Commit e8b47f26 authored by Mac Newbold's avatar Mac Newbold
Browse files

Add statewait changes

parent 2b2a306d
newbold 2003/10/10 08:44:15 MDT
Modified files:
New StateWait changes - the main point of all this is to move to our new
model of waiting for state changes. Before we were watching the database
(which means we can only watch for terminal/stable/long-lived states, and
have to poll the db). Now things that are waiting for states to change
become event listeners, and watch the stream of events flow by, and don't
have to do any polling. They can now watch for any state, and even
sequences of states (ie a Shutdown followed by an Isup).
To do this, there is now a cool library that encapsulates the
functionality needed. To use it, you call initStateWait before you start
the chain of events (ie before you call node reboot). Then do your stuff,
and call waitForState() when you're ready to wait. It can be told to
return periodically with the results so far, and you can cancel waiting
for things. An example program called waitForState is in
testbed/event/stated/ , and can also be used nicely as a command line tool
that wraps up the library functionality.
This also required the introduction of a TBFAILED event that can be sent
when a node isn't going to make it to the state that someone may be
waiting for. Ie if it gets wedged coming up, and stated retries, but
eventually gives up on it, it sends this to let things know that the node
is hozed and won't ever come up.
Another thing that is part of this is that node_reboot moves (back) to the
fully-event-driven model, where users call node reboot, and it does some
checks and sends some events. Then stated calls node_reboot in "real mode"
to actually do the work, and handles doing the appropriate retries until
the node either comes up or is deemed "failed" and stated gives up on it.
This means stated is also the gatekeeper of when you can and cannot reboot
a node. (See mail archives for extensive discussions of the details.)
A big part of the motivation for this was to get uninformed timeouts and
retries out of os_load/os_setup and put them in stated where we can make a
wiser choice. So os_load and os_setup now use this new stuff and don't
have to worry about timing out on nodes and rebooting. Stated makes sure
that they either come up, get retried, or fail to boot. tbrestart also
underwent a similar change.
Revision Changes Path
1.135 +159 -208 testbed/db/
1.5 +37 -14 testbed/event/stated/
1.52 +41 -18 testbed/event/stated/
1.4 +4 -3 testbed/event/stated/
1.43 +42 -11 testbed/tbsetup/
1.54 +22 -97 testbed/tbsetup/
1.81 +212 -157 testbed/tbsetup/
1.5 +63 -19 testbed/tbsetup/
stoller 2003/10/09 14:03:10 MDT
Modified files:
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