On 12/09/13 at 09:37pm, Zhi Zou wrote:
----- Original Message -----
> On 12/09/13 at 04:45pm, Zhi Zou wrote:
> > Description of problem:
> > Kdump can dump the vmcore to remote nfs target if kdump was
> > configred by using nfs dump and nfs target was mounted before
> > building kdump initramfs. But if we use hostname to configure
> > nfs dump, Though the kdump service will start successfully, dump
> > will fail because there isn't a /etc/hosts file in initramfs.
> >
> > Resolution:
> > copy /etc/hosts to initramfs.
>
> I think it would be useful if we install /etc/hosts to kdump initramfs.
> But what I concern is when the host ip changed in /etc/hosts, a rebuild
> wouldn't be triggered, and in 2nd kernel, mount nfs server would fail.
>
Yes, That is really a problem.
> Moreover, this seems like a dracut issue. dracut can mount nfs in
> initramfs and it does need /etc/hosts to look up for static configured
> hostname.
>
I think mkdumprd just add a "mount" argument and a "nfs" module in
dracut
when using nfs. The way dracut address the "mount" argument is add a entry
in "${initdir}/etc/fstab. So if there isn't /etc/hosts in intramfs, the 2nd
kernel still can't mount the target.
That's exactly what I was talking about.
Think about the case of normal boot, if we want to mount such static
hostname in initramfs, we still need /etc/hosts. That's why a normal
boot and a kdump boot share the same concern in this case.
What's more, /etc/hosts is not necessary for dracut nfs and ssh
module.
Why? Is it because dracut doesn't support static hostname or dracut just
need to be fixed?
So I think the better way is test if we should install /etc/hosts to
initramfs
in mkdumprd.
If we really need /etc/hosts to do static hostname lookup, we should
install it.
If we don't need /etc/hosts because the hostname is a dynamic name
configured by DNS server, it's harmless whether or not we install it.
I think I'd like to support what dracut supports (unless it's kdump
specific stuff). So my idea is:
1. Try to fix it in dracut. Because this is not kdump only issue.
2. If we can't fix it in dracut, we can always encourage user to specify
'dracut_args --install /etc/hosts' in /etc/kdump.conf, when they want
to use a static hostname.
Thanks
WANG Chao
> >
> > Signed-off-by: arthur <zzou(a)redhat.com>
> > ---
> > mkdumprd | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/mkdumprd b/mkdumprd
> > index 6de1755..d18882a 100644
> > --- a/mkdumprd
> > +++ b/mkdumprd
> > @@ -520,6 +520,7 @@ do
> >
> > if [ "$config_opt" = "nfs" ]; then
> > add_dracut_module "nfs"
> > + add_dracut_arg "--install" "/etc/hosts"
>
> ssh dump is in the same situation here.
>
Yes, ssh should have the same problem.
> Thanks
> WANG Chao
>
> > fi
> > add_mount "$config_val"
> > mkdir_save_path_fs $config_val
> > --
> > 1.8.4.2
> >
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