Azure Diagnostics is the capability within Azure that enables the collection of diagnostic data on a deployed application. You can use the diagnostics extension to collect diagnostic data like application logs or performance counters from an Azure virtual machine.
This is supported for Windows and Linux environments.
To enable this you should go into the Virtual Machine instance that you want to enable the “diagnostics extension” then click on Diagnostic settings
If this was not enabled, then you will get the above mentioned window and by clicking on “enable Guest level Monitoring” you will be able to enable this.
Under performance counter Tab you can select the counters that you want to monitor.
Once you select Custom, then you can do the customization to the counters and add new counters as well.
Under Logs, you can enable the Event logs that you want to get the alerts. If you want to customize them, then you can go with the custom Tab.
Can select the Storage account can be select under the Agent tab and if you want to remove the Diagnostics Agent, that is also you can do here.
Hope this will help you to the Log analytics through OMS. Next post will be more into the OMS fine-tuning.