About Custom CA Root Certificates

If you’re using Rancher in an internal production environment where you aren’t exposing apps publicly, use a certificate from a private certificate authority (CA).

Services that Rancher needs to access are sometimes configured with a certificate from a custom/internal CA root, also known as self signed certificate. If the presented certificate from the service cannot be validated by Rancher, the following error displays: x509: certificate signed by unknown authority.

To validate the certificate, the CA root certificates need to be added to Rancher. As Rancher is written in Go, we can use the environment variable SSL_CERT_DIR to point to the directory where the CA root certificates are located in the container. The CA root certificates directory can be mounted using the Docker volume option (-v host-source-directory:container-destination-directory) when starting the Rancher container.

Examples of services that Rancher can access: