For Redhat / CentOS / Oracle Linux
Install the certificate in your enviroment using the update-ca-trust command
For Example, Let's Encrypt Certificate(s) trust chain:
- Download Active PEM certificate from: https://letsencrypt.org/certificates/ and put it in /etc/pki/ca-trust/source/anchors
Run: # update-ca-trust - Also, you might need to run: # update-ca-trust enable to enable the dynamic generation of the ca-bundle file. By default, it's a static file from the RPM installed.
- (man update-ca-trust is your friend!)