[lxc-users] {Disarmed} Re: How to release IP for inactive containers?

[Michael H. Warfield]

On Fri, 2015-04-10 at 17:47 -0700, Dan Shi wrote:
> One dumb question, how can I setup lxc-net to support a subnet larger
> than 253? I tried following:
> LXC_NETWORK="MailScanner warning: numerical links are often malicious:
> 10.0.3.0/16"
> LXC_DHCP_RANGE="10.0.3.2,10.0.254.254,1h"
> LXC_DHCP_MAX="61500"

10.0.3.0/16 is an invalid subnet.  For a /16, the last two octets must
be zero.  So....

10.0.0.0/16 is valid for 10.0.0.0 -> 10.0.255.255

10.3.0.0/16 is valid for 10.3.0.0 -> 10.3.255.255

10.0.3.0/16 is not valid.

> New container can't get IP with such settings.

Try a valid subnet.
> 
> Thanks,
> 
> Dan

Regards,
Mike
> 
> 
> 
> On Fri, Apr 10, 2015 at 3:34 PM, Dan Shi <bruingo at gmail.com> wrote:
>         Hi Fajar,
>         
>         
>         Thanks for the reply! I tried to stop container gracefully
>         (lxc-stop), but the IP is not released, I can still find it
>         in /var/lib/misc/dnsmasq.lxcbr0.leases.
>         
>         
>         However, the IP assignment does get cleaned up after a while
>         (once a day?) it seems to be controlled by lease time, maybe
>         default to 24 hours. I will look into that.
>         
>         
>         Thanks,
>         
>         Dan
>         
>         
>         
>         On Thu, Apr 9, 2015 at 3:39 PM, Fajar A. Nugraha
>         <list at fajar.net> wrote:
>                 On Fri, Apr 10, 2015 at 5:29 AM, Dan Shi
>                 <bruingo at gmail.com> wrote:
>                 > I ran into a problem that only 253 containers get
>                 network connection. New
>                 > containers after that can't getIP from lxc bridge,
>                 even if I stop/destroy
>                 > existing running containers. The problem,
>                 apparently, is that the default in
>                 > /etc/default/lxc-net, has LXC_DHCP_MAX set to 253.
>                 >
>                 > I suppose I can increase that number to have a large
>                 enough subnet. However,
>                 > I'm wondering if there is a more elegant solution.
>                 For example, I can
>                 > periodically call a script, or call it before
>                 destroying a container, to
>                 > release IP for dead containers?
>                 
>                 
>                 The elegant solution should be letting the container
>                 shutdown
>                 gracefully (IIRC the default with lxc-stop since some
>                 time), which
>                 should release its DHCP lease.
>                 
>                 You could also look
>                 at /var/lib/misc/dnsmasq.lxcbr0.leases , but IMHO
>                 it's not worth the effort. Simply
>                 adjust /etc/default/lxc-net
>                 according to your needs (including changing its
>                 address and netmask if
>                 you plan to use more than 253 max dhcp clients) and
>                 shutdown your
>                 containers cleanly whenever possible.
>                 
>                 See also dnsmasq man page
>                 (http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html).
>                 
>                 --
>                 Fajar
>                 _______________________________________________
>                 lxc-users mailing list
>                 lxc-users at lists.linuxcontainers.org
>                 http://lists.linuxcontainers.org/listinfo/lxc-users
>         
>         
> 
> 
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-- 
Michael H. Warfield (AI4NB) | (770) 978-7061 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
 PGP Key: 0x674627FF        | possible worlds.  A pessimist is sure of it!

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