Parse Events via PowerShell into table

Parsing Events via PowerShell into table — Optometrist eye testing equipment picture

Parse Events via PowerShell into table. Ever have need to parse an event, and grab a field from the event description, then perform some action after that?

Here’s some PowerShell that may help you first to create a table, then setup columns, gather data, then parse what you need, and run a command to then output to the table

# Create Table for alerts

$Table = @()

$Table = $null

$Table = New-Object System.Data.DataTable “Failed Hosts List”

$Col1 = New-Object System.Data.DataColumn Host

$Col2 = New-Object System.Data.DataColumn IPAddress

$Table.Columns.Add($Col1)

$Table.Columns.Add($Col2)

$Alert20046 = Get-WinEvent -FilterHashtable @{LogName=’Operations Manager’;

ID=’20046′;}

$Alerts20046 = $Alert20046.Message

$Alerts20046.count

$Alerts20046uniq = $Alerts20046 | sort -uniq

$Alerts20046uniq.count

# $DeniedUniq = $Denied20046 | Sort-Object -Uniq

# $ServersDenied = @()

foreach ( $server in $DeniedUniq)

{

$Name = nslookup $server

foreach ($server in $Name)

{

# Add to Table

# $Name.Split(“:”)[6]

# $Name.Split(“:”)[8]

$row = $Table.NewRow()

$row.Host = $Name.Split(“:”)[6]

$row.IPAddress = $Name.Split(“:”)[8]

$Table.Rows.Add($row)

}

Mining Windows Event Log

Mining Ore from the Windows Event Log and finding a way to make it portable

Use Get-WinEvent to use XML and filters from event viewer, to mine an event, including examples for a specific string, from a specific event, in a specific event log?

Hopefully this post will help with a few tips to simplify monitoring for events, whether in AzMon, SCOM, or via PowerShell.

Let’s start with the Dr Scripto blog post from quite a while ago –

https://devblogs.microsoft.com/scripting/data-mine-the-windows-event-log-by-using-powershell-and-xml/

Not sure how many people use get-WinEvent, but this is one tool in PowerShell that can help an admin parse the XML side of an event.

Example 1

Query Application Event Log for Severity, Event, and Event Data contains lync.exe

$query = @”

<Select Path=”Application”>*[System[Provider[@Name=’Application Hang’]

and (Level=2) and (EventID=1002)]]

and *[EventData[Data=’lync.exe’]]</Select>

</Query>

</QueryList>

“@

Get-WinEvent -FilterXml $query

PowerShell output

Use Get-WinEvent to use XML and filters from event viewer

The Tip or Trick part of this – leverage your Event Viewer Filter as a query to use with get-WinEvent

Credit for this tip comes from Andrew Blumhardt!

See below for examples to ‘use Get-WinEvent to use XML and filters from event viewer’

Navigating via Event Viewer:

Hop onto your favorite server, or connect to another server via Event Viewer

Go to the Event Log > Click Filter Current Log

Build out your filter (i.e. choose specific Event Sources, exclude events, include severities, timeframe (start/end), etc.)

Switch to the XML tab (and note you can edit your query further!)

You can copy the query from the Event Viewer into your Get-WinEvent syntax

$query = @”

<QueryList>
<Query Id=”0″ Path=”Application”>
<Select Path=”Application”>*[System[Provider[@Name=’Microsoft.SystemCenter.VirtualMachineManager.2012.Monitor.UserRoleQuotaUsageMonitor’ or @Name=’Microsoft.SystemCenter.VirtualMachineManager.2012.Report.ServiceUsageCollection’ or @Name=’Microsoft.SystemCenter.VirtualMachineManager.2012.Report.VMUsageCollection’ or @Name=’Microsoft.SystemCenter.VirtualMachineManager.2016.EnableCredSSPClient’ or @Name=’Microsoft.SystemCenter.VirtualMachineManager.2016.Monitor.UserRoleQuotaUsageMonitor’ or @Name=’Microsoft.SystemCenter.VirtualMachineManager.2016.Report.ServiceUsageCollection’ or @Name=’Microsoft.SystemCenter.VirtualMachineManager.2016.Report.VMUsageCollection’] and (Level=2 or Level=3) and (EventID=25933)]]</Select>
</Query>
</QueryList>

“@

Get-WinEvent -FilterXml $query

PowerShell output

Example 3

Grab System Event Log, Event ID 5827 (NetLogon denied events)

get-WinEvent -FilterHashtable @{LogName=’System’; ID=’5827′;}

PowerShell output

Documentation:

Get-WinEvent https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.diagnostics/get-winevent?view=powershell-7.1

MSFT DevBlogs https://devblogs.microsoft.com/scripting/data-mine-the-windows-event-log-by-using-powershell-and-xml/

Which subscription was the trigger?

Hello Again,

Surprise!

I am back, as a rusty nail, and back to make lemonade from lemons!

Rusty Nail through Lemon

Ever run into an email you don’t want to get, but have difficulty finding

the subscription entry?

Do you get a subscription Email, and that channel has the Notification ID, but you’re not sure what subscription sent the alert email?

Let’s start with the notification email

Example

Notification subscription ID generating this message:

{AA0C1081-D04F-F5CA-DEB7-92B9ECA619E2}

On SCOM MS > Open PowerShell

Get-SCOMNotificationSubscription

Example

PS C:\windows\system32> Get-SCOMNotificationSubscription -ID

“BD52BB72-3FDE-9D7F-6214-B9A47A311896”

Configuration :

Microsoft.EnterpriseManagement.Administration.AlertChangedSubscriptionConfiguration

ManagementGroup : SCOMTestLab

Name : Subscription168e29fd_a8e5_4ee4_956f_d9591b845475

DisplayName : AD DailyTasks Report

Description : +CRITERIA = Alert Name Contains ‘Proactive DailyTasks AD

Team Report’ +RESOLUTIONSTATE = (0)

New +SUBSCRIBERS = AD team, USER Kevin Justin via EMAIL +CHANNEL = SMTP Email

Actions : {SMTPAction_a6a5314d_83f5_47c0_910a_e60040b4c808}

ToRecipients : {USER <blank> via EMAIL, USER <blank> via EMAIL, USER

<blank> via Email, USER <blank> via EMAIL…}

CcRecipients : {}

BccRecipients : {}

Enabled : True

Id : bd52bb72-3fde-9d7f-6214-b9a47a311896

ManagementGroupId : 001b9265-3c9f-816c-aa36-a8687c05be8e

Get-SCOMNotificationSubscription | ? { $_.ID -eq

“BD52BB72-3FDE-9D7F-6214-B9A47A311896” }

Example

PS C:\windows\system32> Get-SCOMNotificationSubscription | ? { $_.ID -eq “BD52BB72-3FDE-9D7F-6214-B9A47A311896” }

Configuration :

Microsoft.EnterpriseManagement.Administration.AlertChangedSubscriptionConfiguration

ManagementGroup : SCOMTestLab

Name : Subscription168e29fd_a8e5_4ee4_956f_d9591b845475

DisplayName : AD DailyTasks Report

Description : +CRITERIA = Alert Name Contains ‘Proactive DailyTasks AD

Team Report’ +RESOLUTIONSTATE = (0)

New +SUBSCRIBERS = AD team, USER Kevin Justin via EMAIL +CHANNEL = SMTP Email

Actions : {SMTPAction_a6a5314d_83f5_47c0_910a_e60040b4c808}

ToRecipients : {USER <blank> via EMAIL, USER <blank> via EMAIL, USER

<blank> via Email, USER <blank> via EMAIL…}CcRecipients : {}

BccRecipients : {}

Enabled : True

Id : bd52bb72-3fde-9d7f-6214-b9a47a311896

ManagementGroupId : 001b9265-3c9f-816c-aa36-a8687c05be8e

Update the subscription

Depending on the subscription criteria, you may need to adjust the classes, or rules/monitors, or even the criteria (properties)

Example

Using Subscription Description for more details into what is filtered, who alert is delivered to, and the channel used

Example

Expanding Subscription Criteria to see details into what criteria is filtered for subscription

SubscriptionCriteria

See previous blogs for the best practice / how to set up subscriptions to show useful data without all the clicks

Subscription set up guide

Docs article How to Create Notification Subscriptions | Microsoft Docs

SCOM 2016 web console hot fix released

Burglar stealing a monitor — Security hotfix for SCOM 2016 web console released before your information is stolen

SCOM 2016 web console hot fix

Security teams may be contacting you for CVE-2020-1331 vulnerability on the 2016 web console. In my example, the Tenable scanner listed ALL SCOM management group servers – under SCOM2016/2019).

NOTE KB does not install on server, so does not show up under ‘Installed Updates’

Background

HotFix DLL comes with a readme to replace the DLL for the SCOM 2016 WebConsole role

If you don’t already know this, the roles each get their own directory on your SCOM server

Security scanners run scripts to help validate if system is vulnerable. It is possible that the scanner is just looking for some string for the install of SCOM, NOT the actual role that is vulnerable.

SCOM 2016 typically installs @ (‘\Program Files\Microsoft System Center 2016’)

SCOM 2019 typically installs @ (‘\Program Files\Microsoft System Center’)

Identify SCOM roles

Open PowerShell window to identify roles

cd “D:\Program Files\Microsoft System Center 2016\Operations Manager”

Resolve Web Console vulnerability

High level steps

Download the KB here

Execute KB

Copy dll and readme file

Backup DLL and replace

Reboot server

Contact Security Team to re-scan server

Mitigate vulnerability

Download the KB here

Extract downloaded the KB

Click Run to extract, and list extraction path

Copy Windows Explorer Path you want to extract to, and paste in the path

Example

S:\MonAdmin\MSDN images\SCOM\2016\WebConsole HotFix

Enter path to extract Hot Fix — Extract Hot Fix

Copy current DLL & replace with hotfix DLL

Open PowerShell window (as admin)

# Backup DLL

# Change Drive letter if you hopefully installed SCOM on D: drive (non-system drive)

copy “C:\Program Files\Microsoft System Center 2016\Operations Manager\WebConsole\MonitoringView\bin\Microsoft.EnterpriseManagement.OperationsManager.MonitoringViews.dll” “C:\Program Files\Microsoft System Center 2016\Operations Manager\WebConsole\MonitoringView\bin\Microsoft.EnterpriseManagement.OperationsManager.MonitoringViews-old.dll”

# Replace DLL

copy “C:\MonAdmin\Microsoft*.dll” “C:\Program Files\Microsoft System Center 2016\Operations Mana
ger\WebConsole\MonitoringView\bin”

# Verify

cd “D:\Program Files\Microsoft System Center 2016\Operations Manager\WebConsole\MonitoringView \bin”

gci Microsoft.EnterpriseManagement.Operations*.dll

Sample screenshot from Windows Explorer view of Bin directory for replaced DLL – Same size, only timestamp changes July Page 4

Windows Explorer window showing DLL's — Windows Explorer window showing DLL’s

Reboot server

Test WebConsole functionality

Verify from SCOM Console > Administration Tab > Settings > Web

Example

http://16ms01/OperationsManager

Contact Security Team to re-scan SCOM asset(s)

References

CVE-2020-1331 https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1331

Microsoft Support article

https://support.microsoft.com/en-us/help/4566040/prevent-javascript-injection-in-operations-manager-2016-web-console

Tenable forum post https://community.tenable.com/s/question/0D53a000074LGapCAG/plugin-137369-security-updatesfor-microsoft-system-center-operations-manager

Identify orphaned agent properties

Back again, I’m going to ‘Identify orphaned agent properties’. For instance, does an agent still show up under Windows Computer, or more classes, like Windows Operating System? Typically we have handled this by using Holman’s purge blog.

Deleting and Purging data from the SCOM Database

First, my thanks to Kevin H, Mihai S from the SCOM PG, & Premier Support CSS, for their help. Let’s begin the ‘Identify orphaned agent properties’ discussion with ‘how’. First, how do you get an orphaned property? Second, how to you resolve?

Some example scenarios

1. Server rebuilt with same name. New agent runs discovery, and creates new set of GUID’s in the database.
2. The Monitoring Tab > Windows Computer view contains unhealthy <gray> server objects. Upon further inspection, the server does NOT show up in the Administration > Agent Managed view.
3. Custom management pack authoring extends the Windows Computer class, or others (via SDK or PowerShell)

‘Identify and resolve’ orphaned agent properties

1. Check for COMMIT or Overrides in management packs

PG recommended looking at Windows Computer extended class properties, and Connector Framework discoveries.

Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData.Commit()

Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData.Override()

Search for the ConnectorFramework

Search management packs (MP) via SCOM OpsDB (OperationsManager Database)

1. Login to your SCOM OpsDB > New Query

select MPName, convert(xml, MPXML)

from ManagementPack

where

MPXML like ‘%Commit(%’ or

MPXML like ‘%Override(%’

Export management pack output or snag it/snippet screenshot

Example Snapshot from SQL query

SQL Query output of Management Pack output with Commit or Override — SQL query of MP Commit or Override pack matches

FYI – mgmt packs above use %Commit(%, but not the connectorFramework

Correct discoveries that use ConnectorFramework

Replace Discoveries

Update discoveries that contain:

New-Object Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData.Commit()

New-Object Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData.Override()

Replace with:

New-Object -comObject MOM.ScriptAPI for discovery

Test discoveries that use Remove method

Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData.Remove()

Example management pack discovery script

Contains

$discovery = New-Object Microsoft.EnterpriseManagement.ConnectorFramework.IncrementalDiscoveryData

$discovery.RemoveInternal($Instance,$ClassInstance.GetClasses()[0])

$discovery.Commit($mg) <– This is the offender that causes the orphans

}

ADCS – Active Directory Certificate Services Addendum pack

Time to talk Certificates! — Certificate of Achievement

Hello again, it’s time to talk about ADCS – Active Directory Certificate Services Addendum!

First, I’d like to call out Bob Williams and Vance Cozier for their help and expertise!

SCOM-ADCS-Addendum download

Background

ADCS is Active Directory Certificate Services, or what we would know as a Certificate Authority. The goal was to improve the pack, because the focus is on how important certificates are to a modern enterprise. Let’s begin the Active Directory Certificate Services Addendum pack review.

Collaboration

In this paragraph, let’s talk through the Certificate Services packs for 2016+, and how we as Microsoft consultants, and field engineers, recommend changes to the pack. First, for some background, the collaboration process gets a better result improving Microsoft products. Second, the collaboration result can vary. Third, collaboration input can be based on customer input, or field engineer experience. Most importantly, this is how we ‘would have liked’ the pack to work.

AD Certificate Services Monitoring

The Certificate services pack alerts on events/services. Therefore, the pack does NOT monitor the SCEP URL. For instance, a transaction web monitor was added. The collaboration effort was focused on improving the ADCS pack, resulting in the creation of the Active Directory Certificate Services Addendum and customizations packs.

Download File

Let’s delve into the download file

SCOM-ADCS-Addendum download

Review file contents

Download.txt (in case you need to find it later!)
Version.Info.txt (MP version history, what was added & when)
XLS MP export of rules/monitors
ADCS Addendum & Customizations packs

References

Configuring Certificate Services docs site

ADCS download

Management Pack wiki

Don’t forget python as pre-req for agent install

Grocery List, items to get and notes — Grocery List

Hey guys, don’t forget python as pre-req for agent install! Came across this again, where the docs site doesn’t mention python-ctypes as pre-req for agent install. Let’s flip to GitHub for the agent. GitHub lists the python pre-req here. Otherwise, it’s Openssl 1.1.0 is only supported on x86_64 platforms (64-bit).

Let’s begin by starting with a Linux server. I’ve used Ubuntu in my lab, specifically, Ubuntu v16.04.

Regular user run ‘sudo apt-get install python-ctypes‘

Super user/root ‘apt-get install python-ctypes‘

As of 1 July, v1.13.7.0 is current (latest) 64 bit OMS for Linux agent released.

References

GitHub link https://github.com/Microsoft/OMS-Agent-for-Linux

GitHub Agent Download (AzMon/ALA/OMS/SCOM agent for Linux ) https://github.com/microsoft/OMS-Agent-for-Linux/releases/download/OMSAgent_v1.13.7-0/omsagent-1.13.7-0.universal.x64.sh

Python requirements https://github.com/Microsoft/OMS-Agent-for-Linux#python-requrements

Install guide https://github.com/Microsoft/OMS-Agent-for-Linux#azure-install-guide

Need to find the command UNIX pack runs for perf counter

Have you ever needed to find the command UNIX pack runs for perf counter? Say the processor time value doesn’t match what the Unix admin may be saying SCOM is showing.

Many times you can look at the SCOM management pack, and those commands trace back to the UNIX library.

Background: The SCOM management server runs many of the cross-plat/xplat workflows to the UNIX agent through WinRM.

Agenda

Unseal SCOM UNIX management pack to obtain URI
Understand command line options from UNIX/Linux side, and how to view the output
Enumerate command line
Test Command line from SCOM MS

Unseal SCOM UNIX management pack

The screenshot below is unsealing the Solaris10 pack to XML, and then viewing/searching to show the processor reference.

Solaris 10 processor rules

NOTE that’s a URI, not a script

How UNIX admin may supply processor output

Example – Unix admin typically uses vmstat or iostat.

The screenshot uses ‘vmstat 2 10‘ – a snapshot every 2 second intervals, 10 times

We can discuss the vmstat output, but it shows way more than just processor (ready queue, swap, user, system, and cpu %) to help figure out which operating system component is the problem.

Enumerate command line test

How do we test the command line syntax, to verify what SCOM pulls when running the rule?

For example, we need to make the URI actionable from the management pack. What is needed to make a usable command?

Grab the URI from the pack –

http://schemas.microsoft.com/wbem/wscim/1/cim-schema/2/SCX_ProcessorStatisticalInformation?__cimnamespace=root/scx

Because we know the URI, we now build out the syntax with WinRM

winrm enumerate http://schemas.microsoft.com/wbem/wscim/1/cim-schema/2/SCX_ProcessorStatisticalInformation?__cimnamespace=root/scx -auth:basic -remote:https://<servername>:1270 -username:<scomID, not necessarily root> -skipCACheck -skipCNCheck -skiprevocationcheck –encoding:utf-8

Test WinRM command from SCOM MS

For instance, we want to test the WinRM command from the MS to the UNIX server

winrm enumerate http://schemas.microsoft.com/wbem/wscim/1/cim-schema/2/SCX_ProcessorStatisticalInformation?__cimnamespace=root/scx -auth:basic -remote:https://ubuntu:1270 -username:scom -skipCACheck -skipCNCheck -skiprevocationcheck –encoding:utf-8

Example output

SCX_ProcessorStatisticalInformation
InstanceID = null
Caption = Processor information
Description = CPU usage statistics
ElementName = null
Name = 0
IsAggregate = FALSE
PercentIdleTime = 99
PercentUserTime = 0
PercentNiceTime = 0
PercentPrivilegedTime = 0
PercentInterruptTime = 0
PercentDPCTime = 0
PercentProcessorTime = 1
PercentIOWaitTime = 0

SCX_ProcessorStatisticalInformation
InstanceID = null
Caption = Processor information
Description = CPU usage statistics
ElementName = null
Name = _Total
IsAggregate = TRUE
PercentIdleTime = 99
PercentUserTime = 0
PercentNiceTime = 0
PercentPrivilegedTime = 0
PercentInterruptTime = 0
PercentDPCTime = 0
PercentProcessorTime = 1
PercentIOWaitTime = 0

Additional references for WinRM syntax and troubleshooting

Warren’s blog

Docs site

Use Unix MP’s for shell commands

Build FluentD conf file

Build trust one block at a time

Ready to build out a FluentD conf file?

Let’s build a FluentD conf file. We can use the docs site for another example. And now, let’s build a simple FluentD configuration file. Paste the XML code below, and save as <yourlogfile>.conf

Create custom log file to test

cd /etc/opt/microsoft/omsagent/scom/conf/omsagent.d/
# vi <yourlogfile>.conf

vi mylog.conf

# Example conf file

<source>
# Specifies input plugin. Tail is a fluentd input plugin – http://docs.fluentd.org/v0.12/articles/in_tail
type tail
# Specify the log file path. Supports wild cards.
path /var/log/mylog
# Recommended so that Fluentd will record the position it last read into this file.
pos_file /home/omsagent/fluent-logging/mylog.pos

# Used to correlate the directives.
tag scom.log.mylog

format /(?<message>.*)/
</source>

<filter scom.log.mylog>
type filter_scom_simple_match
regexp1 message 911
event_id1 911
</filter>

<match scom.log.mylog>
#Disable mutual Auth
enable_server_auth false

# Output plugin to use
type out_scom
log_level trace
num_threads 5

# Size of the buffer chunk. If the top chunk exceeds this limit or the time limit flush_interval, a new empty chunk is pushed to the top of the
queue and bottom chunk is written out.
buffer_chunk_limit 5m
flush_interval 15s
# Specifies the buffer plugin to use.
buffer_type file
# Specifies the file path for buffer. Fluentd must have write access to this directory.
buffer_path /var/opt/microsoft/omsagent/scom/state/out_scom_common*.buffer
# If queue length exceeds the specified limit, events are rejected.
buffer_queue_limit 10
# Control the buffer behavior when the queue becomes full: exception, block, drop_oldest_chunk
buffer_queue_full_action drop_oldest_chunk
# Number of times Fluentd will attempt to write the chunk if it fails.
retry_limit 10
# If the bottom chunk fails to be written out, it will remain in the queue and Fluentd will retry after waiting retry_wait seconds
retry_wait 30s
# The retry wait time doubles each time until max_retry_wait.
max_retry_wait 9m
</match>

Save (:wq!)

# Restart Agent

/opt/microsoft/omsagent/bin/service_control restart

# Check for errors – see blog

grep -i error /var/opt/microsoft/omsagent/scom/log/omsagent.log

# Test strings into your logfile

# Options

echo test >> /var/log/mylog

echo 911 error >> /var/log/mylog

# mimic syslog or messages syntax

echo `date +”%b %e %H:%M:%S”` MYLOG 911 test string. Call 911 >> /var/log/mylog

Please stay tuned for more management pack options to alert on the strings. Refer to the part1/2 blogs for more details on unit testing for alerts.

OMSAgent FluentD debunked – Configure Linux FluentD – part2

Are you stoked and fired up to Configure Linux FluentD - part2 !?

Now to begin – OMSAgent FluentD debunked

Configure Linux FluentD – part2 –> see part one (1) here)

First, my thanks to Mike Johnston@Microsoft (CSS SEE SME) to help validate my steps and testing, to configure Linux FluentD on an Ubuntu server! Are you ready to bust a myth – OMSAgent FluentD debunked

If you’re starting fresh, or just joining, start with Part 1. And Part 1 configures packs and assumes SCOM agent is installed and working. Because it’s time to use the feature, we need to get the agent configured and tested.

Part one (1) quick summary

- Verify pre-reqs – SCOM Linux Management packs for Linux/Universal Linux (2019 @ 10.19.1082.0), UNIX/Linux Log File monitoring (2019 @ 10.19.1008.0)
- Linux server has SCOM Agent installed, configured, and updated (sudoers configured) – GUI blog here
- Use docs.microsoft.com article

Load Sample Log monitoring pack

This piece is missing in the doc, but the content development team has this covered in a subsequent docs article. We need to load a sample log monitoring pack to the SCOM management group, so we can test functionality.

Configure FluentD part 2 - This is a picture of the SCOM console GUI showing the OMED pack installed from the Admin tab > Management Packs > Installed Management Packs > with omed in the 'look for:' bar

Grab the file here, otherwise you can copy/paste from the docs article pretty easily.

Verify OMED service running on Management Server

It’s now time to enable the OMED service on the management server, and we can start with the docs subsection

Navigation steps from SCOM console (GUI)

1. From the Operations console, go to Monitoring>Operations Manager>Management Server>Management Servers State.
2. Select the management server in the Management Servers state.
3. From Tasks, select Health Service Tasks>Enable System Center OMED Server

Steps to set/start service PowerShell (as admin)

# Verify service startup type is automatic

get-Service OMED | select -property Name,Starttype

# Example output

PS C:\Users\admin> Get-Service OMED | select -property name,starttype

Name StartType
—- ———
OMED Automatic

# Set startup type

# Start OMED service on SCOM management server (MS)

start-service OMED

Now we’re ready to test the UNIX agent!

Configure SCOM/OMSagent on Linux server

And now it’s time to switch to the agent side. I’m assuming that you’ve already configured the SCOM agent on the Linux server. So it’s time to verify the SCOM and OMSAgent is configured and working. Let’s go back to the docs subsection for our sanity check, because we need to create folders, and set ownership, etc.

Create files and set permissions

mkdir /etc/opt/microsoft/omsagent/scom/conf/omsagent.d

mkdir /etc/opt/microsoft/omsagent/scom/certs

mkdir /var/opt/microsoft/omsagent/scom/log

mkdir /var/opt/microsoft/omsagent/scom/run

mkdir /var/opt/microsoft/omsagent/scom/state

mkdir /var/opt/microsoft/omsagent/scom/tmp

mkdir /home/omsagent/fluent-logging

# NOTE – This location is flexible for the path to use for log file position files

chown omsagent:omiusers state

chown omsagent:omiusers run

chown omsagent:omiusers log

chown omsagent:omiusers tmp

chown omsagent:omiusers /home/omsagent/fluent-logging

Verify SCOM certificate

Configuring FluentD requires the SCOM management server (MS) has signed the certificate on the UNIX server. The docs article tells you to generate a new certificate for FluentD, which requires the management server.

Overview

Sign the certs on the agent > copy to MS > sign > copy back to agent

Step by step instructions

1. Generate certs

/opt/microsoft/scx/bin/tools/scxsslconfig -c -g /etc/opt/microsoft/omsagent/scom/certs/

2. Rename certificates

cp -p omi-host-server.domain.pem to scom-cert.pem

cp -p omikey.pem to scom-key.pem

3. Copy certs to MS (sftp/ssh via WinSCP, or your app of choice)

4. Sign certs on MS via scxcertconfig -sign

Open PowerShell (as admin)

Go to your SCOM management server directory (hopefully d:)

cd ‘D:\Program Files\Microsoft System Center\Operations Manager\Server’

scxcertconfig -sign scom-cert.pem

scxcertconfig -sign scom-key.pem

5. Copy certs back to agent from MS (sftp/ssh via WinSCP, or your app of choice)

6. Verify the SCOM certificate shows your Management Server (MS) in the DC= line in the certificate

openssl x509 -in scom-cert.pem -noout -text

Verify SSL certificate - openssl syntax, verify the DC= portion is from the SCOM management server (MS)

7. Restart omsagent

As the ALLINONE server is one of my 2019 SCOM labs, I can verify that my cert is now signed by the management server (MS). Time to load the certificate, and then restart the agent to see if we have any errors

# Restart Agent

/opt/microsoft/omsagent/bin/service_control restart

Verify omsagent.log errors

Verify any errors from the omsagent.log

Depending on where you are with your UNIX/Linux commands, this may help provide some context or use case examples.

My example –

First error after restart was ‘permission denied’. FluentD runs under the omsagent ID, and needs to have access to whatever log – at least read (4). For the syslog example, I made omsagent the owner, and omiusers the group. The smarter, security hat on, choice is to leave as root and make it read capable, or add omsagent to the root group

Configure FluentD part 2 - fluentd permission denied alerts on /var/log/syslog

Search /var/opt/microsoft/omsagent/scom/log/omsagent.log for errors. Commands build on another, from simpler to more complex. Don’t worry if UNIX/Linux is new, I’m all about examples, so hope that helps bridge the gap!

# Tail omsagent.log for progress

# Option 1 Continual output updates from file

tail -f /var/opt/microsoft/omsagent/scom/log/omsagent.log

# Option 2 – get last 10 lines

tail /var/opt/microsoft/omsagent/scom/log/omsagent.log

# Option 3 – get last 100 lines

tail -100 /var/opt/microsoft/omsagent/scom/log/omsagent.log

# Option 4 – Get a little fancier – search for a string

grep string /var/opt/microsoft/omsagent/scom/log/omsagent.log

# Option 5 – Specific example = error, case insensitive (-i)

grep -i error /var/opt/microsoft/omsagent/scom/log/omsagent.log

# Option 6 – egrep strings and -v to exclude what you don’t want to see

grep -i error /var/opt/Microsoft/omsagent/scom/log/omsagent.log |egrep -v “Permission denied|stacktrace”

Verify FluentD config files

Verify FluentD conf files and omsagent.conf has INCLUDE line

The INCLUDE lines allows a directory for a ‘Gold depot’ to control what log files are monitored on destination linux servers. The goal is a standard repository (gold depot ) to simply copy the conf file you want for logfile/app/daemon, restart agent, and you’re off to the races monitoring that log file.

Verify omsagent.conf includes directory

grep -i include /etc/opt/Microsoft/omsagent/scom/conf/omsagent.conf

# If there’s output, make sure that omsagent.d path exists

# Verify permissions show omsagent:omiusers

ls -al /etc/opt/Microsoft/omsagent/scom/conf | grep omsagent

10. Back to step 8’s problem, to fix the FluentD conf files, so we can test! Step 9 verified that FluentD is configured via the omsagent.conf, and also for specific configuration files (.conf) in omsagent.d directory.

ls -al output list of the omsagent.d directory and oms config specific files for various log files

Next, we need to restart the agent to verify configuration, and any errors are seen on the FluentD side.

My error for ‘out_scom’ plugin was already used by some other test conf files.

grep -i error /var/opt/Microsoft/omsagent/scom/log/omsagent.log |grep “Permission denied” |tail

Example of omsagent.log where we have traced an event for our mylog

OMSAgent FluentD debunked - omsagent.log permission denied opening logfile errors for /var/log/syslog

Mike explained that my error was due to having multiple FluentD conf files using the same buffer path for ‘out_scom’. I searched the conf files to see who had ‘out_scom’ and removed one of my old test files from months back when I was testing the feature.

# Example of errors in the omsagent.log

Tail of the omsagent.log where we want to look for errors

Don’t forget to restart the omsagent for reading in the new file changes

# Restart Agent

/opt/microsoft/omsagent/bin/service_control restart

I’ll cover building a fluentd conf file in another blog post for brevity.

Time to test for alerts!

Time to test our FluentD conf file and append entries into the log file!

Starting simple again

# Options

echo test >> /var/log/mylog

echo 911 error >> /var/log/mylog

# Echo entries into test logfile to mimic syslog or messages

echo `date +”%b %e %H:%M:%S”` MYLOG 911 test string. Call 911

# Verify

tail /var/log/mylog

Switch over to SCOM management server, and look for alerts

Navigate to the Monitoring Tab > Active alerts

OMSAgent FluentD debunked - scom console alerts for fluentd test patterns

References for more information

In case you need a refresher on all the date options… Found CyberCiti FAQ helpful

All because the goal is to make the echo statement better for testing closer test/UAT examples on string matches, etc.

echo `date +”%b %e %H:%M:%S”` MYLOG 911 test string. Call 911

And what does it look like?

OMSAgent FluentD debunked - tail of created /var/log/mylog that shows various echo options