About Device Clusters
A device cluster (also known as a logical device) is one or more concrete devices that act as a single device. A device cluster has cluster (logical) interfaces, which describe the interface information for the device cluster. During service graph template rendering, function node connectors are associated with cluster (logical) interfaces. The Application Policy Infrastructure Controller (APIC) allocates the network resources (VLAN or Virtual Extensible Local Area Network [VXLAN]) for a function node connector during service graph template instantiation and rendering and programs the network resources onto the cluster (logical) interfaces.
The service graph template uses a specific device that is based on a device selection policy (called a logical device context) that an administrator defines.
An administrator can set up a maximum of two concrete devices in active-standby mode.
To set up a device cluster, you must perform the following tasks:
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Connect the concrete devices to the fabric.
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Assign the management IP address to the device cluster.
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Register the device cluster with the APIC. The APIC validates the device using the device specifications from the device package.
Note |
The APIC does not validate a duplicate IP address that is assigned to two device clusters. The APIC can provision the wrong device cluster when two device clusters have the same management IP address. If you have duplicate IP addresses for your device clusters, delete the IP address configuration on one of the devices and ensure there are no duplicate IP addresses that are provisioned for the management IP address configuration. |
About Managed Device Clusters
A device cluster can be configured as a managed device cluster. In managed mode, the Application Policy Infrastructure Controller (APIC) programs the devices during graph instantiation using the configuration provided to the APIC by an APIC administrator. For a managed device cluster, the APIC requires the device package for managing the devices in the device cluster.
By default, a device cluster is configured as a managed device cluster.
The following settings are needed when a device cluster is configured as managed:
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Device package
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Connectivity information for the logical device (vnsLDevViP) and devices (CDev)-management IP address, credentials, and in-band connectivity information
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Information about supported function types (go-through, go-to)
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Information about context awareness (single context or multi-context)
The APIC needs to know the topology information (logical interface and concrete interface) for the device cluster and devices. This
information is needed so that the APIC can program the appropriate ports on the leaf, and the APIC can also use this information for troubleshooting wizard purposes. The APIC also needs to know the relation to DomP
, which is used for allocating the encapsulation.
About Unmanaged Device Clusters
A device cluster can be configured as an unmanaged device cluster. For an unmanaged device cluster, the Application Policy Infrastructure Controller (APIC) allocates only the network resources for the service graph and program on only the fabric side during graph instantiation. This might be useful if your environment already has an existing orchestrator or a dev-op tool that programs the devices in a device cluster. In some other cases, the device package for the service appliance is not available. Unmanaged mode enables the APIC to work with service devices without needing to have a device package.
The APIC needs to know the topology information (logical interface and concrete interface) for the device cluster and devices. This
information is needed so that the APIC can program the appropriate ports on the leaf, and the APIC can also use this information for troubleshooting wizard purposes. The APIC also needs to know the relation to DomP
, which is used for allocating the encapsulation.