I've configured ec2-plugin with the correct "EC2 Key Pair's Private Key" that starts with "----BEGIN RSA PRIVATE KEY----" and it works fine.
But I've checked the config.xml file of jenkins and I found that the stored key isn't what I configured from Jenkins UI.
I've tried to "Reload Configuration from Disk" and it works fine.
I've also tried restart jenkins and it works fine.
But the issue is that I'm using another plugin which is "SCM Sync configuration" and the real problem is that when I terminate my Jenkins machine and bring up a new one the "EC2 Key Pair's Private Key" got compromised with what stored in config.xml file