On 03/27/17 at 06:46pm, Xunlei Pang wrote:
On 03/27/2017 at 05:51 PM, Baoquan He wrote:
> On 03/27/17 at 05:45pm, Baoquan He wrote:
>> On 03/27/17 at 01:10pm, Pratyush Anand wrote:
>>> Hi Xunlei,
>>> I could not understand why kdump emergency.service needs isolate while, it
>>> is not needed in first kernel (ie in systemd). If kdump would work without
>>> isolate then probably it will be more closer to upstream systemd and we
will
>>> need less modifications in kdump.
>> OK, I got the reason.
>>
>> W/o isolate, any error will trigger kdump emergency service. And default
>> action need be handled in kdump emergence service, namely kdump error
>> handler. If it's dump to rootfs, it will call "systemctl start
dracut-initqueue"
>> . However in dracut-initqueue, it will call "systemctl start
emergency"
>> directly, but not on-failure. The infinite loop happens in case the
>> original failure is triggered in dracut-initqueue.
> And seems there's thing wong in Wang Chao's comment, I remember,
> according to our discussion, isolate is not to stop other service,
> but to stop later new service from being started. isolate could not stop
> other running services.
Should be "to stop current running services" when "systemctl isolate"
is executed.
For example, "dump_to_rootfs" will execute "systemctl start
dracut-initqueue", then
Seems no. Here we execute "systemctl start dracut-initqueue" just
because we can't use systemd service mechanism, the reaons is simple,
isolate is specified in kdump service.
"systemctl start dracut-initqueue" is running command, like we start a
user space program, not by service starting way. My understanding.
Hi Xunlei,
I vaguely remember you are gonna to cleanup away dump to rootfs, then
maybe removing kdump error handler is a choice. Like Pratyush, making it
be consistent with dracut/systemd behaviour is better for our code
maintaining. Personnal opinion.
Thanks
Baoquan
> if it is "to stop later new service from being started", we will never be
able to start
> any new service in case of emergency.
>
> Regards,
> Xunlei
>
> >
> >>> ~Pratyush
> >>>> This will lead to systemd two contradictable jobs queued as an
> >>>> atomic transaction:
> >>>> job 1) the emergency service gets started by initrd-root-fs.target
> >>>> job 2) the emergency service gets stopped due to "systemctl
isolate"
> >>>> thereby throwing "Transaction is destructive".
> >>>>
> >>>> In order to solve it, we can utilize "IgnoreOnIsolate=yes"
for
> >>>> both kdump-emergency.service and kdump-emergency.target to avoid
> >>>> being isolated, then they can keep going on as expected in case
> >>>> of failures.
> >>>>
> >>>> We add kdump-emergency.target dedicated to kdump the similar way
> >>>> as did for kdump-emergency.service(i.e. will replace systemd's
> >>>> emergency.target with kdump-emergency.target under kdump), and
> >>>> adds "IgnoreOnIsolate=yes" into both of them.
> >>>>
> >>>> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com>
> >>>> ---
> >>>> dracut-kdump-emergency.service | 1 +
> >>>> dracut-kdump-emergency.target | 14 ++++++++++++++
> >>>> dracut-module-setup.sh | 3 ++-
> >>>> kexec-tools.spec | 2 ++
> >>>> 4 files changed, 19 insertions(+), 1 deletion(-)
> >>>> create mode 100644 dracut-kdump-emergency.target
> >>>>
> >>>> diff --git a/dracut-kdump-emergency.service
b/dracut-kdump-emergency.service
> >>>> index fb764f2..e023284 100644
> >>>> --- a/dracut-kdump-emergency.service
> >>>> +++ b/dracut-kdump-emergency.service
> >>>> @@ -12,6 +12,7 @@
> >>>> [Unit]
> >>>> Description=Kdump Emergency
> >>>> DefaultDependencies=no
> >>>> +IgnoreOnIsolate=yes
> >>>>
> >>>> [Service]
> >>>> ExecStart=/usr/bin/systemctl --no-block isolate
kdump-error-handler.service
> >>>> diff --git a/dracut-kdump-emergency.target
b/dracut-kdump-emergency.target
> >>>> new file mode 100644
> >>>> index 0000000..a1bb493
> >>>> --- /dev/null
> >>>> +++ b/dracut-kdump-emergency.target
> >>>> @@ -0,0 +1,14 @@
> >>>> +# This file is part of systemd.
> >>>> +#
> >>>> +# systemd is free software; you can redistribute it and/or modify
it
> >>>> +# under the terms of the GNU Lesser General Public License as
published by
> >>>> +# the Free Software Foundation; either version 2.1 of the License,
or
> >>>> +# (at your option) any later version.
> >>>> +
> >>>> +[Unit]
> >>>> +Description=Emergency Mode
> >>>> +Documentation=man:systemd.special(7)
> >>>> +Requires=emergency.service
> >>>> +After=emergency.service
> >>>> +AllowIsolate=yes
> >>>> +IgnoreOnIsolate=yes
> >>>> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> >>>> index 1f96bb8..fa4fa2a 100755
> >>>> --- a/dracut-module-setup.sh
> >>>> +++ b/dracut-module-setup.sh
> >>>> @@ -734,8 +734,9 @@ install() {
> >>>> ln_r "$systemdsystemunitdir/kdump-capture.service"
"$systemdsystemunitdir/initrd.target.wants/kdump-capture.service"
> >>>> inst "$moddir/kdump-error-handler.sh"
"/usr/bin/kdump-error-handler.sh"
> >>>> inst "$moddir/kdump-error-handler.service"
"$systemdsystemunitdir/kdump-error-handler.service"
> >>>> - # Replace existing emergency service
> >>>> + # Replace existing emergency service and emergency target
> >>>> cp "$moddir/kdump-emergency.service"
"$initdir/$systemdsystemunitdir/emergency.service"
> >>>> + cp "$moddir/kdump-emergency.target"
"$initdir/$systemdsystemunitdir/emergency.target"
> >>>> # Also redirect dracut-emergency to kdump error handler
> >>>> ln_r "$systemdsystemunitdir/emergency.service"
"$systemdsystemunitdir/dracut-emergency.service"
> >>>>
> >>>> diff --git a/kexec-tools.spec b/kexec-tools.spec
> >>>> index 2a176f3..c3359fb 100644
> >>>> --- a/kexec-tools.spec
> >>>> +++ b/kexec-tools.spec
> >>>> @@ -41,6 +41,7 @@ Source103: dracut-kdump-error-handler.sh
> >>>> Source104: dracut-kdump-emergency.service
> >>>> Source105: dracut-kdump-error-handler.service
> >>>> Source106: dracut-kdump-capture.service
> >>>> +Source107: dracut-kdump-emergency.target
> >>>>
> >>>> Requires(post): systemd-units
> >>>> Requires(preun): systemd-units
> >>>> @@ -197,6 +198,7 @@ cp %{SOURCE103}
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpb
> >>>> cp %{SOURCE104}
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix
%{SOURCE104}}
> >>>> cp %{SOURCE105}
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix
%{SOURCE105}}
> >>>> cp %{SOURCE106}
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix
%{SOURCE106}}
> >>>> +cp %{SOURCE107}
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix
%{SOURCE107}}
> >>>> chmod 755
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix
%{SOURCE100}}
> >>>> chmod 755
$RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix
%{SOURCE101}}
> >>>>
> >>>>
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