The same users and passwords for several machines?

Dims · 08-11-2010, 04:11 AM

How to make users, groups, paswords and their IDs be the same on several computers (for example, on cluster)?

Sorry this is a newbie question maybe...

acid_kewpie · 08-11-2010, 04:52 AM

well in general you'd use some form of centralised authentication, e.g. an ldap server, but going solely by what you've said, why not just add the user accounts to each machine and put in the same password?

EricTRA · 08-11-2010, 04:57 AM

Hi,

If you just want to 'copy' the users data over to another server instead of using a centralized authentication system you could follow the instructions on this page:
Move / migrate user accounts on Linux

Kind regards,

Eric

Dims · 08-11-2010, 07:17 AM

Quote:

Originally Posted by acid_kewpie

but going solely by what you've said, why not just add the user accounts to each machine and put in the same password?

Because, as I know, the owner of a file is stored within it by user or group ID, which may be different on different machines.

So, if the file is owned by user 1002, from the point of view of first machine it may be "advanced user", while on other machine this ID may belong to "stupid user" and, thereafter, belong to this user, which may be wrong.

EricTRA · 08-11-2010, 07:28 AM

Quote:

Originally Posted by Dims

Because, as I know, the owner of a file is stored within it by user or group ID, which may be different on different machines.

So, if the file is owned by user 1002, from the point of view of first machine it may be "advanced user", while on other machine this ID may belong to "stupid user" and, thereafter, belong to this user, which may be wrong.

Hi,

As clarified in the link I provided. Migrating/moving/copying regular users, NOT system users, to another machine using the instructions on that page will conserve the UID and GID and other information.

Kind regards,

Eric

acid_kewpie · 08-11-2010, 09:35 AM

Quote:

Originally Posted by Dims

Because, as I know, the owner of a file is stored within it by user or group ID, which may be different on different machines.

So, if the file is owned by user 1002, from the point of view of first machine it may be "advanced user", while on other machine this ID may belong to "stupid user" and, thereafter, belong to this user, which may be wrong.

That's only an issue if you're moving files between systems in certain ways, and seeing as you said nothing about what these systems are, it's still valid advice, especially as creating the users multiple times doesn't mean you can't set your own UID's anyway, just read the manpage.

tredegar · 08-11-2010, 12:42 PM

If you now realise that you have created users with the "wrong" UIDs, and you'd like to alter them, this is easy to do:

Make sure none of them are logged in. As root, go to "Single user mode" (well, I did).
Then the command (as root)

Code:

usermod -u new_uid_number username

will make the change for you.

Eg

Code:

usermod  -u 2001 tred

Will change my UID to 2001, and fix up all my files so they are now owned by UID 2001

Make sure the new_uid_number is not already in use!