locks in addition to the default exclusive mode locks, which is
handy for allowing multiple containers to set up in parallel
since in general they won't be changing anything, just reading.

What a mess.  Conflicts, syntax errors, the works conspired to keep this
from going in.

are the details, so they are recorded someplace.

The Racks do not have a real 172 router for the "jail" network.
This is a mild pain, and one possibility would be to make the
router be the physical node, so that each set of VMs is using its own
router thus spreading the load.

Well, that does not work because we use bridge mode on the physical
host, and so the packets leave the node before they have a chance to
go through the routing code. Yes, iptables does have something called
a brouter via etables, but I could not make that work after a lot of
trying and tearing my hair out

So the next not so best thing is to make the control node be the
router by sticking an alias on xenbr0 for 172.16.0.1. Fine, that works
although performance could suffer.

But what about NFS traffic to ops? It would be really silly to send
that through the routing code on the control node, just to end up
bridging into into the ops VM. So figured I would optimize that by
changing domounts to return mounts that reference ops address on the
jail network. And in fact this worked fine, but only for shared
nodes.

But it failed for exclusive VMs! In this case, we add a SNAT rule on
the physical host that changes the source IP to be that of the
physical host so that users cannot spoof a VM on a shared node and
mount an NFS filesystem they should not have access to. In fact, it
failed for UDP mounts but not for TCP mounts. When I looked at the
traffic with tcpdump, it appeared that return TCP traffic from ops was
using its jail IP, but return UDP traffic was using the public IP.
This confuses SNAT and so the packets never get back into the VM.

So, this change basically looks at the sharing mode of the node, and
if its shared we use the jailip in the mounts, and if it is exclusive
we use the public IP (and thus, that traffic gets routed through the
control node). This sucks, but I am worn down on this.

This is essentially a port of tmcc to Python, without any caching (yet)
and an interface tailored to retrieving GENI information.

I was there, I changed the callers of convertPortFormat to actually
look at the return value, and stop if it gets back no results!

avoid routing through the control node, but also need to
add this to the SNAT rule for NFS.

Just need to turn the amapiv3 variable flag on in the code.
This gets my keys and creates a new user called "testuser" with
the same keys. Tested and works under V3.

Return VOLNAME instead of BSID and VOLSIZE instead of SIZE. This is what
the client-side parser expects based on what I was told previously.
Didn't notice til now because we had no local disk state in the DB.

This helps when pruning out old images so that I can see not only what
experiments are still associated with the image, but when they were last used.

"reset" now just unmounts blockstores, it does not destroy them.
Need this so that people can include a SYSVOL blockstore in a custom image
(the only place where "reset" is used). Also, destroying blockstores would
have come as an unpleasant surprise to anyone who created a custom image
and then expected their data to still be around afterward!

Also work around a bizzare bug in BSD sed that happens in the prepare script.
That script does:

     sed -e '/# next line is swap device/,+1d' /etc/fstab

which should remove the matched comment and the line after it (the swapdev
entry). But if there are EXACTLY two additional lines after the matched line,
it would remove both of them (effectively "+2")! So if there was a mount for
a blockstore device after the swap device, prepare would remove that line too.

So in the finest tradition of "if it hurts, don't do it", the blockstore code
makes sure that it adds at least two additional lines.

If number was positive, was converting to "(N)" for some reason.
Parens don't compare well with integers...

Also don't need "bc" just to compute abs(), just use "tr" to remove '-'.

Also adjust the max offset a smidge to 5ms, 1ms is a bit tight.

This allows nodes in GENI slices to retrieve information about their
sliver and slice via tmcc (or equivalent client-side support).  The
set of queries available and their names were agreed upon in GEC 17
sessions and subsequent discussions.

we update last_ext_act, since this is how idle determines staleness.
Not sure this is the best approach though.