Configure certificate for repository-s3 with ceph

I made a truststore

keytool -import -alias ceph -file ceph.crt -keystore ceph.jks

and then passed the file and password:

ES_JAVA_OPTS=-Xms2048m -Xmx2048m \
  -Djavax.net.ssl.trustStore=/usr/share/elasticsearch/config/ceph.jks \
  -Djavax.net.ssl.keyStorePassword=secretpasswordyoudontknow"

And now it works !
Thanks !!