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Cfengine packages WAS Re: Other possible cfengine weak areas?


From: John Sechrest
Subject: Cfengine packages WAS Re: Other possible cfengine weak areas?
Date: Mon, 02 Feb 2004 07:55:58 -0800


 David Douthitt <address@hidden> writes:
 
  % > > I do this already.  Set up a class (such as "web" for web
  % > > servers) and put each host into each class.  Then, as I use
  % > > apt-rpm, I do the following:
 
  % > > web::
  % > >     "apt-get -qyy <rpms....>"
 
 ...
  % I was thinking I should write a script to handle some of this (in Ruby 
  % of course) and send it a list of RPMs with a leading + or - and let 
  % it remove and add as appropriate.  Thus you could specify what a 
  % particular server looks like, and replicate it elsewhere.
 
 
 In order to solve a problem with the MLN setup that we are working
 on, we in fact wrote a program to do this in perl.
 
 It works like a charm. 
 
 I do not remove packages yet, thinking that disk space is cheap
 and system failure is expensive. But we do turn off services.
 
 Here is a perl program that looks at two files, one is a role to host
 mapping and the other is a role to package mapping.
 
 I have other programs that do each of these seperately.
 
 - 
 to call the module, I use:
 control:
    hosts2role = ( /var/mln/hosts2role )
    packagebyrole = ( /var/mln/packagebyrole ) 
 
 
 # This finds all of the roles that this machine are bound to. 
    gotinit = ( PrepModule(module:getpkgbyrolefromhost,"${hosts2role} 
${packageby
 role} ${host}") )
 
 
 --
 
 PrepModule is a new feature in the 2.1.2a6 version of cfengine. 
 It was needed as a way to call the module in the right way.
 
 
 
 
 
 
 
 -- cut here----
 #!/usr/bin/perl
 #
 # 2004/01/24
 # John Sechrest/ Kyrre Begnum
 # address@hidden / address@hidden
 #
 # module:getpkgbyrolefromhost
 #
 # Given the file named: $file - /var/mln/hosts2role
 # and a file named: $rolefile - /var/mln/packagebyrole
 # and a hostname called $host
 # then find all of the roles that the host has
 # and then print them out with a + in front
 # And print out a list of all the packagestohave as a variable 
 
 
 # This is a merger of the idea of getrolebyhost and get packagebyrole.
 # Given
 
 
 # The hosts2role is of the form:
 # ID  machine   host   role featurelist
 # as a tab seperated file 
 # Like: 
 # 3 rex host1 web 
 # 4 rex host2 dns
 
 # the packagebyrole file is of the form:
 # ID  role package  featurelist
 # as a tab seperated file 
 # Like: 
 # 3 web apache
 # 4 dns bind9
 
 
 
 $debug=0;
 
 # Get the filename and hostname out of the parameters
 # They should be in ArgV
 # assume that $ARGV[0] = filename;
 # and that $ARGV[1] = hostname;
 
 if ($debug) {print "#Argv: $#ARGV\n";}
 if ($#ARGV != 2) {
     print "MODULE ERROR: Arguments to getrolebyhost must be: hosts2role 
packageb
 yrole hostname\n";
     exit(1);
 }
 
 $filename=$ARGV[0];
 $rolename=$ARGV[1];
 $hostname=$ARGV[2];
 
 #Open the file
 if ($debug) {print "Filename: $filename\n";}
 if ($debug) {print "rolename: $rolename\n";}
 if ($debug) {print "hostname: $hostname\n";}
 
 $i = 0;
 open (PACKAGELIST , "< $rolename") or die"Module ERROR: Could Not open 
$rolename
 \n" ;
 while ( $line=<PACKAGELIST> ){
     if ($debug) {print "package line: $line\n";}
     $line=~s/#.*$//;    # Delete any comments
     if ($debug) {print "package line w/o #: $line\n";}
     chop ($line);
     ($id,$role,$package,$featurelist) = split /\t+/, $line;
     if ($debug) {print "packagerole: $role\n";}
     if ($debug) {print "package: $package\n";}
     $rolelist[$i][0]=$role;
     $rolelist[$i][1]=$package;
     $rolelist[$i][2]=$featurelist;
     $i=$i+1;
 }
 $rolearraysize= $i-1;
 $modulelist ="";
 close (PACKAGELIST);
 
 
 open (MYFILE , "< $filename") or die"Module ERROR: Could Not open $filename\n" 
;
 
 
 
 # For each line in the file
 while ( $line=<MYFILE> ){
     if ($debug) {print "line: $line\n";}
     $line=~s/#.*$//;    # Delete any comments
     if ($debug) {print "line w/o #: $line\n";}
 
     ($id,$machine,$host,$role,$featurelist) = split /\t+/, $line; 
     if ($debug) {print "host: $host\n";}
     if ($debug) {print "hostname: $hostname\n";}
 
   # if it is for host $host, then get the role
   #  write out +role
 
     if ( $host eq $hostname ){
         print "+$role\n";
         $i=0;
         while ($i < $rolearraysize ){
             if ($rolelist[$i][0] eq $role )
             {  $modulelist = $modulelist . " " . $rolelist[$i][1];  
                 if ($debug) {print "modulelist: $modulelist\n";}
                 if ($debug) {print "rolelist: $rolelist[$i][1]\n";}
                 }
             $i=$i+1;
         }
     }
     if ($debug) {print "host: $host ->  role printend and packages assigned 
\n";
 }
     
 # end
 }
 
        if ( $modulelist ne "" ) {
          print "=packagestohave = ( $modulelist ) \n";
            }
 
 
 # close file
 close MYFILE;
 
 
 
 
 -----
 John Sechrest          .         Helping people use
                         .           computers and the Internet
                           .            more effectively
                              .                      
                                  .       Internet: address@hidden
                                       .   
                                               . http://www.peak.org/~sechrest






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