On Fri, 17 Jan 2020 at 07:37, Asle Ommundsen <aommundsen@xxxxxxxxx> wrote:
>
> On Thu, 16 Jan 2020 15:34:43 +0100, Stephen John Smoogen
> <smooge@xxxxxxxxx> wrote:
>
> > On Thu, 16 Jan 2020 at 07:58, Asle Ommundsen <aommundsen@xxxxxxxxx>
> > wrote:
> >>
> >> Hi,
> >>
> >> Tonight I upgraded two CentOS 8 boxes to CentOS 8.1 (1911). Then after a
> >> reboot of the first server the network was unavailable. In IPMI console
> >> everything except the network was looking good. Network was unreachable.
> >> No errors in NetworkManager. I also restarted NetworkManager, but it did
> >> not help. Then I discovered that the default gateway suddenly was
> >> missing.
> >>
> >> Then I rebooted the server one more time, but network was still down.
> >>
> >> Then both myself and a technician in my datcenter was debugging this (I
> >> had to wake him up in the middle of the night, costing me a lot of
> >> money),
> >> without finding any reason for why the default gateway was missing after
> >> reboot.
> >>
> >> Then we rebooted the server a third time, and all of a sudden the
> >> problem
> >> was gone and the default gateway was back. [...cut...]
>
> > In order to determine what is going on you need to give a lot more
> > information.
> >
> > 1. How do these boxes get their network information? DHCP or static
> > 2. If they are static, what controls the setting of ips:
> > NetworkManager or network-scripts
> > 3. If they are static, how are they set in
> > /etc/sysconfig/network-scripts/
> > 4. Do the files in /etc/sysconfig/network-scripts list a GATEWAY=
> > 5. If you are using network-manager, what does nmtui or the graphical
> > tool say the gateway or default route is?
>
> Here is answers to your list. I have anonymized the some of the data:
>
Thank you for the detailed answers.. they eliminated most of the
'easy-to-fix' problems. If you do not have ipv6 you might want to turn
that off as I have seen some problems where a router gives enough info
to cause routing issues but shouldn't have. If you do have ipv6 and it
works.. then never mind.
The only other confused one i have seen is where eno1 and eno2 both
have DEFROUTE=yes defined.. and you can't do that. Otherwise.. I am
not sure and it will take going through the logs or repeating it
happen to diagnose better.
> 1) Static ip configuration
>
> 2) This should be NetworkManager.
> nmcli output:
>
> eno1: connected to eno1
> inet4 1.1.1.234/29
> route4 1.1.1.232/29
> route4 0.0.0.0/0
>
> eno2: connected to eno2
> inet4 192.168.0.5/24
> route4 192.168.0.0/24
>
> [root@server ~]# nmcli d show | grep IP4.GATEWA
> IP4.GATEWAY: 1.1.1.1.233
>
> 3)
> TYPE=Ethernet
> PROXY_METHOD=none
> BROWSER_ONLY=no
> BOOTPROTO=none
> DEFROUTE=yes
> IPV4_FAILURE_FATAL=yes
> IPV6INIT=yes
> IPV6_AUTOCONF=yes
> IPV6_DEFROUTE=yes
> IPV6_FAILURE_FATAL=no
> IPV6_ADDR_GEN_MODE=stable-privacy
> NAME=eno1
> UUID=1f9ec889-3c64-470a-894b-05543ee44c29
> DEVICE=eno1
> ONBOOT=yes
> IPADDR=1.1.1..234
> PREFIX=29
> GATEWAY=1.1.1.233
> IPV6_PRIVACY=no
>
> 4) Yes
>
> 5)
> [root@server ~]# nmcli d show | grep IP4.GATEWA
> IP4.GATEWAY: 1.1.1.233
>
> nmtui shows the same gateway.
>
> Kind regards,
> Asle Ommundsen
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--
Stephen J Smoogen.
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