Re: [Xen-users] Xen 4.2.2 /etc/init.d/xendomains save and restore of domains does not work

[Andreas Greve <greve-ml@xxxxxxxxxx>]

first sorry that I explained it bad but my English is not very well:

second I realize why you could not reproduce my problems under xl JSON 
format:
short: my symlink names in $XENDOMAINS_AUTO differ from the "real" 
domain name. Later more about that
Problem description detail:

File: /etc/init.d/xendomains (from 4.3 git 
commit543a2657182dbb9237d1feeb1d3193096ab2cb2d )
The sed "expression in function rdname()

rdname()
{
    NM=$($CMD create --quiet --dryrun --defconfig "$1" |
         sed -n 's/^.*(name \(.*\))$/\1/p')
}

    called by

is_running $dom

   called from

start

   in the if block

if contains_something "$XENDOMAINS_AUTO"
then
[....]
if [ $? -eq 0 ] || is_running $dom; then

    works only for the SXP format and not for the  JSON format. For 
JSON fromat the funktion is_running $dom  will nearly always return false

Example to show that:

root@srv01:~# xl create --quiet --dryrun --defconfig 
/etc/xen/auto/03_gnomedag | head -10
{
    "domid": null,
    "config": {
        "c_info": {
            "type": "pv",
            "hap": "<default>",
            "oos": "<default>",
            "ssidref": 0,
            "name": "gnomedag",
            "uuid": "2d33d9c8-7efe-4060-8e61-b47af2796a5c",
root@srv01:~#


root@srv01:~# xl create --quiet --dryrun --defconfig 
/etc/xen/auto/03_gnomedag \
| sed -n 's/^.*(name \(.*\))$/\1/p'
root@srv01:~#


So $NM will always be empty and is_running() will nearly always return 
false;
is_running()
{
    rdname $1
    RC=1
    name=;id=
    while read LN; do
        parseln "$LN" || continue
        if test $id = 0; then continue; fi
        case $name in
            ($NM)
            RC=0
            ;;
        esac
    done < <($CMD list -l | grep "$LIST_GREP")
    return $RC
}


In contrast my sed "expression" will work for JSON format but not for 
SXP (Yes with that you are right. Sorry ! Up to now I did not know or 
have forgotten that xl supports both formats).
root@srv01:~# xl create --quiet --dryrun --defconfig 
/etc/xen/auto/03_gnomedag \
| sed -n 's/^.*"name": "\(.*\)",$/\1/p'
gnomedag
root@srv01:~#

That is what I expected for JSON format.


I found why our both test have different results for the JSON fromat:

On my System (historical reason) the name of the symlinks in 
$XENDOMAINS_AUTO/* differ from the "real" domain name (example: domain 
name: gnomedag   symlink name: /etc/xen/auto/03_gnomedag -> 
/etc/xen/gnomedag.cfg).
        shortdom=$(echo $dom | sed -n 's/^.*\/\(.*\)$/\1/p')
        echo $saved_domains | grep -w $shortdom > /dev/null
        if [ $? -eq 0 ] || is_running $dom; then
              echo -n "(skip)"
        else

In your configuration the restored domain names  are filtered by the 
echo ... | grep -w ... instruction. So
is_running $dom is never called for them. So you will never see the 
semantical error produced  by rdname().
In my system  the "real" domain name stored  in saved_domains differ 
from the value in $dom. So
is_running $dom is always called and always returns false. Which leads 
to a "second start" of the already restored domain.

In the moment I have no good idea how to combine the two needed sed 
expressions for the rdname() function
sed -n 's/^.*(name \(.*\))$/\1/p'     #SXP

sed -n 's/^.*"name": "\(.*\)",$/\1/p' #JSON



On 07/01/13 02:06, Ian Murray wrote:
> >  I download the file by from git and give him a chance. It works 
> > nearly perfect.
> > On xendomains stop there was all ok.
> >
> > On xendomains start it restores the saved domains but after that it 
> > tries to start them again and produce some error messages like domain 
> > is already running.
> It appears to be working fine for me. I am running 4.3 rc 6 + next 
> commit. Rather than saying the output has changed for xl, I think you 
> may be referring to the fact that xl now can output JSON as well as 
> xm's SXP. Having said this, xendomains works both properly for me both 
> using JSON and SXP although I am not sure why the skipping of the 
> autostart domains is working when I select JSON in xl.conf. Certainly 
> the xl ... sed line fails when I execute it manually when using JSON.
> I think your solution is not the right approach because xl can produce 
> JSON and SXP format and that is defined in xl.conf. Your solution will 
> have a problem when setting xl to produce SXP, I think.
> root@xen6:/etc/xen/auto# service xendomains stop
> Shutting down Xen domains: 
> ubuntu-email(save)................................
>  vpn2(save)....
>  *   [done]
> root@xen6:/etc/xen/auto# service xendomains start
> Restoring Xen domains: ubuntu-email vpn2
> Starting auto Xen domains: ubuntu-email(skip) vpn2(skip) *   [done]
>
> Not tested against xm as I have no means to do so.
>
>
> > The reason is  the sed script in rdname() does not work with xl output.
> > I'll changed it in the way as you have done with HEADCOMP (see the 
> > diff below).
> > After that all was nice for me
> >
> >
> > ------------------------------------------------
> > root@srv01:/etc/init.d# diff -u .xendomains.4.3.original xendomains
> > --- .xendomains.4.3.original    2013-06-30 20:54:14.000000000 +0200
> > +++ xendomains  2013-06-30 23:27:44.000000000 +0200
> > @@ -31,11 +31,13 @@
> >
> >  CMD=${SBINDIR}/xm
> >  HEADCOMP="LinuxGuestRecord"
> > +RDNAMESED='s/^.*(name \(.*\))$/\1/p'
> >  $CMD list &> /dev/null
> >  if test $? -ne 0
> >  then
> >         CMD=${SBINDIR}/xl
> >         HEADCOMP="Xen saved domain"
> > +        RDNAMESED='s/^.*"name": "\(.*\)",$/\1/p'
> >  fi
> >
> >  $CMD list &> /dev/null
> > @@ -185,8 +187,8 @@
> >  # read name from xen config file
> >  rdname()
> >  {
> > -    NM=$($CMD create --quiet --dryrun --defconfig "$1" |
> > -         sed -n 's/^.*(name \(.*\))$/\1/p')
> > +    NM=$( $CMD create --quiet --dryrun --defconfig "$1" |
> > +         sed -n "${RDNAMESED}" )
> >  }
> >
> >  rdnames()
> > ----------------------------------------------------
> >
> > > I am surprised you did not have issue with 4.2.1 because the header 
> > > issues have been present ever since xl became the default/preferred 
> > > toolstack, unless your Xen 4.2.1 came from a third-party.
> > Your are right I remember that there were some problems with 4.2.1 
> > too. As I switched from 4.1 to 4.2.1.
> > Sorry at that time I had not much time. If I remember right, I fixed 
> > that in any way for me, but forget to report.
> > Thanks for your help. I learned a lot about bash (bla) seams to be 
> > equal to bla) in case instructions. That was new for me.
> >
> > Best wishes
> >
> >
> > Andreas
> >
> > > _______________________________________________
> > > Xen-users mailing list
> > > Xen-users@xxxxxxxxxxxxx
> > > http://lists.xen.org/xen-users

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