often a heterogeneous usage of resources. Most of the servers are underutilized while some can never have enough resources to service the load, creating a bottleneck referred to as 'underutilized server sprawl'. With an IaaS scenario, this can be fixed by dynamically rearranging the load on a particular resource. The engineered systems allow for resource quota for the users/accounts (Account Resource Limit).
  • Oracle Virtual Machine Server - Virtualizer
  • Virtual CPU/CPU oversubscription
  • Common memory pool
  • Common storage
  • Shared network access  

Rapid Elasticity: 

Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time.
We currently follow these steps in order to change the memory, vCPU, and/or the Network resource allocation for an existing guest vServer (Reference - Exalogic: Changing the Memory, vCPU and Network Resources for an existing guest vServer (Doc ID 1586296.1)):
  1. Stop the vServer
  2. Create a template
  3. Create a vServer type with the required memory and vCPU resources
  4. Delete the old server
  5. Create a new vServer by using the template in step #2 and the vServer type created in step #3
I am hopeful that upcoming releases will make this process more streamlined and easier to manage.
Ideally, to ensure elasticity, the virtual servers should have memory, vCPU, network bandwidth, and storage quotas within a range. The servers should also have a priority definition which will help mitigate resource contention issue in case multiple vServers are trying. The vServer should be able to negotiate the resources based on its priority among other servers, the current load on the vServer, and the Virtual Server as a whole.
The disk space is shared among all the compute nodes and virtual machines.  Shares and projects can be created by the cloud admins to be mounted on the VMs. These shares can also be shared among multiple VMs.
Resource quotas are established at a cloud-account level. Any VM created within the account has access to the resources allocated to the account.
What’s missing?
  • Networking quota
  • Prioritization (if a resource is oversubscribed, which account/VM/process gets access to the resource if the physical limit is reached)
  • Time slot-based allocation   

Measured service:
Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service.
Enterprise Manager 12c provides the capability to meter the usage and calculate chargeback of different resources (targets).  A universal charge plan contains rates for CPU, Memory and storage. Extended charge plans can be used across various target types. Details can be found in the OEM - Chargeback Administration.

What’s missing? 

  • This functionality is not available for Exalytics servers yet. However, in an OBIEE implementation, certain Usage Tracking reports can be configured to provide this functionality.

Tech Term of the Day 

NIST - National Institute of Standards and Technology

Architect - Oracle Engineered Systems
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1 comment :

Adarsh Kumar said...

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