Resolve an “uninitialized constant error” when using Puppet Development Kit

When using the Puppet Development Kit (PDK), you get an error message.

Error message

top (required)>': uninitialized constant Concurrent::RubyThreadLocalVar (NameError)

Version and installation information

PDK version: All supported

Solution

To resolve the error, follow these steps:

1. Upgrade to a version of PDK greater than or equal to 2.6.1.
2. Select the latest Puppet version when using the command: --puppet-version, or don’t specify a puppet-version, which defaults to the latest version.

For example:

• Puppet 6: pdk validate --puppet-version 6.29
• Puppet 7: pdk validate --puppet-version 7.22

Don’t use the command: --pe version. This command translates to a Puppet version that causes the error.

To learn more about this known issue, read our documentation.