[PATCH] Add /etc/resolve.conf to kdump initrd if it's managed manually

[Coiby Xu]

Some users may choose to manage /etc/resolve.conf manually. In this case,
network dumping will not work because DNS resolution doesn't work. Copy
/etc/resolve.conf to kdump initrd if this file is not managed by
systemd-resolved or NetworkManager.

Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
initrd")
Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
Cc: Jie Li <jieli(a)redhat.com&gt;
Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
---
 dracut-module-setup.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index ff53d084..e6355973 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -563,6 +563,19 @@ kdump_collect_netif_usage() {
     fi
 }
 
+kdump_install_resolv_conf() {
+
+    local _resolv_conf=/etc/resolv.conf
+
+    # Some users may choose to manage /etc/resolve.conf manually.
+    #
+    # We can tell this case by confirming this file is not manged by
+    # systemd-resolved or NetworkManager.
+    if ! grep -qs "^nameserver 127.0.0.53" "$_resolv_conf" &&
! grep -qs "^# Generated by NetworkManager" "$_resolv_conf"; then
+        dracut_install "$_resolv_conf"
+    fi
+}
+
 # Setup dracut to bring up network interface that enable
 # initramfs accessing giving destination
 kdump_install_net() {
@@ -575,6 +588,7 @@ kdump_install_net() {
         kdump_setup_znet
         kdump_install_nm_netif_allowlist "$_netifs"
         kdump_install_nic_driver "$_netifs"
+        kdump_install_resolv_conf
     fi
 }
 
-- 
2.41.0

[PATCH v2] Add /etc/resolve.conf to kdump initrd if it's managed manually

[Coiby Xu]

Resolves: https://issues.redhat.com/browse/RHEL-11897

Some users may choose to manage /etc/resolve.conf manually (e.g. by
setting dns=none in NetworkManager.conf [1]). In this case, network
dumping will not work because DNS resolution doesn't work. Copy
/etc/resolve.conf to kdump initrd if this file is not managed by
systemd-resolved or NetworkManager.

[1] https://bugzilla.gnome.org/show_bug.cgi?id=690404

Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
initrd")
Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
Cc: Jie Li <jieli(a)redhat.com&gt;
Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
---
v2
 - use 'grep "\|"' instead of 'grep | grep' for multiple
patterns
	  matching
	- improve commit message
---
 dracut-module-setup.sh | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index ff53d084..d062f7fd 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -563,6 +563,19 @@ kdump_collect_netif_usage() {
     fi
 }
 
+kdump_install_resolv_conf() {
+
+    local _resolv_conf=/etc/resolv.conf
+
+    # Some users may choose to manage /etc/resolve.conf manually.
+    #
+    # We can tell this case by confirming this file is not manged by
+    # systemd-resolved or NetworkManager.
+    if ! grep -qs "^nameserver 127.0.0.53\|^# Generated by NetworkManager"
"$_resolv_conf"; then
+        dracut_install "$_resolv_conf"
+    fi
+}
+
 # Setup dracut to bring up network interface that enable
 # initramfs accessing giving destination
 kdump_install_net() {
@@ -575,6 +588,7 @@ kdump_install_net() {
         kdump_setup_znet
         kdump_install_nm_netif_allowlist "$_netifs"
         kdump_install_nic_driver "$_netifs"
+        kdump_install_resolv_conf
     fi
 }
 
-- 
2.41.0

[Dave Young]

Hi Coiby,

On Fri, 10 Nov 2023 at 08:40, Coiby Xu <coxu(a)redhat.com&gt; wrote:
>  Some users may choose to manage /etc/resolve.conf manually. In this case,
>  network dumping will not work because DNS resolution doesn't work. Copy
>  /etc/resolve.conf to kdump initrd if this file is not managed by
>  systemd-resolved or NetworkManager.
>
>  Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
> initrd")
>  Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
>  Cc: Jie Li <jieli(a)redhat.com&gt;
>  Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
>  ---
>   dracut-module-setup.sh | 14 ++++++++++++++
>   1 file changed, 14 insertions(+)
>
>  diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
>  index ff53d084..e6355973 100755
>  --- a/dracut-module-setup.sh
>  +++ b/dracut-module-setup.sh
>  @@ -563,6 +563,19 @@ kdump_collect_netif_usage() {
>       fi
>   }
>
>  +kdump_install_resolv_conf() {
>  +
>  +    local _resolv_conf=/etc/resolv.conf
>  +
>  +    # Some users may choose to manage /etc/resolve.conf manually.
>  +    #
>  +    # We can tell this case by confirming this file is not manged by
>  +    # systemd-resolved or NetworkManager.
>  +    if ! grep -qs "^nameserver 127.0.0.53" "$_resolv_conf"
> && ! grep -qs "^# Generated by NetworkManager"
> "$_resolv_conf"; then 
Is the 127.0.0.53, is it systemd-resolved specific?  How about just
check the status of systemd-resolvd by checking return value of below:
systemctl -q is-active systemd-resolved

Otherwise for NetworkManager setup, it could be that people just edit
the NM generated resolv.conf, but keep the comment line there:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...

If we just blindly install the resolv.conf, I think it will be
overwritten by NM in kdump kernel initramfs during bootup if people
use NM, so it does not matter to have it copied without any checking.


>  +        dracut_install "$_resolv_conf"
>  +    fi
>  +}
>  +
>   # Setup dracut to bring up network interface that enable
>   # initramfs accessing giving destination
>   kdump_install_net() {
>  @@ -575,6 +588,7 @@ kdump_install_net() {
>           kdump_setup_znet
>           kdump_install_nm_netif_allowlist "$_netifs"
>           kdump_install_nic_driver "$_netifs"
>  +        kdump_install_resolv_conf
>       fi
>   }
>
>  --
>  2.41.0
>  _______________________________________________
>  kexec mailing list -- kexec(a)lists.fedoraproject.org
>  To unsubscribe send an email to kexec-leave(a)lists.fedoraproject.org
>  Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
>  List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>  List Archives:
> https://lists.fedoraproject.org/archives/list/[e-mail]
>  Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
Thanks
Dave

[Coiby Xu]

On Fri, Nov 10, 2023 at 09:46:03AM +0800, Dave Young wrote:
> Hi Coiby, 
Hi Dave,

Thanks for reviewing the patch!

> On Fri, 10 Nov 2023 at 08:40, Coiby Xu <coxu(a)redhat.com&gt; wrote:
> >
> > Some users may choose to manage /etc/resolve.conf manually. In this case,
> > network dumping will not work because DNS resolution doesn't work. Copy
> > /etc/resolve.conf to kdump initrd if this file is not managed by
> > systemd-resolved or NetworkManager.
> >
> > Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile
> to initrd")
> > Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
> > Cc: Jie Li <jieli(a)redhat.com&gt;
> > Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
> > ---
> >  dracut-module-setup.sh | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> > index ff53d084..e6355973 100755
> > --- a/dracut-module-setup.sh
> > +++ b/dracut-module-setup.sh
> > @@ -563,6 +563,19 @@ kdump_collect_netif_usage() {
> >      fi
> >  }
> >
> > +kdump_install_resolv_conf() {
> > +
> > +    local _resolv_conf=/etc/resolv.conf
> > +
> > +    # Some users may choose to manage /etc/resolve.conf manually.
> > +    #
> > +    # We can tell this case by confirming this file is not manged by
> > +    # systemd-resolved or NetworkManager.
> > +    if ! grep -qs "^nameserver 127.0.0.53" "$_resolv_conf"
> && ! grep -qs "^# Generated by NetworkManager"
> "$_resolv_conf"; then
>
> Is the 127.0.0.53, is it systemd-resolved specific?  How about just
> check the status of systemd-resolvd by checking return value of below:
> systemctl -q is-active systemd-resolved 
Yes, I think it's systemd-resolved specific according to "man
systemd-resolved". I've applied this suggestion in v3 as it's simpler.
Thanks!

> Otherwise for NetworkManager setup, it could be that people just edit
> the NM generated resolv.conf, but keep the comment line there:
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
> If we just blindly install the resolv.conf, I think it will be
> overwritten by NM in kdump kernel initramfs during bootup if people
> use NM, so it does not matter to have it copied without any checking. 
Thanks for sharing the helpful doc which made I realize I missed the
case where users could also manually configure resolv.conf by using a
symbolic file. In v3, I've addressed this case. And yes, grep -qs "^#
Generated by NetworkManager" is unreliable and unnecessary, thanks for
pointing out it!

> > +        dracut_install "$_resolv_conf"
> > +    fi
> > +}
> > +
> >  # Setup dracut to bring up network interface that enable
> >  # initramfs accessing giving destination
> >  kdump_install_net() {
> > @@ -575,6 +588,7 @@ kdump_install_net() {
> >          kdump_setup_znet
> >          kdump_install_nm_netif_allowlist "$_netifs"
> >          kdump_install_nic_driver "$_netifs"
> > +        kdump_install_resolv_conf
> >      fi
> >  }
> >
> > --
> > 2.41.0
> > _______________________________________________
> > kexec mailing list -- kexec(a)lists.fedoraproject.org
> > To unsubscribe send an email to kexec-leave(a)lists.fedoraproject.org
> > Fedora Code of Conduct:
> https://docs.fedoraproject.org/en-US/project/code-of-conduct/
> > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
> > List Archives:
> https://lists.fedoraproject.org/archives/list/[e-mail]
> > Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
>
> Thanks
> Dave
>  
-- 
Best regards,
Coiby

[PATCH v3] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[Coiby Xu]

Resolves: https://issues.redhat.com/browse/RHEL-11897

Some users may choose to manage /etc/resolve.conf manually [1]
by setting dns=none or use a symbolic link resolve.conf [2].
In this case, network dumping will not work because DNS resolution
fails. Use the same /etc/resolve.conf in kdump initrd to fix this
problem.

[1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
[2]
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...

Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
initrd")
Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
Cc: Jie Li <jieli(a)redhat.com&gt;
Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
---
v3
 - Dave
   - use "systemctl -q is-active systemd-resolved" to tell if
			/etc/resolv.conf is managed by systemd-resolved
   - drop needless and unreliable check on whether resolv.conf is generated by NM

  - configure dns=none for NM to prevent resolv.conf being overwritten by NM
  - take care of the case where user-configured resolv.conf is a symbolic file

v2
 - use 'grep "\|"' instead of 'grep | grep' for multiple
patterns
   matching
 - improve commit message
---
 dracut-module-setup.sh | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index ff53d084..8368ee47 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -563,6 +563,31 @@ kdump_collect_netif_usage() {
     fi
 }
 
+kdump_install_resolv_conf() {
+    local _resolv_conf=/etc/resolv.conf _nm_conf_dir=/etc/NetworkManager/conf.d
+
+    # Some users may choose to manage /etc/resolve.conf manually [1]
+    # by setting dns=none or use a symbolic link resolve.conf [2].
+    # So resolve.conf should be installed to kdump initrd as well. To prevent
+    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
+    # also set dns=none for NM.
+    #
+    # Note:
+    # 1. When resolv.conf is managed by systemd-resolved.service, it could also be a
+    #    symbolic link So exclude this case by teling if systemd-resolved is enabled
+    #
+    # 2. It's harmless to bindly copy /etc/resolve.conf to the initrd because
+    #    by default in initramfs this file will be overwritten by NetworkManager.
+    #
+    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
+    # [2]
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
+    systemctl -q is-enabled systemd-resolved && return 0
+    inst "$(readlink -f "$_resolv_conf")" "$_resolv_conf"
+    if NetworkManager --print-config | grep -qs "^dns=none" || [[ -L
"$_resolv_conf" ]]; then
+        echo "[main]\ndns=none" >
"$_nm_conf_dir"/90-dns-none.conf
+    fi
+}
+
 # Setup dracut to bring up network interface that enable
 # initramfs accessing giving destination
 kdump_install_net() {
@@ -575,6 +600,7 @@ kdump_install_net() {
         kdump_setup_znet
         kdump_install_nm_netif_allowlist "$_netifs"
         kdump_install_nic_driver "$_netifs"
+        kdump_install_resolv_conf
     fi
 }
 
-- 
2.41.0

[PATCH v3] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[RuiRui Yang]

Hi Coiby,

Thanks for the update! I still have some questions though, please see
the inline comments.

On Tue, 14 Nov 2023 at 17:22, Coiby Xu <coxu(a)redhat.com&gt; wrote:
>  Resolves: https://issues.redhat.com/browse/RHEL-11897
>
>  Some users may choose to manage /etc/resolve.conf manually [1]
>  by setting dns=none or use a symbolic link resolve.conf [2].
>  In this case, network dumping will not work because DNS resolution
>  fails. Use the same /etc/resolve.conf in kdump initrd to fix this
>  problem.
>
>  [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
>  [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
>
>  Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
> initrd")
>  Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
>  Cc: Jie Li <jieli(a)redhat.com&gt;
>  Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
>  ---
>  v3
>   - Dave
>     - use "systemctl -q is-active systemd-resolved" to tell if
>                          /etc/resolv.conf is managed by systemd-resolved
>     - drop needless and unreliable check on whether resolv.conf is generated by NM
>
>    - configure dns=none for NM to prevent resolv.conf being overwritten by NM
>    - take care of the case where user-configured resolv.conf is a symbolic file
>
>  v2
>   - use 'grep "\|"' instead of 'grep | grep' for multiple
> patterns
>     matching
>   - improve commit message
>  ---
>   dracut-module-setup.sh | 26 ++++++++++++++++++++++++++
>   1 file changed, 26 insertions(+)
>
>  diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
>  index ff53d084..8368ee47 100755
>  --- a/dracut-module-setup.sh
>  +++ b/dracut-module-setup.sh
>  @@ -563,6 +563,31 @@ kdump_collect_netif_usage() {
>       fi
>   }
>
>  +kdump_install_resolv_conf() {
>  +    local _resolv_conf=/etc/resolv.conf _nm_conf_dir=/etc/NetworkManager/conf.d
>  +
>  +    # Some users may choose to manage /etc/resolve.conf manually [1]
>  +    # by setting dns=none or use a symbolic link resolve.conf [2].
>  +    # So resolve.conf should be installed to kdump initrd as well. To prevent
>  +    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
>  +    # also set dns=none for NM.
>  +    #
>  +    # Note:
>  +    # 1. When resolv.conf is managed by systemd-resolved.service, it could also be a
>  +    #    symbolic link So exclude this case by teling if systemd-resolved is enabled
>  +    #
>  +    # 2. It's harmless to bindly copy /etc/resolve.conf to the initrd because
s/bindly/blindly

>  +    #    by default in initramfs this file will be overwritten by
> NetworkManager.
>  +    #
>  +    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
>  +    # [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
>  +    systemctl -q is-enabled systemd-resolved && return 0
>  +    inst "$(readlink -f "$_resolv_conf")" "$_resolv_conf"
>  +    if NetworkManager --print-config | grep -qs "^dns=none" || [[ -L
> "$_resolv_conf" ]]; then 
What is the reason to check the [[ -L "$_resolv_conf" ]] here?  it
would be better to have the dns-none chunk to handle the dns-none case
only and it will be easier to understand.

>  +        echo "[main]\ndns=none" >
> "$_nm_conf_dir"/90-dns-none.conf 
BTW, would this be better to add in dracut hostonly code?

>  +    fi
>  +}
>  +
>   # Setup dracut to bring up network interface that enable
>   # initramfs accessing giving destination
>   kdump_install_net() {
>  @@ -575,6 +600,7 @@ kdump_install_net() {
>           kdump_setup_znet
>           kdump_install_nm_netif_allowlist "$_netifs"
>           kdump_install_nic_driver "$_netifs"
>  +        kdump_install_resolv_conf
>       fi
>   }
>
>  --
>  2.41.0
>  _______________________________________________
>  kexec mailing list -- kexec(a)lists.fedoraproject.org
>  To unsubscribe send an email to kexec-leave(a)lists.fedoraproject.org
>  Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
>  List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>  List Archives:
> https://lists.fedoraproject.org/archives/list/[e-mail]
>  Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue

[PATCH v3] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[Coiby Xu]

On Wed, Nov 15, 2023 at 10:54:36AM +0800, RuiRui Yang wrote:
> Hi Coiby,
>
> Thanks for the update! I still have some questions though, please see
> the inline comments. 
Hi Dave,

Thanks for the quick response!

> On Tue, 14 Nov 2023 at 17:22, Coiby Xu <coxu(a)redhat.com&gt; wrote:
> [...]
> >
> > +kdump_install_resolv_conf() {
> > +    local _resolv_conf=/etc/resolv.conf _nm_conf_dir=/etc/NetworkManager/conf.d
> > +
> > +    # Some users may choose to manage /etc/resolve.conf manually [1]
> > +    # by setting dns=none or use a symbolic link resolve.conf [2].
> > +    # So resolve.conf should be installed to kdump initrd as well. To prevent
> > +    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
> > +    # also set dns=none for NM.
> > +    #
> > +    # Note:
> > +    # 1. When resolv.conf is managed by systemd-resolved.service, it could also be
> a
> > +    #    symbolic link So exclude this case by teling if systemd-resolved is
> enabled
> > +    #
> > +    # 2. It's harmless to bindly copy /etc/resolve.conf to the initrd because
> s/bindly/blindly 
Thanks for catching this typo!

> > +    #    by default in initramfs this file will be overwritten by NetworkManager.
> > +    #
> > +    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
> > +    # [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
> > +    systemctl -q is-enabled systemd-resolved && return 0
> > +    inst "$(readlink -f "$_resolv_conf")"
> "$_resolv_conf"
> > +    if NetworkManager --print-config | grep -qs "^dns=none" || [[ -L
> "$_resolv_conf" ]]; then
>
> What is the reason to check the [[ -L "$_resolv_conf" ]] here?  it
> would be better to have the dns-none chunk to handle the dns-none case
> only and it will be easier to understand. 
Because users could also self-manage /etc/resolve.conf via a symbolic
link. When resolve.conf is a symbolic file, NM won't touch resolve.conf
even without dns=none.

> > +        echo "[main]\ndns=none" >
> "$_nm_conf_dir"/90-dns-none.conf
>
> BTW, would this be better to add in dracut hostonly code? 
dns=none is strongly coupled with the code before, so it doesn't seemm to 
ake sense to fragment the code? Btw, I'm not sure if dracut wants this
code because currently the only user is the kdump dracut module which is
still out of tree.

-- 
Best regards,
Coiby

[PATCH v3] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[Dave Young]

On Wed, 15 Nov 2023 at 11:40, Coiby Xu <coxu(a)redhat.com&gt; wrote:
>  On Wed, Nov 15, 2023 at 10:54:36AM +0800, RuiRui Yang wrote:
>  >Hi Coiby,
>  >
>  >Thanks for the update! I still have some questions though, please see
>  >the inline comments.
>
>  Hi Dave,
>
>  Thanks for the quick response!
>
>  >
>  >On Tue, 14 Nov 2023 at 17:22, Coiby Xu <coxu(a)redhat.com&gt; wrote:
>  >[...]
>  >>
>  >> +kdump_install_resolv_conf() {
>  >> +    local _resolv_conf=/etc/resolv.conf
> _nm_conf_dir=/etc/NetworkManager/conf.d
>  >> +
>  >> +    # Some users may choose to manage /etc/resolve.conf manually [1]
>  >> +    # by setting dns=none or use a symbolic link resolve.conf [2].
>  >> +    # So resolve.conf should be installed to kdump initrd as well. To prevent
>  >> +    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
>  >> +    # also set dns=none for NM.
>  >> +    #
>  >> +    # Note:
>  >> +    # 1. When resolv.conf is managed by systemd-resolved.service, it could also
> be a
>  >> +    #    symbolic link So exclude this case by teling if systemd-resolved is
> enabled
>  >> +    #
>  >> +    # 2. It's harmless to bindly copy /etc/resolve.conf to the initrd
> because
>  >s/bindly/blindly
>
>  Thanks for catching this typo!
>
>  >
>  >> +    #    by default in initramfs this file will be overwritten by
> NetworkManager.
>  >> +    #
>  >> +    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
>  >> +    # [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
>  >> +    systemctl -q is-enabled systemd-resolved && return 0
>  >> +    inst "$(readlink -f "$_resolv_conf")"
> "$_resolv_conf"
>  >> +    if NetworkManager --print-config | grep -qs "^dns=none" || [[ -L
> "$_resolv_conf" ]]; then
>  >
>  >What is the reason to check the [[ -L "$_resolv_conf" ]] here?  it
>  >would be better to have the dns-none chunk to handle the dns-none case
>  >only and it will be easier to understand.
>
>  Because users could also self-manage /etc/resolve.conf via a symbolic
>  link. When resolve.conf is a symbolic file, NM won't touch resolve.conf
>  even without dns=none. 
Hi Coiby, ok, thanks for the explanation.

It seems dracut "inst" will automatically install the original file
and the target symlink,  if so as you said we do not need to add the
dns=none for this case and it will just work?

Not sure about  'inst "$(readlink -f "$_resolv_conf")"
"$_resolv_conf"', at least 'inst "$_resolv_conf"
"$_resolv_conf"'
works fine for me.

>  >
>  >> +        echo "[main]\ndns=none" >
> "$_nm_conf_dir"/90-dns-none.conf
>  >
>  >BTW, would this be better to add in dracut hostonly code?
>
>  dns=none is strongly coupled with the code before, so it doesn't seem to
>  ake sense to fragment the code? Btw, I'm not sure if dracut wants this
>  code because currently the only user is the kdump dracut module which is
>  still out of tree. 
Hostonly exists before the kdump dracut module created, so there are
more users who will manually generate the initrd with host only mode
to do something although we can not have an example for this specific
case.   I previously always tried to move code to dracut as much as
possible.  But since you guys are maintaining the code now, I have no
strong opinion on this.  Please just take what you think is better if
no any other objections.

>  --
>  Best regards,
>  Coiby
>

[PATCH v3] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[Coiby Xu]

On Wed, Nov 15, 2023 at 01:40:10PM +0800, Dave Young wrote:
> It seems dracut "inst" will automatically install the
> original file
> and the target symlink,  if so as you said we do not need to add the
> dns=none for this case and it will just work?
>
> Not sure about  'inst "$(readlink -f "$_resolv_conf")"
> "$_resolv_conf"', at least 'inst "$_resolv_conf"
> "$_resolv_conf"'
> works fine for me. 
I forgot to mention I was mislead by one experiment where
/etc/resolv.conf
was linked to ../run/systemd/resolve/stub-resolv.conf. After using
"inst /etc/resolv.conf", this file doesn't exist when booting into the
initrd
     sh-5.2# ls -l /etc/resolv.conf 
     lrwxrwxrwx 1 root root 39 Nov 15 10:10 /etc/resolv.conf ->
../run/systemd/resolve/stub-resolv.conf
     sh-5.2# cat /etc/resolv.conf 
     cat: /etc/resolv.conf: No such file or directory

Later I linked /etc/custom-resolv.conf to /etc/resolv.conf. Then it
works as expected.  

> >
> > >
> > >> +        echo "[main]\ndns=none" >
> "$_nm_conf_dir"/90-dns-none.conf
> > >
> > >BTW, would this be better to add in dracut hostonly code?
> >
> > dns=none is strongly coupled with the code before, so it doesn't seem to
> > ake sense to fragment the code? Btw, I'm not sure if dracut wants this
> > code because currently the only user is the kdump dracut module which is
> > still out of tree.
>
> Hostonly exists before the kdump dracut module created, so there are
> more users who will manually generate the initrd with host only mode
> to do something although we can not have an example for this specific
> case.   I previously always tried to move code to dracut as much as
> possible.  But since you guys are maintaining the code now, I have no
> strong opinion on this.  Please just take what you think is better if
> no any other objections. 
Thanks for sharing you experience! I'll try adding the code to dracut if
it's also needed for other use cases.

-- 
Best regards,
Coiby

[PATCH v4] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[Coiby Xu]

Resolves: https://issues.redhat.com/browse/RHEL-11897

Some users may choose to manage /etc/resolve.conf manually [1]
by setting dns=none or use a symbolic link resolve.conf [2].
In this case, network dumping will not work because DNS resolution
fails. Use the same /etc/resolve.conf in kdump initrd to fix this
problem.

[1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
[2]
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...

Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
initrd")
Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
Cc: Jie Li <jieli(a)redhat.com&gt;
Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
---
v4
  - use dracut's inst to install the symbolic link and target file
		  automatically [Dave]
  - drop the unneeded check of symbolic link to tell if dns=none for NM

v3
 - Dave
   - use "systemctl -q is-active systemd-resolved" to tell if
			/etc/resolv.conf is managed by systemd-resolved
   - drop needless and unreliable check on whether resolv.conf is generated by NM

  - configure dns=none for NM to prevent resolv.conf being overwritten by NM
  - take care of the case where user-configured resolv.conf is a symbolic file

v2
 - use 'grep "\|"' instead of 'grep | grep' for multiple
patterns
   matching
 - improve commit message
---
 dracut-module-setup.sh | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index ff53d084..ab6dc4f1 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -563,6 +563,33 @@ kdump_collect_netif_usage() {
     fi
 }
 
+kdump_install_resolv_conf() {
+    local _resolv_conf=/etc/resolv.conf _nm_conf_dir=/etc/NetworkManager/conf.d
+
+    # Some users may choose to manage /etc/resolve.conf manually [1]
+    # by setting dns=none or use a symbolic link resolve.conf [2].
+    # So resolve.conf should be installed to kdump initrd as well. To prevent
+    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
+    # also set dns=none for NM.
+    #
+    # Note:
+    # 1. When resolv.conf is managed by systemd-resolved.service, it could also be a
+    #    symbolic link. So exclude this case by teling if systemd-resolved is enabled.
+    #
+    # 2. It's harmless to blindly copy /etc/resolve.conf to the initrd because
+    #    by default in initramfs this file will be overwritten by
+    #    NetworkManager. If user manages it via a symbolic link, it's still
+    #    preserved because NM won't touch a symbolic link file.
+    #
+    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
+    # [2]
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
+    systemctl -q is-enabled systemd-resolved && return 0
+    inst "$_resolv_conf"
+    if NetworkManager --print-config | grep -qs "^dns=none"; then
+        echo "[main]\ndns=none" >
"$_nm_conf_dir"/90-dns-none.conf
+    fi
+}
+
 # Setup dracut to bring up network interface that enable
 # initramfs accessing giving destination
 kdump_install_net() {
@@ -575,6 +602,7 @@ kdump_install_net() {
         kdump_setup_znet
         kdump_install_nm_netif_allowlist "$_netifs"
         kdump_install_nic_driver "$_netifs"
+        kdump_install_resolv_conf
     fi
 }
 
-- 
2.42.0

[PATCH v4] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[RuiRui Yang]

On Wed, 22 Nov 2023 at 14:50, Coiby Xu <coxu(a)redhat.com&gt; wrote:
>  Resolves: https://issues.redhat.com/browse/RHEL-11897
>
>  Some users may choose to manage /etc/resolve.conf manually [1]
>  by setting dns=none or use a symbolic link resolve.conf [2].
>  In this case, network dumping will not work because DNS resolution
>  fails. Use the same /etc/resolve.conf in kdump initrd to fix this
>  problem.
>
>  [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
>  [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
>
>  Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile to
> initrd")
>  Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
>  Cc: Jie Li <jieli(a)redhat.com&gt;
>  Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
>  ---
>  v4
>    - use dracut's inst to install the symbolic link and target file
>                    automatically [Dave]
>    - drop the unneeded check of symbolic link to tell if dns=none for NM
>
>  v3
>   - Dave
>     - use "systemctl -q is-active systemd-resolved" to tell if
>                          /etc/resolv.conf is managed by systemd-resolved
>     - drop needless and unreliable check on whether resolv.conf is generated by NM
>
>    - configure dns=none for NM to prevent resolv.conf being overwritten by NM
>    - take care of the case where user-configured resolv.conf is a symbolic file
>
>  v2
>   - use 'grep "\|"' instead of 'grep | grep' for multiple
> patterns
>     matching
>   - improve commit message
>  ---
>   dracut-module-setup.sh | 28 ++++++++++++++++++++++++++++
>   1 file changed, 28 insertions(+)
>
>  diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
>  index ff53d084..ab6dc4f1 100755
>  --- a/dracut-module-setup.sh
>  +++ b/dracut-module-setup.sh
>  @@ -563,6 +563,33 @@ kdump_collect_netif_usage() {
>       fi
>   }
>
>  +kdump_install_resolv_conf() {
>  +    local _resolv_conf=/etc/resolv.conf _nm_conf_dir=/etc/NetworkManager/conf.d
>  +
>  +    # Some users may choose to manage /etc/resolve.conf manually [1]
>  +    # by setting dns=none or use a symbolic link resolve.conf [2].
>  +    # So resolve.conf should be installed to kdump initrd as well. To prevent
>  +    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
>  +    # also set dns=none for NM.
>  +    #
>  +    # Note:
>  +    # 1. When resolv.conf is managed by systemd-resolved.service, it could also be a
>  +    #    symbolic link. So exclude this case by teling if systemd-resolved is enabled.
>  +    #
>  +    # 2. It's harmless to blindly copy /etc/resolve.conf to the initrd because
>  +    #    by default in initramfs this file will be overwritten by
>  +    #    NetworkManager. If user manages it via a symbolic link, it's still
>  +    #    preserved because NM won't touch a symbolic link file.
>  +    #
>  +    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
>  +    # [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
>  +    systemctl -q is-enabled systemd-resolved && return 0
>  +    inst "$_resolv_conf"
>  +    if NetworkManager --print-config | grep -qs "^dns=none"; then
>  +        echo "[main]\ndns=none" >
> "$_nm_conf_dir"/90-dns-none.conf
>  +    fi
>  +}
>  +
>   # Setup dracut to bring up network interface that enable
>   # initramfs accessing giving destination
>   kdump_install_net() {
>  @@ -575,6 +602,7 @@ kdump_install_net() {
>           kdump_setup_znet
>           kdump_install_nm_netif_allowlist "$_netifs"
>           kdump_install_nic_driver "$_netifs"
>  +        kdump_install_resolv_conf
>       fi
>   } 
Hi Coiby, thanks for the update:

Reviewed-by: Dave Young <dyoung(a)redhat.com&gt;

>  --
>  2.42.0
>  --
>  _______________________________________________
>  kexec mailing list -- kexec(a)lists.fedoraproject.org
>  To unsubscribe send an email to kexec-leave(a)lists.fedoraproject.org
>  Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/
>  List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines
>  List Archives:
> https://lists.fedoraproject.org/archives/list/[e-mail]
>  Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue

[PATCH v4] Use the same /etc/resolve.conf in kdump initrd if it's managed manually

[Coiby Xu]

On Wed, Nov 22, 2023 at 06:44:44PM +0800, RuiRui Yang wrote:
> On Wed, 22 Nov 2023 at 14:50, Coiby Xu <coxu(a)redhat.com&gt; wrote:
> >
> > Resolves: https://issues.redhat.com/browse/RHEL-11897
> >
> > Some users may choose to manage /etc/resolve.conf manually [1]
> > by setting dns=none or use a symbolic link resolve.conf [2].
> > In this case, network dumping will not work because DNS resolution
> > fails. Use the same /etc/resolve.conf in kdump initrd to fix this
> > problem.
> >
> > [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
> > [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
> >
> > Fixes: 63c3805c ("Set up kdump network by directly copying NM connection profile
> to initrd")
> > Reported-by: Curtis Taylor <cutaylor(a)redhat.com&gt;
> > Cc: Jie Li <jieli(a)redhat.com&gt;
> > Signed-off-by: Coiby Xu <coxu(a)redhat.com&gt;
> > ---
> > v4
> >   - use dracut's inst to install the symbolic link and target file
> >                   automatically [Dave]
> >   - drop the unneeded check of symbolic link to tell if dns=none for NM
> >
> > v3
> >  - Dave
> >    - use "systemctl -q is-active systemd-resolved" to tell if
> >                         /etc/resolv.conf is managed by systemd-resolved
> >    - drop needless and unreliable check on whether resolv.conf is generated by NM
> >
> >   - configure dns=none for NM to prevent resolv.conf being overwritten by NM
> >   - take care of the case where user-configured resolv.conf is a symbolic file
> >
> > v2
> >  - use 'grep "\|"' instead of 'grep | grep' for multiple
> patterns
> >    matching
> >  - improve commit message
> > ---
> >  dracut-module-setup.sh | 28 ++++++++++++++++++++++++++++
> >  1 file changed, 28 insertions(+)
> >
> > diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> > index ff53d084..ab6dc4f1 100755
> > --- a/dracut-module-setup.sh
> > +++ b/dracut-module-setup.sh
> > @@ -563,6 +563,33 @@ kdump_collect_netif_usage() {
> >      fi
> >  }
> >
> > +kdump_install_resolv_conf() {
> > +    local _resolv_conf=/etc/resolv.conf _nm_conf_dir=/etc/NetworkManager/conf.d
> > +
> > +    # Some users may choose to manage /etc/resolve.conf manually [1]
> > +    # by setting dns=none or use a symbolic link resolve.conf [2].
> > +    # So resolve.conf should be installed to kdump initrd as well. To prevent
> > +    # NM frome overwritting the user-configured resolve.conf in kdump initrd,
> > +    # also set dns=none for NM.
> > +    #
> > +    # Note:
> > +    # 1. When resolv.conf is managed by systemd-resolved.service, it could also be
> a
> > +    #    symbolic link. So exclude this case by teling if systemd-resolved is
> enabled.
> > +    #
> > +    # 2. It's harmless to blindly copy /etc/resolve.conf to the initrd because
> > +    #    by default in initramfs this file will be overwritten by
> > +    #    NetworkManager. If user manages it via a symbolic link, it's still
> > +    #    preserved because NM won't touch a symbolic link file.
> > +    #
> > +    # [1] https://bugzilla.gnome.org/show_bug.cgi?id=690404
> > +    # [2]
> https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
> > +    systemctl -q is-enabled systemd-resolved && return 0
> > +    inst "$_resolv_conf"
> > +    if NetworkManager --print-config | grep -qs "^dns=none"; then
> > +        echo "[main]\ndns=none" >
> "$_nm_conf_dir"/90-dns-none.conf
> > +    fi
> > +}
> > +
> >  # Setup dracut to bring up network interface that enable
> >  # initramfs accessing giving destination
> >  kdump_install_net() {
> > @@ -575,6 +602,7 @@ kdump_install_net() {
> >          kdump_setup_znet
> >          kdump_install_nm_netif_allowlist "$_netifs"
> >          kdump_install_nic_driver "$_netifs"
> > +        kdump_install_resolv_conf
> >      fi
> >  }
>
> Hi Coiby, thanks for the update:
>
> Reviewed-by: Dave Young <dyoung(a)redhat.com&gt; 
This patch was merged, thanks for the code review!

-- 
Best regards,
Coiby