+++ /dev/null
-WHAT?
------
-
-This is a templated-based configuration utility for clusters. It
-allows CTDB and various services (Samba, NFS, vsftpd, ...) to be
-configured. It should be installed/run on each node after relevant
-packages are installed or after any master configuration/template
-change.
-
-WHY?
-----
-
-This is meant to be flexible and allow subsets of services to be
-configured.
-
-HOW?
-----
-
-Run like this to test template expansion into a staging subdirectory
-"t/":
-
- ./cluster-configure.py -vv -n -t templates/rhel -s t example.conf
-
-Or without -n but as root to test actual installation of files and
-reload of services.
-
-Try --help to see the options.
-
-Notes - this sounds complex, but it isn't... see the example
-configuration file and templates. Run the above command with the "-n"
-option and check out the files in the staging area... :-)
-
-* Master configuration file
-
- The master configuration file is parsed by Python's ConfigParser
- module. Therefore, it is subject to any restrictions of that
- module. For example, older versions do not allow identation of
- settings.
-
-* Template structure
-
- Each subdirectory of templates directory is a package name, with a
- 2-digit-plus-dot prefix used to order the processing of packages.
- If, according to the system's package manager, that package is not
- installed on the system then no further processing is done.
-
- A package subdirectory should have one or more version
- subdirectories that are matched to the version of the package
- reported by the package manager. A version subdirectory is named as
- <min>#<max> with a literal '#' as the separator. A missing limit
- implies no limit, so a version subdirectory of "#" matches all
- version. Comparisons with <min> use <= and comparisons with <max>
- use <. This allows simple ranges like "3.0#4.0" to work sensibly
- with "4.0#". The highest matching version is used, so the above
- could just be written "3.0#" and "4.0#".
-
- A "files" subdirectory of a version subdirectory contains a
- directory tree of configuration files that have template
- substitution done and are then installed into the root filesystem.
- A file is only actually installed if, after substitutions, it is
- different to the currently/previously installed file.
-
- An "events" subdirectory of a version subdirectory can contain "pre"
- and "post" files. If any configuration files are (to be) installed
- the "pre" is run before installation of these files and "post" is
- run afterwards.
-
- For example, consider the following:
-
- templates/rhel/60.nfs-utils/1.0#/files/etc/exports
- templates/rhel/60.nfs-utils/1.0#/files/etc/sysconfig/nfs
- templates/rhel/60.nfs-utils/1.0#/events/post
-
- If nfs-utils with a version >= 1.0 is installed then:
-
- 1. Template substitution is done on both files the /etc/exports and
- /etc/sysconfig/nfs files, and each resulting file is installed if
- it is different to the already installed corresponding file.
-
- 2. If a file was installed then "post" is run. This tells NFS to
- reload its configuration.
-
-* Template substitutions
-
- !!variable!!
-
- The template format is !!variable!!. @@variable@@ has been avoided
- so that you can install a configuration and templates with
- autocluster.
-
- !!|expr!!
-
- Apart from simple variables, templates can contain expression
- evaluations. !!|expr!! causes expr to be processed with Python's
- eval() function and the *return value* (not the output) is
- substituted for the template expression.
-
- !!%plugin.func(args)!!
-
- Plugin expressions are an extension to expression evaluations. If a
- plugin called "export.py" contains a function called "format" then a
- template can contain:
-
- !!%export.format(REST)!!
-
- and this will cause the return value the following to be substituted:
-
- export.format(config, self.name, ... REST ...)
-
- where:
-
- - config is the global configuration object
-
- - self.name is the name of the current package being processed
-
- - ... REST ... is usually a printf-style format string followed by a
- list of configuration keys who's values should be substituted into
- the
-
- Note that, for robustness, plugins don't actually get imported into
- the regular namespace so plugin expressions are quite useful... even
- though they might look confusing at first.
-
- An example is illustrative...
-
- Assuming that export.py contains:
-
- def format(config, package, format, items):
- ...
-
- In config (the master configuration file), several exports may be
- defined for the given package. Each will be of the form:
-
- [export:nfs-utils:data]
- share = data
- fsid = 834258092
-
- This will inherit the directory and other options from the share
- "data":
-
- [share:data]
- directory = /srv/xyz123/data
- filesystem = /srv/xyz123
- permissions = 0777
- comment = An example share
-
- To create export defintions for NFS, something like this can be
- used:
-
- !!%export:format("\"%s\" *(rw,fsid=%s)\n", ["directory", "fsid"])!!
-
- This produces a line of output for each export, substituting the
- values for "directory" and "fsid" appropriately. In the above case,
- the output would be:
-
- "/srv/xyz123/data" *(rw,fsid=834258092)
-
-WHERE?
-------
-
-This is part of autocluster, so you can get it from:
-
- git://git.samba.org/autocluster.git
-
-WHO?
-----
-
-Martin Schwenke <martin@meltin.net>
git.samba.org / autocluster.git / blobdiff