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RE: running pgsql 7 under Jail'ed virtual machine on FreeBSD 4.2

From: "Dave VanAuken" <dave(at)hawk-systems(dot)com>
To: <pgsql-general(at)postgresql(dot)org>
Subject: RE: running pgsql 7 under Jail'ed virtual machine on FreeBSD 4.2
Date: 2001-01-05 20:08:57
Message-ID: DBEIKNMKGOBGNDHAAKGNGENLCLAA.dave@hawk-systems.com (view raw or flat)
Thread:
Lists: pgsql-adminpgsql-generalpgsql-hackers
Knew about #1... and I'm not holding my breath for change gicing where
the development on that angle is heading.

In the installation directory for the jail i don't have the /storage
directory, or for that matter the ipc.h file anywhere in the pgsql
tree (both in the jail and host installations).  The version installed
was 7.0.2

What about hacking supplimentary installations and hardcoding new
offsets for each subsequent installation of pgsql (can't even look
into that until i detemine where the ipc.h code now exists).

Appreciate the input...  the best description so far from the pgsql
pov regarding the situation...  have been working almost entirely from
the fbsd pov up until not and running out of options.  May be a wash
for using pgsql in this situation.

Dave

-----Original Message-----
From: pgsql-general-owner(at)postgresql(dot)org
[mailto:pgsql-general-owner(at)postgresql(dot)org]On Behalf Of Alex Pilosov
Sent: Friday, January 05, 2001 1:50 PM
To: Dave VanAuken
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: running pgsql 7 under Jail'ed virtual machine on FreeBSD
4.2


Here's the story about pgsql and jail:

1. FreeBSD shared memory is _really_ shared across all jail VMs. I
think
its not going to change, as this seems like a great way for processes
to
exchange data...But I could be wrong. :)

2. Postgres uses some funky math to determine which shmid to use for
different memory allocations it needs. The problem with that it has no
idea about jails and will not generate a different shmid for different
processes, so postgres processes end up stepping on each other's toes.

See include/storage/ipc.h, definition of SystemPortAddressGetIPCKey,
and
you'll understand what I mean.

To properly fix this, I think this should be done:

Another (optional) backend parameter which should determine offset
(hardcoded now to 17491) for allocation of different shmids...

comments? TODO?


On Thu, 4 Jan 2001, Dave VanAuken wrote:

> Have a FreeBSD 4.2 box...  have created two Virtual machines with
the
> jail process.
> Apache and PHp configure and execute fine, but am having some
> configuration and execution problems with pgsql... not sure if I am
> missing something or if pgsql just cannot deal with being in the
jail
> and sharing the sysv memory
>
> Attempting to manually start the postmaster produces the following:
>
> %postmaster -i
> IpcMemoryCreate: shmget failed (Function not implemented)
key=5432010,
> size=144, permission=700
> This type of error is usually caused by an improper
> shared memory or System V IPC semaphore configuration.
> For more information, see the FAQ and platform-specific
> FAQ's in the source directory pgsql/doc or on our
> web site at http://www.postgresql.org.
> IpcMemoryIdGet: shmget failed (Function not implemented)
key=5432010,
> size=144, permission=0
> IpcMemoryAttach: shmat failed (Function not implemented) id=-2
> FATAL 1:  AttachSLockMemory: could not attach segment
> %
>
> Have modified the sysctl.conf file to allow usage of sysv memory,
but
> as it is already shared from the host machine, this may be causing
> pgsql to barf on it.
>
> Searching for jail faq's and posts regarding this matter produces
some
> close, but not helpful posts regarding chroot'ed environments.
>
> Any insights, requests for details, and assistance are appreciated.
>
> Dave
>
>



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