Re: [vserver] Hardcoded Context Limits

From: Herbert Poetzl <herbert_at_13thfloor.at>
Date: Thu 25 Nov 2010 - 13:17:17 GMT
Message-ID: <20101125131717.GN22394@MAIL.13thfloor.at>

On Thu, Nov 25, 2010 at 01:55:58PM +0100, Marcus Mülbüsch wrote:
> Hello all,

> using util-vserver-0.30.215-r3 on 2.6.22-vs2.2.0.7-gentoo (yes, I
> know, quite old; but the only one not in ~testing), and I found
> something strange:

> http://linux-vserver.org/Context tells me that there may be a
> hardcoded limit of 49152. However, I have a perfectly well running
> vserver with a XID of 61128 so I thought this limit didn't
> apply here.

the xid/nid is a 16 bit value, so the range is 0-65535,
but 0 and 1 are special and 49152-65535 are reserved
for dynamic context creation (was removed in recent
kernels). note that 65535 is used to mark expired
contexts but it can be used like a normal context if
you don't care about debugging ...

> But alas, after I build a vserver with the XID of 91126 it
> doesn't start but fails with:

> "
> vserver test start
> ncontext: vc_net_migrate(): No such process

> An error occured while executing the vserver startup sequence; when
> there are no other messages, it is very likely that the init-script
> (env TERM=linux /lib/rc/sh/init-vserver.sh default) failed.

> Common causes are:
> * /etc/rc.d/rc on Fedora Core 1 and RH9 fails always; the 'apt-rpm' build
> method knows how to deal with this, but on existing installations,
> appending 'true' to this file will help.

> Failed to start vserver 'test'
> "

> Building the same vserver with another XID works perfectly fine.

> Out of curiosity: Is there another limit that does apply here?
> is it by some chance 65535?

you guessed correctly, but I doubt that you will use up
all 65533 contexts that easily ...

best,
Herbert

> Thank you,
> Marcus
Received on Thu Nov 25 13:17:55 2010

[Next/Previous Months] [Main vserver Project Homepage] [Howto Subscribe/Unsubscribe] [Paul Sladen's vserver stuff]
Generated on Thu 25 Nov 2010 - 13:17:55 GMT by hypermail 2.1.8