On Fri, 17 Jan 2020 at 07:37, Asle Ommundsen aommundsen@gmail.com wrote:
On Thu, 16 Jan 2020 15:34:43 +0100, Stephen John Smoogen smooge@gmail.com wrote:
On Thu, 16 Jan 2020 at 07:58, Asle Ommundsen aommundsen@gmail.com 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.
- How do these boxes get their network information? DHCP or static
- 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.
Static ip configuration
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
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
Yes
[root@server ~]# nmcli d show | grep IP4.GATEWA IP4.GATEWAY: 1.1.1.233
nmtui shows the same gateway.
Kind regards, Asle Ommundsen _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos