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This chapter describes how to configure object tracking on Cisco NX-OS devices.
This chapter includes the following sections:
•Information About Object Tracking
•Licensing Requirements for Object Tracking
•Prerequisites for Object Tracking
•Verifying Object Tracking Configuration
•Object Tracking Example Configuration
•Feature History for Object Tracking
Object tracking allows you to track specific objects on the device, such as the interface line protocol state, IP routing, and route reachability, and to take action when the tracked object's state changes. This feature allows you to increase the availability of the network and shorten recovery time if an object state goes down.
This section includes the following topics:
The object tracking feature allows you to create a tracked object that multiple clients can use to modify the client behavior when a tracked object changes. Several clients register their interest with the tracking process, track the same object, and take different actions when the object state changes.
Clients include the following features:
•Embedded Event Manager (EEM)
•Gateway Load Balancing Protocol (GLBP)
•Hot Standby Redundancy Protocol (HSRP)
•VirtualPort Channel (vPC)
•Virtual Router Redundancy Protocol (VRRP)
The object tracking monitors the status of the tracked objects and communicates any changes made to interested clients. Each tracked object is identified by a unique number that clients can use to configure the action to take when a tracked object changes state.
Cisco NX-OS tracks the following object types:
•Interface line protocol state—Tracks whether the line protocol state is up or down.
•Interface IP routing state—Tracks whether the interface has an IPv4 or IPv6 address and if IPv4 or IPv6 routing is enabled and active.
•IP route reachability—Tracks whether an Ipv4 or IPv6 route exists and is reachable from the local device.
For example, you can configure HSRP to track the line protocol of the interface that connects one of the redundant routers to the rest of the network. If that link protocol goes down, you can modify the priority of the affected HSRP router and cause a switchover to a backup router that has better network connectivity.
An object track list allows you to track the combined states of multiple objects. Object track lists support the following capabilities:
•Boolean "and" function—Each object defined within the track list t must be in an up state so that the track list object can become up.
•Boolean "or" function—At least one object defined within the track list must be in an up state so that the tracked object can become up.
•Threshold percentage—The percentage of up objects in the tracked list must be greater than the configured up threshold for the tracked list to be in the up state. If the percentage of down objects in the tracked list is above the configured track list down threshold, the tracked list is marked as down.
•Threshold weight—Assign a weight value to each object in the tracked list, and a weight threshold for the track list. If the combined weights of all up objects exceeds the track list weight up threshold, the track list is in an up state. If the combined weights of all the down objects exceeds the track list weight down threshold, the track list is in the down state.
Other entities, such as virtual Port Channels (vPCs) can use an object track list to modify the state of a vPC based on the state of the multiple peer links that create the vPC. See the Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide, Release 4.x for more information on vPCs.
See the "Configuring an Object Track List with a Boolean Expression" section for more information on track lists.
Object tracking supports high availability through stateful restarts. A stateful restart occurs when the object tracking process crashes. Object tracking also supports stateful switchover on a dual supervisor system. Cisco NX-OS applies the runtime configuration after the switchover.
You can also use object tracking to modify the behavior of a client to improve overall network availability.
Object tracking supports Virtual Routing and Forwarding (VRF) instances. VRFs exist within virtual device contexts (VDCs). By default, Cisco NX-OS places you in the default VDC and default VRF unless you specifically configure another VDC and VRF. By default, Cisco NX-OS tracks the route reachability state of objects in the default VRF. If you want to track objects in another VRF, you must configure the object to be a member of that VRF (see the "Configuring Object Tracking for a Nondefault VRF" section).
For more information, see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.x and see Chapter 14, "Configuring Layer 3 Virtualization."
The following table shows the licensing requirements for this feature:
Object tracking has the following prerequisite:
•If you configure VDCs, install the Advanced Services license and enter the desired VDC (see the Cisco Nexus 7000 Series NX-OS Virtual Device Context Configuration Guide, Release 4.x).
Object tracking has the following guidelines and limitations:
•Supports up to 500 tracked objects per VDC.
•Supports Ethernet, subinterfaces, tunnels, port channels, loopback interfaces, and VLAN interfaces.
•Supports one tracked object per HSRP group or GLBP group.
This section includes the following topics:
•Configuring Object Tracking for an Interface
•Configuring Object Tracking for Route Reachability
•Configuring an Object Track List with a Boolean Expression
•Configuring an Object Track List with a Percentage Threshold
•Configuring an Object Track List with a Weight Threshold
•Configuring an Object Tracking Delay
•Configuring Object Tracking for a Nondefault VRF
Note If you are familiar with the Cisco IOS CLI, be aware that the Cisco NX-OS commands for this feature might differ from the Cisco IOS commands that you would use.
You can configure Cisco NX-OS to track the line protocol or IPv4 or IPv6 routing state of an interface.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track object-id interface interface-type number {{ip | ipv6} routing | line-protocol}
3. show track [object-id]
4. copy running-config startup-config
This example shows how to configure object tracking for the line protocol state on Ethernet 1/2:
switch# config t
switch(config)# track 1 interface ethernet 1/2 line-protocol
switch(config-track)# copy running-config startup-config
This example shows how to configure object tracking for the IPv4 routing state on Ethernet 1/2:
switch# config t
switch(config)# track 2 interface ethernet 1/2 ip routing
switch(config-track)# copy running-config startup-config
This example shows how to configure object tracking for the IPv6 routing state on Ethernet 1/2:
switch# config t
switch(config)# track 3 interface ethernet 1/2 ipv6 routing
switch(config-track)# copy running-config startup-config
You can configure Cisco NX-OS to track the existence and reachability of an IP route.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track object-id {ip | ipv6} route prefix/length reachability
3. show track [object-id]
4. copy running-config startup-config
This example shows how to configure object tracking for an IPv4 route in the default VRF.
switch# config t
switch(config)# track 4 ip route 192.0.2.0/8 reachability
switch(config-track)# copy running-config startup-config
This example shows how to configure object tracking for an IPv6 route in the default VRF.
switch# config t
switch(config)# track 5 ipv6 route 10::10/128 reachability
switch(config-track)# copy running-config startup-config
You can configure an object track list that contains multiple tracked objects. A tracked list contains one or more objects. The Boolean expression enables two types of calculation by using either "and" or "or" operators. For example, when tracking two interfaces using the "and" operator, up means that both interfaces are up, and down means that either interface is down.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track track-number list boolean {and | or}
3. object object-number [not]
4. show track
5. copy running-config startup-config
This example shows how to configure a track list with multiple objects as a Boolean "and":
switch# config t
switch(config)# track 1 list boolean and
switch(config-track)# object 10
switch(config-track)# object 20 not
You can configure an object track list that contains a percentage threshold. A tracked list contains one or more objects. The percentage of up objects must exceed the configured track list up percent threshold before the track list is in an up state. For example, if the tracked list has three objects, and you configure an up threshold of 60%, two of the objects must be in the up state (66% of all objects) for the track list to be in the up state.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track track-number list threshold percentage
3. threshold percentage up up-value down down-value
4. object object-number
5. show track
6. copy running-config startup-config
This example shows how to configure a track list with an up threshold of 70% and a down threshold of 30%:
switch# config t
switch(config)# track 1 list threshold percentage
switch(config-track)# threshold percentage up 70 down 30
switch(config-track)# object 10
switch(config-track)# object 20
switch(config-track)# object 30
You can configure an object track list that contains a weight threshold. A tracked list contains one or more objects. The combined weight of up objects must exceed the configured track list up weight threshold before the track list is in an up state. For example, if the tracked list has three objects with the default weight of 10 each, and you configure an up threshold of 15, two of the objects must be in the up state (combined weight of 20) for the track list to be in the up state.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track track-number list threshold weight
3. threshold weight up up-value down down-value
4. object object-number weight value
5. show track
6. copy running-config startup-config
This example shows how to configure a track list with an up weight threshold of 30 and a down threshold of 10:
switch# config t
switch(config)# track 1 list threshold weight
switch(config-track)# threshold weight up 30 down 10
switch(config-track)# object 10 weight 15
switch(config-track)# object 20 weight 15
switch(config-track)# object 30
In this example, the track list is up if object 10 and object 20 are up, and the track list goes to the down state if all three objects are down.
You can configure a delay timer for a tracked object or an object track list that delays when the object or list triggers a stage change. The tracked object or track list starts the delay timer when a state change occurs but does recognize a state change until the delay timer reaches zero. At that point, Cisco NX-OS checks the object state again and records a state change only if the object or list currently has a changed state. Object tracking ignores any intermediate state changes before the delay timer expires.
For example, for an interface line-protocol tracked object that is in the up state with a 20 second delay timer, the delay timer starts when the line protocol goes down. The object is not in the down state unless the line protocol is down 20 seconds later.
You can configure independent up delay timers and down delay timers for a tracked object or track list. When you delete the delay timer, object tracking deletes both the up and down delay timers.
You can change the delay timer at any point. IF the object or list is already counting down the delay timer from a triggered event, the new delay timer is computed as the following:
New delay timer value + current timer countdown - old delay timer value
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track object-id {parameters}
or
track track-number list {parameters}
3. delay {up up-time [down down-time] | down down-time [up up-time]}
4. show track
5. copy running-config startup-config
This example shows how to configure object tracking for a route and use delay timers:
switch# config t
switch(config)# track 2 ip route 209.165.201.0/8 reachability
switch(config-track)# delay up 20 down 30
switch(config-track)# copy running-config startup-config
This example shows how to configure a track list with an up weight threshold of 30 and a down threshold of 10 with delay timers:
switch# config t
switch(config)# track 1 list threshold weight
switch(config-track)# threshold weight up 30 down 10
switch(config-track)# object 10 weight 15
switch(config-track)# object 20 weight 15
switch(config-track)# object 30
switch(config-track)# delay up 20 down 30
You can configure Cisco NX-OS to track an object in a specific VRF.
Ensure that you are in the correct VDC (or use the switchto vdc command).
1. config t
2. track object-id {ip | ipv6} route prefix/length reachability
3. vrf member vrf-name
4. show track [object-id]
5. copy running-config startup-config
This example shows how to configure object tracking for a route and use VRF Red to look up reachability information for this object:
switch# config t
switch(config)# track 2 ip route 209.165.201.0/8 reachability
switch(config-track)# vrf member Red
switch(config-track)# copy running-config startup-config
This example shows how to modify tracked object 2 to use VRF Blue instead of VRF RED to look up reachability information for this object:
switch# config t
switch(config)# track 2
switch(config-track)# vrf member Blue
switch(config-track)# copy running-config startup-config
To verify object tracking configuration information, use the following commands:
This example shows how to configure object tracking for route reachability and use VRF Red to look up reachability information for this route:
switch# config t
switch(config)# track 2 ip route 209.165.201.0/8 reachability
switch(config-track)# vrf member Red
switch(config-track)# copy running-config startup-config
See the following topics for information related to object tracking:
•Chapter 14, "Configuring Layer 3 Virtualization"
•Chapter 18, "Configuring GLBP"
•Chapter 19, "Configuring HSRP"
Table 21-1 lists the default settings for object tracking parameters.
|
|
---|---|
Tracked Object VRF |
Member of default VRF |
For additional information related to implementing object tracking, see the following sections:
|
|
---|---|
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
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Table 21-2 lists the release history for this feature.