VMware vSphere and Virtual Hard Disk (VHD) for
Microsoft Hyper-V and can be downloaded from
http://www.cisco.com.
Next, let’s go over some essential concepts needed to
understand how the Cisco UCS Director orchestrator
works. First, there is the concept of a task. A task is an
atomic unit of work in Cisco UCS Director; it cannot be
decomposed into smaller actions and represents a single
action with inputs and outputs. Cisco UCS Director has a
task library that contains hundreds of predefined tasks,
such as an SSH command task (executing a command in
a Secure Shell session), an inventory collection task
(gathering information about available devices), a new
VM provisioning task (creating a new virtual machine),
and many more. In the event that there is no suitable
predefined task, the system offers the option of creating
custom tasks, as described later in this section.
The second concept is the workflow. A workflow is a
series of tasks arranged to automate a complex
operation. The simplest workflow contains a single task,
but workflows can contain any number of tasks.
Workflows are at the heart of Cisco UCS Director
orchestration. They automate processes of any level of
complexity. Workflows are built using the Workflow
Designer, which is a drag-and-drop interface. In
Workflow Designer, the tasks are arranged in sequence
and define inputs and outputs to those tasks. Loops and
conditionals can be implemented using flow of control
tasks. Every time a workflow is executed, a service
request is generated. Workflows can be scheduled for
later execution, and Cisco UCS Director stores details of
completed service requests. A service request can have
one of several states, depending on its execution status:
scheduled, running, blocked, completed, or failed.