linux-um archives
 help / color / mirror / Atom feed
* [uml-devel] demo of SBUML - swsusp functionality for UML
@ 2003-12-13  4:07 Richard Potter
  2003-12-13 15:34 ` roland
  2003-12-14 15:08 ` BlaisorBlade
  0 siblings, 2 replies; 5+ messages in thread
From: Richard Potter @ 2003-12-13  4:07 UTC (permalink / raw)
  To: user-mode-linux-devel

Dear UML developers:

We have been working on a type of software suspend and restore for
UML.  Eventually it will be announced and hosted at
sbuml.sourceforge.net, however while that site is being prepared, it
seems appropriate for people on this User-mode-linux-devel mailing
to have a chance to try out the system in its present form.

If you would like, you can download a demo from:
http://sbuml.sourceforge.net/demo-for-umldev-list.html

Source code for the scripts is included in the demo.  Source code for
the binary will be available soon.

SBUML was created to support research in "Computation Scrapbook" based
programming tools and to support research in model checking.
(http://hagi.is.s.u-tokyo.ac.jp/members/potter/pubs/) There are also
potentially many other applications.  However, our short term
development (and bug fixing) focus will be using SBUML to distribute
pre-configured runtime state.  Potential users might include software
developers who wish to prepare demos without bothering potential users
with setup instructions, teachers of programming who want to distribute
debugging scenarios to students, or software users who would like
provide detailed bug reports (super core dumps :-) to developers.

To make this more practical, it should be possible to run SBUML on
many different distributions of host Linux.  Therefore a high-priority
task will be to understand exactly what host details SBUML and the
snapshots depend on.  Hopefully most of these dependencies can be
removed.  For dependencies that remain, a simple tool should be
developed so potential users can quickly test if SBUML or a particular
set of snapshots will work with their host Linux.  At this time, the
only way to find out is to download the system and give it a try.....

For now, please post questions/comments about SBUML in this
User-mode-linux-devel mailing list.  If traffic becomes excessive,
maybe we can move discussions over to a mailing list at
sbuml.sourceforge.net.

--Richard

The readme.txt file:

This is a quick readme file to give people already familiar with
User-Mode Linux enough information to play with SBUML a bit.  More
information, simple manuals, and sample snapshots will be posted 
at http://sbuml.sourceforge.net

What is SBUML?
==============

SBUML is an extension to User-mode Linux (UML) for saving and
restoring UML state in mid-execution. It provides a *computation
ScrapBook* for UML that can be used to distribute/migrate
pre-configured runtime state and aid debugging activities.  It can
be used for swsusp.

It it based on UML version 2.4.18-36, and thus only supports the tt
mode of UML.  After releasing this demo, the highest priority task
will be to update SBUML to work with the latest UML kernel.  Only one
post-2.4.18-26 bug fix has been patched in, which was the that makes
UML run on RedHat 9.0.

What should be known before running the SBUML demo?
===================================================

1) It requires about 1.5gig to 2.0gig of hard disk space.  
2) All file changes will be in the demo's "sbumldemo" directory
   and subdirectories.  Removing this directory tree should uninstall
   the demo and all side effects, except for a few small files in /tmp.
3) It has been run successfully on hosts with RedHat 7.2, 8.0, and 9.0.  
   It is more likely to work if you have vncviewer, curl, xdelta, and 
   nc (netcat) installed, because any library incompatibilities with 
   the binaries included in the demo will be avoided.
4) The demo will grab IP addresses on your subnet.  For example, if
   the host's IP is 192.168.1.90, SBUML will assign restored machines
   addresses like 192.168.1.22, 192.168.1.23, etc.  (Addresses that
   respond to pings will automatically be skipped.)  Therefore, the
   current demo is only suitable for running on a subnet that you own.
   (This whole scheme needs to be replaced with something more polite and
   reliable.)
5) It runs fine with Linux hosts running inside of VMWare.  Therefore 
   running VMWare's NAT network will avoid most potential problems with
   item #4.
6) The two most essential commands are: 
   1- sbumlhalt -all   #this will clean up all SBUML machines and their directories
   2- sbuml--kill-all-xterm-linux   # a very aggressive scan of /proc to kill any
         processes that *seems* to be related to SBUML, because sbumlhalt sometimes
         misses a few.  If you have any non-SBUML UMLs running, it will probably kill
         them too.
7) A few known bugs that you might run into:
   1- Only one xterm console window can be saved into a snapshot.
   2- SIGWINCH has been disabled, so resizing the xterm windows does not work right.
   3- Xterm state is not saved. (this is an intentional limitation, not a bug)
   4- Some versions of ping do not support the -w timeout parameter, which hangs
      the sbumlvnc script.
   5- The technique used to update /etc/resolv.conf in a UML can be unreliable and
      needs to be replaced.  Firewall settings on the host can make it fail.
   6- Failed snapshot downloads are not handled gracefully

How do you download/install it?
===============================

SBUML is packed as a demo in 4 files with these or similar names:
sbuml-core-2.4.18-36um-2sb-b.tarz (800KB)
  --the specially built UML binary and high-level control scripts.
sbumldemo-bases.tar.gz (220MB)
  --backing files for a UML running a small RedHat 7.2 distribution
sbumldemo-snapshots-120503.tar.gz (65MB)
  --example snapshots of running UMLs
sbumldemo-support-bin-redhat72-120503.tar.gz (294KB)
  --binaries that *might* make it easier for some people to get
    sbuml working on their Linux Host installation.  The xdelta and
    vncviewer binaries seem to be quite portable.  curl and nc are more
    troublesome. (Please tell me if you know how to build a portable 
    curl or nc.)

To install:
(1) untar all the files.  
(2) cd into the sbumldemo directory
(3) execute ./sbumlinitdemo

With just a little luck, downloading and untaring can be automated by
downloading the small file named "sbuml-download-and-install-script-xxxxxxx"
and typing 
$ source sbuml-download-and-install-script-xxxxxxx
If you mirror the demo, please be sure to change the download path in this file.

Then just read the short messages carefully.  It will probably ask you
to execute ./scripts/install_uml_net_as_root in a root shell to give
uml_net root privileges.  If you want, you can alternatively copy an
older version of uml_net into the ./scripts directory.  Recently I noticed
that the latest build of uml_net did not work, but I have not had time
to find out why.


How do you run it quickly?
==========================

After you have run ./sbumlinitdemo and have a 
"[(sbumldemo subshell) cur-dir] $" prompt, execute 
the "sbumlquick" command.  You will then get
something like this:

[(sbumldemo subshell) sbumldemo]$ sbumlquick 
1) /home/test/doit/sbumldemo/scripts/../snapshots/rh72-32m-f7185deab716119d
2) /home/test/doit/sbumldemo/scripts/../snapshots/rh72-32m-vnc-800x600-41ab54e69365d2cc
3) /home/test/doit/sbumldemo/scripts/../snapshots/rh72-64m-kde-800x600-2e5a7cfde430c80e
4) /home/test/doit/sbumldemo/scripts/../snapshots/rh72-64m-vnc-800x600-d18f29698f8c071c
5) /home/test/doit/sbumldemo/scripts/../snapshots/rh72-96m-kde-800x600-a3551ca7e09e2300
6) /home/test/doit/sbumldemo/scripts/../snapshots/rh72-96m-vnc-800x600-8e19871e9036a776
#? 

The snapshots in the default snapshot directory are listed.  Enter 1
(for the "rh72-32m-f7185deab716119d" snapshot) and return and soon (3
to 30 seconds, certainly within 60 seconds), a new xterm should open
with a 32meg machine prebooted.  Press return to see the login prompt.

Snapshots with vnc or kde in the name will try to assign an IP
address and connect vncviewer to a gui in the UML, so these really
require compatible versions of nc, xdelta, and vncviewer to be on the
shell path.

The "sbumlhalt -all" should be used to remove the machines.

What other commands are there to play with?
===========================================

All the commands are implemented as bash scripts in the ./scripts
directory, so reading through those may give some clues.  However,
here are the main ones presented as an example scenario:

[(sbumldemo subshell) sbumldemo]$ sbumlboot m1  
  --This command boots a new machine and call it m1
  --After the machine boots, log in as root using "root" as the password.
  --Start some eye candy to make the demo more interesting, e.g. run
    the "top" command.
[(sbumldemo subshell) sbumldemo]$ sbumlfreeze m1
  --This command freezes the top command's updates (and the whole UML)
[(sbumldemo subshell) sbumldemo]$ sbumlcontinue m1
  --This command continues the top command's updates (and the whole UML)
[(sbumldemo subshell) sbumldemo]$ sbumlsave m1 topuml -f -c
  --This command makes a snapshots of the UML's state and saves it as "topuml"
  --(The -f means "freeze first", and the -c means "continue after")
[(sbumldemo subshell) sbumldemo]$ sbumlrestore m2 topuml -c
  --This command starts another machine called "m2" using the state in topuml.
  --(The -c means "continue after restoring")
[(sbumldemo subshell) sbumldemo]$ sbumlrestore m topuml -c
  --Same as above, only the machine name is chosen automatically to be
    the first free machine name of the form m followed by some integer.
[(sbumldemo subshell) sbumldemo]$ sbumlquick topuml
  --Same as above, just easier to type.
[(sbumldemo subshell) sbumldemo]$ sbumlquick topuml ; sbumlquick topuml ; sbumlquick topuml ; 
  --Quickly create three more copies...just for the fun of it.
[(sbumldemo subshell) sbumldemo]$ sbumlhalt m1
  --This command gets rid of the original UML machine that was booted from scratch
[(sbumldemo subshell) sbumldemo]$ sbumlhalt -all
  --This command gets rid of the rest of the running UMLs
[(sbumldemo subshell) sbumldemo]$ sbuml--kill-all-xterm-linux
  --This command will kill off any stubborn UML processes that did not
    listen to sbumlhalt, which should not be many, if any.

How reliable is it?
===================

There is really not enough experience or rigorous testing to know yet.
However, what experience there is indicates that a saved snapshot will
usually restore into a machine that will continue running successfully.
Occasionally, a snapshot will not restore.  However, once a snapshot
has been successfully restored once, it (almost?) always will restore
successfully every time thereafter.

One conclusion from all this is that if you want to use it for typical
software suspend and resume functionality (swsusp), make sure you can
successfully restore the snapshot *before* halting the original machine.

Acknowledgments
===============

SBUML was supported in part by a Grant-in-Aid for Precursory Research
for Embryonic Science and Technology (PRESTO), from Japan Science and
Technology Agency (JST).  Addition support has been provided by the
Exploratory Software Project of the Information-technology Promotion
Agency (IPA).  Study of Jeff Dike's UML code (with all its trampolines
and other interesting techniques) was done jointly with Osamu Sato and
Professor Masami Hagiya of Tokyo University.  Important portions of
the current code were written by Osamu Sato.  Mitsuharu Yamamoto helped
with testing and provided needed Linux expertise.

Special acknowledgments must be given to Jeff Dike, for creating the
UML system, and Greg Lonnon, who contributed UML's original
copy-on-write(COW) feature, which has been essential for making
snapshots small enough to be practical.

Contact
=======

Richard Potter
suml at zar.att.nt.jp
potter at is.s.u-tokyo.ac.jp

Last edited: 12-12-2003





-------------------------------------------------------
This SF.net email is sponsored by: IBM Linux Tutorials.
Become an expert in LINUX or just sharpen your skills.  Sign up for IBM's
Free Linux Tutorials.  Learn everything from the bash shell to sys admin.
Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2003-12-16 14:09 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2003-12-13  4:07 [uml-devel] demo of SBUML - swsusp functionality for UML Richard Potter
2003-12-13 15:34 ` roland
2003-12-14  9:24   ` Richard Potter
2003-12-14 15:08 ` BlaisorBlade
2003-12-16 14:09   ` Richard Potter

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox