"Authentication failed" errors from node.execute()

[sajith]

I came across some fablib errors when working through some mflib notebooks in FABRIC jupyter-examples repository. I got stuck at create topology three times: twice while creating the slice, and once when testing connectivity between nodes.

On the two occasions when slice creation failed, fablib (and therefore the notebook) got stuck waiting for network configuration. However, on FABRIC portal, the slices were in "StableOK" state. According to the logs, it seemed that Interface.get_ip_addr_ssh() kept failing because Node.execute() kept failing. I could individually ssh into all of the nodes in these slices in question at the time, so it is not clear to me why this happened.

The third time I tried the notebook, slice creation worked, but the next step (getting IP addresses and setting up routes) failed, again because Node.execute() failed in a similar fashion.

(Could not copy the log text because my JupyterHub session had expired.)