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8 <title>MyPLC User's Guide</title>
11 <firstname>Mark Huang</firstname>
15 <orgname>Princeton University</orgname>
19 <para>This document describes the design, installation, and
20 administration of MyPLC, a complete PlanetLab Central (PLC)
21 portable installation contained within a
22 <command>chroot</command> jail. This document assumes advanced
23 knowledge of the PlanetLab architecture and Linux system
24 administration.</para>
29 <revnumber>1.0</revnumber>
31 <date>April 7, 2006</date>
33 <authorinitials>MLH</authorinitials>
36 <para>Initial draft.</para>
43 <title>Overview</title>
45 <para>MyPLC is a complete PlanetLab Central (PLC) portable
46 installation contained within a <command>chroot</command>
47 jail. The default installation consists of a web server, an
48 XML-RPC API server, a boot server, and a database server: the core
49 components of PLC. The installation is customized through an
50 easy-to-use graphical interface. All PLC services are started up
51 and shut down through a single script installed on the host
52 system. The usually complex process of installing and
53 administering the PlanetLab backend is reduced by containing PLC
54 services within a virtual filesystem. By packaging it in such a
55 manner, MyPLC may also be run on any modern Linux distribution,
56 and could conceivably even run in a PlanetLab slice.</para>
58 <figure id="Architecture">
59 <title>MyPLC architecture</title>
62 <imagedata fileref="architecture.eps" format="EPS" align="center" scale="50" />
65 <imagedata fileref="architecture.png" format="PNG" align="center" scale="50" />
68 <phrase>MyPLC architecture</phrase>
71 <para>MyPLC should be viewed as a single application that
72 provides multiple functions and can run on any host
80 <title>Installation</title>
82 <para>Though internally composed of commodity software
83 subpackages, MyPLC should be treated as a monolithic software
84 application. MyPLC is distributed as single RPM package that has
85 no external dependencies, allowing it to be installed on
86 practically any Linux 2.6 based distribution:</para>
89 <title>Installing MyPLC.</title>
91 <programlisting><![CDATA[# If your distribution supports RPM
92 rpm -U myplc-0.3-1.planetlab.i386.rpm
94 # If your distribution does not support RPM
96 rpm2cpio myplc-0.3-1.planetlab.i386.rpm | cpio -diu]]></programlisting>
99 <para>MyPLC installs the following files and directories:</para>
103 <listitem><para><filename>/plc/root.img</filename>: The main
104 root filesystem of the MyPLC application. This file is an
105 uncompressed ext3 filesystem that is loopback mounted on
106 <filename>/plc/root</filename> when MyPLC starts. The
107 filesystem, even when mounted, should be treated an opaque
108 binary that can and will be replaced in its entirety by any
109 upgrade of MyPLC.</para></listitem>
111 <listitem><para><filename>/plc/root</filename>: The mount point
112 for <filename>/plc/root.img</filename>. Once the root filesystem
113 is mounted, all MyPLC services run in a
114 <command>chroot</command> jail based in this
115 directory.</para></listitem>
118 <para><filename>/plc/data</filename>: The directory where user
119 data and generated files are stored. This directory is bind
120 mounted into the <command>chroot</command> jail on
121 <filename>/data</filename>. Files in this directory are marked
122 with <command>%config(noreplace)</command> in the RPM. That
123 is, during an upgrade of MyPLC, if a file has not changed
124 since the last installation or upgrade of MyPLC, it is subject
125 to upgrade and replacement. If the file has chanegd, the new
126 version of the file will be created with a
127 <filename>.rpmnew</filename> extension. Symlinks within the
128 MyPLC root filesystem ensure that the following directories
129 (relative to <filename>/plc/root</filename>) are stored
130 outside the MyPLC filesystem image:</para>
133 <listitem><para><filename>/etc/planetlab</filename>: This
134 directory contains the configuration files, keys, and
135 certificates that define your MyPLC
136 installation.</para></listitem>
138 <listitem><para><filename>/var/lib/pgsql</filename>: This
139 directory contains PostgreSQL database
140 files.</para></listitem>
142 <listitem><para><filename>/var/www/html/alpina-logs</filename>: This
143 directory contains node installation logs.</para></listitem>
145 <listitem><para><filename>/var/www/html/boot</filename>: This
146 directory contains the Boot Manager, customized for your MyPLC
147 installation, and its data files.</para></listitem>
149 <listitem><para><filename>/var/www/html/download</filename>: This
150 directory contains Boot CD images, customized for your MyPLC
151 installation.</para></listitem>
153 <listitem><para><filename>/var/www/html/install-rpms</filename>: This
154 directory is where you should install node package updates,
155 if any. By default, nodes are installed from the tarball
157 <filename>/var/www/html/boot/PlanetLab-Bootstrap.tar.bz2</filename>,
158 which is pre-built from the latest PlanetLab Central
159 sources, and installed as part of your MyPLC
160 installation. However, nodes will attempt to install any
161 newer RPMs located in
162 <filename>/var/www/html/install-rpms/planetlab</filename>,
163 after initial installation and periodically thereafter. You
164 must run <command>yum-arch</command> and
165 <command>createrepo</command> to update the
166 <command>yum</command> caches in this directory after
167 installing a new RPM. PlanetLab Central cannot support any
168 changes to this directory.</para></listitem>
170 <listitem><para><filename>/var/www/html/xml</filename>: This
171 directory contains various XML files that the Slice Creation
172 Service uses to determine the state of slices. These XML
173 files are refreshed periodically by <command>cron</command>
174 jobs running in the MyPLC root.</para></listitem>
179 <para><filename>/etc/init.d/plc</filename>: This file
180 is a System V init script installed on your host filesystem,
181 that allows you to start up and shut down MyPLC with a single
182 command. On a Red Hat or Fedora host system, it is customary to
183 use the <command>service</command> command to invoke System V
186 <example id="StartingAndStoppingMyPLC">
187 <title>Starting and stopping MyPLC.</title>
189 <programlisting><![CDATA[# Starting MyPLC
193 service plc stop]]></programlisting>
196 <para>Like all other registered System V init services, MyPLC is
197 started and shut down automatically when your host system boots
198 and powers off. You may disable automatic startup by invoking
199 the <command>chkconfig</command> command on a Red Hat or Fedora
203 <title>Disabling automatic startup of MyPLC.</title>
205 <programlisting><![CDATA[# Disable automatic startup
208 # Enable automatic startup
209 chkconfig plc on]]></programlisting>
213 <listitem><para><filename>/etc/sysconfig/plc</filename>: This
214 file is a shell script fragment that defines the variables
215 <envar>PLC_ROOT</envar> and <envar>PLC_DATA</envar>. By default,
216 the values of these variables are <filename>/plc/root</filename>
217 and <filename>/plc/data</filename>, respectively. If you wish,
218 you may move your MyPLC installation to another location on your
219 host filesystem and edit the values of these variables
220 appropriately, but you will break the RPM upgrade
221 process. PlanetLab Central cannot support any changes to this
222 file.</para></listitem>
224 <listitem><para><filename>/etc/planetlab</filename>: This
225 symlink to <filename>/plc/data/etc/planetlab</filename> is
226 installed on the host system for convenience.</para></listitem>
231 <title>Quickstart</title>
233 <para>Once installed, start MyPLC (see <xref
234 linkend="StartingAndStoppingMyPLC" />). MyPLC must be started as
235 root. Observe the output of this command for any failures. If no
236 failures occur, you should see output similar to the
240 <title>A successful MyPLC startup.</title>
242 <programlisting><![CDATA[Mounting PLC: [ OK ]
243 PLC: Generating network files: [ OK ]
244 PLC: Starting system logger: [ OK ]
245 PLC: Starting database server: [ OK ]
246 PLC: Generating SSL certificates: [ OK ]
247 PLC: Generating SSH keys: [ OK ]
248 PLC: Starting web server: [ OK ]
249 PLC: Bootstrapping the database: [ OK ]
250 PLC: Starting DNS server: [ OK ]
251 PLC: Starting crond: [ OK ]
252 PLC: Rebuilding Boot CD: [ OK ]
253 PLC: Rebuilding Boot Manager: [ OK ]
254 PLC: Signing node packages: [ OK ]
258 <para>If <filename>/plc/root</filename> is mounted successfully, a
259 complete log file of the startup process may be found at
260 <filename>/plc/root/var/log/boot.log</filename>. Possible reasons
261 for failure of each step include:</para>
264 <listitem><para><literal>Mounting PLC</literal>: If this step
265 fails, first ensure that you started MyPLC as root. Check
266 <filename>/etc/sysconfig/plc</filename> to ensure that
267 <envar>PLC_ROOT</envar> and <envar>PLC_DATA</envar> refer to the
268 right locations. You may also have too many existing loopback
269 mounts, or your kernel may not support loopback mounting, bind
270 mounting, or the ext3 filesystem. Try freeing at least one
271 loopback device, or re-compiling your kernel to support loopback
272 mounting, bind mounting, and the ext3 filesystem. SELinux may
273 also be enabled. If you install MyPLC on Fedora Core 4 or 5, use
274 the <application>Security Level Configuration</application>
275 utility to configure SELinux to be
276 <literal>Permissive</literal>.</para></listitem>
278 <listitem><para><literal>Starting database server</literal>: If
279 this step fails, check
280 <filename>/plc/root/var/log/pgsql</filename> and
281 <filename>/plc/root/var/log/boot.log</filename>. The most common
282 reason for failure is that the default PostgreSQL port, TCP port
283 5432, is already in use. Check that you are not running a
284 PostgreSQL server on the host system.</para></listitem>
286 <listitem><para><literal>Starting web server</literal>: If this
288 <filename>/plc/root/var/log/httpd/error_log</filename> and
289 <filename>/plc/root/var/log/boot.log</filename> for obvious
290 errors. The most common reason for failure is that the default
291 web ports, TCP ports 80 and 443, are already in use. Check that
292 you are not running a web server on the host
293 system.</para></listitem>
295 <listitem><para><literal>Bootstrapping the database</literal>:
296 If this step fails, it is likely that the previous step
297 (<literal>Starting web server</literal>) also failed. Another
298 reason that it could fail is if <envar>PLC_API_HOST</envar> (see
299 <xref linkend="ChangingTheConfiguration" />) does not resolve to
300 the host on which the API server has been enabled. By default,
301 all services, including the API server, are enabled and run on
302 the same host, so check that <envar>PLC_API_HOST</envar> is
303 either <filename>localhost</filename> or resolves to a local IP
304 address.</para></listitem>
306 <listitem><para><literal>Starting crond</literal>: If this step
307 fails, it is likely that the previous steps (<literal>Starting
308 web server</literal> and <literal>Bootstrapping the
309 database</literal>) also failed. If not, check
310 <filename>/plc/root/var/log/boot.log</filename> for obvious
311 errors. This step starts the <command>cron</command> service and
312 generates the initial set of XML files that the Slice Creation
313 Service uses to determine slice state.</para></listitem>
316 <para>If no failures occur, then MyPLC should be active with a
317 default configuration. Open a web browser on the host system and
318 visit <literal>http://localhost/</literal>, which should bring you
319 to the front page of your PLC installation. The password of the
320 default administrator account
321 <literal>root@localhost.localdomain</literal> (set by
322 <envar>PLC_ROOT_USER</envar>) is <literal>root</literal> (set by
323 <envar>PLC_ROOT_PASSWORD</envar>).</para>
325 <section id="ChangingTheConfiguration">
326 <title>Changing the configuration</title>
328 <para>After verifying that MyPLC is working correctly, shut it
329 down and begin changing some of the default variable
330 values. Shut down MyPLC with <command>service plc stop</command>
331 (see <xref linkend="StartingAndStoppingMyPLC" />). With a text
332 editor, open the file
333 <filename>/etc/planetlab/plc_config.xml</filename>. This file is
334 a self-documenting configuration file written in XML. Variables
335 are divided into categories. Variable identifiers must be
336 alphanumeric, plus underscore. A variable is referred to
337 canonically as the uppercase concatenation of its category
338 identifier, an underscore, and its variable identifier. Thus, a
339 variable with an <literal>id</literal> of
340 <literal>slice_prefix</literal> in the <literal>plc</literal>
341 category is referred to canonically as
342 <envar>PLC_SLICE_PREFIX</envar>.</para>
344 <para>The reason for this convention is that during MyPLC
345 startup, <filename>plc_config.xml</filename> is translated into
346 several different languages—shell, PHP, and
347 Python—so that scripts written in each of these languages
348 can refer to the same underlying configuration. Most MyPLC
349 scripts are written in shell, so the convention for shell
350 variables predominates.</para>
352 <para>The variables that you should change immediately are:</para>
355 <listitem><para><envar>PLC_NAME</envar>: Change this to the
356 name of your PLC installation.</para></listitem>
357 <listitem><para><envar>PLC_ROOT_PASSWORD</envar>: Change this
358 to a more secure password.</para></listitem>
360 <listitem><para><envar>PLC_MAIL_SUPPORT_ADDRESS</envar>:
361 Change this to the e-mail address at which you would like to
362 receive support requests.</para></listitem>
364 <listitem><para><envar>PLC_DB_HOST</envar>,
365 <envar>PLC_DB_IP</envar>, <envar>PLC_API_HOST</envar>,
366 <envar>PLC_API_IP</envar>, <envar>PLC_WWW_HOST</envar>,
367 <envar>PLC_WWW_IP</envar>, <envar>PLC_BOOT_HOST</envar>,
368 <envar>PLC_BOOT_IP</envar>: Change all of these to the
369 preferred FQDN and external IP address of your host
370 system.</para></listitem>
373 <para>After changing these variables, save the file, then
374 restart MyPLC with <command>service plc start</command>. You
375 should notice that the password of the default administrator
376 account is no longer <literal>root</literal>, and that the
377 default site name includes the name of your PLC installation
378 instead of PlanetLab.</para>
382 <title>Installing nodes</title>
384 <para>Install your first node by clicking <literal>Add
385 Node</literal> under the <literal>Nodes</literal> tab. Fill in
386 all the appropriate details, then click
387 <literal>Add</literal>. Download the node's configuration file
388 by clicking <literal>Download configuration file</literal> on
389 the <emphasis role="bold">Node Details</emphasis> page for the
390 node. Save it to a floppy disk or USB key as detailed in <xref
391 linkend="TechsGuide" />.</para>
393 <para>Follow the rest of the instructions in <xref
394 linkend="TechsGuide" /> for creating a Boot CD and installing
395 the node, except download the Boot CD image from the
396 <filename>/download</filename> directory of your PLC
397 installation, not from PlanetLab Central. The images located
398 here are customized for your installation. If you change the
399 hostname of your boot server (<envar>PLC_BOOT_HOST</envar>), or
400 if the SSL certificate of your boot server expires, MyPLC will
401 regenerate it and rebuild the Boot CD with the new
402 certificate. If this occurs, you must replace all Boot CDs
403 created before the certificate was regenerated.</para>
405 <para>The installation process for a node has significantly
406 improved since PlanetLab 3.3. It should now take only a few
407 seconds for a new node to become ready to create slices.</para>
411 <title>Administering nodes</title>
413 <para>You may administer nodes as <literal>root</literal> by
414 using the SSH key stored in
415 <filename>/etc/planetlab/root_ssh_key.rsa</filename>.</para>
418 <title>Accessing nodes via SSH. Replace
419 <literal>node</literal> with the hostname of the node.</title>
421 <programlisting>ssh -i /etc/planetlab/root_ssh_key.rsa root@node</programlisting>
424 <para>Besides the standard Linux log files located in
425 <filename>/var/log</filename>, several other files can give you
426 clues about any problems with active processes:</para>
429 <listitem><para><filename>/var/log/pl_nm</filename>: The log
430 file for the Node Manager.</para></listitem>
432 <listitem><para><filename>/vservers/pl_conf/var/log/pl_conf</filename>:
433 The log file for the Slice Creation Service.</para></listitem>
435 <listitem><para><filename>/var/log/propd</filename>: The log
436 file for Proper, the service which allows certain slices to
437 perform certain privileged operations in the root
438 context.</para></listitem>
440 <listitem><para><filename>/vservers/pl_netflow/var/log/netflow.log</filename>:
441 The log file for PlanetFlow, the network traffic auditing
442 service.</para></listitem>
447 <title>Creating a slice</title>
449 <para>Create a slice by clicking <literal>Create Slice</literal>
450 under the <literal>Slices</literal> tab. Fill in all the
451 appropriate details, then click <literal>Create</literal>. Add
452 nodes to the slice by clicking <literal>Manage Nodes</literal>
453 on the <emphasis role="bold">Slice Details</emphasis> page for
456 <para>A <command>cron</command> job runs every five minutes and
458 <filename>/plc/data/var/www/html/xml/slices-0.5.xml</filename>
459 with information about current slice state. The Slice Creation
460 Service running on every node polls this file every ten minutes
461 to determine if it needs to create or delete any slices. You may
462 accelerate this process manually if desired.</para>
465 <title>Forcing slice creation on a node.</title>
467 <programlisting><![CDATA[# Update slices.xml immediately
468 service plc start crond
470 # Kick the Slice Creation Service on a particular node.
471 ssh -i /etc/planetlab/root_ssh_key.rsa root@node \
472 vserver pl_conf exec service pl_conf restart]]></programlisting>
478 <title>Configuration variables</title>
480 <para>Listed below is the set of standard configuration variables
481 and their default values, defined in the template
482 <filename>/etc/planetlab/default_config.xml</filename>. Additional
483 variables and their defaults may be defined in site-specific XML
484 templates that should be placed in
485 <filename>/etc/planetlab/configs/</filename>.</para>
491 <title>Bibliography</title>
493 <biblioentry id="TechsGuide">
494 <author><firstname>Mark</firstname><surname>Huang</surname></author>
496 url="http://www.planet-lab.org/doc/TechsGuide.php">PlanetLab
497 Technical Contact's Guide</ulink></title>