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Justin

2012-Jul-23 21:09 UTC

[Puppet Users] Adding file dependencies to existing service

Hi all,

I''m trying to configure Puppet to allow the creation of multiple
memcached
instances on a system. However, I''m running into the message that only 
subclasses can override parameters. Perhaps I''m going about this the
wrong
way, or maybe I just have something slightly wrong. Any advice is welcome.


class memcached {
    package { ''memcached'': ensure => present }

    # do not want basic configuration
    file { ''/etc/memcached.conf'': ensure => absent }

    service { ''memcached'':
        ensure  => running,
        enable  => true,
        require => Package[''memcached''],
    }
}

define memcached::instance () {
    include memcached

    $conf = "/etc/memcached_${name}.conf"

    file { $conf: ensure => present }

*    Service[''memcached''] { require +> File[$conf] }*
}

# create first instance in file /etc/memcached_en.conf
memcached::instance { ''en'': }

The other thing I''d like to do is have
Service[''memcached''] set to NOT
start unless there is at least one instance, i.e. not start until after the 
first instance''s config file is in place, but that''s not a
showstopper.

Thanks,
Justin

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Christopher Wood

2012-Jul-23 21:33 UTC

head link

Re: [Puppet Users] Adding file dependencies to existing service

(inline)

On Mon, Jul 23, 2012 at 02:09:01PM -0700, Justin wrote:>    Hi all,
>    I''m trying to configure Puppet to allow the creation of
multiple memcached
>    instances on a system. However, I''m running into the message
that only
>    subclasses can override parameters. Perhaps I''m going about
this the wrong
>    way, or maybe I just have something slightly wrong. Any advice is
welcome.
>    class memcached {
>        package { ''memcached'': ensure => present }
>        # do not want basic configuration
>        file { ''/etc/memcached.conf'': ensure => absent
}
>        service { ''memcached'':
>            ensure  => running,
>            enable  => true,
>            require => Package[''memcached''],
>        }
>    }
>    define memcached::instance () {
>        include memcached
>        $conf = "/etc/memcached_${name}.conf"
>        file { $conf: ensure => present }
>        Service[''memcached''] { require +> File[$conf] }
This bit is a problem because all defines will declare
Service[''memcached''] and thus you''ll get spammed with
duplicate definitions. I solved this by using multiple daemons, useful to me
because I want to be able to kill a daemon in an emergency without affecting
more than one service. Another generic technique I''ve found useful is
to have several classes in my module, for instance:

1) thing::software class (installs the defaults file per below, installs the
package, installs the init script)
2) thing::extraconfig define (includes thing::software, throw a config file in
/etc/thing.d/, something inside this notifies the service)
3) thing::service class (includes thing:;software, declares service {
''thing'': }, basically exists so the service is separate from
the software)

In your manifest where you call all these, you would have to ensure that
thing::extraconfig is declared before thing::service.

(Just food for thought.)
>    }
>    # create first instance in file /etc/memcached_en.conf
>    memcached::instance { ''en'': }
>    The other thing I''d like to do is have
Service[''memcached''] set to NOT
>    start unless there is at least one instance, i.e. not start until after
>    the first instance''s config file is in place, but
that''s not a
>    showstopper.
By my experimentation, memcached will be started by the postinstall scripts when
you install the deb/rpm. One technique I''ve found useful (on
Ubuntu/Debian) is to declare file { "/etc/default/$software": content
=> "start=no" } before installing said software. Apt won''t
overwrite the defaults file so the daemon won''t start, and you can lay
down a custom init script (which doesn''t check the defaults file) after
your config files are installed.

Here''s how I solved the memcached thing to pop up multiple memcached
daemons (obviously derived from https://github.com/saz/puppet-memcached):

class memcached::orig_off {

  $classname = ''memcached''
  
  package { $classname:
    ensure => installed,
  }
  
  service { $classname:
    ensure     => stopped,
    enable     => false,
    hasrestart => true,
    hasstatus  => true,
    require => Package[''memcached''],
  }

}

define memcached::daemon ( $max_memory = false, $listen_ip =
''0.0.0.0'', $port = ''11211'', $max_connections
= ''8192'' ) {

  $classname = ''memcached''
  $filesource = "puppet:///modules/$classname"

  case $::operatingsystem {
    ubuntu, debian: {
      $user = ''nobody''
      $mconfdir = ''/etc/monit/conf.d''
    }
    centos, redhat: {
      $user = ''memcached''
      $mconfdir = ''/etc/monit.d''
    }
    default: {
      fail("Unsupported platform: ${::operatingsystem}")
    }
  }

  $service1 = "memcached${port}"
  $config1  = "/etc/memcached${port}.conf"
  $config1template  = "$classname/memcached_sp.conf.erb"
  $init1 = "/usr/local/sbin/start-memcached${port}"
  $init1template = "$classname/start_memcached.erb"
  $init2 = "/etc/init.d/memcached${port}"
  $init2template = "$classname/init_memcached.erb"
  $mfile1 = "$mconfdir/${classname}${port}"
  $mfile1template = "$classname/memcached_monit.erb"  
  $logfile = "/var/log/memcached${port}.log"

  include memcached::orig_off

  file { $init1:
    content => template($init1template),
    mode => 744,
  }

  file { $init2:
    content => template($init2template),
    mode => 744,
  }

  file { $config1:
    content => template($config1template),
    require => Class[''memcached::orig_off''],
  }

  service { $service1:
    ensure     => running,
    enable     => true,
    hasrestart => true,
    hasstatus  => false,
    require => [File[$init1], File[$init2], File[$config1]],
    subscribe  => File[$config1],
  }

  file { $mfile1:
    content => template($mfile1template),
    mode => 600,
    require => Service[$service1],
  }

}

>    Thanks,
>    Justin
> 
>    --
>    You received this message because you are subscribed to the Google
Groups
>    "Puppet Users" group.
>    To view this discussion on the web visit
>    [1]https://groups.google.com/d/msg/puppet-users/-/fic-AkDAfAoJ.
>    To post to this group, send email to puppet-users@googlegroups.com.
>    To unsubscribe from this group, send email to
>    puppet-users+unsubscribe@googlegroups.com.
>    For more options, visit this group at
>    http://groups.google.com/group/puppet-users?hl=en.
> 
> References
> 
>    Visible links
>    1. https://groups.google.com/d/msg/puppet-users/-/fic-AkDAfAoJ
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Justin

2012-Jul-24 00:44 UTC

head link

Re: [Puppet Users] Adding file dependencies to existing service

Chris,

Thanks for your  response. Your post got me thinking about a different 
approach that I''m surprised I didn''t think of in the first
place. I do
prefer to have a single service handling multiple daemons, but I also 
realized I should be using Hiera for this. So I''m now defining a hash
in
Hiera on a per-node basis (i.e. %{fqdn}.yaml) like so:

memcached_instances:
  xx: { tcp_port: ''11211'', max_memory: ''512''
}
  yy: { tcp_port: ''11212'', max_memory: ''512''
}
  zz: { tcp_port: ''11213'', max_memory: ''512''
}

and here''s what I''ve boiled my class down to:

class memcached {

    $instances      = hiera_hash(''memcached_instances'')
    $instance_names = split(inline_template(''<%=
instances.keys.join(",")
%>''), '','')

    package { ''memcached'':
        ensure => present
    }

    file { ''/etc/memcached.conf'':
        ensure  => absent,
        require => Package[''memcached''],
    }

    define memcached::instance ( $instance_name = $title ) {
        $log_file        = "/var/log/memcached-${instance_name}.log"
        $user            = ''memcache''
        $max_connections = ''1024''

        $tcp_port        =
$memcached::instances[$instance_name][''tcp_port'']
        $max_memory      = 
$memcached::instances[$instance_name][''max_memory'']

        file { "/etc/memcached_${instance_name}.conf":
            ensure  => present,
            content =>
template(''memcached/etc/memcached.conf.erb''),
        }
    }

    memcached::instance { $instance_names:
        require => Package[''memcached''],
        notify  => Service[''memcached''],
    }

    service { ''memcached'':
        ensure     => running,
        enable     => true,
        hasrestart => true,
        hasstatus  => false,
        require    => Package[''memcached''],
    }

}

It could use some work in how it handles other values in the templates, but 
it seems to work nicely so far and should scale well.

Thanks again for taking the time to post your thoughts and code!

Justin



On Monday, July 23, 2012 2:33:31 PM UTC-7, Christopher Wood
wrote:>
> (inline) 
>
> On Mon, Jul 23, 2012 at 02:09:01PM -0700, Justin wrote: 
> >    Hi all, 
> >    I''m trying to configure Puppet to allow the creation of
multiple
> memcached 
> >    instances on a system. However, I''m running into the
message that
> only 
> >    subclasses can override parameters. Perhaps I''m going
about this the
> wrong 
> >    way, or maybe I just have something slightly wrong. Any advice is 
> welcome. 
> >    class memcached { 
> >        package { ''memcached'': ensure => present }
> >        # do not want basic configuration 
> >        file { ''/etc/memcached.conf'': ensure =>
absent }
> >        service { ''memcached'': 
> >            ensure  => running, 
> >            enable  => true, 
> >            require => Package[''memcached''], 
> >        } 
> >    } 
> >    define memcached::instance () { 
> >        include memcached 
> >        $conf = "/etc/memcached_${name}.conf" 
> >        file { $conf: ensure => present } 
> >        Service[''memcached''] { require +>
File[$conf] }
>
> This bit is a problem because all defines will declare 
> Service[''memcached''] and thus you''ll get spammed
with duplicate
> definitions. I solved this by using multiple daemons, useful to me because 
> I want to be able to kill a daemon in an emergency without affecting more 
> than one service. Another generic technique I''ve found useful is
to have
> several classes in my module, for instance: 
>
> 1) thing::software class (installs the defaults file per below, installs 
> the package, installs the init script) 
> 2) thing::extraconfig define (includes thing::software, throw a config 
> file in /etc/thing.d/, something inside this notifies the service) 
> 3) thing::service class (includes thing:;software, declares service { 
> ''thing'': }, basically exists so the service is separate
from the software)
>
> In your manifest where you call all these, you would have to ensure that 
> thing::extraconfig is declared before thing::service. 
>
> (Just food for thought.) 
>
> >    } 
> >    # create first instance in file /etc/memcached_en.conf 
> >    memcached::instance { ''en'': } 
> >    The other thing I''d like to do is have
Service[''memcached''] set to
> NOT 
> >    start unless there is at least one instance, i.e. not start until 
> after 
> >    the first instance''s config file is in place, but
that''s not a
> >    showstopper. 
>
> By my experimentation, memcached will be started by the postinstall 
> scripts when you install the deb/rpm. One technique I''ve found
useful (on
> Ubuntu/Debian) is to declare file { "/etc/default/$software":
content =>
> "start=no" } before installing said software. Apt won''t
overwrite the
> defaults file so the daemon won''t start, and you can lay down a
custom init
> script (which doesn''t check the defaults file) after your config
files are
> installed. 
>
> Here''s how I solved the memcached thing to pop up multiple
memcached
> daemons (obviously derived from https://github.com/saz/puppet-memcached): 
>
> class memcached::orig_off { 
>
>   $classname = ''memcached'' 
>   
>   package { $classname: 
>     ensure => installed, 
>   } 
>   
>   service { $classname: 
>     ensure     => stopped, 
>     enable     => false, 
>     hasrestart => true, 
>     hasstatus  => true, 
>     require => Package[''memcached''], 
>   } 
>
> } 
>
> define memcached::daemon ( $max_memory = false, $listen_ip =
''0.0.0.0'',
> $port = ''11211'', $max_connections =
''8192'' ) {
>
>   $classname = ''memcached'' 
>   $filesource = "puppet:///modules/$classname" 
>
>   case $::operatingsystem { 
>     ubuntu, debian: { 
>       $user = ''nobody'' 
>       $mconfdir = ''/etc/monit/conf.d'' 
>     } 
>     centos, redhat: { 
>       $user = ''memcached'' 
>       $mconfdir = ''/etc/monit.d'' 
>     } 
>     default: { 
>       fail("Unsupported platform: ${::operatingsystem}") 
>     } 
>   } 
>
>   $service1 = "memcached${port}" 
>   $config1  = "/etc/memcached${port}.conf" 
>   $config1template  = "$classname/memcached_sp.conf.erb" 
>   $init1 = "/usr/local/sbin/start-memcached${port}" 
>   $init1template = "$classname/start_memcached.erb" 
>   $init2 = "/etc/init.d/memcached${port}" 
>   $init2template = "$classname/init_memcached.erb" 
>   $mfile1 = "$mconfdir/${classname}${port}" 
>   $mfile1template = "$classname/memcached_monit.erb"   
>   $logfile = "/var/log/memcached${port}.log" 
>
>   include memcached::orig_off 
>
>   file { $init1: 
>     content => template($init1template), 
>     mode => 744, 
>   } 
>
>   file { $init2: 
>     content => template($init2template), 
>     mode => 744, 
>   } 
>
>   file { $config1: 
>     content => template($config1template), 
>     require => Class[''memcached::orig_off''], 
>   } 
>
>   service { $service1: 
>     ensure     => running, 
>     enable     => true, 
>     hasrestart => true, 
>     hasstatus  => false, 
>     require => [File[$init1], File[$init2], File[$config1]], 
>     subscribe  => File[$config1], 
>   } 
>
>   file { $mfile1: 
>     content => template($mfile1template), 
>     mode => 600, 
>     require => Service[$service1], 
>   } 
>
> } 
>
>
> >    Thanks, 
> >    Justin 
> > 
> >    -- 
> >    You received this message because you are subscribed to the Google 
> Groups 
> >    "Puppet Users" group. 
> >    To view this discussion on the web visit 
> >    [1]https://groups.google.com/d/msg/puppet-users/-/fic-AkDAfAoJ. 
> >    To post to this group, send email to puppet-users@googlegroups.com.
> >    To unsubscribe from this group, send email to 
> >    puppet-users+unsubscribe@googlegroups.com. 
> >    For more options, visit this group at 
> >    http://groups.google.com/group/puppet-users?hl=en. 
> > 
> > References 
> > 
> >    Visible links 
> >    1. https://groups.google.com/d/msg/puppet-users/-/fic-AkDAfAoJ 
>
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Puppet users - Jul 2012 - Adding file dependencies to existing service

[Puppet Users] Adding file dependencies to existing service

Re: [Puppet Users] Adding file dependencies to existing service

Re: [Puppet Users] Adding file dependencies to existing service