kexec June 2016

kexec@lists.fedoraproject.org

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13 discussions

[PATCH v2 1/2] kdump.conf: Support passing special mount information via "dracut_args"
by Xunlei Pang 15 Jun '16

15 Jun '16

There are some complaints about nfs kdump that users must mount nfs beforehand, which may cause some overhead to nfs server. For example, there're thounsands of diskless clients deployed with nfs dumping, each time the client is boot up, it will trigger kdump rebuilding so will mount nfs, thus resulting in thousands of nfs request concurrently imposed on the same nfs server. We introduce a new way of specifying mount information via the already-existent "dracut_args" directive(so avoid adding extra directives in /etc/kdump.conf), we will skip all the filesystem mounting and checking stuff for it. So it can be used in the above-mentioned nfs scenario to avoid severe nfs server overhead. Specifically, if there is any "--mount" information specified via "dracut_args" in /etc/kdump.conf, always use it as the final mount without any validation(mounting or checking like mount options, fs size, etc), so users are expected to ensure its correctness. When doing nfs mount via "dracut_args", because nfs needn't to be mounted beforehand, some nfs-related ko modules must be explicitly specified as needed together in the "dracut_args"(or via directive "extra_modules" in /etc/kdump.conf). As an nfs example: dracut_args --mount "192.168.1.1:/test /test nfs defaults" --add-driver "nfs nfsv4" NOTE: -Only one mount target is allowed using "dracut_args" globally. -Dracut will create <mountpoint> if it doesn't exist in kdump kernel, <mountpoint> must be specified in an absolute path. -There must be double quotation marks behind "--mount", i.e. --mount "<mount info>". -Users should do a test first and ensure it works because kdump does not prepare the mount and check all the validity. Suggested-by: Dave Young <dyoung(a)redhat.com> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com> --- dracut-kdump.sh | 6 +++++- dracut-module-setup.sh | 5 +++++ kdump-lib.sh | 41 ++++++++++++++++++++++++++++++++++++++++- kdumpctl | 13 ++++++++++++- mkdumprd | 3 +++ 5 files changed, 65 insertions(+), 3 deletions(-) diff --git a/dracut-kdump.sh b/dracut-kdump.sh index 4aab205..8747dba 100755 --- a/dracut-kdump.sh +++ b/dracut-kdump.sh @@ -117,7 +117,7 @@ save_vmcore_dmesg_ssh() { get_host_ip() { local _host - if is_nfs_dump_target || is_ssh_dump_target + if is_nfs_dump_target || is_ssh_dump_target || does_dracut_args_contain_nfsmount then kdumpnic=$(getarg kdumpnic=) [ -z "$kdumpnic" ] && echo "kdump: failed to get kdumpnic!" && return 1 @@ -146,6 +146,10 @@ read_kdump_conf() # remove inline comments after the end of a directive. config_val=$(strip_comments $config_val) case "$config_opt" in + dracut_args) + config_val=$(get_dracut_args_target "$config_val") + [[ -n "$config_val" ]] && add_dump_code "dump_fs $config_val" + ;; ext[234]|xfs|btrfs|minix|nfs) add_dump_code "dump_fs $config_val" ;; diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh index 4cd7107..5f03558 100755 --- a/dracut-module-setup.sh +++ b/dracut-module-setup.sh @@ -433,6 +433,11 @@ kdump_install_conf() { ssh|nfs) kdump_install_net "$config_val" ;; + dracut_args) + if is_nfs_in_dracut_args "$config_val"; then + kdump_install_net "$(get_dracut_args_target "$config_val")" + fi + ;; kdump_pre|kdump_post|extra_bins) dracut_install $config_val ;; diff --git a/kdump-lib.sh b/kdump-lib.sh index fc2c036..a486db6 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -45,7 +45,8 @@ is_fs_dump_target() is_user_configured_dump_target() { - return $(is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target || is_fs_dump_target) + return $(does_dracut_args_contain_mount || is_ssh_dump_target || is_nfs_dump_target || \ + is_raw_dump_target || is_fs_dump_target) } strip_comments() @@ -279,3 +280,41 @@ is_hostname() fi echo $1 | grep -q "[a-zA-Z]" } + +# If "dracut_args" contains "--mount" information, use it +# directly without any check(users are expected to ensure +# its correctness). +does_dracut_args_contain_mount() +{ + return $(grep ^dracut_args /etc/kdump.conf | grep -q "\-\-mount") +} + +does_dracut_args_contain_nfsmount() +{ + local fstype + + fstype=$(grep "^dracut_args .*\-\-mount" /etc/kdump.conf | sed "s/.*--mount \"$.*$/\1/" | cut -d' ' -f3) + [[ $fstype = nfs* ]] && return 0 + + return 1 +} + +# $1: configuration value of "dracut_args". +is_nfs_in_dracut_args() +{ + [[ $(get_dracut_args_fstype "$1") = nfs* ]] && return 0 + + return 1 +} + +# $1: configuration value of "dracut_args". +get_dracut_args_fstype() +{ + echo $1 | grep "\-\-mount" | sed "s/.*--mount \"$.*$/\1/" | cut -d' ' -f3 +} + +# $1: configuration value of "dracut_args". +get_dracut_args_target() +{ + echo $1 | grep "\-\-mount" | sed "s/.*--mount \"$.*$/\1/" | cut -d' ' -f1 +} diff --git a/kdumpctl b/kdumpctl index fcc9ad0..fbed66d 100755 --- a/kdumpctl +++ b/kdumpctl @@ -236,12 +236,18 @@ check_config() { local nr - nr=$(awk 'BEGIN{cnt=0} /^raw|^ssh[[:blank:]]|^nfs|^ext[234]|^xfs|^btrfs|^minix/{cnt++} END{print cnt}' $KDUMP_CONFIG_FILE) + nr=$(awk 'BEGIN{cnt=0} /^raw|^ssh[[:blank:]]|^nfs|^ext[234]|^xfs|^btrfs|^minix|^dracut_args .*\-\-mount/{cnt++} END{print cnt}' $KDUMP_CONFIG_FILE) [ $nr -gt 1 ] && { echo "More than one dump targets specified." return 1 } + nr=$(grep "^dracut_args .*\-\-mount" $KDUMP_CONFIG_FILE | grep -o "\-\-mount" | wc -l) + [ $nr -gt 1 ] && { + echo "More than one mount targets specified in \"dracut_args\"." + return 1 + } + while read config_opt config_val; do # remove inline comments after the end of a directive. config_val=$(strip_comments $config_val) @@ -365,6 +371,11 @@ check_dump_fs_modified() local _new_dev _new_mntpoint _new_fstype local _target _path _dracut_args + # No need to check in case of mount target specified via "dracut_args". + if does_dracut_args_contain_mount; then + return 0 + fi + # No need to check in case of raw target. # Currently we do not check also if ssh/nfs target is specified if is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target; then diff --git a/mkdumprd b/mkdumprd index 78afb1a..7a0e733 100644 --- a/mkdumprd +++ b/mkdumprd @@ -544,6 +544,9 @@ do verify_core_collector "$config_val" ;; dracut_args) + if is_nfs_in_dracut_args "$config_val"; then + add_dracut_module "nfs" + fi add_dracut_arg $config_val ;; *) -- 1.8.3.1

4 36

[PATCH v2] documentation fix
by Freeman Zhang 14 Jun '16

14 Jun '16

There are lots of typos and incorrect expressions in kdump.conf, as well as its manpage kdump.conf.5. Fix them to make it less confusing. Signed-off-by: Freeman Zhang <zhezhang(a)redhat.com> Reported-by: Donald Berry <dberry(a)redhat.com> --- v1->v2: Incorporating comments given by Dave Yang, Pratyush Anand and Donald Berry. Thanks for reviewing. I have learnt my lesson. kdump.conf | 89 ++++++++++++++++++++++++++++-------------------------------- kdump.conf.5 | 77 ++++++++++++++++++++++------------------------------ 2 files changed, 74 insertions(+), 92 deletions(-) diff --git a/kdump.conf b/kdump.conf index 54b581d..14b734a 100644 --- a/kdump.conf +++ b/kdump.conf @@ -3,14 +3,14 @@ # This file contains a series of commands to perform (in order) when a # kernel crash has happened and the kdump kernel has been loaded. Directives in # this file are only applicable to the kdump initramfs, and have no effect if -# the root filesystem is mounted and the normal init scripts are processed +# the root filesystem is mounted and the normal init scripts are processed. # -# Currently only one dump target and path may be configured at once -# if the configured dump target fails, the default action will be preformed -# the default action may be configured with the default directive below. If the -# configured dump target succedes +# Currently, only one dump target and path can be specified. If the configured +# dump target fails, the default action will be performed. The default action +# may be configured with the default directive. +# +# Supported options: # -# Basics commands supported are: # raw <partition> - Will dd /proc/vmcore into <partition>. # Use persistent device names for partition devices, # such as /dev/vg/<devname>. @@ -21,11 +21,11 @@ # ssh <user@server> - Will scp /proc/vmcore to # <user@server>:/var/crash/%HOST-%DATE/, supports DNS # NOTE: make sure user has necessary write -# permissions on server +# permissions on the server. # -# sshkey <path> - Will use the sshkey to do ssh dump -# Specifies the path of the ssh key you want to use -# when do ssh dump, the default value is +# sshkey <path> - Will use the sshkey to do ssh dump. +# Specifies the path of the ssh key to use +# when dumping via ssh. The default value is # /root/.ssh/kdump_id_rsa. # # <fs type> <partition> - Will mount -t <fs type> <partition> /mnt and copy @@ -50,17 +50,15 @@ # # core_collector <command> <options> # - This allows you to specify the command to copy -# the vmcore. You could use the dump filtering -# program makedumpfile, the default one, to retrieve -# your core, which on some arches can drastically -# reduce core file size. See /sbin/makedumpfile --help -# for a list of options. Note that the -i and -g -# options are not needed here, as the initrd will -# automatically be populated with a config file -# appropriate for the running kernel. -# Default core_collector for raw/ssh dump is: +# the vmcore. The default is makedumpfile, which on +# some architectures can drastically reduce core file size. +# See /sbin/makedumpfile --help for a list of options. +# Note that the -i and -g options are not needed here, +# as the initrd will automatically be populated with a +# config file appropriate for the running kernel. +# The default core_collector for raw/ssh dump is: # "makedumpfile -F -l --message-level 1 -d 31". -# Default core_collector for other targets is: +# The default core_collector for other targets is: # "makedumpfile -l --message-level 1 -d 31". # For core_collector format details please refer to # kexec-kdump-howto.txt or kdump.conf manpage. @@ -70,13 +68,13 @@ # executable just after the memory dump process # terminates. The exit status from the dump process # is fed to the kdump_post executable, which can be -# used to trigger different actions for success or -# failure. +# used to trigger actions for success or failure +# respectively. # # kdump_pre <binary | script> -# - works just like the kdump_post directive, but instead +# - Works just like the kdump_post directive, but instead # of running after the dump process, runs immediately -# before. Exit status of this binary is interpreted +# before. Exit status of this binary is interpreted # as follows: # 0 - continue with dump process as usual # non 0 - reboot the system @@ -94,23 +92,18 @@ # initrd, typically used to set up access to # non-boot-path dump targets that might otherwise # not be accessible in the kdump environment. Multiple -# modules can be listed, separated by a space, and any +# modules can be listed, separated by spaces, and any # dependent modules will automatically be included. # # default <reboot | halt | poweroff | shell | dump_to_rootfs> -# - Action to preform in case dumping to intended target -# fails. If no default action is specified, "reboot" -# is assumed default. -# reboot: If the default action is reboot simply reboot -# the system and loose the core that you are -# trying to retrieve. -# halt: If the default action is halt, then simply -# halt the system after attempting to capture -# a vmcore, regardless of success or failure. -# poweroff: The system will be powered down -# shell: If the default action is shell, then drop to -# an shell session inside the initramfs from -# where you can try to record the core manually. +# - Action to perform in case dumping to intended target +# fails. The default is "reboot". +# reboot: Reboot the system. The vmcore will be lost. +# halt: Halt the system. The vmcore will be lost. +# poweroff: The system will be powered down. +# shell: Drop to a shell session inside the initramfs, +# from which you can try to save the core +# manually. # Exiting this shell reboots the system. # Note: kdump uses bash as the default shell. # dump_to_rootfs: If non-root dump target is specified, @@ -119,15 +112,16 @@ # to rootfs from initramfs context and reboot. # # force_rebuild <0 | 1> -# - By default, kdump initrd only will be rebuilt when +# - By default, kdump initrd will only be rebuilt when # necessary. Specify 1 to force rebuilding kdump # initrd every time when kdump service starts. # -#override_resettable <0 | 1> -# - Usually a unresettable block device can't be dump target. -# Specifying 1 means though block target is unresettable, user -# understand this situation and want to try dumping. By default, -# it's set to 0, means not to try a destined failure. +# override_resettable <0 | 1> +# - Usually an unresettable block device can't be a dump +# target. Specifying 1 means that even though the block +# target is unresettable, the user wants to try dumping +# anyway. By default, it's set to 0, which will not try +# something destined to failure. # # dracut_args <arg(s)> # - Pass extra dracut options when rebuilding kdump @@ -135,11 +129,12 @@ # # fence_kdump_args <arg(s)> # - Command line arguments for fence_kdump_send (it can contain -# all valid arguments except hosts to send notification to). +# all valid arguments except hosts to send notification to). # # fence_kdump_nodes <node(s)> -# - List of cluster node(s) separated by space to send fence_kdump -# notification to (this option is mandatory to enable fence_kdump). +# - List of cluster node(s), separated by spaces, to send +# fence_kdump notifications to (this option is mandatory to +# enable fence_kdump). # #raw /dev/vg/lv_kdump diff --git a/kdump.conf.5 b/kdump.conf.5 index f1c2a2c..7036de3 100644 --- a/kdump.conf.5 +++ b/kdump.conf.5 @@ -10,14 +10,14 @@ collection service. kdump.conf provides post-kexec instructions to the kdump kernel. It is stored in the initrd file managed by the kdump service. If you change -this file and do not want to restart before it takes effect, restart -the kdump service to rebuild to initrd. +this file and do not want to have to reboot in order for the changes +to take effect, restart the kdump service to rebuild the initrd. For most configurations, you can simply review the examples provided in the stock /etc/kdump.conf. .B NOTE: -For filesystem dump the dump target must be mounted before building +For filesystem dumps the dump target must be mounted before building kdump initramfs. kdump.conf only affects the behavior of the initramfs. Please read the @@ -48,8 +48,8 @@ server and that a fqdn is used as the server name .B sshkey <path> .RS -Specifies the path of the ssh key you want to use when do ssh dump, -the default value is /root/.ssh/kdump_id_rsa. +Specifies the path of the ssh key to use when dumping via ssh. +The default value is /root/.ssh/kdump_id_rsa. .RE .B <fs type> <partition> @@ -77,26 +77,20 @@ Ignored for raw device dumps. If unset, will default to /var/crash. .B core_collector <command> <options> .RS This allows you to specify the command to copy the vmcore. -You could use the dump filtering program makedumpfile, the default one, -to retrieve your core, which on some arches can drastically reduce -core file size. See /sbin/makedumpfile --help for a list of options. +The default is makedumpfile, which on some architectures can drastically reduce +core file size. See /sbin/makedumpfile --help for a list of options. Note that the -i and -g options are not needed here, as the initrd will automatically be populated with a config file appropriate for the running kernel. .PP -Note 1: About default core collector: -Default core_collector for raw/ssh dump is: +Note 1: The default core_collector for raw/ssh dump is: "makedumpfile -F -l --message-level 1 -d 31". -Default core_collector for other targets is: +The default core_collector for other targets is: "makedumpfile -l --message-level 1 -d 31". -Even if core_collector option is commented out in kdump.conf, makedumpfile -is default core collector and kdump uses it internally. -If one does not want makedumpfile as default core_collector, then they -need to specify one using core_collector option to change the behavior. .PP Note 2: If "makedumpfile -F" is used then you will get a flattened format vmcore.flat, you will need to use "makedumpfile -R" to rearrange the -dump data from stdard input to a normal dumpfile (readable with analysis +dump data from standard input to a normal dumpfile (readable with analysis tools). ie. "makedumpfile -R vmcore < vmcore.flat" @@ -108,11 +102,10 @@ This directive allows you to run a specified executable just after the memory dump process terminates. The exit status from the dump process is fed to the kdump_post executable, which can be -used to trigger different actions for success or -failure. +used to trigger actions for success or failure respectively. .PP Note that scripts written for use with this -directive must use the /bin/bash interpreter +directive must use the /bin/bash interpreter. .RE .B kdump_pre <binary | script> @@ -127,7 +120,7 @@ as follows: non 0 - reboot the system .PP Note that scripts written for this directive must use -the /bin/bash interpreter +the /bin/bash interpreter. .RE .B extra_bins <binaries | shell scripts> @@ -146,36 +139,32 @@ modules that you want to be loaded in the kdump initrd, typically used to set up access to non-boot-path dump targets that might otherwise not be accessible in the kdump environment. Multiple -modules can be listed, separated by a space, and any +modules can be listed, separated by spaces, and any dependent modules will automatically be included. .RE .B default <reboot | halt | poweroff | shell | dump_to_rootfs> .RS -Action to preform in case dumping to intended target fails. If no default -action is specified, "reboot" is assumed default. -reboot: If the default action is reboot simply reboot the system (this is what -most people will want, as it returns the system to a nominal state). shell: If the default -action is shell, then drop to an shell session inside the initramfs from -where you can manually preform additional recovery actions. Exiting this shell -reboots the system. halt: bring the system to a halt, requiring manual reset -poweroff: The system will be powered down. dump_to_rootfs:If the default action -is dump_to_rootfs, specified root will be mounted and dump will be saved in "path" -directory. +Action to perform in case dumping to intended target fails. The default is "reboot". +reboot: reboot the system (this is what most people will want, as it returns the +system to a normal state). shell: drop to a shell session inside the initramfs, +from where you can manually perform additional recovery actions. Exiting this shell +reboots the system. halt: bring the system to a halt, requiring manual reset. +poweroff: the system will be powered down. dump_to_rootfs: specified root will be mounted and dump will be saved in "path" directory. Note: kdump uses bash as the default shell. .RE .B force_rebuild <0 | 1> .RS -By default, kdump initrd only will be rebuilt when necessary. +By default, kdump initrd will only be rebuilt when necessary. Specify 1 to force rebuilding kdump initrd every time when kdump service starts. .RE .B override_resettable <0 | 1> .RS -Usually a unresettable block device can't be dump target. Specifying 1 means -though block target is unresettable, user understand this situation and want -to try dumping. By default, it's set to 0, means not to try a destined failure. +Usually an unresettable block device can't be dump target. Specifying 1 means +that even though block target is unresettable, user wants to try dumping anyway. +By default, it's set to 0, which will not try something destined to failure. .RE @@ -195,7 +184,7 @@ arguments except hosts to send notification to). .B fence_kdump_nodes <node(s)> .RS -List of cluster node(s) separated by space to send fence_kdump notification +List of cluster node(s), separated by spaces, to send fence_kdump notification to (this option is mandatory to enable fence_kdump). .RE @@ -210,25 +199,23 @@ directly. .B options <module> <option list> .RS -Use KDUMP_COMMANDLINE_APPEND in /etc/sysconfig/kdump to add proper -module option as kernel command line params. Such as append loop.max_loop=1 -to limit maximum loop devices to 1. +Use KDUMP_COMMANDLINE_APPEND in /etc/sysconfig/kdump to add module options as kernel command line parameters. For example, specify 'append loop.max_loop=1' to limit maximum loop devices to 1. .RE .B link_delay <seconds> .RS -link_delay was used to wait a network device to initialize before using it. -Now dracut network module take care of this issue automaticlly. +link_delay was used to wait for a network device to initialize before using it. +Now dracut network module take care of this issue automatically. .RE .B disk_timeout <seconds> .RS -Similar to link_delay, dracut ensures disks being ready before kdump uses them. +Similar to link_delay, dracut ensures disks are ready before kdump uses them. .RE .B debug_mem_level <0-3> .RS -This was used to turns on debug/verbose output of kdump scripts regarding +This was used to turn on debug/verbose output of kdump scripts regarding free/used memory at various points of execution. This feature has been moved to dracut now. Use KDUMP_COMMANDLINE_APPEND in /etc/sysconfig/kdump and @@ -253,7 +240,7 @@ present in initramfs but it is not actually loaded in kernel. Hence retaining blacklist option creates more confusing behavior. It has been deprecated. .PP -Instead use rd.driver.blacklist option on second kernel to blacklist +Instead, use rd.driver.blacklist option on second kernel to blacklist a certain module. One can edit /etc/sysconfig/kdump.conf and edit KDUMP_COMMANDLINE_APPEND to pass kernel command line options. Refer to dracut.cmdline man page for more details on module blacklist option. @@ -262,7 +249,7 @@ to dracut.cmdline man page for more details on module blacklist option. .RE .SH EXAMPLES -Here is some examples for core_collector option: +Here are some examples for core_collector option: .PP Core collector command format depends on dump target type. Typically for filesystem (local/remote), core_collector should accept two arguments. -- 2.5.5

2 2

[PATCH] documentation fix
by Freeman Zhang 03 Jun '16

03 Jun '16

There are lots of typos and incorrect expressions in kdump.conf, as well as its manpage kdump.conf.5. Fix them to make it less confusing. Signed-off-by: Freeman Zhang <zhezhang(a)redhat.com> Reported-by: Donald Berry <dberry(a)redhat.com> --- kdump.conf | 73 +++++++++++++++++++++++++++++----------------------------- kdump.conf.5 | 75 ++++++++++++++++++++++++++---------------------------------- 2 files changed, 70 insertions(+), 78 deletions(-) diff --git a/kdump.conf b/kdump.conf index 54b581d..09716d7 100644 --- a/kdump.conf +++ b/kdump.conf @@ -1,16 +1,16 @@ -# Configures where to put the kdump /proc/vmcore files +# Configure where&how to save the kdump /proc/vmcore files # # This file contains a series of commands to perform (in order) when a # kernel crash has happened and the kdump kernel has been loaded. Directives in -# this file are only applicable to the kdump initramfs, and have no effect if +# this file are only applicable to the kdump initramfs, and show no effect if # the root filesystem is mounted and the normal init scripts are processed # -# Currently only one dump target and path may be configured at once -# if the configured dump target fails, the default action will be preformed -# the default action may be configured with the default directive below. If the -# configured dump target succedes +# Currently, only one dump target and path can be specified at a time. +# If the configured dump target fails, the default action will be performed. +# The default action may be configured with the default directive. +# +# Basic commands supported are: # -# Basics commands supported are: # raw <partition> - Will dd /proc/vmcore into <partition>. # Use persistent device names for partition devices, # such as /dev/vg/<devname>. @@ -23,9 +23,9 @@ # NOTE: make sure user has necessary write # permissions on server # -# sshkey <path> - Will use the sshkey to do ssh dump -# Specifies the path of the ssh key you want to use -# when do ssh dump, the default value is +# sshkey <path> - Will use the sshkey to do ssh dump. +# Specify the path of the ssh key you want to use +# when dumping via ssh, the default value is # /root/.ssh/kdump_id_rsa. # # <fs type> <partition> - Will mount -t <fs type> <partition> /mnt and copy @@ -58,9 +58,9 @@ # options are not needed here, as the initrd will # automatically be populated with a config file # appropriate for the running kernel. -# Default core_collector for raw/ssh dump is: +# The default core_collector for raw/ssh dump is: # "makedumpfile -F -l --message-level 1 -d 31". -# Default core_collector for other targets is: +# The default core_collector for other targets is: # "makedumpfile -l --message-level 1 -d 31". # For core_collector format details please refer to # kexec-kdump-howto.txt or kdump.conf manpage. @@ -70,14 +70,14 @@ # executable just after the memory dump process # terminates. The exit status from the dump process # is fed to the kdump_post executable, which can be -# used to trigger different actions for success or -# failure. +# used to trigger actions for success or failure +# respectively. # # kdump_pre <binary | script> -# - works just like the kdump_post directive, but instead -# of running after the dump process, runs immediately -# before. Exit status of this binary is interpreted -# as follows: +# - Works just like the kdump_post directive, but instead +# of running after the dump process, the executable runs +# right before the dumping. Exit status of the execution +# is interpreted as follows: # 0 - continue with dump process as usual # non 0 - reboot the system # @@ -90,28 +90,27 @@ # # extra_modules <module(s)> # - This directive allows you to specify extra kernel -# modules that you want to be loaded in the kdump +# modules that you wish to be loaded in the kdump # initrd, typically used to set up access to # non-boot-path dump targets that might otherwise # not be accessible in the kdump environment. Multiple -# modules can be listed, separated by a space, and any +# modules can be listed, separated by spaces, and any # dependent modules will automatically be included. # # default <reboot | halt | poweroff | shell | dump_to_rootfs> -# - Action to preform in case dumping to intended target +# - Action to perform in case dumping to intended target # fails. If no default action is specified, "reboot" # is assumed default. # reboot: If the default action is reboot simply reboot -# the system and loose the core that you are +# the system and drop the core that you are # trying to retrieve. # halt: If the default action is halt, then simply -# halt the system after attempting to capture -# a vmcore, regardless of success or failure. +# halt the system after failure. # poweroff: The system will be powered down # shell: If the default action is shell, then drop to -# an shell session inside the initramfs from -# where you can try to record the core manually. -# Exiting this shell reboots the system. +# a shell session inside the initramfs from +# where you can try to save the core manually. +# Then exit this shell to reboot the system. # Note: kdump uses bash as the default shell. # dump_to_rootfs: If non-root dump target is specified, # the default action can be set as dump_to_rootfs. @@ -119,15 +118,16 @@ # to rootfs from initramfs context and reboot. # # force_rebuild <0 | 1> -# - By default, kdump initrd only will be rebuilt when +# - By default, kdump initrd will only be rebuilt when # necessary. Specify 1 to force rebuilding kdump # initrd every time when kdump service starts. # -#override_resettable <0 | 1> -# - Usually a unresettable block device can't be dump target. -# Specifying 1 means though block target is unresettable, user -# understand this situation and want to try dumping. By default, -# it's set to 0, means not to try a destined failure. +# override_resettable <0 | 1> +# - Usually an unresettable block device can't be a dump +# target. Specifying 1 means that even though the block +# target is unresettable, the user wants to try dumping +# anyway. By default, it's set to 0, which will not try +# something destined to failure. # # dracut_args <arg(s)> # - Pass extra dracut options when rebuilding kdump @@ -135,11 +135,12 @@ # # fence_kdump_args <arg(s)> # - Command line arguments for fence_kdump_send (it can contain -# all valid arguments except hosts to send notification to). +# all valid arguments except hosts to send notification to). # # fence_kdump_nodes <node(s)> -# - List of cluster node(s) separated by space to send fence_kdump -# notification to (this option is mandatory to enable fence_kdump). +# - List of cluster node(s), separated by spaces, to send +# fence_kdump notifications to (this option is mandatory to +# enable fence_kdump). # #raw /dev/vg/lv_kdump diff --git a/kdump.conf.5 b/kdump.conf.5 index f1c2a2c..5eabad7 100644 --- a/kdump.conf.5 +++ b/kdump.conf.5 @@ -11,13 +11,13 @@ collection service. kdump.conf provides post-kexec instructions to the kdump kernel. It is stored in the initrd file managed by the kdump service. If you change this file and do not want to restart before it takes effect, restart -the kdump service to rebuild to initrd. +the kdump service to rebuild the initrd. For most configurations, you can simply review the examples provided in the stock /etc/kdump.conf. .B NOTE: -For filesystem dump the dump target must be mounted before building +For filesystem dumps the dump target must be mounted before building kdump initramfs. kdump.conf only affects the behavior of the initramfs. Please read the @@ -48,8 +48,8 @@ server and that a fqdn is used as the server name .B sshkey <path> .RS -Specifies the path of the ssh key you want to use when do ssh dump, -the default value is /root/.ssh/kdump_id_rsa. +Specifies the path of the ssh key you want to use when dumping via ssh. +The default value is /root/.ssh/kdump_id_rsa. .RE .B <fs type> <partition> @@ -77,26 +77,20 @@ Ignored for raw device dumps. If unset, will default to /var/crash. .B core_collector <command> <options> .RS This allows you to specify the command to copy the vmcore. -You could use the dump filtering program makedumpfile, the default one, -to retrieve your core, which on some arches can drastically reduce -core file size. See /sbin/makedumpfile --help for a list of options. +The default is makedumpfile, which can drastically reduce core file size on +some architectures. See /sbin/makedumpfile --help for a list of options. Note that the -i and -g options are not needed here, as the initrd -will automatically be populated with a config file appropriate -for the running kernel. +will automatically be populated with a config file appropriate for the +running kernel. .PP -Note 1: About default core collector: -Default core_collector for raw/ssh dump is: +Note 1: The default core_collector for raw/ssh dump is: "makedumpfile -F -l --message-level 1 -d 31". -Default core_collector for other targets is: +The default core_collector for other targets is: "makedumpfile -l --message-level 1 -d 31". -Even if core_collector option is commented out in kdump.conf, makedumpfile -is default core collector and kdump uses it internally. -If one does not want makedumpfile as default core_collector, then they -need to specify one using core_collector option to change the behavior. .PP Note 2: If "makedumpfile -F" is used then you will get a flattened format vmcore.flat, you will need to use "makedumpfile -R" to rearrange the -dump data from stdard input to a normal dumpfile (readable with analysis +dump data from standard input to a normal dumpfile (readable with analysis tools). ie. "makedumpfile -R vmcore < vmcore.flat" @@ -108,26 +102,25 @@ This directive allows you to run a specified executable just after the memory dump process terminates. The exit status from the dump process is fed to the kdump_post executable, which can be -used to trigger different actions for success or -failure. +used to trigger actions for success or failure repectively. .PP Note that scripts written for use with this -directive must use the /bin/bash interpreter +directive must use the /bin/bash interpreter. .RE .B kdump_pre <binary | script> .RS Works just like the kdump_post directive, but instead -of running after the dump process, runs immediately -before. Exit status of this binary is interpreted -as follows: +of running after the dump process, the specified executable +runs right before dumping. Exit status of the execution is +interpreted as follows: .PP 0 - continue with dump process as usual .PP non 0 - reboot the system .PP Note that scripts written for this directive must use -the /bin/bash interpreter +the /bin/bash interpreter. .RE .B extra_bins <binaries | shell scripts> @@ -142,22 +135,22 @@ relies on other binaries or scripts. .B extra_modules <module(s)> .RS This directive allows you to specify extra kernel -modules that you want to be loaded in the kdump +modules that you wish to be loaded in the kdump initrd, typically used to set up access to non-boot-path dump targets that might otherwise not be accessible in the kdump environment. Multiple -modules can be listed, separated by a space, and any +modules can be listed, separated by spaces, and any dependent modules will automatically be included. .RE .B default <reboot | halt | poweroff | shell | dump_to_rootfs> .RS -Action to preform in case dumping to intended target fails. If no default +Action to perform in case dumping to intended target fails. If no default action is specified, "reboot" is assumed default. reboot: If the default action is reboot simply reboot the system (this is what most people will want, as it returns the system to a nominal state). shell: If the default -action is shell, then drop to an shell session inside the initramfs from -where you can manually preform additional recovery actions. Exiting this shell +action is shell, then drop to a shell session inside the initramfs from +where you can manually perform additional recovery actions. Exiting this shell reboots the system. halt: bring the system to a halt, requiring manual reset poweroff: The system will be powered down. dump_to_rootfs:If the default action is dump_to_rootfs, specified root will be mounted and dump will be saved in "path" @@ -167,15 +160,15 @@ Note: kdump uses bash as the default shell. .B force_rebuild <0 | 1> .RS -By default, kdump initrd only will be rebuilt when necessary. +By default, kdump initrd will only be rebuilt when necessary. Specify 1 to force rebuilding kdump initrd every time when kdump service starts. .RE .B override_resettable <0 | 1> .RS -Usually a unresettable block device can't be dump target. Specifying 1 means -though block target is unresettable, user understand this situation and want -to try dumping. By default, it's set to 0, means not to try a destined failure. +Usually an unresettable block device can't be dump target. Specifying 1 means +that even though block target is unresettable, user wants to try dumping anyway. +By default, it's set to 0, which will not try something destined to failure. .RE @@ -195,7 +188,7 @@ arguments except hosts to send notification to). .B fence_kdump_nodes <node(s)> .RS -List of cluster node(s) separated by space to send fence_kdump notification +List of cluster node(s), separated by spaces, to send fence_kdump notification to (this option is mandatory to enable fence_kdump). .RE @@ -210,25 +203,23 @@ directly. .B options <module> <option list> .RS -Use KDUMP_COMMANDLINE_APPEND in /etc/sysconfig/kdump to add proper -module option as kernel command line params. Such as append loop.max_loop=1 -to limit maximum loop devices to 1. +Use KDUMP_COMMANDLINE_APPEND in /etc/sysconfig/kdump to add module options as kernel command line parameters. For example, specify 'append loop.max_loop=1' to limit maximum loop devices to 1. .RE .B link_delay <seconds> .RS -link_delay was used to wait a network device to initialize before using it. +link_delay was used to wait for a network device to initialize before using it. Now dracut network module take care of this issue automaticlly. .RE .B disk_timeout <seconds> .RS -Similar to link_delay, dracut ensures disks being ready before kdump uses them. +Similar to link_delay, dracut ensures disks are ready before kdump uses them. .RE .B debug_mem_level <0-3> .RS -This was used to turns on debug/verbose output of kdump scripts regarding +This was used to turn on debug/verbose output of kdump scripts regarding free/used memory at various points of execution. This feature has been moved to dracut now. Use KDUMP_COMMANDLINE_APPEND in /etc/sysconfig/kdump and @@ -253,7 +244,7 @@ present in initramfs but it is not actually loaded in kernel. Hence retaining blacklist option creates more confusing behavior. It has been deprecated. .PP -Instead use rd.driver.blacklist option on second kernel to blacklist +Instead, use rd.driver.blacklist option on second kernel to blacklist a certain module. One can edit /etc/sysconfig/kdump.conf and edit KDUMP_COMMANDLINE_APPEND to pass kernel command line options. Refer to dracut.cmdline man page for more details on module blacklist option. @@ -262,7 +253,7 @@ to dracut.cmdline man page for more details on module blacklist option. .RE .SH EXAMPLES -Here is some examples for core_collector option: +Here are some examples for core_collector option: .PP Core collector command format depends on dump target type. Typically for filesystem (local/remote), core_collector should accept two arguments. -- 2.5.5

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kexec June 2016