Improve the Management of DPK Archives

In Episode 127 of the podcast, Kyle and I discuss some strategies for managing the DPK archive files. The discussion started because I am starting a PeopleTools 8.56. To upgrade each server we copy the new DPK archive files to every server and run the DPK. Having a copy of those archives on every server is redundant and not the best solution.

A better solution is to store the DPK archives in centralized place. We run into a problem in the DPK when the archive folder has multiple versions of the same archive. For example, if we have two versions of the Weblogic archive, the DPK will return an error because it doesn’t know which one to deploy.

This error is generated from the function get_matched_file(). get_matched_file() is a custom DPK function that looks at the DPK Archive location and returns a filename based on a tag. The tags are string values like weblogic, pshome, and jdk. The DPK looks for all the file names that match the tag. If there is more than one file, the function returns an error.

Specifying Archive Files

Instead of letting the DPK search a directroy for matching archive files, we could explicity define which archive files we want to deploy. While this isn’t as dynamic, the method would give us more control over which version of each software we deploy. It could also solve the issue with centralizing all our DPK Archives.

To use this method, we have to make two changes to the DPK:

• Create a new hash to store the archives we want to deploy
• Update the Puppet code to read from the new hash

Hash to Store Archive Data

In the psft_customizations.yaml file, we create a new archive_files: hash. This hash is where we can explicitly define which archive files we want to use.

archive_files:
  weblogic:             "%{hiera('archive_location')}/pt-weblogic12.2.1.2.20180116.tgz"
  tuxedo:               "%{hiera('archive_location')}/pt-tuxedo12.2.2.0.tgz"
  jdk:                  "%{hiera('archive_location')}/pt-jdk1.8.0_144.tgz"
  pshome:               "%{hiera('archive_location')}/pt-pshome8.56.06.tgz"
  oracleclient:         "%{hiera('archive_location')}/pt-oracleclient12.1.0.2.tgz"
  psapphome:            "%{hiera('archive_location')}/fscm-psapphome027.tgz"

The keys to use the hash are the DPK tags for each piece of software. This lets us leverage the built-in tagging system in the DPK. If you want to take it a step further, you can define the hash with additional variables for each version. For example, in a common.yaml file, configure the archive_files: hash like this:

archive_files:
  jdk:                  "%{hiera('archive_location')}/pt-jdk%{hiera('jdk_version')}.tgz"
  pshome:               "%{hiera('archive_location')}/pt-pshome%{hiera('tools_version')}.tgz"

Then, in your psft_customizations.yaml file you can specify:

jdk_version:    1.8.0_144
tools_version:  8.56.06

Update Puppet to Read the Hash

Next, in the tools_deployment.pp file (under dpk/puppet/modules/pt_setup/manifests) we need to modify the code to use our archive_list: hash. In the delivered code, the DPK archive location and software tag are passed to the Ruby function get_matched_files(). What we will do instead is check if the archive_list: hash is defined. If it is, we will use the path from the hash instead of calling get_matched_file. If the archive_files: hash does not have the tag defined (like pshome), the get_matched_file() function is called.

Here is the code for deplying WebLogic:

$archive_files = hiera('archive_files', '')

if $archive_files {
  $weblogic_archive_file   = $archive_files[$weblogic_tag]
} 
if $weblogic_archive_file == '' {
  $weblogic_archive_file = get_matched_file($tools_archive_location, $weblogic_tag)
}
if $weblogic_archive_file == '' {
  fail("Unable to locate archive (tgz) file for Weblogic in ${tools_archive_location}")
}

You can copy this code for the rest of the archive types in the tools_deployment.pp and app_deployment. For DPK types that you do not specify, the DPK will revert to the original behavior.

I like this setup better. We get more control over which DPK archives we deploy, we can store multiple archives in a central location, and we retain the delivered behavior as the default.