I finally passed my Jenkins exam yesterday. It took a week to prepare for the exam. As always I created a github repo available by the link:
The main course that I relied on was LinuxAcademy's Certified Jenkins Engineer course. It has awesome practical lessons and labs to complete. However, the final practice exam is too oversimplified, I got very tough questions regarding Pipelines and plugins.
The following other resources that I used to prepare are: