Re: diskless package issues...

[Adam C Powell IV <hazelsct@mit.edu>]

Adam C Powell IV wrote:

> Junichi Uekawa (Junichi Uekawa mikilab) wrote:
>
> > On Mon, 01 Jul 2002 19:32:47 -0400
> > Adam C Powell IV <hazelsct@mit.edu> wrote:
> >
> > Hi,
> >
> > > I have three questions.  First, when I chroot to 
> > > /var/lib/diskless/default/root and install new packages, /etc and 
> > > /var updates don't propagate to the host /etc and /var directories.  
> > > Are there plans to make this work -- for example, to have a 
> > > "diskless-update" script to update all of those dirs?
> > >   
> >
> > I think that would be very difficult to implement, considering that 
> > the differences on each individual clients would be pretty difficult 
> > to track, to say the least.
Okay, I've come up with three possible ways to do this:

  1. Touch a file e.g. $diskless-rootdir/lastupdate, and after
     subsequent updates, copy newer files than it from /etc and /var to
     all of the $diskless-hostdir/etc and var.  Problem: though there
     are some conffiles in /var, we don't want to copy everything in
     /var, that could overwrite some important information there.
  2. Update individual packages.  Look at the package's
     /var/lib/dpkg/info/<package>.conffiles and copy them all from
     $diskless-rootdir to $diskless-hostdirs.
  3. Have a "diskless-rebuild-hosts" script which looks at each
     $diskless-hostdir, gets etc/hostname, removes that dir, and runs
     diskless-newhost for that host.  If nothing else, this would
     automate the process of rebuilding all of the host files, which
     we've been doing by hand (and is kind of annoying).  The problem
     is that this seriously messes up running systems, and can't be
     done on the fly, only once in a while as major maintenance with
     all of the nodes shut down.

I've attached a simple hybrid of 1 and 2 which uses update-cluster and a 
hypothetical (but optional) /etc/default/diskless for variable settings, 
I've put it in /usr/lib/update-cluster so it will run with the other 
scripts called by update-cluster-regenerate.  It's pretty simple and 
non-invasive, and should be okay to do with a running cluster.  I 
suppose it should also check to see whether a particular hostdir exists, 
and if not, then run diskless-newhost to create it...

I've also attached a simple script for 3, though if there's a new entry 
in cluster.xml without a corresponding dir, then it doesn't have a 
hostname or mailname, so diskless-newhost prompts the user.  I haven't 
tested it just yet, but plan to do so next time we bring down the cluster...

What do you think?

One other thing: it would be nice if diskless-newhost could use the 
root/etc/fstab to create the $ip/etc/fstab, so one can easily set up 
uniform swap, /scratch (or /tmp overrides), etc.  Also, if /home should 
be mounted from an NFS server different from the head node, this 
override could also go in root/etc/fstab, and take the place of the 
standard /home entry.  Makes sense?  If so I'll investigate a patch.

> Thanks again for a really nice package!

Zeen,
--

-Adam P.

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#!/bin/bash

IMAGEROOT=/var/lib/diskless/default/root
UPDATEFILE=$IMAGEROOT/.lastupdate
HOSTROOT=/var/lib/diskless/default

[ -f /etc/default/diskless ] && . /etc/default/diskless

conffilelist=`cat $IMAGEROOT/var/lib/dpkg/info/*.conffiles`

for file in $conffilelist; do \
  if [ `find $IMAGEROOT/$file -cnewer $UPDATEFILE` ]; then\
    echo Copying $file to host directories; \
    for hostip in `cat $CLUSTERXML | \
                   update-cluster-remove --master | \
		   update-cluster-parseconfig ip`; do \
      install -p $IMAGEROOT/$file $HOSTROOT/$hostip/$file; \
    done; \
  fi; \
done

touch $UPDATEFILE

#!/bin/bash

IMAGEROOT=/var/lib/diskless/default/root
UPDATEFILE=$IMAGEROOT/.lastupdate
HOSTROOT=/var/lib/diskless/default

[ -f /etc/default/diskless ] && . /etc/default/diskless

for hostip in `cat $CLUSTERXML | \
	       update-cluster-remove --master | \
	       update-cluster-parseconfig ip`; do \
  if [ -f $HOSTROOT/$hostip/etc/hostname ]; then \
    hostname=`cat $HOSTROOT/$hostip/etc/hostname`; \
    mailname=`cat $HOSTROOT/$hostip/etc/mailname`;
    diskless-newhost $IMAGEROOT $hostip host=$hostname mailname=$mailname; \
  else \
    diskless-newhost $IMAGEROOT $hostip; \
  fi; \
done