Just a thought really not saying that definitively....

if you run "sudo docker logs iristest2" do you have any logs?  Also I notice that you are running your docker commands via sudo...  Have you thought about adding the docker group (if you don't have one) and adding your user to the docker group, and then restarting your session, so that you don't have to use sudo (see below).  I'm wondering if you are having a permission issue with the volume

  1. sudo groupadd docker
  2. sudo usermod -aG docker $USER