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Network Information Services (NIS and NIS+) Guide
Suggested Transition Phases
The following outline is a suggested NIS-to-NIS+ transition
process:
- Review basic Transition Principles.
- Become familiar with NIS+. (See Become Familiar with NIS+.)
- Design your final NIS+ namespace. (See Design Your Final NIS+ Namespace.)
- Select security measures. (See Plan Security Measures.)
- Decide how to use NIS-compatibility mode. (See Decide How to Use NIS-Compatibility Mode.)
- Complete prerequisites to transition. (See Complete Prerequisites to Transition.)
- Implement the transition. (See Implement the Transition.)
Transition Principles
Before you begin the transition, review the following basic principles:
- Consider the alternatives to immediately making the transition. You can
defer the upgrade to NIS+ until after your site has completed
its transition to the AIX 4.3.3 release. This would allow you to focus
your resources on one transition effort at a time.
- Take steps to simplify the transition. While these steps may diminish
the effectiveness of NIS+ in the short term, they consume fewer
servers and less administrative time. Once the transition is complete, you
can change the NIS+ setup to better suit your needs. The following
are some suggestions:
- Do not change domain names unless they violate name restrictions. See
Naming Conventions.
- Do not use any hierarchies; keep a flat NIS+ namespace.
- Use the NIS-compatibility features.
- Use default tables and directory structures.
- Do not establish credentials for clients.
- Minimize impact on client users by recognizing two major user-related
considerations. First, users should not notice any change in service. Second,
the transition phase itself should cause minimal disruption to client users.
To ensure the second consideration, be sure the administrators responsible
for each domain migrate their client machines to NIS+, rather
than ask the users to implement the migration. This ensures that proper procedures
are implemented, that procedures are consistent across client machines, and
that irregularities can be dealt with immediately by the administrator.
- Use the lessons learned by other administrators in previous transitions,
such as:
- Do not change the name services currently provided by NIS or
the way NIS functions.
- Do not change the structure of DNS.
- Do not change the IP network topology.
- Do not upgrade applications that use NIS to NIS+;
leave the migration to NIS+ APIs for the future.
- Do not consider additional uses for NIS+ during the implementation
phase; add them later.
Become Familiar with NIS+
One of the best ways to become familiar with NIS+ is to build
a prototype namespace. There is no substitute for hands-on experience with
the product; administrators need the opportunity to practice in a test environment.
Note: Do not use your prototype domain as the
basis for your actual running NIS+ namespace. Deleting your prototype
when you have learned all you can from it will avoid namespace configuration
problems. Start anew to create the real namespace after following all the
planning steps.
Create small, manageable test domains. For guidance, you can use Prerequisites for Installing and Configuring NIS+, which describes how to plan and create a simple test domain
and subdomain (with or without NIS-compatibility mode) using the NIS+
setup scripts.
Note: The NIS+ scripts described
in Using NIS+ Setup Scripts are the recommended method of setting up an NIS+
namespace. The recommended procedure is to first set up your basic NIS+
namespace using the scripts, and then customize that namespace for your particular
needs using the NIS+ command set.
Design Your Final NIS+ Namespace
Design the final NIS+ namespace, following the guidelines in
Designing the NIS+ Namespace. While designing the namespace, do not worry about
limitations imposed by the transition from NIS. You can add those
later, once you know what your final NIS+ goal is.
Plan Security Measures
NIS+ security measures provide a great benefit to users and
administrators, but they require additional knowledge and setup steps on the
part of both users and administrators. They also require several planning
decisions. Planning NIS+ Security Measures describes the implications of NIS+
security and the decisions you need to make for using it in your NIS+
namespace.
Decide How to Use NIS-Compatibility Mode
The use of parallel NIS and NIS+ namespaces is virtually
unavoidable during a transition. Because of the additional resources required
for parallel namespaces, try to develop a transition sequence that reduces
the amount of time your site uses dual services or the extent of dual services
within the namespace (for example, convert as many domains as possible to NIS+
only).
Using NIS-Compatibility Mode explains the transition issues associated with
the NIS-compatibility mode and suggests a way to make the transition
from NIS, through NIS compatibility, to NIS+
alone.
Complete Prerequisites to Transition
In addition to the planning decisions mentioned above, you must complete
several miscellaneous prerequisites, as described in Prerequisites to Transition.
Implement the Transition
The section on Implementing the Transition provides suggested steps to implement
the transition you have planned in the previous steps.
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