Re: Need to send the dhclient6 to background in Centos 8

[Thomas Haller <thaller redhat com>]

On Tue, 2019-10-08 at 16:14 +0000, Jorge Perez Higuera via
networkmanager-list wrote:
> So that is not working here. The machine gets the Ipv4 address
> quickly and the dhclient ipv6 process starts getting an ip. 30
> seconds later the NetworkManager-wait-online service waits until it
> fails. 
> If I create an ipv6 reservation in the dhcp server the machine boots
> good with bot ipv4 and ipv6 addresses

That sounds not correct.

I would enable level=TRACE logging. See [1] for hints about logging
and rate-limiting of journal.

[1] https://cgit.freedesktop.org/NetworkManager/NetworkManager/tree/contrib/fedora/rpm/NetworkManager.conf#n28


Then look at the log for a message like

  <info>  [1570445723.4941] manager: startup complete

NetworkManager-wait-online basically waits for this point.


There are also logging messages earlier, telling you why "startup
complete" is not yet reached, and why NM waits longer...


A common reason is that you have a bridge/bond/team master that
autoactivates without slaves. Such a device has no carrier and cannot
fully activate, delaying "startup complete" indefinitely.


best,
Thomas


> The network setup is correct in this environment:
> NAME="whatever"
> TYPE=Ethernet
> DEVICE=<interface>
> ONBOOT=yes
> BOOTPROTO=dhcp
> IPV6INIT=yes
> IPV6_AUTOCONF=no
> IPV6_FAILURE_FATAL=no  (inverse "may fail" meaning)
> DHCPV6C=yes
> DHCPV6_DUID=ll
>
>
> -----Mensaje original-----
> De: Thomas Haller [mailto:thaller redhat com] 
> Enviado el: martes, 8 de octubre de 2019 18:05
> Para: Jorge Perez Higuera; networkmanager-list gnome org
> Asunto: Re: Need to send the dhclient6 to background in Centos 8
>
> On Tue, 2019-10-08 at 15:10 +0000, Jorge Perez Higuera via
> networkmanager-list wrote:
> > If the dhcp server does not send an ipv6 lease IP, dhclient ipv6 
> > process tries to get that ip during 30 seconds. That causes (i can
> > see 
> > that via systemd-analyze blame) the startup of the  
> > NetworkManager-wait-online service is delayed, delaying the 
> > network-online.target I have services depending of this target and 
> > that delay causes some troubles to me.
>
> Hi,
>
>
> DHCPv6 is only done if either
>
> - "ipv6.method=dhcp" is configured in the profile
>
> - "ipv6.method=auto" is configured in the profile, and the IPv6
> router in your network sets the managed flag in its router
> advertisements, to indicate to use DHCPv6.
>
>
> It seems better to fix your configuration and/or networking setup.
>
> Also, if you configure ipv6.may-fail=yes and the device gets a IPv4
> address, then the entire device is considered active (and no longer
> blocks NetworkManager-wait-online). So, if you care about IPv6, you
> maybe want to set ipv6.may-fail=no.
>
>
> best,
> Thomas
>
>
> > -----Mensaje original-----
> > De: Thomas Haller [mailto:thaller redhat com] Enviado el: martes, 8
> > de 
> > octubre de 2019 14:00
> > Para: Jorge Perez Higuera; networkmanager-list gnome org
> > Asunto: Re: Need to send the dhclient6 to background in Centos 8
> >
> > On Tue, 2019-10-08 at 11:37 +0000, Jorge Perez Higuera via 
> > networkmanager-list wrote:
> > > Hi all. I need some help
> > >  
> > > I need to send the dhclient ipv6 process to background (I use
> > > dhcp=dhclient)
> > > I know it can be done passing the –nw parameter via dhclient but
> > > i 
> > > don’t know how to pass this to dhclient via NetworkManager Also
> > > in 
> > > Centos 8 it start in foreground (-d parameter)
> > >  
> > > Is there any way to do this?
> > > Is is posible via internal client?
> > >  
> > > NetworkManager 1.14.0
> > > Centos 8
> > >  
> > > Thank you
> >
> > Hi,
> >
> > when NetworkManager uses dhclient as its DHCP plugin, then the
> > process 
> > is controlled by NetworkManager. In that case, NetworkManager will 
> > always spawn the process in the background. That is regardless
> > whether 
> > NetworkManager itself is in the background or not). Anyway, the
> > way 
> > NetworkManager spawns this process is of little concern to the
> > user.
> >
> > In fact, when using NetworkManager you usually would be not
> > concerned 
> > with dhclient at all. The process is for the most part an 
> > implementation detail of how NetworkManager does DHCP.
> >
> > Which problem are you trying to solve?
> >
> > best,
> > Thomas
> > _______________________________________________
> > networkmanager-list mailing list
> > networkmanager-list gnome org
> > https://mail.gnome.org/mailman/listinfo/networkmanager-list
> _______________________________________________
> networkmanager-list mailing list
> networkmanager-list gnome org
> https://mail.gnome.org/mailman/listinfo/networkmanager-list

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