Amazon SSM Reporting Error AWS API's with multiple network interfaces

[TerryjGates]

I setup Amazon SSM connection on a Greengrass Device using a WiFi connection. When disabled WiFi and enabled a cellular connection, I get the error:

ERROR [ssm-agent-worker] [HealthCheck] error when calling AWS APIs. error details - InvalidParameter: 1 validation error(s) found.

It seems like Amazon SSM is locked to a specific network interface so it stops working when that interface is disabled. How do I change the settings to use any interface to go out to the internet?

[leslieecv]

There's a filter that excludes p2p interfaces.

amazon-ssm-agent/agent/platform/platformIp.go

Line 113 in 31994a7

if (v.Flags&net.FlagUp != 0) && (v.Flags&net.FlagLoopback == 0) && (v.Flags&net.FlagPointToPoint == 0) {

I had the same problem, and the solution was to create a dummy interface:
ip link add dummy0 type dummy
ip addr add 10.255.255.1/32 dev dummy0
ip link set dummy0 up
Then restart ssm.

It's not very elegant, but it worked for me. The traffic will go through the wwan interface, but ssm won't fail.