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Re: cfengine-1.6.2 copy doesn't replicate symlinks properly?

From: J. Maynard Gelinas
Subject: Re: cfengine-1.6.2 copy doesn't replicate symlinks properly?
Date: Sat, 03 Mar 2001 13:59:42 -0500

  Hi Mark,

  Thanks for the tip. I'm sorry I haven't replied sooner, I've just been busy. 
So it looks like setting typecheck=false in my script will resolve my problem 
with symbolic links.  Good.

   But I want to make the point that there's no way I would have correlated 
what the reference manual says about the typecheck directive, and the effect I 
desired from cfengine. I had looked at typecheck carefully and concluded that 
it limits only the output of error messages from cfengine, not what *action* 
cfengine might take.

   In the copy action similar problems of ambiguity within the cfengine 
reference include the "ignore" directive, the "include" directive and the 
"exclude" directive. From testing I've determined that the difference between 
"ignore" and "exclude" is that:


   a) ignore can take a comma separated list of directories similar to a $PATH 
   b) ignore won't purge files on a client down an ignored path, unlike 
"exclude", if purge is set to "true"
   c) ignore can be set globally using the global ignore directive, which 
passes a list of ignored directories to every action listed in the action 
sequence, or defined on the command line.


   a) Exclude takes only "patterns", not paths. One cannot give a list of 
absolute paths to individual files or directories which won't be copied, only 
patterns which represent files or directories. For example:

 exclude = hosts passwd shadow group lilo.conf 

works, while:

 exclude = /etc/hosts:/etc/passwd:/etc/shadow:/etc/group:/etc/lilo.conf

Will NOT work. 

    b) Exclude and include don't affect purge operations, which could cause 
serious data loss with a misconfigured cfengine.conf.
    b) Exclude can be configured globally by defining ExcludeCopy variable 
within the control: section and providing a list of *patters* to exclude from 

   On the difference between exclude and ignore, the reference manual states 
"... Unlike include, exclude this affects the way cfengine parses directory 
trees". And for exclude the manual states "This option may be repeated a 
number of times to specify the names of files or wildcards which match files 
which are to be excluded from a copy operation." I can find no examples of 
exclude and include in the sample scripts provided, however based on this one 
would assume that exclude (or it's global variable) should be able to take 
complete paths to files one wishes to exclude. One might also conclude that 
within a copy operation one can list multiple exclude directives.


 (and I guess)


  These multiple exclude directives will be ignored (based upon my tests) 
within cfengine-1.6.2, but the only way I could have determined this would be 
by running tests and watching -d1 and -d2 debug output to determine how 
cfengine parsed the config file, and then watching what it does. The 
difference between how ignore and exclude are parsed by cfengine, and the fact 
that one is globally configured by a directive, while the other by setting a 
variable within control: also lead to confusion. None of this appears 
explicitly stated either in the reference manual, or the tutorial.

   I want to make clear that I'm *NOT* writing this to personally insult or
criticize the core developers and documentation authors of the cfengine
project, but I *DO* think you need feedback about the ambiguities within the
cfengine reference manual. I repeat: there's simply no way I would have
concluded that suppressing error output should or would affect the success of a
copy operation.  In the same way that I couldn't have determined the
differences between the exclude and ignore directives without directly testing
them myself and watching the debug output combined with the results of a copy

    cfeninge is still a wonderfully useful tool which I'm glad I discovered. I 
thank you for the valuable tool, and your helpful reply.


> Mark Burgess Wrote:

> On 27 Feb, J. Maynard Gelinas wrote:

> > 
> >    I've got the copy operation working properly, and it appears to
> > work for the most part. However, I've noticed what appears to be a
> > serious problem in it's handling of Symbolic links: if a client has
> > a symlink down the directory path, but the server has replaced that
> > link with a file, the copy operation will fail and leave the original
> > link in place on the client. It also appears that if a file is in
> > place on the client, but a symbolic link with that filename is on
> > the server, the client cfengine won't replace the file with the 
> > proper link. 
> > 

> From the manual:
> typecheck=false (default is true)
> Switches on/off error messages if source and existing
> destination files do not match in type, e.g. if a file would overwrite a
> directory or link. 

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