Host/Agent should not install if there are no changes in file

[Suresh]

Can you guys please help me address this host configuration?

1) I have 5 different modules that need to be installed to each host/agent

1.1) from one of the modules, a large application tar file is downloaded by agent and performs untar to required folder structure.

1.2) before the "untar", required application services are stopped and after "untar' is complete all the services are started

What I have observed is, agent is downloading the application tar file every 30 minutes (agent is running in daemon mode)

and performing the complete process (1, 1.1, 1.2) which it shouldn't if the file is unchanged from its previous download.

How can I configure agent, such that it should perform the installation, only if downloaded file is changed from previous download?

Suresh

[Michael Baydoun]

The file ensure for the tar file should only download when it changes

The untar can have a require on the file resource, and so on

Can you post your file resource and untar exec resource?

Suresh

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[Suresh]

class filecheck {

  include myapp

  file { "puppet:///modules/myapp/MyApp_GA.tar.gz":

    owner => 'myapp',

    group => 'myapp',

    ensure => latest,

    path => "/opt/apps/myapp/artifacts/MyApp_GA.tar.gz",

  }

}

class myapp::decompress {  

  exec { "myapp::decompress":

    owner => 'myapp',

    group => 'myapp',

    mode => 0755,

    command => "/bin/tar -xzf MyApp_GA.tar.gz -C /opt/apps/myapp/release"

}

in my puppet manifests/nodes.pp

I have defined several stages e.g.

nodes.pp

========

stage {

  "stop_service": ;

 }

 

 node mynode.com {

   include filecheck, myapp

 }

 

What I need is if filecheck fails, then execution should stop and should go no further.

-Suresh

[jcbollinger]

On Apr 25, 10:02 pm, Suresh <suresh.k.u...@gmail.com> wrote:
> class filecheck {
>   include myapp
>   file { "puppet:///modules/myapp/MyApp_GA.tar.gz":
>     owner => 'myapp',
>     group => 'myapp',
>     ensure => latest,
>     path => "/opt/apps/myapp/artifacts/MyApp_GA.tar.gz",
>   }
>
> }
>
> class myapp::decompress {
>   exec { "myapp::decompress":
>     owner => 'myapp',
>     group => 'myapp',
>     mode => 0755,
>     command => "/bin/tar -xzf MyApp_GA.tar.gz -C /opt/apps/myapp/release"
>
> }
>
> in my puppet manifests/nodes.pp
> I have defined several stages e.g.
>
> nodes.pp
> ========
> stage {
>   "stop_service": ;
>  }
>
>  node mynode.com {
>    include filecheck, myapp
>  }
>
> What I need is if filecheck fails, then execution should stop and should go
> no further.

That should indeed happen if filecheck failed, but File['puppet:///
modules/myapp/MyApp_GA.tar.gz'] (and thus Class['filecheck']) will not
fail on account of the file already being present. It should not
download the file again either in that case (are you sure it's doing
so?) unless the version on the server is different from the one on the
client, but nothing I see in your manifests would prevent Puppet from
proceeding to Exec[ 'myapp::decompress' ].

You need to adjust your mental model. Your class names and your
expectations suggest that you regard Puppet as some kind of scripting
engine. It isn't. Rather, it is a state management service. It
takes your specifications for a target *state*, and does whatever is
necessary (broadly speaking) to achieve that state. "Whatever it
takes" can be nothing, and that's just fine with Puppet -- by no means
is it a failure.

To address your problem, it would be far better build a package for
"myapp" (RPM, DEB, or whatever is appropriate for your target system),
put it in a local package repository, and use Puppet's Package
resource type to ensure it installed. Even stopping and restarting
the service around an installation or update would be better done in
the package's scripts than directly under Puppet control. Don't
reinvent the wheel here.


John

[Michael Baydoun]

add something like 

notify   => Exec["myapp::decompress"],

to your file resource

also, according to the documentation, for a file resource the ensure parameter 

possible values are absent, present, file, and directory

I'm not sure what latest is going to do there, but you don't need it, just say present

ensure => latest is usually used for the package resource type, though I would suggest never doing that either, unless you really want your package management trying to update everytime puppet runs

[jcbollinger]

On Apr 25, 10:02 pm, Suresh <suresh.k.u...@gmail.com> wrote:

>   file { "puppet:///modules/myapp/MyApp_GA.tar.gz":
>     owner => 'myapp',
>     group => 'myapp',
>     ensure => latest,
>     path => "/opt/apps/myapp/artifacts/MyApp_GA.tar.gz",
>   }

Furthermore, if you continue to use File and Exec resources instead of
packaging it up, you should really write that File resource in one of
these two forms:

# using a logical name for the resource
file { 'myapp::tarball':
ensure => 'file',
path => '/opt/apps/myapp/artifacts/MyApp_GA.tar.gz',

owner => 'myapp',
group => 'myapp',
ensure => latest,

# exactly one of 'source', 'content', or 'target':
source => 'puppet:///modules/myapp/MyApp_GA.tar.gz',
}

# using the destination path as the resource name
file { '/opt/apps/myapp/artifacts/MyApp_GA.tar.gz':
ensure => 'file',

owner => 'myapp',
group => 'myapp',
ensure => latest,

# exactly one of 'source', 'content', or 'target':
source => 'puppet:///modules/myapp/MyApp_GA.tar.gz',
}

You should *not* name the resource by the server-side path / URL.

Also, you absolutely should specify the file content via either
'content' or 'source'. That it worked at all as you presented it
(supposing that it did) is an undocumented implementation quirk on
which you should not rely. Furthermore, you should specify an
explicit 'ensure' value at least for clarity, and maybe for
correctness.


John