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Re: New work on java-package

On 04/03/2012 12:29 AM, Emmanuel Bourg wrote:
> Le 31/03/2012 21:10, Andrew Haley a écrit :
>>> While reading the authbind documentation I saw it was doing some fork
>>> tricks behind the scene. Maybe the forked process can't allocate its
>>> memory due to OpenVZ and quits?
>> Hold on, do you see this problem outside OpenVZ?  I know that there is
>> a virtualization container that doesn't support memory overcommit, but
>> I can't remember its name.  If so, that's a big problem; Java's GC
>> strategy really needs overcommit to work.
> This problem doesn't happen outside the OpenVZ container.
> OpenVZ has a setting to fiddle with memory overcommit (the privvmpages 
> parameter), but I'm not sure it'll work with a 32 bits container and 4GB 
> assigned, the limit can't be extended.
> If the JVM could allocate gradually the memory as the heap grows that 
> would help, but I guess that's not possible.

Not really.  To be frank, overcommit is such a basic Linux feature that
any container which doesn't fully support it is just broken.

>>> That's probably one more good reason to replace authbind with iptable in
>>> my case. The other reason being the lack of IPv6 support.
>> Right.  I expect that every Java VM will move to IPv6, so authbind
>> would stop working everywhere.
> The sad thing is there is no good alternative yet. I realized today that 
> ip6table doesn't support port redirection (because it works with NAT and 
> NAT is discouraged with IPv6). The only solution left is to put a 
> reverse proxy in front of Tomcat.

It doesn't look difficult to make authbind work with IPv6.  I don't know
why no-one has yet done it.


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