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Cloud computing is the next stage in the Internet's evolution, providing the means through which everything — from computing power to computing infrastructure, applications, business processes to personal collaboration — can be delivered to you as a service wherever and whenever you need.

The “cloud” in cloud computing can be defined as the set of hardware, networks, storage, services, and interfaces that combine to deliver aspects of computing as a service. Cloud services include the delivery of software, infrastructure, and storage over the Internet (either as separate components or a complete platform) based on user demand. (See Cloud Computing Models for the lowdown on the way clouds are used.

Cloud computing has four essential characteristics: elasticity and the ability to scale up and down, self-service provisioning and automatic deprovisioning, application programming interfaces (APIs), billing and metering of service usage in a pay-as-you-go model. (Cloud Computing Characteristics discusses these elements in detail.This flexibility is what is attracting individuals and businesses to move to the cloud.

·         Deployment Models:

There are Four different deployment models of cloud computing:

1)    Public Cloud:

Public or external cloud is traditional cloud computing where resources are dynamically provisioned on a fine-grained, self-service basis over the Internet or via and or from an off-site third-party provider who bills on a fine-grained basis.

2)    Community Cloud:

If several organizations have similar requirements and seek to share infrastructure to realize the benefits of cloud computing, then a community cloud can be established.  This is a more expensive option as compared to public cloud as the costs are spread over fewer users as compared to a public cloud. However, this option may offer a higher level of privacy, security and/or policy compliance.

3)    Hybrid Cloud:

Hybrid Cloud means either two separate clouds joined together (public, private, internal or external or a combination of virtualized cloud server instances used together with real physical hardware. The most correct definition of the term "Hybrid Cloud" is probably the use of physical hardware and virtualized cloud server instances together to provide a single common service. Two clouds that have been joined together are more correctly called a "combined cloud". Private Clouds: Private clouds describe offerings that deploy cloud computing on private networks.  It consists of applications or virtual machines in a company's own set of hosts. They provide the benefits of utility computing-shared hardware costs, the ability to recover from failure, and the ability to scale up or down depending upon demand.

4)      Community Cloud:

If several organizations have similar requirements and seek to share infrastructure to realize the benefits of cloud computing, then a community cloud can be established.  This is a more expensive option as compared to public cloud as the costs are spread over fewer users as compared to a public cloud. However, this option may offer a higher level of privacy, security and/or policy compliance.

implementation

Eucalyptus is a Linux-based software architecture that implements scalable private and hybrid clouds within your existing IT infrastructure. Eucalyptus allows you to provision your own collections of resources (hardware, storage, and network) using a self-service interface on an as-needed basis.

You can install Eucalyptus on the following Linux distributions:

·         CentOS 5.6 and above

·         Red Hat Enterprise Linux 5.6 and above

·         Red Hat Enterprise Linux 6

·         Ubuntu 10.04 LTS

The software framework is modular, with industry-standard, language-agnostic communication. Eucalyptus provides a virtual network overlay that both isolates network traffic of different users and allows two or more clusters to appear to belong to the same Local Area Network (LAN). Also, Eucalyptus offers API compatability with Amazon’s EC2, S3, and IAM services. This offers you the capability of a hybrid cloud.

Eucalyptus Components :

·         Cloud Controllers

·         Node Controler

·         Cluster Controller

·         Storage Controllers

·         Walurus

·         System Requirements :

To install Eucalyptus, your system must meet the following baseline requirements.

Note: The specific requirements of your Eucalyptus deployment, including the number of physical machines, structure of the physical network, storage requirements, and access to software are ultimately determined by the features you choose for your cloud and the availability of infrastructure required supporting those features.

·         Hypervisor: CentOS 5 and RHEL 5 installations must have Xen installed and configured on NC host.

·         RHEL 6 and Ubuntu 10.04 LTS installations must have KVM installed and configured  on host.

·         VMware-based installations do not include NCs, but must have a VMware hypervisor pool installed and configured.

·         Machine Access: Verify that all machines in your network allow SSH login, and that root or sudo access is available

·         Compute Requirements

•    Physical Machines: All Eucalyptus components must be installed on physical machines, not virtual machines.

•    Central Processing Units (CPUs): We recommend that each machine in your Eucalyptus cloud contain either an Intel or AMD processor with a minimum of two, 2GHz cores.

·         Operating Systems: Eucalyptus supports the following Linux distributions: CentOS 5, RHEL 5, RHEL 6, and Ubuntu 10.04 LTS.

·         Machine Clocks: Each Eucalyptus component machine and any client machine clocks must be synchronized (for example, using NTP). These clocks must be synchronized all the time, not just at installation.

·        Storage and Memory Requirements

1.       Each machine in your network needs a minimum of 30 GB of storage.

2.       We recommend at least 100GB for Walrus and SC hosts running Linux VMs. We recommend at least 250GB for Walrus and SC hosts running Windows VMs.

3.       We recommend a range of 50-100GB per NC host running Linux VMs, and at least 250GB per NC host for running Windows VMs. Note that larger available disk space enables greater number of Vms.

·        Network Configuration

·         All NCs must have access to a minimum of 1Gb Ethernet network connectivity.

·         All Eucalyptus components must have at least one Network Interface Card (NIC) for a base-line deployment. For better network isolation and scale, the CC should have two NICS (one facing the CLC/user network and one facing the NC/VM network). For HA configurations that include network failure resilience, each machine should have one extra NIC for each functional NIC (they will be bonded and connected to separate physical network hardware components).

·          Some configurations require that machines hosting a CC have two network interfaces, each with a minimum of 1Gb Ethernet.           

·         In order to enable all of the networking features, Eucalyptus requires that you make available two sets of IP addresses. The first range is private, to be used only within the Eucalyptus system itself. The second range is public, to be routable to and from end-users and VM instances. Both sets must be unique to Eucalyptus, not in use by other components or applications within your network.

·        The network interconnecting physical servers hosting Eucalyptus components must support UDP multicast for IP address 228.7.7.3. Note that UDP multicast is not used over the network that interconnects the CC to the NCs.Once you are satisfied that  your  systems requirements  are   met,  you  are ready to  plan  your Eucalyptus installation.

To successfully plan for your Eucalyptus installation, you must determine two things:

·        The infrastructure you plan to install Eucalyptus on: Think about the application workload performance and resource utilization tuning. Think about how many machines you want on your system.

·        The amount of control you plan to give Eucalyptus on your network: Use your existing architecture and policies to determine the Eucalyptus networking features you want to enable: elastic IPs, security groups, DHCP server, and Layer 2 VM isolation.

Managing the Cloud

2.5.1 Managing the Cloud

Eucalyptus is comprised of six components: Cloud Controller, Walrus, Cluster Controller, Storage Controller, Node Controller, and an optional VMWare Broker. Each component is a stand-alone web service. This architecture allows Eucalyptus both to expose each web service as a well-defined, language-agnostic API, and to support existing web service standards for secure communication between its components.         

Cloud  The Cloud Controller (CLC) is the entry-point into the cloud for administrators, developers, project Controller        managers, and end-users. The CLC queries the Node Controller for information about resources, makes high-level scheduling decisions, and makes requests to the Cluster Controllers. As the interface to the management platform, the CLC is responsible for exposing and managing the underlying virtualized resources (servers, network, and storage). You can access the CLC through Amazon’s Elastic Compute Cloud (EC2) and through a web-based Dashboard.

Walrus : Walrus allows users to store persistent data, organized as buckets and objects. You can use Walrus to create, delete, and list buckets, or to put, get, and delete objects, or to set access control policies.Walrus is interface compatible with Amazon’s Simple Storage Service (S3). It provides a mechanism for storing and accessing virtual machine images and user data. Walrus can be accessed by end-users, whether the user is running a client from outside the cloud or from a virtual machine instance running inside the cloud.       

Cluster Controller     The Cluster Controller (CC) generally executes on a machine that has network connectivity to both Controller the machines running the Node Controller (NC) and to the machine running the CLC. CCs gather information about a set of node machines and schedules virtual machine (VM) execution on specific nodes. The CC also manages the virtual machine networks. All nodes associated with a single CC must be in the same subnet.

Storage Controller :  The Storage Controller (SC) provides functionality similar to the Amazon Elastic Block Store Controller (Amazon EBS). The SC is capable of interfacing with various storage systems (NFS, iSCSI, SAN devices, etc.). Elastic block storage exports storage volumes that can be attached by a VM and mounted or accessed as a raw block device. EBS volumes persist past VM termination and are commonly used to store persistent data. An EBS volume cannot be shared between VMs and can only be accessed within the same availability zone in which the VM is running. Users can create snapshots from EBS volumes. Snapshots are stored in Walrus and made available across availability zones. Eucalyptus with SAN support lets you use your enterprise-grade SAN devices to host EBS storage within a Eucalyptus cloud.

Node Controller: The Node Controller (NC) executes on any machine that hosts VM instances. The NC controls VM Controller            activities, including the execution, inspection, and termination of VM instances. It also fetches and maintains a local cache of instance images, and it queries and controls the system software (host OS and the hypervisor) in response to queries and control requests from the CC. The NC is also responsible for the management of the virtual network endpoint.

VMware Broker : VMware Broker (Broker) is an optional Eucalyptus component activated only in versions of Eucalyptus with VMware support. Broker enables Eucalyptus to deploy virtual machines (VMs) on VMware infrastructure elements. Broker mediates all interactions between the CC and VMware hypervisors (ESX/ESXi) either directly or through VMware vCenter. For more information about working with vSphere Server