ssh disconnect during upgrade

Question

So I follow this tutorial to upgrade ubuntu 14.04 to ubuntu 16.04 in aws. ssh disconnects itself after 60s. I think the upgrade stuck and waiting for user input. e.g.

I ssh it back and never see the input screen. I do sudo apt-get update and it is not able to lock.

Is it a way to resolve this. Will restart the machine cause issues?

Answer 1

If you are getting broken pipe error after N minutes of time in your SSH connection then this is usually happens because of TCP connection inactivity.

So, you can enable it in the server's /etc/ssh/sshd_config with the parameter:

"ClientAliveInterval = 'specify your time'" 

or in the client's /etc/ssh/ssh_config file with

"ServerAliveInterval = 'Specify Your Time Interval'"

be sure, Time interval time must be in seconds. (e.g 60 means 1 min)

hope this will solve your issue.

Answer 2

Set the environment variable, whether it is noninteractive or not.

export DEBIAN_FRONTEND=noninteractive

then try again.