nimbus-nodes notes

nimbusproject · Oct 26, 2010 · df28306 · df28306
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diff --git a/docs/src/admin/reference.html b/docs/src/admin/reference.html
@@ -1255,27 +1255,11 @@ <h4>* Service hostname:</h4>
 
 
 <h4>* VMM names:</h4>
-<p>
-    TODO: redo this part with nimbus-nodes instructions
-</p>
-
-
-<div class="screen"><pre>
-some-vmm-node 1024</pre>
-</div>
 
 <p>
-    You can SSH there without password from the nimbus account, right?
+    See the <a href="#resource-pool">resource pool</a> section to learn how to add VMM names.
 </p>
 
-_EXAMPLE_CMD_BEGIN
-ssh some-vmm-node
-_EXAMPLE_CMD_END
-
-<div class="screen"><pre>
-nimbus@some-vmm-node $ ...</pre>
-</div>
-
 <a name="networks"> </a>
 <h4>* Networks:</h4>
 <p>
@@ -1363,67 +1347,89 @@ <h3>Resource pool _NAMELINK(resource-pool)</h3>
     This is the default, see the <a href="#resource-pool-and-pilot">overview</a>.
 </p>
 
-<p>TODO: redo this part with nimbus-nodes instructions</p>
 
 <p>
-    A directory of files is located at
+    In the <a href="z2c/index.html">Zero to Cloud Guide</a>, the configuration script that you interacted with at end of the <a href="z2c/ssh-setup.html">SSH Setup</a> section took care of configuring the workspace service with the first VMM to use.
-    "services/etc/nimbus/workspace-service/<b>vmm-pools</b>/"
 </p>
+
 <p>
-   The pool file format is currently simple: for each node in the pool,
+    A cloud with one VMM is perfectly reasonable for a test setup, but when it comes time to offer resources to others for real use, we bet you might want to add a few more.  Maybe a few hundred more.
-   list the hostname and the amount of RAM it can spare for running guest VMs.
 </p>
+
 <p>
-   Optionally, you can also specify that certain hosts can only
+    As of Nimbus 2.6, it is possible to configure the running service dynamically.  You can interact with the scheduler and add and remove nodes on the fly.  The <tt class="literal">nimbus-nodes</tt> program is what you use to do this.
-   support a subset of the available networks (see the
-   file comments for syntax).
 </p>
+
 <p>
-   If you change these configuration files after starting the
+    Have a look at the help output:
-   container, only a fresh container reboot will actually incur the
-   changes.
 </p>
 
-<ul>
+<div class="screen"><pre>
+cd $NIMBUS_HOME
+./bin/nimbus-nodes -h</pre>
+</div>
 
-    <li>
+<p>
-        If you <b>add</b> a node, this will be available
+    The following example assumes you have homogenous nodes.  Each node has, let's say, 8GB RAM and you want to dedicate the nodes exclusively to hosting VMs.  Some RAM needs to be saved for the system (in Xen for example this is "domain 0" memory), so we decide to offer 7.5GB to VMs.  For RAM, there is no overcommit possible with Nimbus.
-        immediately after the container reboot.
+</p>
-    </li>
 
-    <li>
+<div class="note">
-        If you <b>remove</b> a node that is currently
+<p class="note-title">nimbus-nodes needs a running service</p>
-        in use, no new deployments will be mapped to this VMM.
+    If the service is not running, the nimbus-nodes program will fail to adjust anything.  Make sure the workspace service is running with "./bin/nimbusctl start".
-        However, this will not destroy (or migrate) any current VMs
+</p>
-        running there.  If that is necessary it currently needs to be
+</div>
-        accomplished explicitly.
-    </li>
 
-    <li>
+<p>
-        If you <b>change</b> a node that is currently
+    You can SSH to each node without password from the nimbus account, right?
-        in use, the change will take effect for the next lease.
+</p>
 
-        <p>
+<div class="screen"><pre>
-        If you've removed support for an association on a VMM that
+service-node $ whoami
-        the current VM(s) is using, this change will not destroy (or
+nimbus
-        migrate) the VM(s) to adjust to this restriction.
+service-node $ ssh nequals01</pre>
-        If that is necessary it currently needs to be accomplished
+</div>
-        explicitly.
-        </p>
 
+<div class="screen"><pre>
+nequals01 $ ...</pre>
+</div>
 
-        <p>
+<p>
-        If you've reduced the memory allocation below what the
+    The nodes in the cluster are named based on numbers, so for example "nequals01", "nequals02", etc.  This means we can construct the command with a for loop.
-        current VM(s) on the node is/are currently using, this will
+</p>
-        not destroy (or migrate) the current VM(s) to adjust to this
-        restriction.
-        If that is necessary it currently needs to be accomplished
-        explicitly.  Once the VM(s) are gone, the maximum memory
-        available on that VMM will be the new, lower maximum.
-        </p>
-    </li>
 
-</ul>
+<div class="screen"><pre>
+$ NODES="nequals01"
+$ for n in `seq 2 10`; do NODES="$NODES,nequals$n"; done
+$ echo $NODES
+nequals01,nequals2,nequals3,nequals4,nequals5,nequals6,nequals7,nequals8,nequals9,nequals10
+</pre>
+</div>
+
+<p>
+    With the <tt class="literal">$NODES</tt> variable in hand, we can make the node-addition call.
+</p>
+
+<div class="screen"><pre>
+$ ./bin/nimbus-nodes --add $NODES --memory 7680
+</pre>
+</div>
+
+<p>
+    At any time you can use the "--list" action to see what the current state of the pool is.
+</p>
+
+<p>
+    There are several other options discussed in the <tt class="literal">nimbus-nodes -h</tt> text, we will highlight one of the most important ones here.
+</p>
+
+<p>
+    If you ever want to disable a VMM, use the live-update feature.  After running the following command, no new VMs can be launched on the node.  Any current VMs, however, will continue running.  So this is a way to "drain" your nodes of work if there is maintenance coming up, etc.
+</p>
+
+<div class="screen"><pre>
+$ ./bin/nimbus-nodes --update nequals08 --inactive
+</pre>
+</div>
 
 
 <a name="pilot"> </a>

diff --git a/docs/src/faq.html b/docs/src/faq.html
@@ -92,7 +92,7 @@ <h2>Frequently Asked Questions</h2>
         <a href="#cumulusbackend">What type of storage system backs the Cumulus repository</a>?
     </li>
     <li>
-        <a href="#lantorrent">What is lantorrent</a>?
+        <a href="#lantorrent">What is LANTorrent</a>?
     </li>
     <li>
         <a href="#license">How is the software licensed</a>?