doc/en/openafs.xml

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<!DOCTYPE guide SYSTEM "/dtd/guide.dtd">

<guide link = "/doc/en/openafs.xml">
<title>Gentoo Linux OpenAFS Guide</title>
<author title="Editor">
  <mail link="darks@gentoo.org">Holger Brueckner</mail>
</author>
<author title="Editor">
  <mail link="bennyc@gentoo.org">Benny Chuang</mail>
</author>
<author title="Editor">
  <mail link="blubber@gentoo.org">Tiemo Kieft</mail>
</author>
<author title="Editor">
  <mail link="fnjordy@gmail.com">Steven McCoy</mail>
</author>

<abstract>
This guide shows you how to install a openafs server and client on gentoo linux 
</abstract>

<license/>

<version>0.7</version>
<date>September 22, 2004</date>

<chapter>
  <title>Overview</title>
  <section>
    <title>About this Document</title>
    <body>
      <p>This document provides you with all neccessary steps to install an openafs server on Gentoo Linux.
      Parts of this document are taken from the AFS FAQ and IBM's Quick Beginnings guide on AFS. Well, never reinvent
      the wheel :)</p>
    </body>
  </section>
  <section>
    <title>What is AFS ?</title>
    <body>
    
    <p>
    AFS is a distributed filesystem that enables co-operating hosts
   (clients and servers) to efficiently share filesystem resources
   across both local area and wide area networks. Clients hold a 
   cache for often used objects (files), to get quicker
   access to them.
   </p>
   <p>
   AFS is based on a distributed file system originally developed
   at the Information Technology Center at Carnegie-Mellon University
   that was called the "Andrew File System". "Andrew" was the name of the research project at CMU - honouring the
   founders of the University.  Once Transarc was formed and AFS became a
   product, the "Andrew" was dropped to indicate that AFS had gone beyond
   the Andrew research project and had become a supported, product quality
   filesystem. However, there were a number of existing cells that rooted
   their filesystem as /afs. At the time, changing the root of the filesystem
   was a non-trivial undertaking. So, to save the early AFS sites from having
   to rename their filesystem, AFS remained as the name and filesystem root.
   </p> 
   </body>
  </section>  
    <section>
    <title>What is an AFS cell ?</title>
    <body>
    <p>An AFS cell is a collection of servers grouped together administratively
    and presenting a single, cohesive filesystem.  Typically, an AFS cell is a set of 
    hosts that use the same Internet domain name (like for example gentoo.org)
    Users log into AFS client workstations which request information and files
    from the cell's servers on behalf of the users. Users won't know on which server
    a file which they are accessing, is located. They even won't notice if a server
    will be located to another room, since every volume can be replicated and moved
    to another server without any user noticing. The files are always accessable.
    Well it's like NFS on steroids :) 
   </p>
    </body>
  </section>  
  <section>
    <title>What are the benefits of using AFS ?</title>
    <body>
    <p>The main strengths of AFS are its:
 
       caching facility (on client side, typically 100M to 1GB),
       security features (Kerberos 4 based, access control lists),
       simplicity of addressing (you just have one filesystem),
       scalability (add further servers to your cell as needed),
       communications protocol. 
    </p>
    </body>
  </section>  
  <section>
    <title>Where can i get more information ?</title>
    <body>
    <p>
    Read the <uri link="http://www.angelfire.com/hi/plutonic/afs-faq.html">AFS FAQ</uri>.
    </p>
    <p>
    Openafs main page is at <uri link="http://www.openafs.org">www.openafs.org</uri>.
    </p>
    <p>
    AFS was originally developed by Transarc which is now owned by IBM.
    You can find some information about AFS on
    <uri link="http://www.transarc.ibm.com/Product/EFS/AFS/index.html">Transarcs Webpage</uri>
    </p>
    </body>
  </section>  

</chapter>

<chapter>
<title>Documentation</title>
  <section>
    <title>Getting AFS Documentation</title>
    <body>
    <p>
    You can get the original IBM AFS Documentation. It is very well written and you 
    really want 
    read it if it is up to you to administer a AFS Server.
    </p>
<pre>
# <i>emerge app-doc/afsdoc</i>
</pre>
    </body>   
  </section>
</chapter>

<chapter>
<title>Client Installation</title>
   <section>
     <title>Preliminary Work</title>
     <body>
       <note>
         All commands should be written in one line !! In this document they are
         sometimes wrapped to two lines to make them easier to read.
       </note>
       <note>
         Unfortunately the AFS Client needs a ext2 partiton for it's cache to run 
         correctly, because there are some locking issues with reiserfs. You need to 
         create a ext2 partition of approx. 200MB (more won't hurt) and mount it to 
         <path>/usr/vice/cache</path>
       </note>
       <p>
       You should adjust the two files CellServDB and ThisCell before you build the 
       afs client. (These files are in <path>/usr/portage/net-fs/openafs/files</path>)
       </p>
 <pre>
 CellServDB:
 >netlabs        #Cell name
 10.0.0.1        #storage
 
 ThisCell:
 netlabs       
 </pre>

 <warn>
 Only use spaces inside the <path>CellServDB</path> file. The client will most
 likely fail if you use TABs.
 </warn>
 
       <p>
       CellServDB tells your client which server(s) he needs to contact for a 
       specific cell. ThisCell should be quite obvious. Normally you use a name
       which is unique for your organisation. Your (official) domain might be a
       good choice. 
       </p>
     </body>
   </section>
   <section>
     <title>Building the Client</title>
     <body>
<pre>
# <i>emerge net-fs/openafs</i>
</pre>
       <p>
       After successful compilation you're ready to go.
       </p>
     </body>
   </section>
   <section>
     <title>Starting afs on startup</title>
     <body>
       <p>
       The following command will create the appropriate links to start your afs client
       on system startup.
       </p>
       <warn>
       You should always have a running afs server in your domain when trying to start the afs client. You're system won't boot
       until it gets some timeout if your afs server is down. (and this is quite a long long time)
       </warn>
<pre>
# <i>rc-update add afs default</i>
</pre>
     </body>
   </section>
</chapter>

<chapter>
<title>Server Installation</title>
   <section>
     <title>Building the Server</title>
     <body>
       <p>
       The following command will install all necessary binaries for setting up a AFS Server 
       <e>and</e> Client.
       </p>
<pre>
# <i>emerge net-fs/openafs</i>
</pre>
     </body>
   </section>
  <section>
    <title>Starting AFS Server</title>    
    <body>
      <p>
      You need to remove the sample CellServDB and ThisCell file first.
      </p>
<pre>
# <i>rm /usr/vice/etc/ThisCell</i>
# <i>rm /usr/vice/etc/CellServDB</i>
</pre>
      <p>
      Next you will run the <b>bosserver</b> command to initialize the Basic OverSeer (BOS) 
      Server, which monitors and controls other AFS server processes on its server 
      machine. Think of it as init for the system. Include the <b>-noauth</b>
      flag to disable authorization checking, since you haven't added the admin user yet.
      </p>
      <warn>
      Disabling authorization checking gravely compromises cell security. 
      You must complete all subsequent steps in one uninterrupted pass 
      and must not leave the machine unattended until you restart the BOS Server with
      authorization checking enabled. Well this is what the AFS documentation says :)
      </warn>
<pre>
# <i>/usr/afs/bin/bosserver -noauth &amp;</i>
</pre>
      <p>
      Verify that the BOS Server created <path>/usr/vice/etc/CellServDB</path> 
      and <path>/usr/vice/etc/ThisCell</path>
      </p>
<pre>
# <i>ls -al /usr/vice/etc/</i>
-rw-r--r--    1 root     root           41 Jun  4 22:21 CellServDB
-rw-r--r--    1 root     root            7 Jun  4 22:21 ThisCell
</pre>
      
    </body>    
  </section>
  <section>
    <title>Defining Cell Name and Membership for Server Process</title>
    <body>
      <p>
      Now assign your cells name. 
      </p>
      <impo>There are some restrictions on the name format. 
      Two of the most important restrictions are that the name
      cannot include uppercase letters or more than 64 characters. Remember that
      your cell name will show up under <path>/afs</path>, so you might want to choose
      a short one.</impo>
      <note>In the following and every instruction in this guide, for the &lt;server name&gt;
      argument substitute the full-qualified hostname 
      (such as <b>afs.gentoo.org</b>) of the machine you are installing. 
      For the &lt;cell name&gt;
      argument substitute your cell's complete name (such as <b>gentoo</b>)</note>
      <p>
      Run the <b>bos setcellname</b> command to set the cell name:
      </p>
<pre>
# <i>/usr/afs/bin/bos setcellname &lt;server name&gt; &lt;cell name&gt; -noauth</i>
</pre>
    </body>
  </section>
  <section>
    <title>Starting the Database Server Process</title>
    <body><p>
       Next use the <b>bos create</b> command to create entries for the four database 
       server processes in the
       <path>/usr/afs/local/BosConfig</path> file. The four processes run on database 
       server machines only.
       </p>

       <table>
       <tr>
         <ti>kaserver</ti>
         <ti>The Authentication Server maintains the Authentication Database.
             This can be replaced by a Kerberos 5 daemon. If anybody want's to try that
             feel free to update this document :)</ti>
       </tr>
       <tr>
         <ti>buserver</ti>
         <ti>The Backup Server maintains the Backup Database</ti>
       </tr>
       <tr>
         <ti>ptserver</ti>
         <ti>The Protection Server maintains the Protection Database</ti>
       </tr>
       <tr>
         <ti>vlserver</ti>
         <ti>The Volume Location Server maintains the Volume Location Database (VLDB).
             Very important :)</ti>
       </tr>
       </table>    
<pre>
# <i>/usr/afs/bin/bos create &lt;server name&gt; kaserver simple 
    /usr/afs/bin/kaserver -cell &lt;cell name&gt; -noauth</i>
# <i>/usr/afs/bin/bos create &lt;server name&gt; buserver simple 
    /usr/afs/bin/buserver -cell &lt;cell name&gt; -noauth</i>
# <i>/usr/afs/bin/bos create &lt;server name&gt; ptserver simple 
    /usr/afs/bin/ptserver -cell &lt;cell name&gt; -noauth</i>
# <i>/usr/afs/bin/bos create &lt;server name&gt; vlserver simple 
    /usr/afs/bin/vlserver -cell &lt;cell name&gt; -noauth</i>
</pre>
       <p>
       You can verify that all servers are running with the <b>bos status</b> command:
       </p>
<pre>
# <i>/usr/afs/bin/bos status &lt;server name&gt; -noauth</i>
Instance kaserver, currently running normally.
Instance buserver, currently running normally.
Instance ptserver, currently running normally.
Instance vlserver, currently running normally.
</pre>
       
    </body>
  </section>
  <section>
    <title>Initializing Cell Security</title>
    <body>
      <p>
      Now we'll initialize the cell's security mechanisms. We'll begin by creating the 
      following two initial entries in the
      Authentication Database: The main administrative account, called <b>admin</b> by 
      convention and an entry for
      the AFS server processes, called <b>afs</b>. No user logs in under the 
      identity <b>afs</b>, but the Authentication
      Server's Ticket Granting Service (TGS) module uses the account
      to encrypt the server tickets that it grants to AFS clients. This sounds 
      pretty much like Kerberos :)
      </p>
      <p>
      Enter <b>kas</b> interactive mode
      </p>
<pre>
# <i>/usr/afs/bin/kas -cell &lt;cell name&gt; -noauth</i>
ka&gt; <i>create afs</i>
initial_password:
Verifying, please re-enter initial_password:
ka&gt; <i>create admin</i>
initial_password:
Verifying, please re-enter initial_password:
ka&gt; <i>examine afs</i>

User data for afs
  key (0) cksum is 2651715259, last cpw: Mon Jun  4 20:49:30 2001
  password will never expire.
  An unlimited number of unsuccessful authentications is permitted.
  entry never expires.  Max ticket lifetime 100.00 hours.
  last mod on Mon Jun  4 20:49:30 2001 by $lt;none&gt;
  permit password reuse
ka&gt; <i>setfields admin -flags admin</i>
ka&gt; <i>examine admin</i>
 
User data for admin (ADMIN)
  key (0) cksum is 2651715259, last cpw: Mon Jun  4 20:49:59 2001
  password will never expire.
  An unlimited number of unsuccessful authentications is permitted.
  entry never expires.  Max ticket lifetime 25.00 hours.
  last mod on Mon Jun  4 20:51:10 2001 by $lt;none&gt;
  permit password reuse
ka&gt;
</pre>
      <p>
        Run the <b>bos adduser</b> command, to add the <b>admin</b> user to 
        the <path>/usr/afs/etc/UserList</path>.
      </p>
<pre>
# <i>/usr/afs/bin/bos adduser &lt;server name&gt; admin -cell &lt;cell name&gt; -noauth</i>
</pre>
      <p>
        Issue the <b>bos addkey</b> command to define the AFS Server 
        encryption key in <path>/usr/afs/etc/KeyFile</path>
      </p>
      <note>
        If asked for the input key, give the password you entered when creating 
        the afs entry with <b>kas</b>
      </note>
<pre>
# <i>/usr/afs/bin/bos addkey  &lt;server name&gt; -kvno 0 -cell &lt;cell name&gt; -noauth</i>
    input key:
    Retype input key:
</pre>
      <p>
        Issue the <b>pts createuser</b> command to create a Protection Database 
        entry for the admin user
      </p>
      <note>
        By default, the Protection Server assigns AFS UID 1 to the <b>admin</b> user, because 
        it is the first user
        entry you are creating. If the local password file (/etc/passwd or equivalent) 
        already has an entry for
        <b>admin</b> that assigns a different UID use the <b>-id</b> argument 
        to create matching UID's
       </note>
<pre>
# <i>/usr/afs/bin/pts createuser -name admin -cell &lt;cell name&gt; [-id &lt;AFS UID&gt;] -noauth</i>
</pre>
      <p>
        Issue the <b>pts adduser</b> command to make the <b>admin</b> user a member 
        of the system:administrators group,
        and the <b>pts membership</b> command to verify the new membership
      </p>
<pre>
# <i>/usr/afs/bin/pts adduser admin system:administrators -cell &lt;cell name&gt; -noauth</i>
# <i>/usr/afs/bin/pts membership admin -cell &lt;cell name&gt; -noauth</i>
      Groups admin (id: 1) is a member of:
        system:administrators
</pre>
      <p>
        Restart all AFS Server processes
      </p>
<pre>
# <i>/usr/afs/bin/bos restart &lt;server name&gt; -all -cell &lt;cell name&gt; -noauth</i>
</pre>
    </body>
  </section>
  <section>
    <title>Starting the File Server, Volume Server and Salvager</title>
    <body>
    <p>
      Start the <b>fs</b> process, which consists of the File Server, Volume Server and Salvager (fileserver,
      volserver and salvager processes).
    </p>
<pre>
# <i>/usr/afs/bin/bos create &lt;server name&gt; fs fs /usr/afs/bin/fileserver 
                                              /usr/afs/bin/volserver 
                                              /usr/afs/bin/salvager 
                                              -cell &lt;cell name&gt; -noauth</i>
</pre>
    <p>
    Verify that all processes are running
    </p>
<pre>
 # <i>/usr/afs/bin/bos status &lt;server name&gt; -long -noauth</i>
 Instance kaserver, (type is simple) currently running normally.
     Process last started at Mon Jun  4 21:07:17 2001 (2 proc starts)
     Last exit at Mon Jun  4 21:07:17 2001
     Command 1 is '/usr/afs/bin/kaserver'

 Instance buserver, (type is simple) currently running normally.
     Process last started at Mon Jun  4 21:07:17 2001 (2 proc starts)
     Last exit at Mon Jun  4 21:07:17 2001
     Command 1 is '/usr/afs/bin/buserver'

 Instance ptserver, (type is simple) currently running normally.
     Process last started at Mon Jun  4 21:07:17 2001 (2 proc starts)
     Last exit at Mon Jun  4 21:07:17 2001
     Command 1 is '/usr/afs/bin/ptserver'

 Instance vlserver, (type is simple) currently running normally.
     Process last started at Mon Jun  4 21:07:17 2001 (2 proc starts)
     Last exit at Mon Jun  4 21:07:17 2001
     Command 1 is '/usr/afs/bin/vlserver'

 Instance fs, (type is fs) currently running normally.
     Auxiliary status is: file server running.
     Process last started at Mon Jun  4 21:09:30 2001 (2 proc starts)
     Command 1 is '/usr/afs/bin/fileserver'
     Command 2 is '/usr/afs/bin/volserver'
     Command 3 is '/usr/afs/bin/salvager'
</pre>
    <p>
      Your next action depends on whether you have ever run AFS file server machines 
      in the cell:
    </p>
    <p>
      If you are installing the first AFS Server ever in the cell create the 
      first AFS volume, <b>root.afs</b>
    </p>
    <note>
    For the partition name argument, substitute the name of one of the machine's 
    AFS Server partitions. By convention
    these partitions are named <path>/vicepx</path>, where x is in the range of a-z.
    </note>
<pre>
  # <i>/usr/afs/bin/vos create &lt;server name&gt; 
                            &lt;partition name&gt; root.afs 
                                -cell &lt;cell name&gt; -noauth</i>
</pre>
    <p>
      If there are existing AFS file server machines and volumes in the cell 
      issue the <b>vos sncvldb</b> and <b>vos
      syncserv</b> commands to synchronize the VLDB (Volume Location Database) with 
      the actual state of volumes on the local machine. This will copy all necessary data to your
      new server.
    </p>
    <p>
      If the command fails with the message "partition /vicepa does not exist on
      the server", ensure that the partition is mounted before running OpenAFS
      servers, or mount the directory and restart the processes using
      <c>/usr/afs/bin/bos restart &lt;server name&gt; -all -cell &lt;cell
      name&gt; -noauth</c>.
    </p>
<pre>
  # <i>/usr/afs/bin/vos syncvldb &lt;server name&gt; -cell &lt;cell name&gt; -verbose -noauth</i>
  # <i>/usr/afs/bin/vos syncserv &lt;server name&gt; -cell &lt;cell name&gt; -verbose -noauth</i> 
</pre>
    </body>
  </section>
  <section>
    <title>Starting the Server Portion of the Update Server</title>
    <body>
<pre>
# <i>/usr/afs/bin/bos create &lt;server name&gt; 
                    upserver simple "/usr/afs/bin/upserver 
                    -crypt /usr/afs/etc -clear /usr/afs/bin" 
                    -cell &lt;cell name&gt; -noauth</i>
</pre>
    </body>
  </section>
  <section>
    <title>Configuring the Top Level of the AFS filespace</title>
    <body>
      <p>
        First you need to set some acl's, so that any user can lookup <path>/afs</path>.        
      </p>
<pre>
# <i>/usr/afs/bin/fs setacl /afs system:anyuser rl</i>
</pre>
      <p>
       Then you need to create the root volume, mount it readonly on <path>/afs/&lt;cell name&gt;</path> and read/write
       on <path>/afs/.&lt;cell name&gt;</path>
      </p>
<pre>
# <i>/usr/afs/bin/vos create &lt;server name&gt;&lt;partition name&gt; root.cell</i>
# <i>/usr/afs/bin/fs mkmount /afs/&lt;cell name&gt; root.cell </i>
# <i>/usr/afs/bin/fs setacl /afs/&lt;cell name&gt; system:anyuser rl</i>
# <i>/usr/afs/bin/fs mkmount /afs/.&lt;cell name&gt; root.cell -rw</i>
</pre>
      <p>
        Finally you're done !!! You should now have a working AFS file server 
        on your local network. Time to get a big
        cup of coffee and print out the AFS documentation !!!
      </p>
      <note>
        It is very important for the AFS server to function properly, that all system 
        clock's are synchronized. 
        This is best
        accomplished by installing a ntp server on one machine (e.g. the AFS server) 
        and synchronize all client clock's
        with the ntp client. This can also be done by the afs client. 
      </note>
    </body>
  </section>
  
</chapter>

<chapter>
<title>Basic Administration</title>
<section>
<title>Disclaimer</title>
<body>

<p>
OpenAFS is an extensive technology. Please read the AFS documentation for more
information. We only list a few administrative tasks in this chapter.
</p>

</body>
</section>
<section>
<title>Configuring PAM to Acquire an AFS Token on Login</title>
<body>

<p>
To use AFS you need to authenticate against the KA Server if using
an implementation AFS Kerberos 4, or against a Kerberos 5 KDC if using
MIT, Heimdal, or ShiShi Kerberos 5.  However in order to login to a
machine you will also need a user account, this can be local in
/etc/passwd, NIS, LDAP (OpenLDAP), or a Hesiod database.  PAM allows
Gentoo to tie the authentication against AFS and login to the user
account.
</p>

<p>
You will need to update /etc/pam.d/system-auth which is used by the
other configurations.  "use_first_pass" indicates it will be checked
first against the user login, and "ignore_root" stops the local super
user being checked so as to order to allow login if AFS or the network
fails.
</p>

<pre caption="/etc/pam.d/system-auth">
auth       required     /lib/security/pam_env.so
auth       sufficient   /lib/security/pam_unix.so likeauth nullok
auth       sufficient   /usr/afsws/lib/pam_afs.so.1 use_first_pass ignore_root
auth       required     /lib/security/pam_deny.so

account    required     /lib/security/pam_unix.so

password   required     /lib/security/pam_cracklib.so retry=3
password   sufficient   /lib/security/pam_unix.so nullok md5 shadow use_authtok
password   required     /lib/security/pam_deny.so

session    required     /lib/security/pam_limits.so
session    required     /lib/security/pam_unix.so
</pre>

<p>
In order for sudo to keep the real user's token and to prevent local
users gaining AFS access change /etc/pam.d/su as follows:
</p>

<pre caption="/etc/pam.d/su">
<comment># Here, users with uid &gt; 100 are considered to belong to AFS and users with
# uid &lt;= 100 are ignored by pam_afs.</comment>
auth       sufficient   /usr/afsws/lib/pam_afs.so.1 ignore_uid 100

auth       sufficient   /lib/security/pam_rootok.so

<comment># If you want to restrict users begin allowed to su even more,
# create /etc/security/suauth.allow (or to that matter) that is only
# writable by root, and add users that are allowed to su to that
# file, one per line.
#auth       required     /lib/security/pam_listfile.so item=ruser \
#       sense=allow onerr=fail file=/etc/security/suauth.allow

# Uncomment this to allow users in the wheel group to su without
# entering a passwd.
#auth       sufficient   /lib/security/pam_wheel.so use_uid trust

# Alternatively to above, you can implement a list of users that do
# not need to supply a passwd with a list.
#auth       sufficient   /lib/security/pam_listfile.so item=ruser \
#       sense=allow onerr=fail file=/etc/security/suauth.nopass

# Comment this to allow any user, even those not in the 'wheel'
# group to su</comment>
auth       required     /lib/security/pam_wheel.so use_uid

auth       required     /lib/security/pam_stack.so service=system-auth

account    required     /lib/security/pam_stack.so service=system-auth

password   required     /lib/security/pam_stack.so service=system-auth

session    required     /lib/security/pam_stack.so service=system-auth
session    optional     /lib/security/pam_xauth.so

<comment># Here we prevent the real user id's token from being dropped</comment>
session    optional     /usr/afsws/lib/pam_afs.so.1 no_unlog
</pre>

</body>
</section>
</chapter>

</guide>