We are having our mongodb cluster at AWS and our production DB mongo is very old - we are still using version 2.6 then latest version at the moment is 3.2.7. We need to upgrade mongodb binaries to the latest version. We can't upgrade existing DB cluster right in place because of versions incompatibility, new storage engine and ITSec requirements to encrypt EBS volumes. That means we need to setup new DB cluster v.3.2 and somehow migrate existing data on it. We have to do this without an outage because DB outage means that whole production delivery stack will be down.
Any idea how I can do it without an outage ?