On 03/03/16 at 10:49am, Xunlei Pang wrote:
Currently kdump uses dracut's "nameserver=" command to
hande DNS,
handle
it is acquired both from ifcfg files and
"/etc/resolv.conf".
This is improper for dhcp cases, as "/etc/resolv.conf" is generated
by dhcp, the proper logic should be:
1) For static cases, DNS can be acquired from corresponding ifcfg file.
2) For dhcp cases, DNS is normally generated by dhcp, but extra DNS
can still be specified in the ifcfg files mannually.
3) For special user-assigned DNS not specified in any ifcfg file, we can
pass it to dracut via "nameserver=".
This patch may cause a regression, since kdump doesn't take care of
/etc/resolv.conf. Kdump kernel cann't get proper DNS, if it is appended
manually in /etc/resolv.conf.
https://bugzilla.redhat.com/show_bug.cgi?id=1196085
This patch improves the logic using the following "ip=" command format
provided by dracut:
ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:
<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<dns1>][:<dns2>]]
Signed-off-by: Xunlei Pang <xlpang(a)redhat.com>
---
dracut-module-setup.sh | 46 ++++++++++++++++++++++++----------------------
1 file changed, 24 insertions(+), 22 deletions(-)
diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
index 4cd7107..a18fdc0 100755
--- a/dracut-module-setup.sh
+++ b/dracut-module-setup.sh
@@ -63,26 +63,19 @@ kdump_is_vlan() {
}
# $1: netdev name
-kdump_setup_dns() {
- local _nameserver _dns
- local _dnsfile=${initdir}/etc/cmdline.d/42dns.conf
- . /etc/sysconfig/network-scripts/ifcfg-$1
-
- [ -n "$DNS1" ] && echo "nameserver=$DNS1" >
"$_dnsfile"
- [ -n "$DNS2" ] && echo "nameserver=$DNS2" >>
"$_dnsfile"
+# return pattern ":<dns1>[<:dns2>]" if not ""
+kdump_get_dns_from_ifcfg() {
+ local _dns
- while read content;
- do
- _nameserver=$(echo $content | grep ^nameserver)
- [ -z "$_nameserver" ] && continue
+ unset DNS1 DNS2
+ if [ -e /etc/sysconfig/network-scripts/ifcfg-$1 ]; then
+ . /etc/sysconfig/network-scripts/ifcfg-$1
+ fi
- _dns=$(echo $_nameserver | cut -d' ' -f2)
- [ -z "$_dns" ] && continue
+ [ -n "$DNS1" ] && _dns=${_dns}:$(echo $DNS1)
+ [ -n "$DNS2" ] && _dns=${_dns}:$(echo $DNS2)
- if [ ! -f $_dnsfile ] || [ ! $(cat $_dnsfile | grep -q $_dns) ]; then
- echo "nameserver=$_dns" >> "$_dnsfile"
- fi
- done < "/etc/resolv.conf"
+ echo -n "${_dns}" | cut -d':' -f1,2,3
Do we need to consider the case of IPv6 DNS?
}
#$1: netdev name
@@ -254,22 +247,27 @@ kdump_setup_znet() {
# Setup dracut to bringup a given network interface
kdump_setup_netdev() {
local _netdev=$1 _srcaddr=$2
- local _static _proto _ip_conf _ip_opts _ifname_opts
+ local _static _proto _ip_conf _ip_opts _ifname_opts _ifcfg_dns
+ local _global_dnsfile=${initdir}/etc/cmdline.d/42dns.conf
if [ "$(uname -m)" = "s390x" ]; then
kdump_setup_znet $_netdev
fi
- _netmac=$(kdump_get_mac_addr $_netdev)
+ # Using below "ip=" command format provided by dracut:
+ #
ip=<client-IP>:[<peer>]:<gateway-IP>:<netmask>:<client_hostname>:
+ #
<interface>:{none|off|dhcp|on|any|dhcp6|auto6|ibft}[:[<dns1>][:<dns2>]]
_static=$(kdump_static_ip $_netdev $_srcaddr)
if [ -n "$_static" ]; then
_proto=none
else
_proto=dhcp
+ _static=":::::"
Is this $_static necessary if the mode is dhcp, since there is no
assignment for _static previously?
fi
+ _ifcfg_dns=$(kdump_get_dns_from_ifcfg $_netdev)
_ip_conf="${initdir}/etc/cmdline.d/40ip.conf"
- _ip_opts=" ip=${_static}$(kdump_setup_ifname $_netdev):${_proto}"
+ _ip_opts=" ip=${_static}$(kdump_setup_ifname
$_netdev):${_proto}${_ifcfg_dns}"
# dracut doesn't allow duplicated configuration for same NIC, even they're
exactly the same.
# so we have to avoid adding duplicates
@@ -278,6 +276,12 @@ kdump_setup_netdev() {
if [ ! -f $_ip_conf ] || ! grep -q $_ip_opts $_ip_conf &&\
! grep -q "ip=[^[:space:]]*$_netdev" /proc/cmdline; then
echo "$_ip_opts" >> $_ip_conf
+ # In case of no DNS specified by iscsi.
+ if [ -n "${_ifcfg_dns}" ]; then
+ _ifcfg_dns=${_ifcfg_dns##:}
+ echo "nameserver=${_ifcfg_dns%%:*}" >> ${_global_dnsfile}
+ [ "${_ifcfg_dns}" = "${_ifcfg_dns%%:*}" ] || echo
"nameserver=${_ifcfg_dns##*:}" >> ${_global_dnsfile}
+ fi
I have a trouble understand why there is extra dns config for iSCSI?
Thanks
Minfei