[libvirt-users] [netcf] Why netcf can not rename a existing physical interface dynamically by itself?
5:46 a.m.
Hi All,
I have a usage question about netcf. Why netcf can not rename a existing physical
interface dynamically by itself? If you have any other method, please share to me, or can
we add support for it in netcf? You can see the following steps for details.
Version:
netcf-0.2.4-1.el6.x86_64
kernel-2.6.32-431.el6.x86_64
1. Select a existing NIC from host, for example eth1.
[root@rhel6 ~]# ncftool list --all
eth0
eth1
lo
[root@rhel6 ~]# ncftool dumpxml eth1
<?xml version="1.0"?>
<interface type="ethernet" name="eth1">
<start mode="none"/>
<mac address="00:1B:21:27:4E:CE"/>
<protocol family="ipv4">
<dhcp/>
</protocol>
</interface>
[root@rhel6 ~]# ifconfig eth1
eth1 Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
[root@rhel6 ~]# ncftool ifup eth1
Interface eth1 successfully brought up
2. Undefine eth1 from host
[root@rhel6 ~]# ncftool ifdown eth1
Interface eth1 successfully brought down
[root@rhel6 ~]# ncftool undefine eth1
eth1 undefined
[root@rhel6 ~]# ncftool list --all
eth0
lo
3. Prepare another xml with same MAC and a new name "jiahu"
[root@rhel6 ~]# cat jiahu.xml
<interface type="ethernet" name="jiahu">
<start mode="none"/>
<mac address="00:1B:21:27:4E:CE"/>
<protocol family="ipv4">
<dhcp/>
</protocol>
</interface>
4. Define the "jiahu", and start it.
[root@rhel6 ~]# ncftool define jiahu.xml
Defined interface jiahu
[root@rhel6 ~]# ncftool dumpxml jiahu
<?xml version="1.0"?>
<interface type="ethernet" name="jiahu">
<start mode="none"/>
<mac address="00:1B:21:27:4E:CE"/>
<protocol family="ipv4">
<dhcp/>
</protocol>
</interface>
[root@rhel6 ~]# ifconfig jiahu
jiahu: error fetching interface information: Device not found
[root@rhel6 ~]# cat /etc/sysconfig/network-scripts/ifcfg-jiahu
DEVICE=jiahu
HWADDR=00:1B:21:27:4E:CE
ONBOOT=no
BOOTPROTO=dhcp
[root@rhel6 ~]# ncftool ifup jiahu
Interface jiahu bring-up failed!
error: failed to execute external program
error: Running 'ifup jiahu' failed with exit code 1: Device jiahu does not seem to
be present, delaying initialization.
[root@rhel6 ~]# ll /sys/class/net/
total 0
lrwxrwxrwx. 1 root root 0 May 23 11:32 eth0 ->
../../devices/pci0000:00/0000:00:19.0/net/eth0
lrwxrwxrwx. 1 root root 0 May 23 11:35 eth1 ->
../../devices/pci0000:00/0000:00:1e.0/0000:02:00.0/net/eth1
lrwxrwxrwx. 1 root root 0 May 23 11:32 lo -> ../../devices/virtual/net/lo
lrwxrwxrwx. 1 root root 0 May 23 11:32 virbr0 -> ../../devices/virtual/net/virbr0
lrwxrwxrwx. 1 root root 0 May 23 11:32 virbr0-nic ->
../../devices/virtual/net/virbr0-nic
5. Reboot the host OS, the jiahu interface appeared.
[root@rhel6 ~]# ifconfig jiahu
jiahu Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
BR,
Jianwei
10:56 a.m.
On 05/23/2014 06:46 AM, Jianwei Hu wrote:
Hi All,
I have a usage question about netcf. Why netcf can not rename a existing physical
interface dynamically by itself?
The name of a physical interface is determined by lower levels of the
operating system, and can't be modified by netcf. the configuration that
is setup by netcf can only reference an *existing* physical device name,
it can't rename it.
If you have any other method, please share to me, or can we add
support for it in netcf?
One source of information is here:
http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterf...
(although that only completely applies to systems running recent
systemd, e.g. Fedora 20, but not to RHEL6 as you appear to be running)
There is a reference there of how to change an interface name in a
system that isn't using "predictable network interface names" (or
biosdevname, which was a short-lived alternative attempt at a solution
to the same problem): modify the file
/etc/udev/rules.d/70-persistent-net.rules. You'll need to reboot the
system for this to take effect.
2:02 p.m.
On 05/23/2014 04:56 PM, Laine Stump wrote:
On 05/23/2014 06:46 AM, Jianwei Hu wrote:
> Hi All,
>
> I have a usage question about netcf. Why netcf can not rename a existing physical
interface dynamically by itself?
The name of a physical interface is determined by lower levels of the
operating system, and can't be modified by netcf. the configuration that
is setup by netcf can only reference an *existing* physical device nam[root@rhel6 ~]# ip
link set name jiahu eth1
[root@rhel6 ~]# ifconfig jiahu
jiahu Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
[root@rhel6 ~]# ifup jiahu
Determining IP information for jiahu... done.
e,
it can't rename it.
OK, thanks, but I think we can use ip command line to
rename existing NIC.
[root@rhel6 ~]# ip link set name jiahu eth1
[root@rhel6 ~]# ifconfig jiahu
jiahu Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
[root@rhel6 ~]# ifup jiahu
Determining IP information for jiahu... done.
> If you have any other method, please share to me, or can we add
support for it in netcf?
One source of information is here:
http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterf...
(although that only completely applies to systems running recent
systemd, e.g. Fedora 20, but not to RHEL6 as you appear to be running)
There is a reference there of how to change an interface name in a
system that isn't using "predictable network interface names" (or
biosdevname, which was a short-lived alternative attempt at a solution
to the same problem): modify the file
/etc/udev/rules.d/70-persistent-net.rules. You'll need to reboot the
system for this to take effect.
4:31 p.m.
On 05/23/2014 03:02 PM, jiahu wrote:
On 05/23/2014 04:56 PM, Laine Stump wrote:
> On 05/23/2014 06:46 AM, Jianwei Hu wrote:
>> Hi All,
>>
>> I have a usage question about netcf. Why netcf can not rename a
>> existing physical interface dynamically by itself?
> The name of a physical interface is determined by lower levels of the
> operating system, and can't be modified by netcf. the configuration that
> is setup by netcf can only reference an *existing* physical device
> nam[root@rhel6 ~]# ip link set name jiahu eth1
> [root@rhel6 ~]# ifconfig jiahu
> jiahu Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
> BROADCAST MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
>
> [root@rhel6 ~]# ifup jiahu
>
> Determining IP information for jiahu... done.
> e,
> it can't rename it.
OK, thanks, but I think we can use ip command line to rename existing
NIC.
[root@rhel6 ~]# ip link set name jiahu eth1
[root@rhel6 ~]# ifconfig jiahu
jiahu Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
[root@rhel6 ~]# ifup jiahu
Determining IP information for jiahu... done.
Neat! That's probably using the same netlink command that's used to
rename it at boot time. However, if you do what you suggest, the name
change won't be persistent across a system reboot.
I still say this is too low level for netcf to be messing with; it was
created to provide a standard way to manipulate the config files, not
mess with the hardware. (Note that it's also possible to change the mac
address of an ethernet device (ip link set $dev address $addr) , but we
don't support that either, and have no plans to do so.)
4:07 a.m.
> OK, thanks, but I think we can use ip command line to rename
existing
> NIC.
>
> [root@rhel6 ~]# ip link set name jiahu eth1
> [root@rhel6 ~]# ifconfig jiahu
> jiahu Link encap:Ethernet HWaddr 00:1B:21:27:4E:CE
> BROADCAST MULTICAST MTU:1500 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:1000
> RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
>
> [root@rhel6 ~]# ifup jiahu
>
> Determining IP information for jiahu... done.
Neat! That's probably using the same netlink command that's used to
rename it at boot time. However, if you do what you suggest, the name
change won't be persistent across a system reboot.
I still say this is too low level for netcf to be messing with; it was
created to provide a standard way to manipulate the config files, not
mess with the hardware. (Note that it's also possible to change the mac
address of an ethernet device (ip link set $dev address $addr) , but we
don't support that either, and have no plans to do so.)
Good conclusion, thanks
again, I agree with you.
3766
days inactive
3769
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4 comments
4 participants
participants (4)
-
hujianwei -
jiahu
-
Jianwei Hu
-
Laine Stump