UID_MIN & GID_MIN changed

["Jóhann B. Guðmundsson"]

On 05/25/2011 12:30 AM, Dennis Gilmore wrote:
> On Tuesday, May 24, 2011 10:25:44 AM Toshio Kuratomi wrote:
>> On Tue, May 24, 2011 at 1:59 AM, Peter Vrabec<pvrabec at redhat.com>  wrote:
>>> Hi all,
>>>
>>> I'd like to inform you that I have changed UID_MIN&  GID_MIN from 500 to
>>> 1000 in upgraded shadow-utils.
>>>
>>> Where?
>>> /etc/login.defs.
>>> shadow-utils-4.1.4.3-1.fc16
>>>
>>> I suppose UID/GID_MIN=1000 is more common(other distros, upstream). We
>>> are not in situation that 500 IDs for system accounts ought to be enough
>>> for anybody. Actually, it was not 500.It was 299 because range 0-200 is
>>> for reserved IDs. There are 799 non reserved IDs for system accounts
>>> available after this change.
>> This change should be made as a Feature for F16 and needs some
>> thought/coordination put behind it.  There's several issues that I
>> see:
>>
>> * AFAIK, we actually have not run into the 500 uid limit yet (although
>> it is a bit low to be comfortable)
>> *  AFAIK, we've only allocated the range 0-100 for reserved IDs.
>> * The 0-100 reserved IDs are actually the pain point that we need to
>> deal with, not the dynamic system ids in the 101-499 range.
>> * We don't know how many, if any IDs this actually gets us for the
>> dynamic range because any site that has already filled the 500-1000
>> UID range won't gain any extra dynamic system account through this
>> change.
>> * This could potentially break sites that are currently using the
>> 500-1000 UID range and rely on the order of allocation of UIDs for
>> their users on new machines matching with the UIDs on old machines.
>> (For instance, NFS UIDs on filesystems matching between a box
>> installed with RHEL5 and a box that gets newly installed with F16).
>>
>> -Toshio
> Im with Toshio here  there is potential pitfalls with many legacy systems.
> there is also great potential that system ids from newer systems will clash
> with legacy ids in ldap and nis setups,  we really should make it a feature as
> it really deserves to be widely anounced.  not quietly on the list here where
> it will likely get forgoten until users are bitten when they start deploying
> f16 boxes.
>
> Dennis

Agreed

Is there a distro wide/*nix wide agreement on what and which range 
reserved/system IDs are supposed to be?

If there is not a general consciousness regarding reserved/system IDs 
and what they are supposed to be there will always be the risk of 
colliding with ids on other distribution and *nix platforms.

I recommend this be made a feature and the feature owners contact at 
least all major distributions and potentially other *nix platforms and 
distro/*nix wide consciousness be made and when this change is made that 
change would reflect the consciousness that was reached.

JBG