SCOM: Updates to the Cisco Management Pack

I have uploaded version 1.01.27 of the Cisco Management Pack.   This minor update includes a few fixes and some new features added in response to some helpful comments from readers who have tried this MP out.  The changes in this version are:

  1. Group Population rules have been fixed so that they can be edited in the GUI
  2. Performance data collection has been modified to not collect data when the interface is in a partially discovered state.  This should prevent duplication of performance counters for interfaces going forward.   Because the Interface discovery occurs in two parts: 1) discovering the interfaces and 2) discovering the interface properties, I added a property to the Interface class named: Discovered.  When the Interface discovery runs (which just discovers the index), the discovered property will be set to False.  Once the Interface Property discovery runs, this property will be set to True.   The performance collection rules have been modified to only collect data if this property is set to true. 
  3. Index discovery can now be filtered with a RegEx expression for a device via an override (create the override on the Discover Cisco Interfaces discovery).   By default, the RegEx expression:  (.|..|…) will be used to discover interfaces, which will discover all interfaces with indexes with 1, 2, or 3 digits in length.  To filter by interface index, the expression can be modified to:  (1|2|3|10|15) where the numbers are the index values for the interfaces to be discovered, separated by pipe characters.   The override for this filter can be targeted at all Cisco devices, a group, or specific devices.
  4. I have added a new property to the Interface class named:  “Speed – Override.”  This property allows for manually defining a speed value for the interface to be used in utilization calculations.  There are two scenarios where this is useful: 1) sometimes the value reported in the RFC-1213 ifTable for an interface’s speed isn’t accurate, and 2) if an Ethernet port is the last monitored hop before a lower bandwidth wide-area connection (i.e. the vendor equipment is not monitored), it can be useful to monitor the Ethernet port as if its speed were equivalent to the wide-area connection bandwidth.   For example, if a switch is the last monitored device before connecting to a vendor-managed MetroE connection with a maximum bandwidth of 500Mbit, monitoring utilization on the gigabit switch port will be more accurate if the speed were overridden to 500Mbit.  This property can be set with an override on the Discover Cisco Interface Properties object discovery, by setting the OverrideIFSpeed value to the desired speed, in bits per second.

SCOM: Advanced SNMP Monitoring Part III: The Completed Cisco Management Pack

Note:  This management pack has been replaced by the more feature-rich xSNMP suite.

I still have some more full-scale testing to complete, but I have finished the first version of the Cisco monitoring management pack that I have described in the last few posts.   This version is R2 only, but I hope to have an SP1 version of it complete soon. 

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SCOM: Advanced SNMP Monitoring Part II: Designing the SNMP Monitors

For the Cisco Management Pack, a handful of different approaches were required when designing the monitors and rules and their supporting workflows.  These approaches can generally be placed into three categories:

  • Simple SNMP GET operations
  • Operations that require data manipulation
  • Operations that require access to previously collected values  

For example, monitoring of an interface’s operational status only requires current SNMP GET requests (to retrieve the ifOperStatus and ifAdminStatus values) from the SNMP ifTable.  Condition detection for the monitor type definition can handle the SNMP values as they are presented with no further manipulation.   However, to monitor a value such as the percent free bytes on a Cisco memory pool, data manipulation is required.  In this example, a percentage value is not exposed via SNMP, but free and available values are.  So, to calculate a percentage, the free and available bytes values must be summed and then the free value divided by that sum.  And lastly, in some cases, a value from a previous poll must be referenced to detect the desired condition, such as monitoring for an increase in the collisions reported for a Cisco interface.  In this example, the locIfCollisions values can be retrieved from the locIfTable, but this is a continually augmenting counter, which is difficult to monitor.   By recording the value from the immediately previous poll, and comparing it with the current poll, a delta value can be established for that polling cycle to determine the number of collisions recorded in a single polling cycle. 

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VBS: Decoding Base64 Strings (in 10 lines of code)

This code snippet can be used to decode Base64 encoded strings into plain text, which I have found useful recently when working on VBscript scripts that require decoding the Base64-encoded SNMP community strings stored in OpsMgr.  I thought it would be worth sharing.

Function Decode(strB64)
 strXML = “<B64DECODE xmlns:dt=” & Chr(34) & _
        “urn:schemas-microsoft-com:datatypes” & Chr(34) & ” ” & _
        “dt:dt=” & Chr(34) & “bin.base64″ & Chr(34) & “>” & _
        strB64 & “</B64DECODE>”
 Set oXMLDoc = CreateObject(“MSXML2.DOMDocument.3.0″)
 oXMLDoc.LoadXML(strXML)
 decode = oXMLDoc.selectsinglenode(“B64DECODE”).nodeTypedValue
 set oXMLDoc = nothing
End Function

SCOM: Advanced SNMP Monitoring Part I: Discovering Cisco Devices and Hosted Classes

When limited to editing within the Authoring pane of the Operations Console in OpsMgr, SNMP monitoring options are relatively limited – only SNMP GET requests are supported and data cannot be manipulated before calculating health state.   However, with some pretty heavy authoring, very complex SNMP monitoring becomes completely viable, particularly in R2.   In the next several posts, I will be describing some methods to perform advanced SNMP discovery and monitoring in OpsMgr 2007, such as discovering hosting relationships for entities like network interfaces, as well as passing Snmp data to script probes in order to perform state change monitoring and mathematical operations.  When all is said and done, I will post my management packs for SNMP monitoring of Cisco, Checkpoint, and Net-SNMP devices.   In this post, I will describe the methods I used for custom discovery of Cisco SNMP devices and their hosted entities (interfaces, power supplies, etc).

Cisco SNMP Management Pack: Designing the Classes and Groups

In order to facilitate monitoring of the device (e.g. CPU, Memory, up/down status), individual interfaces (e.g. status, utilization, resets), and Cisco EnvMon objects (e.g. Power Supplies, Temperature, etc), each of these entities are best represented as a unique class with hosting relationships.   For the objects stored in tables, there are two feasible options for discovery.  In SCOM 2007 R2, the ‘walkreturnmultipleitems’ attribute of the System.SnmpProbe probe action can be set in order to walk an SNMP table and return each snmpdata item individually.   In SCOM 2007 SP1, this option is not available, requiring the use of a script discovery with an external snmp probe (such as WMI) in order to retrieve the discovery items.  In this post, I will describe the R2 method, and I will address the script option using the WMI SNMP provider in a later post.  In either case, the class design will be similar.

For monitoring of Cisco SNMP devices, I created five classes:

  • CiscoSNMP.Class.CiscoDevice
  • CiscoSNMP.Class.CiscoDevice.Interface
  • CiscoSNMP.Class.CiscoDevice.PowerSupply
  • CiscoSNMP.Class.CiscoDevice.Fan
  • CiscoSNMP.Class.CiscoDevice.TemperatureSensor

For the four hardware entities, I created a hosting relationship so that they are hosted by the CiscoDevice class.   The classes, properties, and relationships are represented on this diagram.

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Monitoring for SNMP Value Changes with SolarWinds ORION NPM

I had previously described a few example scenarios in which monitoring SNMP values for changes (from the values in previous polling cycles) could be useful.   In this post, I will describe the steps to configure monitoring for these scenarios in SolarWinds ORION NPM. 

Detecting changes in Checkpoint Firewall (Splat) High Availability State

The checkpoint mib includes a good set of SNMP objects exposed for state and performance monitoring of Checkpoint Secure Platform firewalls.   The state of firewall modules can be polled with the xxStatCode (numeric) or xxStatShortDescr (string) objects.  For example, Secure Virtual Networking can be monitored with the svnStatCode (1.3.6.1.4.1.2620.1.6.101) or svnStatShortDescr (1.3.6.1.4.1.2620.1.6.102) objects.  Likewise for the other modules such as HA, DTPS, or WAM (etc) modules.   However, in order to detect HA failovers, I monitor the haState (1.3.6.1.4.1.2620.1.5.6) object for changes (i.e. from “standby” to “active”).  

Detecting Default Gateway (ipRouteNextHop) Changes on Cisco Routers

In some redundant configurations, a change in the device’s default gateway may be the best indicator of a failover to an alternate Wide-Area connection, which could be a problem if the backup WAN link is a slower bandwidth connection.   The ipRouteNextHop (1.3.6.1.2.1.4.21.1.7) object is located in the ipRoute table of the ubiquitous RFC1213 (MIB II) mib.  The device’s default gateway is the first row listed in this table.

Detecting Serial Interface Flapping

Increases in the locIFResets (1.3.6.1.4.1.9.2.2.1.1.17) Cisco counter on a serial interface are a good indicator of flapping on the serial connection.   If the serial interface resets more than two times in a polling cycle, we can probably assume that it is flapping (an administrative shut and start would be one reset, so by monitoring for 2 or more resets, we can avoid alerts when planned maintenance is being performed).    If the reset count doesn’t change for a few polling cycles, it can probably be assumed that the connection has stabilized. 

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