[PATCH] write-ifcfg.sh: Don't overwrite network config in root filesystem

[PATCH] write-ifcfg.sh: Don't overwrite network config in root filesystem

[Gerhard Wiesinger]

This patch adds the possibility to keep the original
network configuration specified in the root filesystem.
This is necessary in situations with dual stack IPv4 and
IPv6 configurations or different kind on nameservers
(e.g. public ones at boot time, running a dns server
on localhost later on).

Keeping original configuration can be activated by:
networkstatic=yes
on the kernel boot command line.

Signed-off-by: Gerhard Wiesinger <lists-tcxHB8FAk+J54TAoqtyWWQ@public.gmane.org>
---
  modules.d/45ifcfg/write-ifcfg.sh | 7 +++++--
  1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/modules.d/45ifcfg/write-ifcfg.sh b/modules.d/45ifcfg/write-ifcfg.sh
index 803ae8e..033abe5 100755
--- a/modules.d/45ifcfg/write-ifcfg.sh
+++ b/modules.d/45ifcfg/write-ifcfg.sh
@@ -277,7 +277,10 @@ echo "files /etc/sysconfig/network-scripts" >> /run/initramfs/rwtab
  echo "files /var/lib/dhclient" >> /run/initramfs/rwtab
  {
      cp /tmp/net.* /run/initramfs/
-    cp /tmp/net.$netif.resolv.conf /run/initramfs/state/etc/resolv.conf
-    copytree /tmp/ifcfg /run/initramfs/state/etc/sysconfig/network-scripts
+    networkstatic="$(getarg networkstatic=)"
+    if [ -z "${networkstatic}" ]; then
+        cp /tmp/net.$netif.resolv.conf /run/initramfs/state/etc/resolv.conf
+        copytree /tmp/ifcfg /run/initramfs/state/etc/sysconfig/network-scripts
+    fi
      cp /tmp/ifcfg-leases/* /run/initramfs/state/var/lib/dhclient
  } > /dev/null 2>&1
-- 
1.9.3

Re: [PATCH] write-ifcfg.sh: Don't overwrite network config in root filesystem

[Harald Hoyer]

On 21.06.2014 12:40, Gerhard Wiesinger wrote:
> This patch adds the possibility to keep the original
> network configuration specified in the root filesystem.
> This is necessary in situations with dual stack IPv4 and
> IPv6 configurations or different kind on nameservers
> (e.g. public ones at boot time, running a dns server
> on localhost later on).
> 
> Keeping original configuration can be activated by:
> networkstatic=yes
> on the kernel boot command line.
> 
> Signed-off-by: Gerhard Wiesinger <lists-tcxHB8FAk+J54TAoqtyWWQ@public.gmane.org>
> ---
>  modules.d/45ifcfg/write-ifcfg.sh | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/modules.d/45ifcfg/write-ifcfg.sh b/modules.d/45ifcfg/write-ifcfg.sh
> index 803ae8e..033abe5 100755
> --- a/modules.d/45ifcfg/write-ifcfg.sh
> +++ b/modules.d/45ifcfg/write-ifcfg.sh
> @@ -277,7 +277,10 @@ echo "files /etc/sysconfig/network-scripts" >>
> /run/initramfs/rwtab
>  echo "files /var/lib/dhclient" >> /run/initramfs/rwtab
>  {
>      cp /tmp/net.* /run/initramfs/
> -    cp /tmp/net.$netif.resolv.conf /run/initramfs/state/etc/resolv.conf
> -    copytree /tmp/ifcfg /run/initramfs/state/etc/sysconfig/network-scripts
> +    networkstatic="$(getarg networkstatic=)"
> +    if [ -z "${networkstatic}" ]; then
> +        cp /tmp/net.$netif.resolv.conf /run/initramfs/state/etc/resolv.conf
> +        copytree /tmp/ifcfg /run/initramfs/state/etc/sysconfig/network-scripts
> +    fi
>      cp /tmp/ifcfg-leases/* /run/initramfs/state/var/lib/dhclient
>  } > /dev/null 2>&1

I don't understand this. It only copies to /run/initramfs. If you want to keep
your original network configuration, just don't copy over the files from
/run/initramfs to your root filesystem.

Re: [PATCH] write-ifcfg.sh: Don't overwrite network config in root filesystem

[Gerhard Wiesinger]

On 25.06.2014 11:51, Harald Hoyer wrote:
> On 21.06.2014 12:40, Gerhard Wiesinger wrote:
>> This patch adds the possibility to keep the original
>> network configuration specified in the root filesystem.
>> This is necessary in situations with dual stack IPv4 and
>> IPv6 configurations or different kind on nameservers
>> (e.g. public ones at boot time, running a dns server
>> on localhost later on).
>>
>> Keeping original configuration can be activated by:
>> networkstatic=yes
>> on the kernel boot command line.
>>
>>
>> I don't understand this. It only copies to /run/initramfs. If you want to keep
>> your original network configuration, just don't copy over the files from
>> /run/initramfs to your root filesystem.

Hello Harald,

The topic is: /etc/sysconfig/network-scripts/ifcfg-eth0 is overwritten 
by dracut when network config is specified on boot command line (e.g. 
grub config). As normal config is different and more complex (e.g. IPv6 
setup) boot config is different.

I found, that this patch doesn't overwrite the network config in 
/etc/sysconfig/network-scripts/ifcfg-eth0 when you specify network 
config on the boot command line.

I didn't debug into details and I'm not familiar with dracut in detail 
so I can't say why it works but it works. I think that some other code 
parts copy the initramfs afterwards to /etc/sysconfig/....

But maybe you can clarify it.

Ciao,
Gerhard

Re: [PATCH] write-ifcfg.sh: Don't overwrite network config in root filesystem

[Harald Hoyer]

On 25.06.2014 13:07, Gerhard Wiesinger wrote:
> On 25.06.2014 11:51, Harald Hoyer wrote:
>> On 21.06.2014 12:40, Gerhard Wiesinger wrote:
>>> This patch adds the possibility to keep the original
>>> network configuration specified in the root filesystem.
>>> This is necessary in situations with dual stack IPv4 and
>>> IPv6 configurations or different kind on nameservers
>>> (e.g. public ones at boot time, running a dns server
>>> on localhost later on).
>>>
>>> Keeping original configuration can be activated by:
>>> networkstatic=yes
>>> on the kernel boot command line.
>>>
>>>
>>> I don't understand this. It only copies to /run/initramfs. If you want to keep
>>> your original network configuration, just don't copy over the files from
>>> /run/initramfs to your root filesystem.
> 
> Hello Harald,
> 
> The topic is: /etc/sysconfig/network-scripts/ifcfg-eth0 is overwritten by
> dracut when network config is specified on boot command line (e.g. grub
> config). As normal config is different and more complex (e.g. IPv6 setup) boot
> config is different.
> 
> I found, that this patch doesn't overwrite the network config in
> /etc/sysconfig/network-scripts/ifcfg-eth0 when you specify network config on
> the boot command line.
> 
> I didn't debug into details and I'm not familiar with dracut in detail so I
> can't say why it works but it works. I think that some other code parts copy
> the initramfs afterwards to /etc/sysconfig/....
> 
> But maybe you can clarify it.
> 
> Ciao,
> Gerhard

On Fedora, this is fedora-import-state.service, which calls
/lib/systemd/fedora-import-state.

You could disable/mask that with:
$ sudo systemctl mask fedora-import-state.service