6.10 Automount Maps

In order to use the automount information stored in your directory, you must shift your focus to the automount daemon itself, specifically Linux's kernel-based autofs. As it currently stands, autofs (v3.1.7 and the 4.0 preview releases) supports the undocumented automount and automountMap object classes. However, Red Hat has updated the package in its distribution (autofs-3.1.7-28) to look up mount points based on the nisObject and nisMap classes described in RFC 2307 (and included in nis.schema). The LDAPbis workgroup's revisions to RFC 2307 will include new schema items for storing automount information, but for the moment, nisObject and nisMap have the largest support base from Red Hat, Sun, and PADL. Figure 6-8 shows the required and optional attributes for these two new object classes.

Figure 6-8. nisObject and nisMap object classes

Red Hat's automount patches can be obtained from either http://people.redhat.com/nalin/autofs/ or in the latest autofs SRPM at ftp://ftp.redhat.com/pub/redhat/linux/rawhide/SRPMS/SRPMS/.

PADL's migration tools include a script (migrate_automount.pl) for converting an automount map to LDIF. Here, you will convert a single automount point in /opt to a directory entry. You can see from the /etc/auto.opt excerpt that the LDIF entry contains all of the information needed for mounting /opt/src. This time, PADL's script does create the top-level container (nisMapName=auto.opt) for you:

$ grep src /etc/auto.opt
src    -rw,hard,intr    queso.plainjoe.org:/export/u1/src
      
$ ./migrate_automount.pl /etc/auto.opt /tmp/auto.opt.ldif
      
$ cat /tmp/auto.opt.ldif
dn: nisMapName=auto.opt,dc=plainjoe,dc=org
objectClass: top
objectClass: nisMap
nisMapName: auto.opt
      
dn: cn=src,nisMapName=auto.opt,dc=plainjoe,dc=org
objectClass: nisObject
cn: src
nisMapEntry: -rw,hard,intr queso.plainjoe.org:/export/u1/src
nisMapName: auto.opt

After adding the new automount entries to the directory using ldapadd, the autofs server must be informed of auto.opt's map location, the LDAP server's hostname, and the search base. The following line in /etc/auto.master instructs the autofs package to look up mounts for /opt on the host ldap1 beneath ou=auto.opt,dc=plainjoe,dc=org:

## Look up mounts for /opt in the LDAP directory.
   /opt  ldap:ldap1:nisMapName=auto.opt,dc=plainjoe,dc=org  --timeout 300

Now you can launch the automount daemon; it will obtain all information for mount points in /opt from the directory server. If you're curious about what's going on, I recommend viewing the slapd log file on your server for more information on the autofs LDAP queries.