[xen-tools] Re: difference between xen-shell and argo

[Steve Kemp]

On Fri, Dec 01, 2006 at 09:32:44PM +0100, Henning Sprang wrote:

> I hope this is the right list - couldn't find extra adresses of
> Mailing lists for xen-shell and argo - couldn't even see a Link to
> this list here on xen-tools.org - but maybe I'm too blind currently.

  This is mostly a xen-tools specific list, but I'm happy for
 it to be abused a little in the absence of complaints and
 other lists.

  Currently it is linked to from here:

    http://xen-tools.org/software/xen-tools/lists.html

  Argo will get its own list in due time, I know I'm behind and 
 I promised that I would describe my thoughts on how the rewrite/rework
 is going.  I will do that once I get enough time to think...

  (Probably will create a new list shortly afterward if it transpires
 that there is "too much" discussion about it.  Unless people are happy
 to keep it all together.)

> Simple question: I'll try them myself as soon as I find the time,
> maybe someone cann tell me on a short notice the differences between
> xen-shell and argo.

   a)  Argo is dead.  There are sufficiently many technical problems
      with it that I wish to restart it from scratch.  Partly to
      address those problems and partly because I think I have some
      good ideas about how it can be done better now.

   b)  xen-shell works and is in production use.

> Some are obvious: xen-shell doesn't seem to have a GUI, argo seems to
> have  no way to re-install machines.

  Correct on both counts.  Argo v2 will have the same kind of interface
 for creating a new machine across the network, but doesn't do it yet.
 xen-shell essentially cheats and just runs a shell script which it
 assumes will invoke xen-create-image...

> Apart from that, I am not sure what exactly the differences and
> commonalities are, and the descriptions sound quite similar.

  I guess the goals are different.

  xen-shell is soley designed to allow a single user to control a
 single domU upon a xen host.  They should be able to perform basic
 actions such as start/stop/pause/reboot and these actions should
 only be possible against one domU - they shouldn't be allowed/capable
 of modifying any other instances.

  They also get to see the serial console (running inside GNU Screen
 since that is useful for long running jobs).

  It is the kind of thing that a hosting company would install
 and offer to their users.  (And that is why I wrote it, and what
 it is used for: xen-hosting.org)  Basically you don't want to
 give them shell access to the dom0 but you do want them to control
 what they've paid for ..

  Argo, by contrast, is designed to allow an administrator to
 perform similar operations on *arbitrary* domU running on a single
 xen host.  Whilst there are facilities to create a per-user login
 that is just a nice bonus.

  In the next version it is assumed that there will be a single
 client (php/perl/whatever) which will be able to connect to
 N domU and control a *farm* of instances.  Again it will be possible
 to create per domU or per-dom0 logins, but the intention is
 for a sysadmin to manage a number of machines and a number of xen
 instances upon each one.

  (It will work in the single-server setup, but the focus will be
 on a farm/collection of Xen machines.)

  I hope that helps clarify things ..  (I guess it is implied that
 xen-shell is complete.  That is mostly the case, but if there are
 any useful commands that seem applicable I can be persuaded to add
 them.  Similarly I'll add custom code for people like the "reverse dns"
 support that is in place if asked nicely.)

Steve
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