I’m installing it on VM in Google Cloud.
Dpkg had trouble to add the public key, so I tried to download it manually and wget also hangs for a long time (HTTP server accepts the connection, but doesn’t return anything).
On the other hand, all the other files from http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1404/x86_64/ are downloadable.
What could be the cause? Current solution is to keep the key locally, but it still hangs for a long time and delays instance image building.