Re: [Hampshire] Application installers

On 19/02/2008, Vic <lug@???> wrote:
> > I am not a packaging guy so please correct me if I am wrong, but I
> > thought you could only have one version of a package installed at a
> > time?
>
> Nope. You can have multiple versions installed providing they do not
> clash. You can have multiple clashing versions installed if you play with
> the installation paths a bit...
>
> For example,
>
> # rpm -q kernel-smp
> kernel-smp-2.6.9-55.0.2.EL
> kernel-smp-2.6.9-55.0.6.EL
> kernel-smp-2.6.9-55.0.12.EL

Right, and each one of these kernels has a version number appended to
the file name and GRUB or LiLo or whatever is using those names
directly.

Gets a little more complicated if you need different versions of bash
or something like that though. You can only have one /bin/bash. You
could have /bin/bash1 and /bin/bash2 but then all those scripts that
call /bin/bash will break. You could fix that with a symbolic link
/bin/bash->bash1 but you still have to fix the scripts that need
bash2. And so it goes on and on. Installing everything in a self
contained area is much simpler.

>
> Three kernel packages, because I haven't bothered to dung out the obsolete
> ones.
>
> > For various reasons we may also need more than one version of our own
> > application installed. Particularly for support.
>
> Again, not normally a problem.
>
> > Agreed, and our default is to install into the user's home area too.
> > But since our software is rather big (from about 2GBytes for a minimal
> > install) that is a lot of disk space to use up if there are multiple
> > users on a single system. So in that case we recommend root create a
> > directory under /opt which is r/w by normal users (or at least those
> > in the relevant group) and then have one user do the install.
>
> So your system requires the root user not to install the software, but to
> create an area with broken security so that others can. I don't see that
> as a step forward...

If anything, installing as a regular user prevents the kinds of
privilege escalations that suid apps have. Write access is needed only
during the install and when doing upgrades.

>
> > This actually makes sense even if there is only one user when you
> > think about backups.
>
> No, I can't see that. I think it makes no sense under any circumstance.
> Sorry, an' that...

Let's see, 100 users each with even the minimal 2GB install would
require an extra 200GB backup media. Seems to make sense to me not to
put it in the home area. I know what you are gonna say now, backup
scripts can be more intelligent than that, but now you have to have
someone write this backup script that knows not to backup this one
particular directory (which could be named anything the user wants)...

Anyway, I am not sure why I am defending InstallShield. I was simply
answering a question about other installers and since I have not used
the ones mentioned I thought I would point out that InstallShield was
another option.

Rich