kexec April 2016

kexec@lists.fedoraproject.org

6 participants
17 discussions

[PATCH RFC] module-setup.sh: install usb serial driver for ttyUSB0
by Dave Young 27 May '16

27 May '16

In case one want to use usb serial console, we need to pack the usb serial driver into kdump initramfs so that one can see the console output on the usb console. I only handled ttyUSB0, this is like a hard code, but it should be enough for most cases. Also only install the driver for the ttyUSB0 device. Tested with adding "console=ttyUSB0" in 2nd kernel commandline. Tested latest F22 kernel, there's CONFIG_USB_SERIAL_CONSOLE=y, kdump work ok. Signed-off-by: Dave Young <dyoung(a)redhat.com> --- dracut-module-setup.sh | 8 ++++++++ 1 file changed, 8 insertions(+) --- kexec-tools.orig/dracut-module-setup.sh +++ kexec-tools/dracut-module-setup.sh @@ -626,4 +626,12 @@ installkernel() { [ "$wdt" = "iTCO_wdt" ] && instmods lpc_ich instmods $wdt fi + + if [ -c /dev/ttyUSB0 ]; then + _majmin=$(get_maj_min /dev/ttyUSB0) + + _driver=$(readlink /sys/dev/char/$_majmin/device/driver) + _driver=$(basename $_driver) + instmods $_driver + fi }

3 4

[PATCH v4 1/2] kdump-lib: Add get_ifcfg_filename() to get the proper ifcfg file
by Xunlei Pang 23 May '16

23 May '16

Previously, we assumed the ifcfg file of a network "interface" is "/etc/sysconfig/network-scripts/ifcfg-<interface>", but actually it is not the case. For example, for network interface "enp0s25", we are able to generate like "/etc/sysconfig/network-scripts/ifcfg-enp0s25-test" for it via network-manager. The "suffix" in "ifcfg-<suffix>" is actually a "configuration" name not "interface" name, though normally we use the "interface" name as its "configuration" name. You can refer to "man ifup" for some detail. So, this patch adds some assistant helpers to acquire the right ifcfg file for an interface. Borrow some logic from script below: "/etc/sysconfig/network-scripts/network-functions" Signed-off-by: Xunlei Pang <xlpang(a)redhat.com> --- kdump-lib.sh | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) diff --git a/kdump-lib.sh b/kdump-lib.sh index 4d34206..90913c5 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -230,3 +230,105 @@ is_hostname() fi echo $1 | grep -q "[a-zA-Z]" } + +get_hwaddr() +{ + if [ -f "/sys/class/net/${1}/address" ]; then + awk '{ print toupper($0) }' < /sys/class/net/${1}/address + elif [ -d "/sys/class/net/${1}" ]; then + ip -o link show ${1} 2>/dev/null | \ + awk '{ print toupper(gensub(/.*link\/[^ ]* ([[:alnum:]:]*).*/, + "\\1", 1)); }' + fi +} + +get_ifcfg_by_device() +{ + grep -E -i -l "^[[:space:]]*DEVICE=\"*${1}\"*[[:space:]]*$" \ + /etc/sysconfig/network-scripts/ifcfg-* 2>/dev/null | head -1 +} + +get_ifcfg_by_hwaddr() +{ + grep -E -i -l "^[[:space:]]*HWADDR=\"*${1}\"*[[:space:]]*$" \ + /etc/sysconfig/network-scripts/ifcfg-* 2>/dev/null | head -1 +} + +get_ifcfg_by_uuid() +{ + grep -E -i -l "^[[:space:]]*UUID=\"*${1}\"*[[:space:]]*$" \ + /etc/sysconfig/network-scripts/ifcfg-* 2>/dev/null | head -1 +} + +get_ifcfg_by_name() +{ + grep -E -i -l "^[[:space:]]*NAME=\"*${1}\"*[[:space:]]*$" \ + /etc/sysconfig/network-scripts/ifcfg-* 2>/dev/null | head -1 +} + +is_nm_running() +{ + [ "$(LANG=C nmcli -t --fields running general status 2>/dev/null)" = "running" ] +} + +is_nm_handling() +{ + LANG=C nmcli -t --fields device,state dev status 2>/dev/null \ + | grep -q "^$${1}:connected$\|$${1}:connecting.*$$" +} + +# $1: netdev name +get_ifcfg_nmcli() +{ + local nm_uuid nm_name + local ifcfg_file + + # Get the active nmcli config name of $1 + if is_nm_running && is_nm_handling "${1}" ; then + # The configuration "uuid" and "name" generated by nm is wrote to + # the ifcfg file as "UUID=<nm_uuid>" and "NAME=<nm_name>". + nm_uuid=$(LANG=C nmcli -t --fields uuid,device c show --active 2>/dev/null \ + | grep "${1}" | head -1 | cut -d':' -f1) + nm_name=$(LANG=C nmcli -t --fields name,device c show --active 2>/dev/null \ + | grep "${1}" | head -1 | cut -d':' -f1) + ifcfg_file=$(get_ifcfg_by_uuid "${nm_uuid}") + [ -z "${ifcfg_file}" ] && ifcfg_file=$(get_ifcfg_by_name "${nm_name}") + fi + + echo -n "${ifcfg_file}" +} + +# $1: netdev name +get_ifcfg_legacy() +{ + local ifcfg_file + + ifcfg_file="/etc/sysconfig/network-scripts/ifcfg-${1}" + [ -f "${ifcfg_file}" ] && echo -n "${ifcfg_file}" && return + + ifcfg_file=$(get_ifcfg_by_name "${1}") + [ -f "${ifcfg_file}" ] && echo -n "${ifcfg_file}" && return + + local hwaddr=$(get_hwaddr "${1}") + if [ -n "$hwaddr" ]; then + ifcfg_file=$(get_ifcfg_by_hwaddr "${hwaddr}") + [ -f "${ifcfg_file}" ] && echo -n "${ifcfg_file}" && return + fi + + ifcfg_file=$(get_ifcfg_by_device "${1}") + + echo -n "${ifcfg_file}" +} + +# $1: netdev name +# Return the ifcfg file whole name(including the path) of $1 if any. +get_ifcfg_filename() { + local ifcfg_file + + ifcfg_file=$(get_ifcfg_nmcli "${1}") + if [ -z "${ifcfg_file}" ]; then + ifcfg_file=$(get_ifcfg_legacy "${1}") + fi + + echo -n "${ifcfg_file}" +} -- 1.8.3.1

4 8

[PATCH] kdumpctrl: kdump feasibility should fail if no crash memory
by Pratyush Anand 11 May '16

11 May '16

Currently initramfs is rebuilt even when crash kernel memory is not available and then latter on kdump service is failed. Its better to fail during feasibility itself when crash memory is not reserved. Signed-off-by: Pratyush Anand <panand(a)redhat.com> --- kdumpctl | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/kdumpctl b/kdumpctl index c7abaafdda27..38f29d2a305d 100755 --- a/kdumpctl +++ b/kdumpctl @@ -545,13 +545,6 @@ need_64bit_headers() # as the currently running kernel. load_kdump() { - MEM_RESERVED=$(cat /sys/kernel/kexec_crash_size) - if [ $MEM_RESERVED -eq 0 ] - then - echo "No memory reserved for crash kernel." >&2 - return 1 - fi - ARCH=`uname -m` if [ "$ARCH" == "i686" -o "$ARCH" == "i386" ] then @@ -876,8 +869,26 @@ check_fence_kdump_config() return 0 } +is_crash_mem_reserved() +{ + MEM_RESERVED=$(cat /sys/kernel/kexec_crash_size) + if [ $MEM_RESERVED -eq 0 ] + then + echo "No memory reserved for crash kernel." >&2 + return 0 + fi + + return 1 +} + + check_dump_feasibility() { + is_crash_mem_reserved + if [ $? -eq 0 ];then + return 1 + fi + if [ $DEFAULT_DUMP_MODE == "fadump" ]; then return 0 fi -- 2.5.5

4 9

[PATCH] .gitignore: Update to make it more generic
by Pratyush Anand 10 May '16

10 May '16

We do not have *.tar.xz, *.tar.gz as part of repositiry, so ignore them all. Also ignore *.swp, and *.rpm because many of such temporary files are created during development and such files would not be the part of repository. Signed-off-by: Pratyush Anand <panand(a)redhat.com> --- .gitignore | 23 ++++------------------- 1 file changed, 4 insertions(+), 19 deletions(-) diff --git a/.gitignore b/.gitignore index c13b1aed05ce..3c087dafc049 100644 --- a/.gitignore +++ b/.gitignore @@ -1,19 +1,4 @@ -/eppic_030413.tar.gz -/makedumpfile-1.5.7.tar.gz -/kexec-tools-2.0.8.tar.xz -/kdump-anaconda-addon-005-2-g86366ae.tar.gz -/kdump-anaconda-addon-005-5-gbf53665.tar.gz -/kdump-anaconda-addon-005-8-ge6ea581.tar.gz -/kdump-anaconda-addon-005-9-g6115ca7.tar.gz -/kexec-tools-2.0.9.tar.xz -/makedumpfile-1.5.8.tar.gz -/eppic_050615.tar.gz -/kexec-tools-2.0.10.tar.xz -/kdump-anaconda-addon-005-10-gd16915f.tar.gz -/kdump-anaconda-addon-005-11-g59f9b73.tar.gz -/kdump-anaconda-addon-005-12-g60fa4c1.tar.gz -/kdump-anaconda-addon-005-14-g563e904.tar.gz -/kdump-anaconda-addon-005-16-g586cc82.tar.gz -/kexec-tools-2.0.11.tar.xz -/makedumpfile-1.5.9.tar.gz -/kexec-tools-2.0.12.tar.xz +*.gz +*.xz +*.swp +*.rpm -- 2.5.5

2 2

[PATCH 0/5] kdumpctl: force rebuild when dump target is modified
by Pratyush Anand 05 May '16

05 May '16

Kexec-tools should be able to recognize if a dump target is reformatted, or dump path mounts another device. Changes since v4: - patch 4/5 is a new change - patch 4/4 of V3 is now 4/5. There has been many modifications in this patch. It includes feedback from Baoquan and Xunlei. Have also done some modification to recognize changes related to minix and NFS filesystem as well. Infact, whole structure of function is_fs_uuid_changed() has been modified. Now it has been renamed as is_dump_fs_modified() to suit it better. Although I have tested it rigorously, but still a careful review of is_dump_fs_modified() will be helpful. Changes since v3: - "$ret" unquoted - No message for "$system_modified" != "0" - image_time is now global - is_dump_target_modified has been renamed as is_fs_uuid_changed Changes since v2: -- now is_system_modified returns 2 in case of invalid modification, 1 in case of valid modification and 0 in case of no modification. -- file modification check has been moved to is_system_modified now -- variables have been put under "" in if condition check Changes since v1: -- Local variable is defined in shell function now -- raw target does not take persistent names "by-uuid" now -- dracut arguments grep is more robust -- When no UUID then warn and return Pratyush Anand (5): mkdumprd: do not lookup in by-uuid dirs for raw device's persistent name kdumpctl: force rebuild in case of dynamic system modification kdumpctl: Move file modification check logic in is_system_modified() mkdumprd: move to_dev_name() to kdump-lib.sh kdumpctl: force rebuild in case of file system is modified kdump-lib.sh | 14 +++++ kdumpctl | 173 ++++++++++++++++++++++++++++++++++++++++++++++++++--------- mkdumprd | 28 ++++------ 3 files changed, 171 insertions(+), 44 deletions(-) -- 2.5.5

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[PATCH] kdumpctl: rebuild when dump path is mounted to different device
by Pratyush Anand 29 Apr '16

29 Apr '16

If a disk is mounted on /var/crash, and is changed from /dev/diskA to /dev/diskB then rebuild. If /var/crash and / have been mounted on same disk but now a different disk is mounted at /var/crash then also rebuild. Signed-off-by: Pratyush Anand <panand(a)redhat.com> --- This patch would apply on top of series "kdumpctl: force rebuild when dump target is modified". Some testing after this patch: [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change(s) in the following file(s): /etc/kdump.conf Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# egrep -v '^#' /etc/kdump.conf path /var/crash [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# mount /dev/sdc1 /var/crash/ [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change in File System UUID Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# umount /var/crash [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change in File System UUID Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# mount /dev/sdc1 /var/crash/ [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change in File System UUID Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# umount /var/crash [root@localhost panand]# mount /dev/sdb1 /var/crash/ [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change in File System UUID Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] core_collector makedumpfile -l --message-level 1 -d 31 [root@localhost panand]# umount /var/crash Change kdump.conf to dump in ext4 target [root@localhost panand]# egrep -v '^#' /etc/kdump.conf ext4 /dev/sdb1 path /var/crash core_collector makedumpfile -l --message-level 1 -d 31 [root@localhost panand]# mount /dev/sdb1 /mnt/;mkdir /mnt/var;mkdir /mnt/var/crash [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change(s) in the following file(s): /etc/kdump.conf Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# umount /dev/sdb1;mount /dev/sdb1 /mnt/ [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] kexec: loaded kdump kernel Starting kdump: [OK] [root@localhost panand]# umount /dev/sdb1;mkfs.ext4 /dev/sdb1;mount /dev/sdb1 /mnt/;mkdir /mnt/var;mkdir /mnt/var/crash mke2fs 1.42.13 (17-May-2015) /dev/sdb1 contains a ext4 file system last mounted on Thu Apr 21 10:56:33 2016 Proceed anyway? (y,n) y Discarding device blocks: done Creating filesystem with 5242624 4k blocks and 1310720 inodes Filesystem UUID: 29c6c988-3137-418c-a3a7-4cc9490d69e9 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000 Allocating group tables: done Writing inode tables: done Creating journal (32768 blocks): done Writing superblocks and filesystem accounting information: done [root@localhost panand]# kdumpctl restart kexec: unloaded kdump kernel Stopping kdump: [OK] Detected change in File System UUID Rebuilding /boot/initramfs-4.5.0-302.fc24.x86_64+debugkdump.img kexec: loaded kdump kernel Starting kdump: [OK] kdumpctl | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) diff --git a/kdumpctl b/kdumpctl index 30832424562a..2ce00899a1e4 100755 --- a/kdumpctl +++ b/kdumpctl @@ -359,25 +359,44 @@ is_files_modified() return 0 } +# if a device different than root device is mounted at $path then echo +# the name of mounted device +path_mount_device() +{ + local _path _mnt + + _path=$(get_save_path) + #check if _path's mount point is root ("/") + _mnt=$(df $_path 2>/dev/null | tail -1 | awk '{ print $NF }') + if [[ "$_mnt" != "/" ]]; then + echo $(df $_path 2>/dev/null | tail -1 | awk '{ print $1 }') + fi +} + is_fs_uuid_changed() { local _target _dracut_args _uuid _target=$(egrep "^ext[234]|^xfs|^btrfs" /etc/kdump.conf) - #if dump target does not exist then do not rebuild - [[ -n "$_target" ]] || return 0 - _dracut_args=$(lsinitrd $TARGET_INITRD | grep "^Arguments:" | head -1) if [[ -z "$_dracut_args" ]];then echo "Warning: No dracut arguments found in initrd" return 0 fi - #if --mount or --device is not by UUID, then also do not rebuild - echo $_dracut_args | grep "by-uuid" &> /dev/null - [[ $? -eq 0 ]] || return 0 - _target=$(echo $_target | cut -d ' ' -f 2) + # if dump target does not exist, and dump path's mount point is same + # as that of root then do not rebuild + if [[ -n "$_target" ]]; then + _target=$(echo $_target | cut -d ' ' -f 2) + else + _target=$(path_mount_device) + fi + if [[ -z "$_target" ]]; then + echo $_dracut_args | grep "by-uuid" &> /dev/null + [[ $? -eq 0 ]] || return 0 + fi + _uuid=$(blkid $_target | awk -F"UUID=" '{print $2}' | cut -d '"' -f 2) if [[ -z "$_uuid" ]];then echo "Warning: UUID is not present" -- 2.5.0

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Re: [PATCH 0/5] kdumpctl: force rebuild when dump target is modified
by Pratyush Anand 29 Apr '16

29 Apr '16

Oops..forgot to add subject-prefix as V5. Kindly treat this series as "PATCH V5" On Fri, Apr 29, 2016 at 12:20 PM, Pratyush Anand <panand(a)redhat.com> wrote: > Kexec-tools should be able to recognize if a dump target is reformatted, or > dump path mounts another device. > > Changes since v4: > - patch 4/5 is a new change > - patch 4/4 of V3 is now 4/5. There has been many modifications in this > patch. It includes feedback from Baoquan and Xunlei. Have also done some > modification to recognize changes related to minix and NFS filesystem as > well. Infact, whole structure of function is_fs_uuid_changed() has been > modified. Now it has been renamed as is_dump_fs_modified() to suit it > better. Although I have tested it rigorously, but still a careful review > of is_dump_fs_modified() will be helpful. > > Changes since v3: > - "$ret" unquoted > - No message for "$system_modified" != "0" > - image_time is now global > - is_dump_target_modified has been renamed as is_fs_uuid_changed > > Changes since v2: > -- now is_system_modified returns 2 in case of invalid modification, 1 in > case of valid modification and 0 in case of no modification. > -- file modification check has been moved to is_system_modified now > -- variables have been put under "" in if condition check > > Changes since v1: > -- Local variable is defined in shell function now > -- raw target does not take persistent names "by-uuid" now > -- dracut arguments grep is more robust > -- When no UUID then warn and return > > Pratyush Anand (5): > mkdumprd: do not lookup in by-uuid dirs for raw device's persistent > name > kdumpctl: force rebuild in case of dynamic system modification > kdumpctl: Move file modification check logic in is_system_modified() > mkdumprd: move to_dev_name() to kdump-lib.sh > kdumpctl: force rebuild in case of file system is modified > > kdump-lib.sh | 14 +++++ > kdumpctl | 173 ++++++++++++++++++++++++++++++++++++++++++++++++++--------- > mkdumprd | 28 ++++------ > 3 files changed, 171 insertions(+), 44 deletions(-) > > -- > 2.5.5 >

1 0

[PATCH V4 0/4] kdumpctl: force rebuild when dump target is modified
by Pratyush Anand 29 Apr '16

29 Apr '16

When dump target is re-formatted then its UUID changes. These patches add support to recognize such changes and then force initramfs rebuild, if dracut argument has an UUID based root location. Changes since v3: - "$ret" unquoted - No message for "$system_modified" != "0" - image_time is now global - is_dump_target_modified has been renamed as is_fs_uuid_changed Changes since v2: -- now is_system_modified returns 2 in case of invalid modification, 1 in case of valid modification and 0 in case of no modification. -- file modification check has been moved to is_system_modified now -- variables have been put under "" in if condition check Changes since v1: -- Local variable is defined in shell function now -- raw target does not take persistent names "by-uuid" now -- dracut arguments grep is more robust -- When no UUID then warn and return Pratyush Anand (4): mkdumprd: do not lookup in by-uuid dirs for raw device's persistent name kdumpctl: force rebuild in case of dynamic system modification kdumpctl: Move file modification check logic in is_system_modified() kdumpctl: force rebuild in case of file system UUID changes kdumpctl | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++------------- mkdumprd | 14 +++++-- 2 files changed, 111 insertions(+), 30 deletions(-) -- 2.5.0

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Re: [PATCH] module-setup: Fix improper dns setup in kdump_setup_dns()
by Xunlei Pang 26 Apr '16

26 Apr '16

On 2016/04/26 at 17:07, Thomas Haller wrote: > On Mon, 2016-04-25 at 17:47 +0800, Hangbin Liu wrote: >> cc Daniel and network manager development team. They are experts on >> NM. >> >> On Mon, Apr 25, 2016 at 04:45:23PM +0800, Baoquan He wrote: >>> >>> Using NetworkManager or not using it can bring us so different >>> behaviours and different /etc/resolv.conf. Could you give >>> suggestion how >>> we can make decision to choose a reasonable one since kdump >>> probablly >>> need to cope with both of them? > > Hi, > > > Yes, NetworkManager's an initscript's interpretation differs in some > aspects. > > > To quote `man nm-settings-ifcfg-rh`: > > > Semantic change of variables > > NetworkManager had to slightly change the semantic for a few > variables. > > · PEERDNS - initscripts interpret PEERDNS=no to mean "never touch > resolv.conf". NetworkManager interprets it to say "never add > automatic (DHCP, PPP, VPN, etc.) nameservers to resolv.conf". > > > The behavior you described matches the documentation. Thanks! Then dracut follows NetworkManager at this point. But dracut does dhcp after handling nameservers in "nameserver=" and "ip=" specified by users, I guess NetworkManager does dhcp first, then appends DNS1&DNS2 in the ifcfg files. I happened to spot a dracut DNS bug caused by the above-mentioned order, I will try to post a patch to see if can fix it to follow NetworkManager. Regards, Xunlei > > > Thomas

1 0

Re: [PATCH] module-setup: Fix improper dns setup in kdump_setup_dns()
by Baoquan He 25 Apr '16

25 Apr '16

Thanks, Leo. Hi Daniel and NetworkManager team, We are kdump team dev, now have question about DNS handling from NetworkManager and those scripts in /etc/sysconfig/network-scripts. Could you please help to have a look when it's convenient to you? Thanks Baoquan On 04/25/16 at 05:47pm, Hangbin Liu wrote: > cc Daniel and network manager development team. They are experts on NM. > > On Mon, Apr 25, 2016 at 04:45:23PM +0800, Baoquan He wrote: > > Hi network experts, > > > > We got confusion on network DNS handling when we try to fix a kdump > > bug. For better representation let's assume a network interface enp0s25 > > with static DNS setting in ifcfg-enp0s25 as "DNS1=8.8.8.8", and dhclient > > privides 2 DNS server ip: > > > > 10.72.17.5 > > 10.68.5.26 > > > > > > Now the confusion is: > > > > 1) In 1st kernel if NetworkManager take control of the network setup and > > PEERDNS=yes, the behaviour of DNS handling is that it adds dhclient's DNS > > firstly then add static DNS from ifcfg-enp0s25. The result of > > /etc/resolv.conf will be as follows: > > nameserver 10.72.17.5 > > nameserver 10.68.5.26 > > nameserver 8.8.8.8 > > > > - But if we set PEERDNS=no, the result of /etc/resolv.conf is: > > nameserver 8.8.8.8 > > Apprently "PEERDNS=no" doesn't allow dhclient to add its DNS into > > /etc/resolv.conf. > > > > 2) However in 1st kernel if NetworkManager is disabled, means scripts > > under /etc/sysconfig/network-scripts/ take control of network setup and > > PEERDNS=yes, its behaviour is much different with NetworkManager. It > > will firstly add dhclient's DNS, then replace the first entry, namely > > "10.72.17.5" with the found static DNS from ifcfg-enp0s25. The result of > > /etc/resolv.conf will be like: > > nameserver 8.8.8.8 > > nameserver 10.68.5.26 > > > > - If PEERDNS=no set in ifcfg-enp0s25 > > /etc/resolv.conf won't be changed at all. > > > > Using NetworkManager or not using it can bring us so different > > behaviours and different /etc/resolv.conf. Could you give suggestion how > > we can make decision to choose a reasonable one since kdump probablly > > need to cope with both of them? > > > > In fact above cases are not problems we have since dracut have another > > different rules then above, and we need handle it. But now we need to > > clarify how DNS handling acts in 1st kernel. Your suggestions and ideas > > are very precisous to us. > > > > Thanks > > Baoquan > > > > On 04/25/16 at 03:29pm, Xunlei Pang wrote: > > > ============= 3. Conclusion ============= > > > Dracut, network-manager, and "network-scripts" all have different hehavior > > > in handling DNS. > > > > > > As a dhcp example: > > > Suppose enp0s25, the dhcped DNSes are stable: 10.72.17.5 and 10.68.5.26 > > > > > > In ifcfg-enp0s25: > > > DNS1: 8.8.8.8 > > > > > > 1) For 1st kernel's network-manager, the final nameservers in /etc/resolv.conf > > > -) If PEERDNS=yes(default is yes if PEERDNS doesn't exist) in ifcfg-enp0s25 > > > nameserver 10.72.17.5 > > > nameserver 10.68.5.26 > > > nameserver 8.8.8.8 > > > -) If PEERDNS=no in ifcfg-enp0s25 > > > nameserver 10.72.17.5 > > > nameserver 10.68.5.26 > > > nameserver 8.8.8.8 > > > > > > 2) For 1st kernel's scripts under /etc/sysconfig/network-scripts/ without network-manager > > > -) If PEERDNS=yes in ifcfg-enp0s25 > > > nameserver 8.8.8.8 > > > nameserver 10.68.5.26 > > > -) If PEERDNS=no in ifcfg-enp0s25 > > > Not touch /etc/resolv.conf > > > (i.e. /etc/resolv.conf is left unchanged as that before calling "ifup <config>") > > > > > > 3) For dracut in latest fedora kexec-tools(1st kernel using network-manager) > > > "${initdir}/etc/cmdline.d/42dns.conf" will contain: > > > nameserver=8.8.8.8 > > > nameserver=10.72.17.5 > > > nameserver=10.68.5.26 > > > nameserver=8.8.8.8 > > > > > > -) If "rd.peerdns=1"(default is "1" if "rd.peerdns" doesn't exist) is passed which is the default case > > > nameserver 8.8.8.8 > > > nameserver 10.72.17.5 > > > nameserver 10.68.5.26 > > > nameserver 8.8.8.8 > > > nameserver 10.72.17.5 // the last two are drauct' dhcp generated items > > > nameserver 10.68.5.26 > > > -) If "rd.peerdns=0" is passed > > > nameserver 8.8.8.8 > > > nameserver 10.72.17.5 > > > nameserver 10.68.5.26 > > > nameserver 8.8.8.8 > > > > > > > > > Regards, > > > Xunlei > > > > > > >> Regards, > > > >> Xunlei > > > >> > > > >>> Regards, > > > >>> Xunlei > > > >>> > > > >>>> Thanks > > > >>>> Minfei > > > >>>> > > > >>>>> There are two issues by doing this: > > > >>>>> 1) The dns sequence is different from that in 1st system. > > > >>>>> 2) There are some duplicated items. > > > >>>>> NOTE: kdump_setup_dns() meant to avoid the duplication, > > > >>>>> but the original shell command is actually disfunctional: > > > >>>>> "[ ! $(cat $_dnsfile | grep -q $_dns) ]" (always true) > > > >>>>> > > > >>>>> Fix the issues by firstly parsing "/etc/resolv.conf", then > > > >>>>> parsing ifcfg file, finally delete the duplicated items. > > > >>>>> > > > >>>>> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com> > > > >>>>> --- > > > >>>>> dracut-module-setup.sh | 27 ++++++++++++++++----------- > > > >>>>> 1 file changed, 16 insertions(+), 11 deletions(-) > > > >>>>> > > > >>>>> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh > > > >>>>> index 350864e..b7763f7 100755 > > > >>>>> --- a/dracut-module-setup.sh > > > >>>>> +++ b/dracut-module-setup.sh > > > >>>>> @@ -68,14 +68,6 @@ kdump_setup_dns() { > > > >>>>> local _dnsfile=${initdir}/etc/cmdline.d/42dns.conf > > > >>>>> local ifcfg_file > > > >>>>> > > > >>>>> - ifcfg_file=$(get_ifcfg_filename $1) > > > >>>>> - if [ -f "${ifcfg_file}" ]; then > > > >>>>> - . ${ifcfg_file} > > > >>>>> - fi > > > >>>>> - > > > >>>>> - [ -n "$DNS1" ] && echo "nameserver=$DNS1" > "$_dnsfile" > > > >>>>> - [ -n "$DNS2" ] && echo "nameserver=$DNS2" >> "$_dnsfile" > > > >>>>> - > > > >>>>> while read content; > > > >>>>> do > > > >>>>> _nameserver=$(echo $content | grep ^nameserver) > > > >>>>> @@ -84,10 +76,23 @@ kdump_setup_dns() { > > > >>>>> _dns=$(echo $_nameserver | cut -d' ' -f2) > > > >>>>> [ -z "$_dns" ] && continue > > > >>>>> > > > >>>>> - if [ ! -f $_dnsfile ] || [ ! $(cat $_dnsfile | grep -q $_dns) ]; then > > > >>>>> - echo "nameserver=$_dns" >> "$_dnsfile" > > > >>>>> - fi > > > >>>>> + echo "nameserver=$_dns" >> "$_dnsfile" > > > >>>>> done < "/etc/resolv.conf" > > > >>>>> + > > > >>>>> + unset DNS1 DNS2 > > > >>>>> + ifcfg_file=$(get_ifcfg_filename $1) > > > >>>>> + if [ -f "${ifcfg_file}" ]; then > > > >>>>> + . ${ifcfg_file} > > > >>>>> + fi > > > >>>>> + > > > >>>>> + [ -n "$DNS1" ] && echo "nameserver=$DNS1" >> "$_dnsfile" > > > >>>>> + [ -n "$DNS2" ] && echo "nameserver=$DNS2" >> "$_dnsfile" > > > >>>>> + > > > >>>>> + # Delete duplicated lines > > > >>>>> + if [ -f "$_dnsfile" ]; then > > > >>>>> + awk '!a[$0]++' $_dnsfile > $_dnsfile.tmp > > > >>>>> + mv -f $_dnsfile.tmp $_dnsfile > > > >>>>> + fi > > > >>>>> } > > > >>>>> > > > >>>>> #$1: netdev name > > > >>>>> -- > > > >>>>> 1.8.3.1 > > > >>>>> _______________________________________________ > > > >>>>> kexec mailing list > > > >>>>> kexec(a)lists.fedoraproject.org > > > >>>>> http://lists.fedoraproject.org/admin/lists/kexec@lists.fedoraproject.org > > > >>> _______________________________________________ > > > >>> kexec mailing list > > > >>> kexec(a)lists.fedoraproject.org > > > >>> http://lists.fedoraproject.org/admin/lists/kexec@lists.fedoraproject.org > > > >> _______________________________________________ > > > >> kexec mailing list > > > >> kexec(a)lists.fedoraproject.org > > > >> http://lists.fedoraproject.org/admin/lists/kexec@lists.fedoraproject.org > > > > > -- > > Thanks & Best Regards > Hangbin Liu <haliu(a)redhat.com> > Leo on #kernel-qe, #kernel, #eng-china

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kexec April 2016