In a hybrid environment, we can integrate on-premises systems with OMS using three methods:

• Microsoft monitoring agent: Monitoring agent needs to be installed on each and every system, and it will directly connect to OMS to upload the data and run queries. Every system needs to connect to OMS via port 443.
• SCOM: If you already have SCOM installed and configured in your infrastructure, OMS can integrate with it. Data upload to OMS will be done from SCOM management servers. OMS runs the queries to the systems via SCOM. However, some OMS features still need a direct connection to the system to collect specific data.
• OMS gateway: Now OMS supports collecting data and running queries via its own gateway. This works similarly to SCOM gateways. All the systems do not need to have a direct connection to OMS, and the OMS gateway will collect and upload relevant data from its infrastructure.