How to setup the same user/passwd and group on multiple ubuntu machines?

[Colin Law]

On 25 December 2013 10:03, Karl Auer <kauer at biplane.com.au> wrote:
> On Wed, 2013-12-25 at 09:36 +0000, Colin Law wrote:
>> I have six machines in my home, all with myself as a user with the
>> same password.  What is the problem with that?
>
> No problem. Carry on. Small private network, nothing really valuable or
> confidential on it, no regulatory hassles if the machines get pwned, no
> customers to sue you - the perfect use case for identical users and
> passwords on all machines. Convenience wins hands down.

I may have valuable and confidential data, and I may have customers
who could sue me if I lost their data.  Why does having the same
user/pwd make a difference to security on a small private network?

>
> A Black Hat getting access to one and then access to all would be a bad
> thing if any of the above did not apply, though...

If they get access to any of the machines then all is lost anyway, as
I have ssh access between them using keys.  Are you suggesting that I
should not allow access between the machines using keys?

>
> Security is rarely black and white; it's a mass of interconnecting
> tradeoffs. But sharing passwords between accounts, even accounts owned
> by the same person, is a bad idea *in general*.

Well that is not what you said initially.  You said it is a "really bad idea".

Colin