Changes/Add amd map parser to autofs

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Add amd map parser to autofs

Summary

The am-utils package provides automount services for automount maps that use an amd format. However, the am-utils project has not been actively maintained for quite a while now.

The am-utils package in Fedora has significant problems that are not easily resolved so an amd format parser is to be added to the autofs package.

Owner

  • Name: Ian Kent
  • Email: raven@themaw.net
  • Release notes owner:

Current status

Detailed Description

The am-utils package provides automount services for automount maps that use an amd format. Unfortunately the am-utils project has not been actively maintained for quite a while now.

The am-utils package in Fedora has significant problems that are not easily resolved so an amd format parser is to be added to the autofs package.

The goal is to implement enough of the am-utils amd map parsing functionality to cover a large portion of the use cases provided by the am-utils package. Once this is done it will be up to users to describe the missing am-utils feature they need which will then be considered for addition in the upstream implementation.

Benefit to Fedora

Once there has been exposure to community and additional functionality requests considered, evaluated and perhaps implemented we can consider the need to retain am-utils in the Fedora distribution. The goal being to eliminate the need for inclusion of the largely unmaintained am-utils package.

Scope

The implementation of this functionality is restricted to the autofs package.

Some areas of this change will require changes to code common to the autofs parser and the amd parser and the amd parser will leverage existing autofs functionality but there is a high level of code separation because of the way parse modules are added to autofs.

Initially the change will be added as a path series to the autofs package, later when an upstream beta is released the source will be updated, finally when autofs-5.1.0 is released the source will updated again.

The release schedule has not been decided yet but the plan is to release a beta soon followed by 5.1.0 with the timing dependant on community feedback.

Not all the changes (planned for 5.1.0 but not the amd parser itself) will be included in 5.1.0, they will be added as time permits via minor version updates. This is because the amd parser is considered an important feature and needs to be made available sooner rather than later.

  • Proposal owners: upstream the change is nearly ready to be committed to the master branch and a beta released. If the beta is released soon enough updating the Fedora autofs package source is all that will be needed. If not then the existing patch series can be added to the autofs package in the mean time.
  • Other developers: N/A (not a System Wide Change)
  • Release engineering: N/A (not a System Wide Change)
  • Policies and guidelines: N/A (not a System Wide Change)

Upgrade/compatibility impact

There will be significant changes to the autofs configuration sub-system to provide relevant am-utils configuration. Users that want to use this functionality will need to pay attention to this.

Existing configurations for people not using the new parser should continue to function as they did previously.

Part of the configuration change involves splitting the autofs configuration into init configuration and daemon configuration with the daemon configuration moved to the /etc directory. After reading the new autofs configuration the old configuration is read to provide backward compatibility while uses update to the new configuration. One problem is that if a user uses the new functionality and doesn't pay attention to updating their configuration new configuration changes may be overridden by changes in the old configuration. There's no way to maintain backward compatibility and not have this problem but it is much better to not disrupt existing usage and require users pay attention to what needs to be done if they wish to use the new parser.

How To Test

Test examples need to be constructed and and some simple examples will be described here when the change is added to autofs. Most of the maps used during development are private and cannot be released so we will need to develop our own.

Dependencies

There is one kernel change that is recommended when using the amd parser.

This change has been included in 3.14.0 rc kernel and so should be included in Fedora 21. It is not required for function of the new parser but is strongly recommended.

Contingency Plan

  • Contingency mechanism: the change is largely done upstream but if it doesn't meet user requirements we will revert back to the autofs-5.0 release. The autofs-5.0 release will continue to be supported for the foreseeable future and simpler new features may also still be added but significant new features probably will only be added to the master branch (autofs-5.1.0).
  • Blocks release? N/A
  • Blocks product? none

Documentation

One aspect of making this change available in Fedora (and as a beta upstream) is to obtain user review and feedback of the package man pages and the included README for use of amd format maps.

Release Notes

A summary of the points covered in the package README for use of amd format maps will be sufficient and will be added here as part of adding the functionality to Fedora.