SCOM - OMS Gateway Monitoring Addendum Management Pack
Sometimes, it's not clear how many clients that are reporting and if there are any errors with the OMS gateway.
If you use SCOM, you can use it to visualize performance, event and health state of the OMS gateway.
The OMS documentation is clear on what kind of performance counters and event data that we can use: /en-us/azure/log-analytics/log-analytics-oms-gateway
I created an addon Management Pack called "Microsoft System Center Advisor Monitoring Addendum OMS Gateway".
The Management Pack contains the following:
State view
The Management Pack discovers an OMS Gateway Server class with a bunch of useful properties.
There is one Monitor active on the OMS Gateway Server class that monitors the Service of the OMS Gateway.
Performance View
The Management Pack collects 4 performance counters with the following performance collection rules:
| Name | Description |
|---|---|
| OMS Gateway/Active Client Connection | Number of active client network (TCP) connections |
| OMS Gateway/Error Count | Number of errors |
| OMS Gateway/Connected Client | Number of connected clients |
| OMS Gateway/Rejection Count | Number of rejections due to any TLS validation error |
Event view
The Management Pack collects 6 events with the following event collection rules (no alerting): 
| Name | Description |
|---|---|
| OMS Gateway - Event Collection Event 105 | Destination server is not in allowed list or the destination port is not secure port (443).Ensure that the MMA agent on your Gateway server and the agents that are communicating with the Gateway are connected to the same Log Analytics workspace.orERROR TcpConnection – Invalid Client certificate: CN=GatewayEnsure that:- You are using a Gateway with version number 1.0.395.0 or greater.- The MMA agent on your Gateway server and the agents that are communicating with the gateway are connected to the same Log Analytics workspace. |
| OMS Gateway - Event Collection Event 106 | The OMS Gateway only supports TLS 1.0, TLS 1.1 and 1.2. It does not support SSL. For any unsupported TLS/SSL protocol version, OMS Gateway generates event ID 106. |
| OMS Gateway - Event Collection Event 400 | Any application error that does not have a specific ID. |
| OMS Gateway - Event Collection Event 401 | Wrong configuration. For example: listenPort = "text" instead of an integer. |
| OMS Gateway - Event Collection Event 402 | Exception in parsing TLS handshake messages |
| OMS Gateway - Event Collection Event 403 | Networking error. For example: cannot connect to target server. |
You can download the addon Management Pack over here:
https://gallery.technet.microsoft.com/SCOM-OMS-Gateway-Addendum-61c0dc18
I've included the VSAE project over here: