Debug message: Failed to load library 'msgpack' in Puppet Enterprise 3.2 to 2018.1

When the Puppet agent log level is increased to debug, messages might appear concerning the msgpack feature.

Version and installation information

PE version: 3.2 to 2018.1
OS: Any Unix

Debug messages

Debug: Failed to load library 'msgpack' for feature 'msgpack'. Debug: Puppet::Network::Format[msgpack]: feature msgpack is missingDebug: node supports formats: pson b64_zlib_yaml yaml raw

Note: This occurs whe the agent log level is increased to debug, commonly when running puppet agent -t --debug.

When Puppet communicates, it checks to see whether the msgpack format is available. The msgpack library is not required for PE, and not installed by default. Unless you have installed it, the check fails and issues the msgpack debug message.

Solution

Note: Links in this article are for PE 2018.1, make sure that you navigate to the correct version of the documentation for your deployment.

PE does not require the msgpack library because the agent can use other formats, such as PSON (Puppet's variant of JSON), to communicate. No action is required for PE to operate normally. However, installing the msgpack library will stop msgpack-related debug messages.

Warning: Msgpack is an experimental feature which is not officially supported. To learn more about msgpack, including how to enable it, read Experimental features: Msgpack support.