Haizea

resources: 4  CPU:100 Memory:1024

These options are used to describe the characteristics of our simulated cluster. In particular, we're using a 4-node cluster, each node with 1 CPU, 1024 MB of memory. In this document, we will represent this cluster over time like this:

The default value is a sample tracefile included with Haizea. If you copy the file to a different location, make sure to update the \texttt{tracefile} option accordingly. The format of this file is LWF (Lease Workload Format), an XML format which is particular to Haizea. For now, don't worry about parsing the trace format in detail; it is fairly human-readable and you can also find details on the LWF format in Appendix~\ref{app:lwf}.

<lease-workload name="sample">

	<description>

	A simple trace where an AR lease preempts a 

	best-effort lease that is already running. 

	</description>

	<lease-requests>

	<!-- The lease requests are initially commented out -->

	<!-- First lease request -->

	<!--

	...

	-->

	<!-- Second lease request -->

	<!--

	...

	-->

	</lease-requests>

</lease-workload>

\end{wideshellverbatim}

As you can see, there are two lease requests in the file, but they are initially commented out. We will take a closer look at each of these requests next.

[2006-11-25 13:00:00.00] TFILE   Loaded workload with 0 requests ()

[2006-11-25 13:00:00.00] CLOCK   Simulated clock has stopped

[2006-11-25 13:00:00.00] RM      Stopping resource manager gracefully...

Now that you've seen the tracefile, you can see why the simulator starts up and immediately stops: all the lease requests in the tracefile are commented out, and there's nothing to schedule. Go ahead and uncomment the first lease request, which looks like this:

<lease-request arrival="00:00:00">

<lease preemptible="true">

	<nodes>

		<node-set numnodes="1">

			<res type="CPU" amount="100"/>

			<res type="Memory" amount="1024"/>

		</node-set>

	</nodes>	

	<start></start>

	<duration time="01:00:00"/>

	<software>

		<disk-image id="foobar.img" size="1024"/>

	</software>

</lease>

</lease-request>

\end{wideshellverbatim}

This is a request for a best-effort lease (notice how the starting time is left empty, meaning it's up to Haizea to determine the start time), requested at time 00:00:00 (right at the start of the simulation), requiring 1 hour, and only one node. Now run Haizea again. You should now see the following:

\begin{wideshellverbatim}

[2006-11-25 13:00:00.00] TFILE   Loaded workload with 1 requests (1 Best-effort)

[2006-11-25 13:00:00.00] LSCHED  Lease #1 has been requested.

[2006-11-25 13:00:00.00] LSCHED  Lease #1 has been marked as pending.

Now go ahead and uncomment the second lease request, which looks like this:

\begin{wideshellverbatim}

<lease-request arrival="00:15:00">

<lease preemptible="false">

	<nodes>

		<node-set numnodes="4">

			<res type="CPU" amount="100"/>

			<res type="Memory" amount="1024"/>

		</node-set>

	</nodes>

	<start>

		<exact time="00:30:00"/>

	</start>

	<duration time="00:30:00"/>

	<software>

		<disk-image id="foobar.img" size="1024"/>

	</software>

</lease>

</lease-request>

\end{wideshellverbatim}

This is a request for an advance reservation lease (notice how there is an exact starting time specified), requesting all four nodes for 30 minutes. So, what would happen if we also added this AR lease? Since it requires all the cluster resources from 13:30 to 14:00, the best-effort lease will be unable to run in that time interval. Since the leases are implemented as VMs, Haizea will still schedule the best-effort lease to start at 13:00, but will suspend it before the AR lease starts, and will resume it once the AR lease has finished. In effect, we want the schedule to look like this:

[2006-11-25 13:00:00.00] TFILE   Loading tracefile /usr/share/haizea/traces/sample.lwf

[2006-11-25 13:00:00.00] TFILE   Loaded workload with 2 requests (1 Best-effort + 1 AR)

[2006-11-25 13:00:00.00] LSCHED  Lease #1 has been requested.

[2006-11-25 13:00:00.00] LSCHED  Lease #1 has been marked as pending.

[2006-11-25 13:15:00.00] LSCHED  Lease #2 has been requested.

[2006-11-25 13:15:00.00] LSCHED  Lease #2 has been marked as pending.

[2006-11-25 13:15:00.00] LSCHED  AR lease #2 has been scheduled.

[2006-11-25 13:29:28.00] VMSCHED Stopped VMs for lease 1 on nodes [1]

[2006-11-25 13:29:28.00] VMSCHED Suspending lease 1...

                                 from 2006-11-25 14:00:00.00 (resuming) 

                                   to 2006-11-25 14:31:04.00

[2006-11-25 14:00:32.00] VMSCHED Resumed lease 1

[2006-11-25 14:00:32.00] VMSCHED Started VMs for lease 1 on nodes [1]

[2006-11-25 14:31:04.00] VMSCHED Stopped VMs for lease 1 on nodes [1]

[2006-11-25 14:31:04.00] VMSCHED Lease 1's VMs have shutdown.

[2006-11-25 14:31:04.00] CLOCK   Simulated clock has stopped

[2006-11-25 14:31:04.00] RM      Stopping resource manager gracefully...

lease-preparation: imagetransfer

Additionally, you can also write a lease request using the XML format seen previous, save it to a file, and have \texttt{haizea-request-lease} command parse it:

\begin{wideshellverbatim}

haizea-request-lease -f request.xml

\end{wideshellverbatim}

 ID   Type          State      Starting time           Duration      Nodes  

 1    AR            Scheduled  2009-08-04 11:25:57.00  00:10:00.00   1        

 ID   Type          State      Starting time           Duration      Nodes  

 1    AR            Preparing  2009-08-04 11:25:57.00  00:10:00.00   1       

 ID   Type          State      Starting time           Duration      Nodes  

 1    AR            Active     2009-08-04 11:25:57.00  00:10:00.00   1       

 ID   Type          State      Starting time           Duration      Nodes  

 1    AR            Active     2009-08-04 11:25:57.00  00:10:00.00   1       

 2    Best-effort   Scheduled  Unspecified             00:10:00.00   4       

Note how, for best-effort leases, the starting time is set to ``Unspecified'', which means this time is not specified by the user, but instead determined on a best-effort basis by the scheduler. Since the lease is in a ``Scheduled'' state, that means that it has been assigned a starting time (although that information is currently not available through the command-line interface; it can be seen in the Haizea log).

 1    AR            Active     2009-08-04 11:25:57.00  00:10:00.00   1       

 2    Best-effort   Scheduled  Unspecified             00:10:00.00   4       

 3    Best-effort   Queued     Unspecified             00:10:00.00   4       

 4    Best-effort   Queued     Unspecified             00:10:00.00   4       

 5    Best-effort   Queued     Unspecified             00:10:00.00   4       

 6    Best-effort   Queued     Unspecified             00:10:00.00   4       

 ID   Type          State      Starting time           Duration      Nodes  

 3    Best-effort   Queued     Unspecified             00:10:00.00   4       

 4    Best-effort   Queued     Unspecified             00:10:00.00   4       

 5    Best-effort   Queued     Unspecified             00:10:00.00   4       

 6    Best-effort   Queued     Unspecified             00:10:00.00   4