CentOS - Oct 2020 - Unable to get dummy interfaces to persist across reboots in CentOS 8

Have you tried to use NetworkManager ?
After all ,anything network related should be done by it.

[root at system ~]# nmcli connection add con-name dummy0 ifname dummy0 type
dummy ?
Connection 'dummy0' (9fdd74fa-c143-4991-9bac-0e542704ac89) successfully
added.

[root at system ~]# reboot
Shared connection to glustera closed.


[root at system ~]# uptime
03:23:44 up 0 min, ?1 user, ?load average: 1,57, 0,48, 0,17
[root at glustera ~]# nmcli connection show ?
NAME ???UUID ?????????????????????????????????TYPE ?????DEVICE ?
dummy0 ?9fdd74fa-c143-4991-9bac-0e542704ac89 ?dummy ????dummy0


[root at system ~]# ip a s dummy0
3: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UNKNOWN group default qlen 1000
???link/ether ce:c9:83:97:10:ee brd ff:ff:ff:ff:ff:ff
???inet6 fe80::599:a978:9457:df10/64 scope link noprefixroute ?
??????valid_lft forever preferred_lft forever

P.S.: This is the first time I hear about dummy interfaces. What are those used
for ?

Best Regards,
Strahil Nikolov









? ???????, 27 ???????? 2020 ?., 02:42:06 ???????+2, Frank Even
<lists+centos.org at elitists.org> ??????:





Anyone have any ideas?? It's rather annoying that I can't get these to
persist across reboots without using some kind of helper script.

On Fri, Oct 16, 2020 at 6:37 AM Frank Even
<lists+centos.org at elitists.org> wrote:
>
> Hello all, hoping someone can help me out here.
>
> I cannot get dummy interfaces on a new Cent8 build to persist across
reboots.
>
> On Cent7 - this is the process I use:
>
> Create Dummies:
> # cat /etc/modules-load.d/dummy.conf
> dummy
> # cat /etc/modprobe.d/dummyopts.conf
> options dummy numdummies=4
> # ip link add dummy0 type dummy
> ## - repeating a/ ascending dummyN adapters for as many needed
> # service network start
> # dracut -f
>
> Now? this? was? different than even how 6 handled it, forget how I
> finally dug that up (possible I even asked here).? I've applied this
> same configuration to a Cent8 box I'm trying to stand up and it all
> appears to work fine, but unlike the Cent7 boxes,? when the Cent8 box
> comes back up,? all the dummy adapters are missing.? I've been
> searching all over trying to find some documentation on this to no
> avail.? I'm hoping someone has some suggestions here to help out.
>
> Thanks,
> Frank
_______________________________________________
CentOS mailing list
CentOS at centos.org
https://lists.centos.org/mailman/listinfo/centos

No.  Network Manager is always disabled on our builds since at least
Cent5 days.  The network stack has always been able to be managed
properly without relying on Network Manager.  Is that now an absolute
requirement?  It never has been prior.

On Mon, Oct 26, 2020 at 6:26 PM Strahil Nikolov via CentOS
<centos at centos.org> wrote:
>
> Have you tried to use NetworkManager ?
> After all ,anything network related should be done by it.
>
> [root at system ~]# nmcli connection add con-name dummy0 ifname dummy0 type
dummy
> Connection 'dummy0' (9fdd74fa-c143-4991-9bac-0e542704ac89)
successfully added.
>
> [root at system ~]# reboot
> Shared connection to glustera closed.
>
>
> [root at system ~]# uptime
> 03:23:44 up 0 min,  1 user,  load average: 1,57, 0,48, 0,17
> [root at glustera ~]# nmcli connection show
> NAME    UUID                                  TYPE      DEVICE
> dummy0  9fdd74fa-c143-4991-9bac-0e542704ac89  dummy     dummy0
>
>
> [root at system ~]# ip a s dummy0
> 3: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UNKNOWN group default qlen 1000
>    link/ether ce:c9:83:97:10:ee brd ff:ff:ff:ff:ff:ff
>    inet6 fe80::599:a978:9457:df10/64 scope link noprefixroute
>       valid_lft forever preferred_lft forever
>
> P.S.: This is the first time I hear about dummy interfaces. What are those
used for ?
>
> Best Regards,
> Strahil Nikolov
>
>
>
>
>
>
>
>
>
> ? ???????, 27 ???????? 2020 ?., 02:42:06 ???????+2, Frank Even
<lists+centos.org at elitists.org> ??????:
>
>
>
>
>
> Anyone have any ideas?  It's rather annoying that I can't get these
to
> persist across reboots without using some kind of helper script.
>
> On Fri, Oct 16, 2020 at 6:37 AM Frank Even
> <lists+centos.org at elitists.org> wrote:
> >
> > Hello all, hoping someone can help me out here.
> >
> > I cannot get dummy interfaces on a new Cent8 build to persist across
reboots.
> >
> > On Cent7 - this is the process I use:
> >
> > Create Dummies:
> > # cat /etc/modules-load.d/dummy.conf
> > dummy
> > # cat /etc/modprobe.d/dummyopts.conf
> > options dummy numdummies=4
> > # ip link add dummy0 type dummy
> > ## - repeating a/ ascending dummyN adapters for as many needed
> > # service network start
> > # dracut -f
> >
> > Now  this  was  different than even how 6 handled it, forget how I
> > finally dug that up (possible I even asked here).  I've applied
this
> > same configuration to a Cent8 box I'm trying to stand up and it
all
> > appears to work fine, but unlike the Cent7 boxes,  when the Cent8 box
> > comes back up,  all the dummy adapters are missing.  I've been
> > searching all over trying to find some documentation on this to no
> > avail.  I'm hoping someone has some suggestions here to help out.
> >
> > Thanks,
> > Frank
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos

As far as what dummy interfaces are used for, they're basically
loopbacks that allow for some better network management/flexibility
(by separating it from the actual system loopback).

On Mon, Oct 26, 2020 at 6:26 PM Strahil Nikolov via CentOS
<centos at centos.org> wrote:
>
> Have you tried to use NetworkManager ?
> After all ,anything network related should be done by it.
>
> [root at system ~]# nmcli connection add con-name dummy0 ifname dummy0 type
dummy
> Connection 'dummy0' (9fdd74fa-c143-4991-9bac-0e542704ac89)
successfully added.
>
> [root at system ~]# reboot
> Shared connection to glustera closed.
>
>
> [root at system ~]# uptime
> 03:23:44 up 0 min,  1 user,  load average: 1,57, 0,48, 0,17
> [root at glustera ~]# nmcli connection show
> NAME    UUID                                  TYPE      DEVICE
> dummy0  9fdd74fa-c143-4991-9bac-0e542704ac89  dummy     dummy0
>
>
> [root at system ~]# ip a s dummy0
> 3: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UNKNOWN group default qlen 1000
>    link/ether ce:c9:83:97:10:ee brd ff:ff:ff:ff:ff:ff
>    inet6 fe80::599:a978:9457:df10/64 scope link noprefixroute
>       valid_lft forever preferred_lft forever
>
> P.S.: This is the first time I hear about dummy interfaces. What are those
used for ?
>
> Best Regards,
> Strahil Nikolov
>
>
>
>
>
>
>
>
>
> ? ???????, 27 ???????? 2020 ?., 02:42:06 ???????+2, Frank Even
<lists+centos.org at elitists.org> ??????:
>
>
>
>
>
> Anyone have any ideas?  It's rather annoying that I can't get these
to
> persist across reboots without using some kind of helper script.
>
> On Fri, Oct 16, 2020 at 6:37 AM Frank Even
> <lists+centos.org at elitists.org> wrote:
> >
> > Hello all, hoping someone can help me out here.
> >
> > I cannot get dummy interfaces on a new Cent8 build to persist across
reboots.
> >
> > On Cent7 - this is the process I use:
> >
> > Create Dummies:
> > # cat /etc/modules-load.d/dummy.conf
> > dummy
> > # cat /etc/modprobe.d/dummyopts.conf
> > options dummy numdummies=4
> > # ip link add dummy0 type dummy
> > ## - repeating a/ ascending dummyN adapters for as many needed
> > # service network start
> > # dracut -f
> >
> > Now  this  was  different than even how 6 handled it, forget how I
> > finally dug that up (possible I even asked here).  I've applied
this
> > same configuration to a Cent8 box I'm trying to stand up and it
all
> > appears to work fine, but unlike the Cent7 boxes,  when the Cent8 box
> > comes back up,  all the dummy adapters are missing.  I've been
> > searching all over trying to find some documentation on this to no
> > avail.  I'm hoping someone has some suggestions here to help out.
> >
> > Thanks,
> > Frank
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos

> No.  Network Manager is always disabled on our builds since at least
> Cent5 days.  The network stack has always been able to be managed
> properly without relying on Network Manager.  Is that now an absolute
> requirement?  It never has been prior.
IIRC the old style network scripts will go away with the next RHEL
release. I'm afraid NetworkManager will be the way to go in future.

Regards,
Simon

Requirement is a very strong word , but you should consider using it and here is
a short demo why:

- By default, RHEL uses NetworkManager to configure and manage network
connections, and the /usr/sbin/ifup and /usr/sbin/ifdown scripts use
NetworkManager to process ifcfg files in the /etc/sysconfig/network-scripts/
directory.

[root at system ~]# ls -l /usr/sbin/ifup
lrwxrwxrwx. 1 root root 22 21 ??? 21,29 /usr/sbin/ifup ->
/etc/alternatives/ifup

[root at system ~]# alternatives --list? | grep ifup
ifup??????????????????? auto??? /usr/libexec/nm-ifup

[root at system ~]# rpm -qf /usr/libexec/nm-ifup
NetworkManager-1.22.8-5.el8_2.x86_64

- the old networks-scripts have been deprecated and are not the defaults anymore


It's about time to switch to NM, but you got some 5-8 years till next EL
release.

Best Regards,
Strahil Nikolov



? ?????, 28 ???????? 2020 ?., 12:47:12 ???????+2, Frank Even
<lists+centos.org at elitists.org> ??????:





No.? Network Manager is always disabled on our builds since at least
Cent5 days.? The network stack has always been able to be managed
properly without relying on Network Manager.? Is that now an absolute
requirement?? It never has been prior.

On Mon, Oct 26, 2020 at 6:26 PM Strahil Nikolov via CentOS
<centos at centos.org> wrote:
>
> Have you tried to use NetworkManager ?
> After all ,anything network related should be done by it.
>
> [root at system ~]# nmcli connection add con-name dummy0 ifname dummy0 type
dummy
> Connection 'dummy0' (9fdd74fa-c143-4991-9bac-0e542704ac89)
successfully added.
>
> [root at system ~]# reboot
> Shared connection to glustera closed.
>
>
> [root at system ~]# uptime
> 03:23:44 up 0 min,? 1 user,? load average: 1,57, 0,48, 0,17
> [root at glustera ~]# nmcli connection show
> NAME? ? UUID? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? TYPE? ? ? DEVICE
> dummy0? 9fdd74fa-c143-4991-9bac-0e542704ac89? dummy? ? dummy0
>
>
> [root at system ~]# ip a s dummy0
> 3: dummy0: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state
UNKNOWN group default qlen 1000
>? ? link/ether ce:c9:83:97:10:ee brd ff:ff:ff:ff:ff:ff
>? ? inet6 fe80::599:a978:9457:df10/64 scope link noprefixroute
>? ? ? valid_lft forever preferred_lft forever
>
> P.S.: This is the first time I hear about dummy interfaces. What are those
used for ?
>
> Best Regards,
> Strahil Nikolov
>
>
>
>
>
>
>
>
>
> ? ???????, 27 ???????? 2020 ?., 02:42:06 ???????+2, Frank Even
<lists+centos.org at elitists.org> ??????:
>
>
>
>
>
> Anyone have any ideas?? It's rather annoying that I can't get these
to
> persist across reboots without using some kind of helper script.
>
> On Fri, Oct 16, 2020 at 6:37 AM Frank Even
> <lists+centos.org at elitists.org> wrote:
> >
> > Hello all, hoping someone can help me out here.
> >
> > I cannot get dummy interfaces on a new Cent8 build to persist across
reboots.
> >
> > On Cent7 - this is the process I use:
> >
> > Create Dummies:
> > # cat /etc/modules-load.d/dummy.conf
> > dummy
> > # cat /etc/modprobe.d/dummyopts.conf
> > options dummy numdummies=4
> > # ip link add dummy0 type dummy
> > ## - repeating a/ ascending dummyN adapters for as many needed
> > # service network start
> > # dracut -f
> >
> > Now? this? was? different than even how 6 handled it, forget how I
> > finally dug that up (possible I even asked here).? I've applied
this
> > same configuration to a Cent8 box I'm trying to stand up and it
all
> > appears to work fine, but unlike the Cent7 boxes,? when the Cent8 box
> > comes back up,? all the dummy adapters are missing.? I've been
> > searching all over trying to find some documentation on this to no
> > avail.? I'm hoping someone has some suggestions here to help out.
> >
> > Thanks,
> > Frank
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
_______________________________________________
CentOS mailing list
CentOS at centos.org
https://lists.centos.org/mailman/listinfo/centos