Option Directories -- "Vanilla" Workstation

The actual /opt directory on a typical workstation contains three things:

commercial (HP and third-party) application directories,
a link to the "master" /opt directory, and
links to installed applications.

The commercial packages will frequently be in actual directories rather than at the ends of links, since such software is often license-controlled and can't legally be distributed to the entire network like locally maintained and freely available software. However, for any packages for which network distribution is allowed, the link scheme described in this document works fine, whether they are commercial or not.

The link to the "master" opt directory usually references an NFS-mounted location on the "master" opt network node. However, any means for making the directory visible via the filesystem should work, not just NFS. Thus, this scheme will work on an Apollo Domain/OS network (we've done it) and should work equally well on AFS, DFS, EFS, SMBFS, or any other connection mechanisms.

The application links are normally created and maintained using the repln script. They are pretty tedious to manipulate by hand, although it can be done in a pinch.

The "master" link can be changed in an instant to a different machine. This might be required for any of several reasons, including

load balancing, between machines or networks,
performance reasons (eg. a remote opt just won't cut it any more!),
failure of the master opt node,
migration to a new OS rev,

or any number of other reasons. One should be careful that all the applications exported by the original opt directory are present in the new one. If this is an issue, it is normally easier to simply delete all the application links and then re-create them using the repln script once the new master link is established.

This structure can also apply to the master node--it can be a "client" of its own installation. If the master opt directory is actually /opt on the master node, then no "mstr" link need be created. The links of the form

appname ---> pkg/appname-version

appname ---> site/appname-version

will be in the correct place already. If the opt directory is in a different location than /opt (such as is the case in our diagrams, where it lives in /_c/opt.10) then the actual /opt directory on the master node can be built to look just like a workstation's /opt. For our example, the master node's /opt/mstr link has the value /_c/opt.10 instead of an NFS pathname.

[vanilla workstation]

Last modified: Thu 6 Nov 1997