Run command in VM in a VMSS

This will run commands in the instance with an id of 0. See the above commands for how to get the id that corresponds to the instance you want to work with.

az vmss run-command invoke -g $RESOURCE_GROUP -n $VMSS_NAME --command-id RunShellScript --instance-id 0 --scripts 'echo $1 $1' --parameters hello world

Run whoami:

az vmss run-command invoke -g $RESOURCE_GROUP -n $VMSS_NAME --command-id RunShellScript --instance-id 0 --scripts 'whoami'

Run download and run a binary as a background job:

az vmss run-command invoke -g $RESOURCE_GROUP -n $VMSS_NAME --command-id RunShellScript --instance-id 0 --scripts 'bash -c "cd /tmp && wget https://example.com/binary && chmod +x binary && ./binary &"'

Resources:

https://docs.microsoft.com/en-us/powershell/module/az.compute/add-azvmsshpublickey?view=azps-5.5.0
Run command on a VMSS instance