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Monitoring Chassis Cluster Interfaces

 

Interface monitoring monitors the state of an interface by checking if the interface is in an up or down state. When one or more monitored interfaces fail, the redundancy group fails over to the other node in the cluster. For more information, see the following topics:

Understanding Chassis Cluster Redundancy Group Interface Monitoring

For a redundancy group to automatically failover to another node, its interfaces must be monitored. When you configure a redundancy group, you can specify a set of interfaces that the redundancy group is to monitor for status (or “health”) to determine whether the interface is up or down. A monitored interface can be a child interface of any of its redundant Ethernet interfaces. When you configure an interface for a redundancy group to monitor, you give it a weight.

Every redundancy group has a threshold tolerance value initially set to 255. When an interface monitored by a redundancy group becomes unavailable, its weight is subtracted from the redundancy group's threshold. When a redundancy group's threshold reaches 0, it fails over to the other node. For example, if redundancy group 1 was primary on node 0, on the threshold-crossing event, redundancy group 1 becomes primary on node 1. In this case, all the child interfaces of redundancy group 1's redundant Ethernet interfaces begin handling traffic.

To check the interface weight, use the following commands:

  • show chassis cluster information

  • show chassis cluster interfaces

Note

We do not recommend configuring data plane modules such as interface monitoring and IP monitoring on redundancy group 0 (RG0) for SRX Series devices in a chassis cluster.

Caution

Be cautious and judicious in your use of redundancy group 0 manual failovers. A redundancy group 0 failover implies a Routing Engine (RE) failover, in which case all processes running on the primary node are killed and then spawned on the new master Routing Engine (RE). This failover could result in loss of state, such as routing state, and degrade performance by introducing system churn.

A redundancy group failover occurs because the cumulative weight of the redundancy group's monitored interfaces has brought its threshold value to 0. When the monitored interfaces of a redundancy group on both nodes reach their thresholds at the same time, the redundancy group is primary on the node with the lower node ID, in this case node 0.

Note
  • If you want to dampen the failovers occurring because of interface monitoring failures, use the hold-down-interval statement.

  • If a failover occurs on redundancy group 0 (RG0), the interface monitoring on the RG0 secondary is disabled for 30 seconds. This prevents failover of other redundancy groups along with RG0 failover.

Benefits of Monitoring Chassis Cluster Redundancy Group Interfaces

  • Helps todetermine the status of a specific interface in a chassis cluster setup by a specific redundancy group.

  • Enables automatic failover of an interface to another node if the interface is down.

Example: Configuring Chassis Cluster Redundancy Group Interface Monitoring

This example shows how to specify that an interface be monitored by a specific redundancy group for automatic failover to another node. You assign a weight to the interface to be monitored also shows how to verify the process of the remaining threshold of a monitoring interface by configuring two interfaces from each node and mapping them to redundancy groups.

Requirements

Before you begin, create a redundancy group. See Example: Configuring Chassis Cluster Redundancy Groups.

Overview

To retrieve the remaining redundancy group threshold after a monitoring interface is down, you can configure your system to monitor the health of the interfaces belonging to a redundancy group. When you assign a weight to an interface to be monitored, the system monitors the interface for availability. If a physical interface fails, the weight is deducted from the corresponding redundancy group's threshold. Every redundancy group has a threshold of 255. If the threshold hits 0, a failover is triggered, even if the redundancy group is in manual failover mode and the preempt option is not enabled.

In this example, you check the process of the remaining threshold of a monitoring interface by configuring two interfaces from each node and mapping them to redundancy group 1 (RG1), each with different weights. You use 130 and 140 for node 0 interfaces and 150 and 120 for node 1 interfaces. You configure one interface from each node and map the interfaces to redundancy group 2 (RG2), each with default weight of 255.

Figure 1 illustrates the network topology used in this example.

Figure 1: SRX Series Chassis Cluster Interface Monitoring Topology Example
SRX Series Chassis
Cluster Interface Monitoring Topology Example

Configuration

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the edit hierarchy level, and then enter commit from configuration mode.

Step-by-Step Procedure

The following example requires you to navigate various levels in the configuration hierarchy. For instructions on how to do that, see Using the CLI Editor in Configuration Mode in the Junos OS CLI User Guide.

To configure chassis cluster interface monitoring:

  1. Specify the number of redundant Ethernet interfaces.
  2. Set up redundancy group 0 for the Routing Engine failover properties, and set up RG1 and RG2 (all interfaces are in one redundancy group in this example) to define the failover properties for the redundant Ethernet interfaces.
  3. Set up interface monitoring to monitor the health of the interfaces and trigger redundancy group failover.Note

    We do not recommend interface monitoring for RG0, because it causes the control plane to switch from one node to another node in case interface flap occurs.

    Note

    Interface failover only occurs after the weight reaches zero.

  4. Set up the redundant Ethernet (reth) interfaces and assign them to a zone.

Results

From configuration mode, confirm your configuration by entering the show chassis and show interfaces commands. If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it.

If you are done configuring the device, enter commit from configuration mode.

Verification

The following sections walk you through the process of verifying and (in some cases) troubleshooting the interface status. The process shows you how to check the status of each interface in the redundancy group, check them again after they have been disabled, and looks for details about each interface, until you have circled through all interfaces in the redundancy group.

In this example, you verify the process of the remaining threshold of a monitoring interface by configuring two interfaces from each node and mapping them to RG1, each with different weights. You use 130 and 140 for node 0 interfaces and 150 and 120 for node 1 interfaces. You configure one interface from each node and map the interfaces to RG2, each with the default weight of 255.

Verifying Chassis Cluster Status

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with one device functioning as the primary node and the other as the secondary node.

Verifying Chassis Cluster Interfaces

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster interfaces command.

{primary:node0}
user@host> show chassis cluster interfaces

Meaning

The sample output confirms that monitoring interfaces are up and that the weight of each interface being monitored is displayed correctly as configured. These values do not change if the interface goes up or down. The weights only change for the redundant group and can be viewed when you use the show chassis cluster information command.

Verifying Chassis Cluster Information

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster information command.

{primary:node0}
user@host> show chassis cluster information

Meaning

The sample output confirms that node 0 and node 1 are healthy, and the green LED on the device indicates that there are no failures. Also, the default weight of the redundancy group (255) is displayed. The default weight is deducted whenever an interface mapped to the corresponding redundancy group goes down.



Refer to subsequent verification sections to see how the redundancy group value varies when a monitoring interface goes down or comes up.

Verifying Interface ge-0/0/1 Status After Disabling Interface ge-0/0/1 of RG1 in Node 0 with a Weight of 130

Purpose

Verify that the interface ge-0/0/1 is disabled on node 0.

Action

From configuration mode, enter the set interface ge-0/0/1 disable command.

{primary:node0}
user@host# set interface ge-0/0/1 disable
user@host# commit
{primary:node0}
user@host# show interfaces ge-0/0/1

Meaning

The sample output confirms that interface ge-0/0/1 is disabled.

Verifying Chassis Cluster Status After Disabling Interface ge-0/0/1 of RG1 in Node 0 with a Weight of 130

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with one device functioning as the primary node and the other as the secondary node.

Verifying Chassis Cluster Interfaces After Disabling Interface ge-0/0/1 of RG1 in Node 0 with a Weight of 130

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster interfaces command.

{primary:node0}
user@host> show chassis cluster interfaces

Meaning

The sample output confirms that monitoring interface ge-0/0/1 is down.

Verifying Chassis Cluster Information After Disabling Interface ge-0/0/1 of RG1 in Node 0 with a Weight of 130

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster information command.

{primary:node0}
user@host> show chassis cluster information

Meaning

The sample output confirms that in node 0, the RG1 weight is reduced to 125 (that is, 255 minus 130) because monitoring interface ge-0/0/1 (weight of 130) went down. The monitoring status is unhealthy, the device LED is amber, and the interface status of ge-0/0/1 is down.

Note

If interface ge-0/0/1 is brought back up, the weight of RG1 in node 0 becomes 255. Conversely, if interface ge-0/0/2 is also disabled, the weight of RG1 in node 0 becomes 0 or less (in this example, 125 minus 140 = -15) and triggers failover, as indicated in the next verification section.

Verifying Interface ge-0/0/2 Is Disabled

Purpose

Verify that interface ge-0/0/2 is disabled on node 0.

Action

From configuration mode, enter the set interface ge-0/0/2 disable command.

{primary:node0}
user@host# set interface ge-0/0/2 disable
user@host# commit
{primary:node0}
user@host# show interfaces ge-0/0/2

Meaning

The sample output confirms that interface ge-0/0/2 is disabled.

Verifying Chassis Cluster Status After Disabling Interface ge-0/0/2

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with one device functioning as the primary node and the other as the secondary node. On RG1, you see interface failure, because both interfaces mapped to RG1 on node 0 failed during interface monitoring.

Verifying Chassis Cluster Interfaces After Disabling Interface ge-0/0/2

Purpose

Verify information about chassis cluster interfaces.

Action

From operational mode, enter the show chassis cluster interfaces command.

{primary:node0}
user@host> show chassis cluster interfaces

Meaning

The sample output confirms that monitoring interfaces ge-0/0/1 and ge-0/0/2 are down.

Verifying Chassis Cluster Information After Disabling Interface ge-0/0/2

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster information command.

{primary:node0}
user@host> show chassis cluster information

Meaning

The sample output confirms that in node 0, monitoring interfaces ge-0/0/1 and ge-0/0/2 are down. The weight of RG1 on node 0 reached zero value, which triggered RG1 failover during use of the show chassis cluster status command.

Note

For RG2, the default weight of 255 is set for redundant Ethernet interface 2 (reth2). When interface monitoring is required, we recommend that you use the default weight when you do not have backup links like those in RG1. That is, if interface ge-0/0/3 is disabled, it immediately triggers failover because the weight becomes 0 (255 minus 225), as indicated in the next verification section.

Verifying Interface Status After Disabling ge-0/0/3

Purpose

Verify that interface ge-0/0/3 is disabled on node 0.

Action

From configuration mode, enter the set interface ge-0/0/3 disable command.

{primary:node0}
user@host# set interface ge-0/0/3 disable
user@host# commit
{primary:node0}
user@host# show interfaces ge-0/0/3

Meaning

The sample output confirms that interface ge-0/0/3 is disabled.

Verifying Chassis Cluster Status After Disabling Interface ge-0/0/3

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with one device functioning as the primary node and the other as the secondary node.

Verifying Chassis Cluster Interfaces After Disabling Interface ge-0/0/3

Purpose

Verify information about chassis cluster interfaces.

Action

From operational mode, enter the show chassis cluster interfaces command.

{primary:node0}
user@host> show chassis cluster interfaces

Meaning

The sample output confirms that monitoring interfaces ge-0/0/1, ge-0/0/2, and ge-0/0/3 are down.

Verifying Chassis Cluster Information After Disabling Interface ge-0/0/3

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster information command.

{primary:node0}
user@host> show chassis cluster information

Meaning

The sample output confirms that in node 0, monitoring interfaces ge-0/0/1, ge-0/0/2, and ge-0/0/3 are down.

Note

In regard to RG1, allowing any interface in node 0 go up triggers a failover only if the preempt option is enabled. In the example, preempt is not enabled. Therefore the node should return to normal, with no monitor failure showing for RG1.

Verifying That Interface ge-0/0/2 Is Enabled

Purpose

Verify that interface ge-0/0/2 is enabled on node 0.

Action

From configuration mode, enter the delete interfaces ge-0/0/2 disable command.

{primary:node0}
user@host# delete interfaces ge-0/0/2 disable
user@host# commit

Meaning

The sample output confirms that interface ge-0/0/2 disable is deleted.

Verifying Chassis Cluster Status After Enabling Interface ge-0/0/2

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with as one device functioning as the primary node and the other as the secondary node.

Verifying Chassis Cluster Interfaces After Enabling Interface ge-0/0/2

Purpose

Verify information about chassis cluster interfaces.

Action

From operational mode, enter the show chassis cluster interfaces command.

{primary:node0}
user@host> show chassis cluster interfaces

Meaning

The sample output confirms that monitoring interfaces ge-0/0/1 and ge-0/0/3 are down. Monitoring interface ge-0/0/2 is up after the disable has been deleted.

Verifying Chassis Cluster Information After Enabling Interface ge-0/0/2

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster information command.

{primary:node0}
user@host> show chassis cluster information

Meaning

The sample output confirms that in node 0, monitoring interfaces ge-0/0/1 and ge-0/0/3 are down. Monitoring interface ge-0/0/2 is active after the disable has been deleted.

Verifying Chassis Cluster RG2 Preempt

Purpose

Verify that the chassis cluster RG2 is preempted on node 0.

Action

From configuration mode, enter the set chassis cluster redundancy-group 2 preempt command.

{primary:node0}
user@host# set chassis cluster redundancy-group 2 preempt
user@host# commit

Meaning

The sample output confirms that chassis cluster RG2 preempted on node 0.

Note

In the next section, you check that RG2 fails over back to node 0 when preempt is enabled when the disabled node 0 interface is brought online.

Verifying Chassis Cluster Status After Preempting RG2

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with one device functioning as the primary node and the other as the secondary node.

Verifying That Interface ge-0/0/3 Is Enabled

Purpose

Verify that interface ge-0/0/3 is enabled on node 0.

Action

From configuration mode, enter the delete interfaces ge-0/0/3 disable command.

{primary:node0}
user@host# delete interfaces ge-0/0/3 disable
user@host# commit

Meaning

The sample output confirms that interface ge-0/0/3 disable has been deleted.

Verifying Chassis Cluster Status After Enabling Interface ge-0/0/3

Purpose

Verify the chassis cluster status, failover status, and redundancy group information.

Action

From operational mode, enter the show chassis cluster status command.

{primary:node0}
user@host> show chassis cluster status

Meaning

Use the show chassis cluster status command to confirm that devices in the chassis cluster are communicating properly, with one device functioning as the primary node and the other as the secondary node.

Verifying Chassis Cluster Interfaces After Enabling Interface ge-0/0/3

Purpose

Verify information about chassis cluster interfaces.

Action

From operational mode, enter the show chassis cluster interfaces command.

{primary:node0}
user@host> show chassis cluster interfaces

Meaning

The sample output confirms that monitoring interface ge-0/0/1 is down. Monitoring interfaces ge-0/0/2, and ge-0/0/3 are up after deleting the disable.

Verifying Chassis Cluster Information After Enabling Interface ge-0/0/3

Purpose

Verify information about the statistics of the different objects being synchronized, the fabric and control interface hellos, and the status of the monitoring interfaces in the cluster.

Action

From operational mode, enter the show chassis cluster information command.

{primary:node0}
user@host> show chassis cluster information

Meaning

The sample output confirms that in node 0, monitoring interface ge-0/0/1 is down. RG2 on node 0 state is back to primary state (because of the preempt enable) with a healthy weight of 255 when interface ge-0/0/3 is back up.