In an attempt to upgrade all the systems in out computer labs to Ubuntu 12.04, we ran into a couple of problems. Inorder to be able to connect to the central department server, the systems had to have NIS and NFS installed and configured on each of the systems. This way, students would be able to login onto anyone of the systems and still be able to access their files(no matter which system it is).
So, after having installed Ubuntu 12.04, and having done the usual system upgrades after configuring the system proxy (yes, we have proxy in our college, kind of makes our life difficult when we're trying to upgrade on different versions of Linux), we move on to looking up Ubuntu Manuals and start looking for setup and configuration manuals of NIS and NFS.
And well, the good thing about Ubuntu is that there are a looot of installation manuals, and the best ones we found are Ubuntu help for installing NIS and Ubuntu help for installing NFS. Along with installation, he also helps you in basically configuring and making the necessary changes to let your system access NFS server.
Before i go any further, NIS is for remote login and NFS is for remote file sharing, for labs where a person/student maynot be able to login to the same system all the time, having NIS and NFS installed on the desktops and a central server will help him access his files on any one of systems.
So, we have Ubuntu installed and we have NIS and NFS installed and configured. And you may think that your job is done here. Nope. There seem to be quite a few bugs when it comes to using NIS and NFS on Ubuntu 12.04, apparent from we've read and what we've experienced.
The first one being Login. After bootup and during Login, the system should give you an option "other" which you use to access your NFS server, with a relevant username and password. And Ubuntu by default doesnt show your the 'other' option. It will show you the users defined on the particular system and will give you an option to become a guest user. So, first things first, you need to enable the 'other' option for login and you need to disable the 'Guest' option, because it pretty much becomes redundant and you don't want unauthorized access.
So, you need to configure Light DM and as mentioned in the link, you need to restart the service for the 'other' login option to be activated.
allow-guest=false % disables the guest login option
greeter-show-manual-login=true% will enable the 'other' login option.
greeter-hide-users=true % to prevent the system from displaying all of the users available at the NFS server.
sudo service lightdm restart% restarts the service, after which you will be redirected to the login page.
refer to comment #3 here for the same.
And that should pretty much do it.
There are still problems though. At times, when we're trying to use NIS, after the system accepts the username and password (relevant to NIS/NFS and not the current system), the system gives and error message
mountall : disconnected from Plymouth
Why this problem exists, we dont know and the solution/bug fix for this we dont know. But i hope we've been helpful so far. Anyway, that's it for today.
PS - we hate the unity interface as well, so we tried opting out of it and choose Gnome Classic, through GUI and through. Here's a video clearly lining out how to install Gnome classic and opt out of Unity. And then there are some more who tried to uninstall Unity completely here and here. BTW, these were dont through the terminal, unlike the method mentioned in the video above.PPS - you can set proxy at >system-settings>network>proxy and you can choose the server to download updates this way > Ubuntu-Software-Center > Edit > software-sources
well, like i said before, we were having problems with ubuntu login, trying to access the central NFS server through the ubuntu machine and we had to move to a terminal everytime, alter the Light DM config file (as mentioned above) and log in as admin to try and resolve issues.
Having gotten vexed trying to fix the error, we tried installing Cent OS and working on it (as it had already been running without any hitches on a couple of other machines). Well, after the usual installation and setting a Static IP address to the system, we moved on to looking for NIS (ypbind) and NFS. Luckily for us, NFS comes pre-installed, you just have to activate the networking services at >system>admin>services.
And after installed ypbind, you start the service as previously mentioned. And because CentOS already has the other login option pre-enabled, you just restart the services and viola, everything works perfectly fine.