c_rehash specs the certificates in PEM format, so before proceeding we need make sure is in PEM format. The guide for securing communications on Hawkular produces the certificate in DER format it needs to be converted to PEM format.
OpenSSL can be used as follow to convert
hawkular.cert from DER to PEM format.
$ openssl x509 -inform der -in hawkular.cert -out hawkular.pem
Once created, copy your PEM certificate to
OPENSSLDIR/certs (you will need root permissions) and run c_rehash on that dir.
$ sudo cp hawkular.pem OPENSSLDIR/certs
$ sudo c_rehash OPENSSLDIR/certs
If you are using any application that relies on JRuby (such as HawkFX) you will probably need to use old-style hashes. To do that run c_rehash a second time with flags to use the old-style hash and to keep existing hashes.
$ sudo c_rehash -old -n OPENSSLDIR/certs
That should be enough to let Ruby client or any application that uses it (e.g. HawkFX) to communicate with Hawkular Server over SSL.
To use on HawkFX simply put the address with https and the secure port.