About Device Managers and Chassis Managers
A device manager serves as a single point of configuration for a set of clusters in a Cisco Application Centric Infrastructure (ACI) fabric. The administration or operational state is presented in the native GUI of the devices. A device manager handles configuration on individual devices and enables you to simplify the configuration in the Application Policy Infrastructure Controller (APIC). You create a template in device manager, then populate the device manager with instance-specific values from the APIC, which requires only a few values.
The following figure illustrates a device manager controlling multiple devices in a cluster:

A chassis manager is a physical or virtual "container" of processing
resources. A chassis manager supports a number of virtual service devices that
are represented as
CDev
objects. A chassis manager handles networking, while
CDev
handles processing. A chassis manager enables the
on-demand creation of virtual processing nodes. For a virtual device, some
parts of a service (specifically the VLANs) must be applied to the chassis
rather than to the virtual machine. To accomplish this, the chassis management
IP address and credentials must be included in callouts.
The following figure illustrates a chassis manager acting as a container of processing resources:

Without a device manager or chassis manager, the model for service devices contains the following key managed objects:
-
MDev
—Represents a device type (vendor, model, version). -
LDevVIP
—Represents a cluster, a set of identically configured devices for Cold Standby. ContainsCMgmt
andCCred
for access to the device. -
CDev
—Represents a member of a cluster, either physical or virtual. ContainsCMgmt
andCCred
for access to the device. -
VDev
—Represents a context on a cluster, similar to a virtual machine on a server.
The following figure
illustrates the model for the key managed objects, with
CMgmt
(management connectivity) and
CCred
(credentials) included:

CMgmt
(host + port) and
CCred
(username + password) allow the script to access the device and cluster.
A device manager and
chassis manager adds the ability to control the configuration of clusters and
devices from a central management station. The chassis adds a parallel
hierarchy to the
MDev
object and
ALDev
object to allow a
CDev
object to be tagged as belonging to a specific chassis. The following managed
objects are added to the model to support the device and chassis manager
concept:
-
MDevMgr
—Represents a type of device manager. AnMDevMgr
can manage a set of differentMDev
s, which are typically different products from the same vendor. -
DevMgr
—Represents a device manager. Access to the manager is provided using the containedCMgmt
andCCred
managed objects. Each cluster can be associated with only oneDevMgr
. -
MChassis
—Represents a type of chassis. This managed object is typically included in the package. -
Chassis
—Represents a chassis instance. It contains theCMgmt
andCCred
[Secret] managed objects to provide connectivity to the chassis.
The following figure illustrates the device manager object model:

The following figure illustrates the chassis manager object model:
