dummy adapters - greater than 2 are not coming up on reboot

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dfjkl
Posts: 13
Joined: 2010/12/27 07:50:34

dummy adapters - greater than 2 are not coming up on reboot

Post by dfjkl » 2018/03/15 07:30:19

I've got a relatively new system that I've added a couple dummy adapters to (dummy2/dummy3) above the original 2, (dummy0/dummy1). I've got plenty other systems configured like this with no issues. The configuration applies fine to this one system (a newer one), but upon reboot, only the first two will start. I've tried everything I can think of, recreating the configuration files, etc. Nothing seems to work. Any suggestions?

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[root@system ~]# journalctl --since=yesterday | grep dummy
Mar 14 23:58:24 system systemd-modules-load[218]: Inserted module 'dummy'
Mar 14 23:58:37 system network[2125]: Bringing up interface dummy0:  [  OK  ]
Mar 14 23:58:37 system network[2125]: Bringing up interface dummy1:  [  OK  ]
Mar 14 23:58:37 system network[2125]: Bringing up interface dummy2:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device dummy2 does not seem to be present, delaying initialization.
Mar 14 23:58:37 system /etc/sysconfig/network-scripts/ifup-eth[2624]: Device dummy2 does not seem to be present, delaying initialization.
Mar 14 23:58:38 system network[2125]: Bringing up interface dummy3:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device dummy3 does not seem to be present, delaying initialization.
Mar 14 23:58:38 system /etc/sysconfig/network-scripts/ifup-eth[2648]: Device dummy3 does not seem to be present, delaying initialization.
Mar 14 23:58:39 system network[2715]: Bringing up interface dummy0:  RTNETLINK answers: File exists
Mar 14 23:58:39 system network[2715]: Bringing up interface dummy1:  RTNETLINK answers: File exists
Mar 14 23:58:40 system network[2715]: Bringing up interface dummy2:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device dummy2 does not seem to be present, delaying initialization.
Mar 14 23:58:40 system /etc/sysconfig/network-scripts/ifup-eth[4040]: Device dummy2 does not seem to be present, delaying initialization.
Mar 14 23:58:40 system network[2715]: Bringing up interface dummy3:  ERROR     : [/etc/sysconfig/network-scripts/ifup-eth] Device dummy3 does not seem to be present, delaying initialization.
Mar 14 23:58:40 system /etc/sysconfig/network-scripts/ifup-eth[4064]: Device dummy3 does not seem to be present, delaying initialization.
Yet...

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[root@system ~]# cat /etc/modules-load.d/dummy.conf
dummy
[root@system ~]# cat /etc/modprobe.d/dummyopts.conf
options dummy numdummies=6

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[root@system ~]# ip addr | grep dummy
4: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.248/32 brd 10.255.25.248 scope global dummy0
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.31/32 brd 10.255.25.31 scope global dummy1

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[root@system ~]# /sbin/ip link add dummy2 type dummy
[root@system ~]# /sbin/ip link add dummy3 type dummy

[root@system ~]# ip addr | grep dummy
4: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.248/32 brd 10.255.25.248 scope global dummy0
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.31/32 brd 10.255.25.31 scope global dummy1
8: dummy2: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN qlen 1000
9: dummy3: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN qlen 1000

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[root@system ~]# ip addr | grep dummy
4: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.248/32 brd 10.255.25.248 scope global dummy0
5: dummy1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.31/32 brd 10.255.25.31 scope global dummy1
8: dummy2: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.25.30/32 brd 10.255.25.30 scope global dummy2
9: dummy3: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN qlen 1000
    inet 10.255.21.30/32 brd 10.255.21.30 scope global dummy3
    
 (from syslog/journal)
Mar 15 00:17:58 system /etc/sysconfig/network-scripts/ifup-eth[12584]: Device dummy2 does not seem to be present, delaying initialization.
Mar 15 00:24:13 system network[14626]: Bringing up interface dummy0:  RTNETLINK answers: File exists
Mar 15 00:24:14 system network[14626]: Bringing up interface dummy1:  RTNETLINK answers: File exists
Mar 15 00:24:15 system network[14626]: Bringing up interface dummy2:  [  OK  ]
Mar 15 00:24:15 system network[14626]: Bringing up interface dummy3:  [  OK  ]

dfjkl
Posts: 13
Joined: 2010/12/27 07:50:34

Re: dummy adapters - greater than 2 are not coming up on reboot

Post by dfjkl » 2018/03/16 01:58:14

I seem to only be having this issue getting additional dummy adapters to persist across reboots with Cent 7, not Cent 6. Is there some boot cache somewhere that needs to be tweaked? This is something I need to work but cannot for the life of me figure out why it's not.

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TrevorH
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Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: dummy adapters - greater than 2 are not coming up on reboot

Post by TrevorH » 2018/03/16 07:15:58

You might need to rebuild the initramfs to include the /etc/modprobe.d/ file you created with the options line in it. Use dracut -f.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

dfjkl
Posts: 13
Joined: 2010/12/27 07:50:34

Re: dummy adapters - greater than 2 are not coming up on reboot

Post by dfjkl » 2018/03/20 06:48:17

That worked! Thanks! It does make me wonder though if anything has changed in recent updates that causes that to not be rebuilt as often or something. I've never run into this problem before.

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