VDC Virtual Device Context. Prepared By Rajeev Srikant

Transcription

1 VDC Virtual Device Context Prepared By Rajeev Srikant

2 Agenda What is VDC? Why Use VDCs? Creating & Configuring VDCs 2

3 What is VDC? Virtual Device Contexts (VDCs): Cisco s VDC are basically Virtual Ethernet Switches. VDC feature helps enable the virtualization of a single physical device into one or more logical devices. It is similar to contexts in ASA Each of the provisioned logical devices is configured & managed as if it were a separate physical device. Each logical device in the VDC acts as virtual entity with separate data, control & management planes. VLAN 100 in VDC 1 is not the same VLAN 100 in VDC 2 OSPF Process ID 1 in VDC 1 is not the same OSPF PID 1 in VDC 2 VDC is supported on the Cisco 7000 Nexus series platform. 3

4 VDC - Representation Physical Switch Physical Switch Interface 1 Interface1 VDC A Interface 2 Interface 2 Physical View No internal cross VDC communication. Physical cable must be used to connect VDCs. VDC B Logical View 4

5 Why Use VDCs? Multiple logical roles per physical chassis Ex Core & Aggregation/Distribution on same box Multi Tenancy Ex VDCs as a managed service to customers Separate Production & Test environments VDCs significantly improve resource utilization Physical Switch 1 Physical Switch 2 Core VDC 1 Core VDC 2 Aggregation VDC 1 Aggregation VDC 2 5

6 Default VDC If VDC is not required to be deployed in NX-OS switch, it is required to use at least one which is the default VDC which is VDC 1. This context is automatically created during the switch boot & actually represents the physical switch by default. VDC 1 always exists & can not be removed. It is used to create & manage other VDCs Controls VDC port allocations All ports are allocated to default VDC at initialization Controls VDC resource allocations Number of VLANs, VRFs, Routing table memory, etc. Some tasks can be only performed only in the Default VDC. VDC Creation/Deletion/Suspend Resource Allocation NX-OS upgrade across all VDCs ISSU In Service Software Upgrade 6

7 Creating & Configuring VDCs VDCs are defined in global configuration of default VDC. VDC hostname derived from default VDC hostname + VDC name. Step 1: Log in to the default VDC with a username that has the network-admin role. Step 2 : Enter configuration mode and create the VDC using the default settings. Switch# configure terminal Switch(config)# vdc MyVDC Note: Creating VDC, one moment please... Switch(config-vdc)# Step 3 : Allocate interfaces to the VDC. Switch(config-vdc)# allocate interface ethernet 2/1-11 7

8 Creating & Configuring VDCs Continued.. Step 4 : Verify the VDC configuration. Switch(config-vdc)# show vdc MyVDC vdc_id vdc_name state mac MyVDC active 00:00:00:00:00:00 Step 5 : Switch to the new VDC Switch(config-vdc)# switchto vdc MyVDC Switch-MyVDC# 8

9 Resource Allocation & Configuration When VDCs are created it is necessary to allocated how individual VDCs share the available physical resources. It is required to allocate minimum & maximum resources to each VDC. Switch(config)# vdc MyVDC Switch(config-vdc)# limit-resource port-channel minimum 32 maximum 64 Switch(config-vdc)# limit-resource u4route-mem minimum 32 maximum equal-to-min Switch(config-vdc)# limit-resource monitor-session minimum 0 maximum 2 Switch(config-vdc)# limit-resource vlan minimum 32 maximum 64 Switch(config-vdc)# limit-resource vrf minimum 32 maximum equal-to-min 9

10 Virtual Device Context - Fault Isolation When multiple VDCs are created in a physical switch, inherently the architecture of the VDC provides a means to prevent failures within that VDC from affecting other VDCs. For instance, a spanning tree recalculation that might be started in one VDC is not going to affect the spanning tree domains of other VDCs in the same physical chassis. An OSPF process crash is another example where the fault is isolated locally to that VDC. Process isolation within a VDC thus plays an important role in fault isolation and serves as a major benefit for organizations that embrace the VDC concept. As shown below, a fault in a process running in VDC 1 does not affect any of the running processes in the other VDCs. 10

11 Virtual Device Context High Availability(HA) The Cisco NX-OS Software platform incorporates a high-availability feature set that helps ensure minimal or no effect on the data plane should the control plane fail. HA policy defines what happens when a VDC crashes Bringdown Puts the VDC in the failed state. To recover from the failed state, you must reload the physical device. This is the behavior for default VDC. For non-default VDC, there is no need to reload the physical device. Reset Initiates a supervisor module switchover for a Cisco NX-OS device with two supervisor modules, or reloads a Cisco NX-OS device with one supervisor module. Restart Deletes the VDC and recreates it by using the startup configuration. Configured as ha-policy under VDC config mode. Switch(config-vdc)# ha-policy single-sup bringdown dual-sup switchover 11

12 Virtual Device Context User Rights Non default VDC users have 2 possible roles vdc-admin : All Read/Write access to that particular VDC vdc-operator : Read Only access to that particular VDC vdc-admin & vdc-operator cannot switchback to default VDC Default VDC users inherit Read or Read/Write in non-default VDCs. network-admin : Assumes all vdc-admin roles network-operator : Assumes all vdc-operator roles 12