|Oracle® Virtual Assembly Builder User's Guide
11g Release 1.1 (11.1.1)
Part Number E22514-01
Increased operating costs, inefficient hardware utilization and rapidly expanding data centers have made virtualization the most compelling IT technology in years. Virtualization for desktop and server environments has evolved to finally deliver on its promise to lower operating costs by increasing the utilization of hardware and reducing the overall amount of hardware required.
While virtualization has solved a multitude of problems, it is still difficult to deploy and manage complex applications made up of multiple tiers and components. Furthermore, virtualization is quickly becoming a commodity and the focus now shifts to directly virtualizing applications to reap the next level of benefits associated with virtualization.
Virtualization is the process of abstracting hardware resources, such as CPU, memory, storage, and network interfaces, from the operating system and applications. The hardware runs virtualization software (for example, a hypervisor) that enables the installation of multiple operating systems, each capable of running simultaneously and independently, in its own secure physical environment.
The development and deployment of applications in your virtualized environment involves a sequence of operational stages including testing, staging, and production. The transition between these stages can be difficult as there are few facilities within existing virtualization infrastructure that guarantee consistency and correctness of the collection of software components. Implementing the physical to virtual (P2V) or virtual to virtual (V2V) transitions seems simple: create virtual images of the original deployments, then instantiate them in the target environment. Oracle VM can be used to implement such solutions.
Handcrafting the virtualization solution has many pitfalls. Details of network connectivity may change in the deployment environment, but no automatic mechanism exists to perform or even to track these changes. Images may be specific to particular details of the deployment environment. The proliferation of images results in sprawl, creating maintenance overhead as each of the images must be patched at the operating system and application layers. These pitfalls create unanticipated costs.
Oracle Virtual Assembly Builder is a tool for virtualizing installed Oracle components, modifying those components, and then deploying them into a your own environment. Using Oracle Virtual Assembly Builder, you capture the configuration of existing software components in artifacts called software appliances. Appliances can then be grouped, and their relationships defined into artifacts called software assemblies.
Oracle Virtual Assembly Builder allows the logical connections between appliances within an assembly to be reconfigured by a process known as assembly editing. When a desired assembly configuration has been achieved, you use Oracle Virtual Assembly Builder to prepare the assembly for deployment and then deploy it into your environment. The components and processes are described below.
A software appliance (appliance) represents a single software component and its local execution environment. Depending on your choice of deployment technology, the component's local environment may be a single operating system instance or, using Oracle JRockit Virtual Edition, a Java virtual machine instance without a conventional operating system.
A software assembly (assembly) is a collection of interrelated software appliances that are automatically configured to work together upon deployment. Assemblies are deployed onto a pool of hardware resources with minimal user input.
While assemblies are simply a collection of appliances with defined interconnects, assemblies must provide a set of capabilities in order to be useful in a production environment, including:
Allow for the composition of appliances as well as external systems
Externalize configuration in the form of metadata that can easily be customized
Optionally define the start order of appliances to reflect interdependencies
Provide a management domain which integrates into existing management infrastructure allowing for metadata definition, deployment, oversight and diagnostics
In addition to being comprised of appliances, assemblies can also contain references to external systems. This is necessary to represent infrastructure such as databases, servers or security providers that cannot or should not be included in an assembly.
To summarize, the notion of being able to create pre-built assemblies for deployment is extremely powerful and has a number of advantages that drive down operational costs and complexity. These include:
Ability to easily replicate assemblies in production, even allowing for variations of the assembly without adding complexity
Reduced risk of configuration errors as assemblies are moved between development, test and production environments
Replicated environments facilitate high-level standardization and consistency across application infrastructures, allowing for simple implementation of best practices.
Accelerated deployment of new infrastructures and applications
In order to realize these benefits, a simple means of composing assemblies of appliances is required. Specifically what is needed is tooling that allows for the composition of appliances as well as endpoint mapping of externalized systems and other larger non-virtual appliance-based systems such as databases and identity management servers.
Oracle Virtual Assembly Builder includes intuitive visual environment, command line interface, and supporting infrastructure. Oracle Virtual Assembly Builder enables administrators to construct and deploy complete assemblies encompassing all of the components and systems that make up a potentially complex application structure or infrastructure.
Oracle Virtual Assembly Builder provides the following capabilities:
Ability to browse a catalog of existing appliances and assemblies allowing for simple re-use of existing infrastructure
Ability to modify connections between appliances using drag-and-drop
Ability to create templatized definitions of complete configurations, allowing for simple deployment
Single-step deployment of virtualized multi-tier applications onto a pool of virtualized resources
Assembly creation and deployment is a straightforward, four-step process. First, in the introspect phase, the necessary metadata and configuration information is captured from an existing deployment for all components that make up the appliances within an assembly. During the configure phase, the relationships are established among the appliances and any external resources. The prepare phase creates the deployment artifacts necessary for the assembly that is relevant to the particular virtualization platform (that is, virtual images). Finally, the deploy phase deploys the assembly into your environment.
In the introspect phase, you capture configuration metadata for individual software components, or collectively capture metadata for multiple distributed components. Target components may reside locally or remotely on multiple distributed systems that may be physical or virtual.
In the configure phase, you:
Visually drag-and-drop components for creating complex assemblies using appliances maintained in a navigable catalog
Establish relationships and connections between appliances using a wiring tool that automatically checks for protocol compatibility
Create connections from appliances to external resources (such as database, security provider, messaging, and so on) not included within assembly
In the prepare phase, you:
Create bootable virtual machine disk images with customized operating system distributions (for example, Oracle Enterprise Linux) and configurable metadata allowing for deploy-time customization of the software component
Optimize appliances containing Java applications by incorporating Oracle JRockit Virtual Edition (a high-performance JVM specifically designed to run in a virtual environment without the overhead of a general-purpose operating system)
In the deploy phase, you:
Stage all appliance disk images and deploy entire assemblies onto resource pools in a single step
Create customized deployment configurations for assemblies that override base configuration properties for appliances within the assembly
Accommodate late-binding appliances automatically through deployment-specific customization
Scale appliance instances after initial deployment of an assembly and automatically wire the newly deployed instances into the existing assembly
Oracle Virtual Assembly Builder captures the existing condition of a specific set of Oracle Fusion Middleware and Oracle Database software components from your environment, represents them as assemblies and appliances, and enables their deployment into the your environment. Oracle Virtual Assembly Builder does not include the ability to administer the components and does not replace the administrative tools supplied with them.
Oracle Virtual Assembly Builder does not supply the virtual environment into which you deploy your Assemblies. You must establish the deployment environment using one of the target environments that Oracle Virtual Assembly Builder supports. For more information about supported deployment environments, see Oracle Virtual Assembly Builder Installation Guide.
A minimal appliance consists of metadata (name and value pairs) describing the condition of the original component, together with a set of component-specific files that allow its configuration to be recreated at deployment time. As you use Oracle Virtual Assembly Builder to prepare appliance for deployment into your environment, additional configuration information is created and stored along with the metadata.
The appliance metadata includes a description of each of the component's logical inputs and outputs. These inputs and outputs are collectively called endpoints. The HTTP input of an Oracle HTTP Server component is an example of an input endpoint. The
mod_wl_ohs output of the same Oracle HTTP Server component is an example of an output endpoint.
The metadata describing endpoints includes protocols, port numbers, URLs, and so on. Oracle Virtual Assembly Builder captures enough information about each endpoint to allow the connection to be updated after the component is captured and before it is deployed. This capability allows Oracle Virtual Assembly Builder to ensure that appliances will connect correctly within the deployment environment.
Appliances are grouped into assemblies. An assembly is a logical container for appliances and the connections between them. You create assemblies using Oracle Virtual Assembly Builder and populate them with appliances and other assemblies (assemblies may contain other assemblies).
The process of capturing a software component from your environment as an Oracle Virtual Assembly Builder Appliance begins with introspection.
External appliances are virtual machine templates that you import (as appliances) into your catalog. Once imported, external appliances can be edited, added and deployed as part of any assembly as you would any other appliance. Only Oracle virtual machines are eligible to be imported as external appliances at this time.
Use the abctl
importExternalTemplate command to have a virtual machine template (created outside of Oracle Virtual Assembly Builder) captured in your catalog as an external appliance. For more information on using this command, see Appendix A, Command Line Reference.
Introspection is an operation performed on a software component or a group of related components (to create an appliance or assembly). During introspection, Oracle Virtual Assembly Builder creates an xml description of the component and captures a component-specific set of configuration files. This information forms a snapshot of the component's configuration at the time of introspection. The introspection architecture is plug-in based and there is a plug-in for each supported component type. See Appendix B, Oracle Virtual Assembly Builder Introspection Plug-ins for more information about available plug-ins.
In most cases, the result of introspecting a component is an appliance. When you use Oracle Virtual Assembly Builder to introspect an Oracle WebLogic Server domain, however, the Introspector plug-in generates an Assembly. The generated assembly contains an appliance representing the domain's Administration Server and other appliances representing each of the domain's Managed Servers.
Oracle Virtual Assembly Builder can introspect components on a local host or components located on remote, network-accessible hosts. Oracle Virtual Assembly Builder uses the industry-standard SSH protocol to transport the introspection engine to the remote host and to return the introspection results.
Whether the introspection is local or remote, the results are stored locally in the catalog.
Assemblies and appliances are represented on disk in an area called the Catalog. You specify the location of your catalog within the file system using environment variables defined by Oracle Virtual Assembly Builder. For more information about the environment variables, see Oracle Virtual Assembly Builder Installation Guide.
Assembly and appliance metadata is stored in nested directories within the metadata subfolder of the catalog root directory. Additional artifacts required for deployment are stored in other subdirectories defined by Oracle Virtual Assembly Builder. Since some of the on-disk artifacts may be very large, the catalog uses a sharing model for some artifacts of appliances and assemblies.
Only Oracle Virtual Assembly Builder-supplied tools should be used to operate on the catalog. Manually editing Oracle Virtual Assembly Builder metadata files is not supported.
When defining an assembly, it may be necessary to make reference to servers that lie outside it. Your IT environment may, for example, include database, identity management, or other servers that are shared by many unrelated virtual deployments. It may be undesirable or impossible to include these systems within any specific assembly. For this reason, Oracle Virtual Assembly Builder enables you to define external components representing server resources that exist in your environment and will not be deployed as appliances. Representing them as external resources ensures that referencing appliance(s) within the assembly are correctly configured at deployment time, making it unnecessary to manually correct their network configuration after they are deployed to the virtual environment.
The introspection process captures the condition of a component and generates a metadata description of the actual component installation. Introspection does not capture the executables, shared libraries or other binaries of the component. Instead, the Introspector generates package definitions that specify one or more file system hierarchies that must be captured in order to reproduce the same component installation in the deployment environment. After the introspection is complete, you use Oracle Virtual Assembly Builder to capture a copy of the actual installation described by the metadata. This step is known as packaging.
Introspection and packaging are done together whether you use Oracle Virtual Assembly Builder Studio or Oracle Virtual Assembly Builder command line interface.
A Virtual Machine Template is a pre-configured virtual image that requires customization to create multiple running virtual machine images. These templates are used to create and start new virtual machines in virtualized environments. In most cases, templates are made available to the virtualized environment by registering them to that environment. In order to execute an appliance, templates must be created for the appliance. The appliance templates contain a guest operating system and the introspected appliance. Oracle Virtual Assembly Builder supports Oracle Enterprise Linux and Oracle JRockit Virtual Edition.
Resource Managers define and maintain a collection of virtualized hardware resources. Further, these environments generally have the resources partitioned into pools called Resource Pools. A single resource manager may include multiple pools. You must use Oracle Virtual Assembly Builder to specify which resource managers and pools are to be used for the deployment of assemblies.
Deployment Plans are used to customize assemblies prior to deployment. You can use a deployment plan to customize the default assembly and appliance properties. In some cases you must customize certain properties. The deployment plan contains all required overrides as well as all optional overrides.
At deployment time, you choose the assembly to be deployed, one of its deployment plans, and the resource manager and pool to which the assembly will be deployed. This information is used to connect to the pool, select all the necessary templates, and create virtual machine instances. Upon deployment, the target number of virtual machines are started.
Deployment of an assembly may transition through various phases. The phases include: Staged, Deployed, and Failed. Each state allows a subset of operations. For example, when an assembly is deployed, you may start and stop the virtual machines, or you may increase or decrease the number of virtual machines associated with that deployed assembly. Oracle Virtual Assembly Builder does not monitor the health of the deployed application; it will only inform you of whether or not an assembly is deployed or staged, as well as the success or failure of a deployment-related operation.
Here is a summary of the deployment phases:
Deployed When the assembly is deployed and the operation has successfully completed, it reaches the deployed state. The operations that can be performed on a Deployed Deployment are:
Stop This operation will shut down all the running virtual machine instances for the deployment. The deployment is transitioned to the Staged phase after this operation is completed. It leaves the virtual machines in the virtualized environment so that they can be restarted later.
Undeploy This operation will stop all the running virtual machines and remove them from the environment. This operation will also clean up all failed virtual machines. After this operation is completed, the deployment no longer exists.
Scale Appliance Appliances within a deployment can be scaled (the number of virtual machines on which a particular appliance is run) up or down. The number of VMs that can be running for an Appliance must lie between its configured minimum and maximum instance limits. The Deployment continues to remain in the Deployed phases.
Failed When there is a failure in a deployment, the deployment reaches this phase. A deployment may fail for a variety of reasons, such as insufficient resources. The operations that can be performed on a failed deployment are:
Undeploy This operation stops all the running virtual machines and removes them from the pool. The operation will also clean up all failed virtual machines. After this operation is completed, the deployment no longer exists.
Staged The staged phase is reached by stopping a deployment. In this phase all the virtual machines have been shut down. The operations that can be performed from this phase are:
Start This operation will start up all the virtual machines that have been shut down. After this operation is completed, the deployment is returned to the Deployed phase.
Undeploy This operation will clean up all the virtual machines that have been shut down from the virtualized environment. After this operation is completed, the deployment no longer exists.