Skip to main content

System Center Operations Manager 2012 (SCOM) - SNMP device discovery

Lately I have been working in SCOM with SNMP devices. Needless to say I have learned some new tricks I would like to share with you.

Firstly you may have run into the dreaded "No response SNMP" message in Network Devices Pending Management in the SCOM console. First thing that jumps out is network connectivity, however I have seen cases that that is not the issue. Based upon my experience the message is very generic and could have several causes:

1. Network connectivity

Firewall (on the SCOM server or one of the SCOM servers that is a member of the resourcepool specified in the discovery rule) or between the SCOM-server and the SNMP device.
    2. SNMP-device configuration

    The target SNMP device needs to enable the whole system MIB/OID-tree to be discoverable in SCOM. If any of the following OIDs are missing, you will not be able to discover the device:
    • 1.3.6.1.2.1.1.1.0 --> system.sysDescr
    • 1.3.6.1.2.1.1.2.0 --> system.sysObjectID
    • 1.3.6.1.2.1.1.4.0 --> system.sysContact
    • 1.3.6.1.2.1.1.5.0 --> system.sysName
    • 1.3.6.1.2.1.1.6.0 --> system.sysLocation



    3. SCOM host SNMP configuration

    Please follow microsoft recommandations on how to configure your SCOM server to be able to communicate with the SNMP protocol.


    Regarding network connectivity you have a lot of options. First on your list should be to temporarily disable the firewall and verify that you are still unable to discover the device with the firewall turned off. Next step should be to verify that the device is responding to ping requests. Further you should also verify SNMP UDP connectivity on port 161. There are a number of tools available for you to use. Paessler has an SNMP test tool (http://www.paessler.com/tools/snmptester)with a GUI and a console application you can use in scripts. Very handy if you need to add many devices and check if the device is on the certified SNMP device list from Microsoft. More on this later.

    Recently I have been experiencing issues with SCOM when there are no network connectivity issues and I have verified that SCOM is able to communicate with the device via SNMP. Time to get low, dirty and bring out the bag of tricks.

    First thing is to enable SNMP device discovery debug-tracing in SCOM. This is done in the file located in:
    C:\Program Files\System Center 2012\Operations Manager\Server\NetworkMonitoring\conf\discovery 

    and is called discovery.conf. Open the file in notepad and set the following:

    DebugEnabled = TRUE
    LogDiscoveryProgress = TRUE
    enableSNMPTrace = TRUE
    enableICMPTrace = TRUE

    LogDiscoveryProgress is not in the file, you will have to add it. Save the file and restart the healthservice on the SCOM server. You may use this powershell command:
    Get-Servicename healthservice |restart-serviceverbose
    To be continued…

    Comments

    1. Where is the "continued" post?

      ReplyDelete
    2. Hi, sorry, it is one of the many things I have not yet been able to get to. Long overdue I admit.

      ReplyDelete

    Post a Comment

    Popular posts from this blog

    Build your local powershell module repository - ProGet

    So Windows Powershell Blog released a blog a couple of days ago (link). Not too long after, a discussion emerged about it being to complicated to setup. Even though the required software is open source (nugetgalleryserver), it looks like you need to have Visual Studio Installed to compile it. I looked into doing it without visual stuidio, however I have been unable to come up with a solution. I even tweeted about it since I am not an developer. Maybe someone how is familiar with “msbuild” could do a post on how to do it without VS.

    Anyhow one of my twitter-friends (@sstranger) came to the rescue and pointed me in the direction of ProGet, hence the title of this post. ProGet comes in 2 different licensing modes
    Free (reduced functionality)Enterprise (paid version with extra features)The good news is that the free version supports hosting a local PowershellGet repository which was my intention anyway. So off we go and create a Configration that can install ProGet for us. This is the conf…

    Developing PowerShell modules for REST APIs – Part1

    Over the years I have developed different PowerShell modules for different web APIs. I thought it would be a good idea to write a 2 series post about how you could go about to do this. This will be a 2 part blog series where we will run through the entire process of building a module for a REST API. I will try my best to keep this as simple as possible and leave more advanced stuff for a follow up post if the interest is there.What you needDepending on your experience with source control and PowerShell in general, you might want to use GIT or some other software repro for the code. In addition we are going to create a test REST API using the splendid UniversalDashboard PowerShell module created by Adam Driscoll. It is available on the PowershellGallery. Other prerequisites are built-in to Powershell. I will assume that you will be following along using at least PowerShell version 5 or greater.
    What is HTTP metods for REST API.The primary or most common HTTP verbs used are POST, GET, PU…

    Serialize data with PowerShell

    Currently I am working on a big new module. In this module, I need to persist data to disk and reprocess them at some point even if the module/PowerShell session was closed. I needed to serialize objects and save them to disk. It needed to be very efficient to be able to support a high volume of objects. Hence I decided to turn this serializer into a module called HashData.



    Other Serializing methods

    In PowerShell we have several possibilities to serialize objects. There are two cmdlets you can use which are built in:
    Export-CliXmlConvertTo-JSON
    Both are excellent options if you do not care about the size of the file. In my case I needed something lean and mean in terms of the size on disk for the serialized object. Lets do some tests to compare the different types:


    (Hashdata.Object.ps1)

    You might be curious why I do not use the Export-CliXML cmdlet and just use the [System.Management.Automation.PSSerializer]::Serialize static method. The static method will generate the same xml, however we …