Re: [Cfengine] copy: templates

[Bas van der Vlies]

Will Lowe wrote:
> I'm using cfengine 2.x (right now 2.0.4, but I don't mind upgrading)
> under Debian woody.  Let's say I have several variables set in my
> cfagent program named $cfgroot, $site, $type, and $host, with the
> obvious meanings.
>
> I'd like to do something like this:
>
> copy:
>
>         $cfgroot/$host/etc/resolv.conf dest=/etc/resolv.conf recurse=inf
> # if it exists, otherwise try:
>         $cfgroot/$type/etc/resolv.conf dest=/etc/resolv.conf recurse=inf
> # if it exists, otherwise try:
>         $cfgroot/$site/etc/resolv.conf dest=/etc/resolv.conf recurse=inf
> # if it exists, otherwise try:
>         $cfgroot/default/etc/resolv.conf dest=/etc/resolv.conf recurse=inf
>
> .. in other words, I'd like to be able to maintain (possibly partial)
> sets of configs for each of $site, $type, $host, and a default set,
> and have cfengine automatically find the "most specific" action to
> apply.
>
> An additonal catch is that I'd like to do it for *every* *single* copy
> statement anywhere in the cfagent config (find the most specific
> resolv.conf, the most specific set of apache configs, the most
> specific /etc/nsswitch.conf, etc.) -- a generic templating system.
>
> Using groups/classes might be possible:
>
> sitefoo.farma:
>         copy resolv.conf.1234
>
> sitefoo.!farmb.farmc.!sitebar:
>         copy resolv.conf.4321
>
> siteBaz.farmF:
>         copy resolv.conf.0987
>
> .. but with 15 farms, 1000 servers, and 10 sites, the number of
> possibly needed rules becomes insane.  It'd be a lot simpler if
> cfengine could find the "best match" somehow on its own ... any ideas?

I think the trick is: (From the reference manual)
SingleCopy


        singlecopy = ( on )



If singlecopy is defined the behavior of copy: is modified so that a 
file will only be copied once, helping to achieve hierarchical or "most 
specific" file copy overrides, provided that the most specific file 
occurs first. With the following file structure on a host running cfservd:

/dist/hosts/loghost1.example.com/etc/syslog.conf 
/dist/solaris/etc/syslog.conf /dist/all/etc/syslog.conf

The configuration:

     control:
        singlecopy = ( on )

     copy:

      /dist/${fqhost}       dest=/ inform=true syslog=true r=inf 
server=disthost
      /dist/${ostype}       dest=/ inform=true syslog=true r=inf 
server=disthost
      /dist/all             dest=/ inform=true syslog=true r=inf 
server=disthost



Would result in:

     /dist/hosts/loghost1.example.com/etc/syslog.conf being copied to 
loghost1.example.com
     /dist/solaris/etc/syslog.conf being copied to Solaris systems
     /dist/all/etc/syslog.conf being copied to all other systems


--
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*  Bas van der Vlies                     e-mail: basv@sara.nl      *
*  SARA - Academic Computing Services    phone:  +31 20 592 8012   *
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