Adaptive data mirroring in virtual networks

A non-transitory machine readable medium of a host machine storing a program which when executed by at least one processing unit of the host machine mirrors data messages of a data compute node (DCN) executing on the host machine, the program comprising sets of instructions for:

• receiving a data message from a guest DCN;
• determining whether a monitoring DCN, to which a copy of the data message should be sent, executes on the first host machine;
• sending the copy of the data message to the monitoring DCN when the monitoring DCN executes on the first host machine;
• and
• directing a managed forwarding element (MFE) of the host machine to encapsulate the copy of data message with tunneling data of a different host machine when the monitoring DCN executes on the second host machine.

A method for mirroring data messages of a first data compute node (DCN) executing on a first host machine, the method comprising:

• determining that a monitoring DCN that monitors the first DCN executes on a second, different host machine;
• receiving a first data message from a second DCN that also executes on the second host machine;
• calculating a value based on data carried by the first data message and inserting the calculated value into a second data message;
• directing a managed forwarding element (MFE) of the first host machine to encapsulate the second data message with tunneling data of the second host machine and tunnel the second data message to the second host machine.