How to call a puppet provider method from puppet manifest?

Question

I'm using the ibm_installation_manager module from the puppet forge and it is a bit basic because IBM wrote Installation Manager in a time where idempotency was done much. ref: https://forge.puppet.com/puppetlabs/ibm_installation_manager

As such it does not cater nicely for upgrades - so the module will not detect if an upgrade is needed, stop existing processes, do the upgrade and then start the processes again. It will just detect if an upgrade is needed and try to install the desired version and if that constitutes an upgrade that's great, but it will probably fail due to running instances.

So I need to implement some "stop processes" pre-upgrade functionality.

I need to mention at this point I'm new to ruby and fairly new to puppet.

The provider that the module uses (imcl.rb) has an exists method. The ideal way for me to detect if an upgrade is going to happen (and stop the instances if it is) would be for my puppet manifest to be able to somehow call the exists method. Is this possible?

Or how would you approach this problem? Something like imcl.exists(ibm_pkg["my_imcl_pkg_resource"])

Answer 1

The ideal way for me to detect if an upgrade is going to happen (and stop the instances if it is) would be for my puppet manifest to be able to somehow call the exists method. Is this possible?

No, it is not possible, at least not in any useful way. Your manifests describe how to build a catalog of resources describing the target state of the machine. In a master / agent setup, this happens on the master. The catalog is then used as input to a separate step, in which it is transferred to the target machine and applied there. It is in this second step that providers are engaged.

To the extent that you want the contents of your catalogs to be influenced by the current state of the target machine, the Puppet mechanism for that is to convey the needed state details to the catalog builder in the form of facts . It is relatively straightforward to add your own facts. Indeed, there are at least two distinct, non-exclusive mechanisms , going under the names "external facts" and "custom facts".