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This chapter contains the following sections:
Information About System-Level High Availability
The Cisco Nexus 1000V can be configured with a single virtual supervisor module (VSM) or dual VSMs. The following table describes the HA supervisor roles for single and dual VSM operation.
The redundancy role indicates not only whether the VSM interacts with other VSMs, but also the module number it occupies. The following table shows the available HA roles for VSMs.
Independent of its role, the redundancy state of a VSM can be one of the following described in this table.
Redundancy State |
Description |
---|---|
Active |
Controls the system and is visible to the outside world. |
Standby |
Synchronizes its configuration with that of the active VSM so that it is continuously ready to take over in case of a failure or manual switchover. You cannot use Telnet or Secure Shell (SSH) protocols to communicate with the standby VSM. Instead, you can use the attach module command from the active VSM to access the standby VSM console. Only a subset of the CLI commands are available from the standby VSM console. |
The active and standby VSMs are in the operationally HA state and can automatically synchronize when the internal state of one supervisor module is Active with HA Standby and the internal state of the other supervisor module is HA Standby.
If the output of the show system redundancy command indicates that the operational redundancy mode of the active VSM is None, then the active and standby VSMs are not yet synchronized. The following example shows the VSM internal state of dual supervisors as observed in the output of the show system redundancy status command
switch# show system redundancy status Redundancy role --------------- administrative: standalone operational: standalone Redundancy mode --------------- administrative: HA operational: None This supervisor (sup-1) ----------------------- Redundancy state: Active Supervisor state: Active Internal state: Active with no standby Other supervisor (sup-2) ------------------------ Redundancy state: Not present switch#
Information About VSM Restarts and Switchovers
In a system with only one supervisor, when all HA policies have been unsuccessful in restarting a service, the supervisor restarts. The supervisor and all services restart with no prior state information.
When a VSM fails in a system with dual supervisors, the system performs a switchover rather than a system restart in order to maintain a stateful operation. In some cases, however, a switchover may not be possible at the time of the failure. For example, if the standby VSM is not in a stable standby state, a restart rather than a switchover is performed.
A dual VSM configuration allows uninterrupted traffic forwarding with stateful switchover (SSO) when a failure occurs in the VSM. The two VSMs operate in an active/standby capacity in which only one is active at any given time, while the other acts as a standby backup. The two VSMs constantly synchronize the state and configuration in order to provide a seamless and stateful switchover of most services if the active VSM fails.
A switchover occurs when the active supervisor fails (for example, if repeated failures occur in an essential service or if the system hosting the VSM fails).
A user-triggered switchover could occur (for example, if you need to perform maintenance tasks on the system hosting the active VSM).
An HA switchover has the following characteristics:
When a stable standby VSM detects that the active VSM has failed, it initiates a switchover and transitions to active. When a switchover begins, another switchover cannot be started until a stable standby VSM is available.
If a standby VSM that is not stable detects that the active VSM has failed, then, instead of initiating a switchover, it tries to restart the system.
Before you can initiate a manual switchover from the active to the standby VSM, the standby VSM must be stable.
Once you have verified that the standby VSM is stable, you can manually initiate a switchover.
Once a switchover process begins, another switchover process cannot be started until a stable standby VSM is available.
Configuring System-Level High Availability
The Cisco Nexus 1000V VSM software installation provides an opportunity for you to designate the role for each VSM. You can use this procedure to change that initial configuration.
Caution |
Changing the role of a VSM can result in a conflict between the VSM pair. If a primary and secondary VSM see each other as active at the same time, the system resolves this problem by resetting the primary VSM. |
Use this procedure to change the role of a VSM to one of the following after it is already in service:
Before beginning this procedure, you must be logged in to the CLI in EXEC mode.
If you are changing a standalone VSM to a secondary VSM, be sure to first isolate it from the other VSM in the pair to prevent any interaction with the primary VSM during the change. Power the VM off from the vSphere Client before reconnecting it as standby.
For an example of changing the port groups and port profiles assigned to the VSM interfaces in the vSphere Client, see Cisco Nexus 1000V Installation and Upgrade Guide.
You must understand the following information:
switch# system redundancy role standalone switch# show system redundancy status Redundancy role --------------- administrative: standalone operational: standalone Redundancy mode --------------- administrative: HA operational: None This supervisor (sup-1) ----------------------- Redundancy state: Active Supervisor state: Active Internal state:Active with no standby Other supervisor (sup-2) ------------------------ Redundancy state: Not present switch#
Configuring a Switchover
Use one of the following commands to verify the configuration:
Command |
Purpose |
---|---|
show system redundancy status |
Displays the current redundancy status for the VSM(s). If the output indicates the following, then you can proceed with a system switchover, if needed: |
show module |
Displays information about all available VEMs and VSMs in the system. If the output indicates the following, then you can proceed with a system switchover, if needed: |
Be sure you know the following about manually switching the active VSM to a standby VSM
This example shows how to switch an active VSM to the standby VSM and displays the output that appears on the standby VSM as it becomes the active VSM.
switch# system switchover ---------------------------- 2009 Mar 31 04:21:56 n1000v %$ VDC-1 %$ %SYSMGR-2-HASWITCHOVER_PRE_START: This supervisor is becoming active (pre-start phase). 2009 Mar 31 04:21:56 n1000v %$ VDC-1 %$ %SYSMGR-2-HASWITCHOVER_START: This supervisor is becoming active. 2009 Mar 31 04:21:57 n1000v %$ VDC-1 %$ %SYSMGR-2-SWITCHOVER_OVER: Switchover completed. 2009 Mar 31 04:22:03 n1000v %$ VDC-1 %$ %PLATFORM-2-MOD_REMOVE: Module 1 removed (Serial number )
This example shows how to display the difference between the running and startup configurations
switch# show running-config diff *** Startup-config --- Running-config *************** *** 1,38 **** version 4.0(4)SV1(1) role feature-group name new role name testrole username admin password 5 $1$S7HvKc5G$aguYqHl0dPttBJAhEPwsy1 role network-admin telnet server enable ip domain-lookup
Adding a Second VSM to a Standalone System
Complete the following tasks:
Task |
For More Information see: |
---|---|
Change the standalone VSM to a primary VSM |
|
Install the second VSM |
Cisco Nexus 1000V Installation and Upgrade Guide |
Verify the change to a dual VSM system |
Use this procedure to change the role of a VSM from standalone in a single VSM system to primary in a dual VSM system.
A change from a standalone to a primary VSM takes effect immediately.
Before beginning this procedure, you must be logged in to the CLI in EXEC mode.
This example shows how to display the current system redundancy status for the VSM.
switch# system redundancy role primary switch# show system redundancy status Redundancy role --------------- administrative: primary operational: primary Redundancy mode --------------- administrative: HA operational: None This supervisor (sup-1) ----------------------- Redundancy state: Active Supervisor state: Active Internal state: Active with no standby Other supervisor (sup-2) ------------------------ Redundancy state: Not present switch# copy running-config startup-config
Use one of the following commands to verify the configuration:
Command |
Purpose |
---|---|
show system redundancy status |
Displays the current redundancy status for VSMs in the system. |
show module |
Displays information about all available VSMs and VEMs in the system. |
Note |
Equipment Outage—This procedures requires that you power down and reinstall a VSM. During this time, your system will be operating with a single VSM. |
Use this procedure to replace an active/primary VSM in a dual VSM system.
Note |
Equipment Outage—This procedures requires powering down and reinstalling a VSM. During this time, your system will be operating with a single VSM. |
Note |
Equipment Outage—This procedures requires powering down a VSM. During this time, your system will be operating with a single VSM. |
Use one of the following commands to verify the configuration:
Command |
Purpose |
---|---|
show system redundancy status |
Displays the HA status of the system. |
show module |
Displays information about all available VSMs and VEMs in the system. |
show processes |
Displays the state of all processes and the start count of the process. The states and types are described as follows: |
Related Topic |
Document Title |
---|---|
Software upgrades |
Cisco Nexus 1000V Installation and Upgrade Guide |
Cisco Nexus 1000V commands |
Cisco Nexus 1000V Command Reference |
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
MIBs |
MIBs Link |
---|---|
CISCO-PROCESS-MIB |
To locate and download MIBs, go to the following URL: http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml |
No RFCs are supported by this feature.
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This table includes only the updates for those releases that have resulted in additions or changes to the feature.
Feature Name |
Releases |
Feature Information |
---|---|---|
System -Level High Availability |
4.0(4)SV1(1) |
This feature was introduced. |