Currently we are using Elasticsaerch 6.4 and all the other stack part like kibana, logstash and beats also have versio 6.4
But now we want to use the some security feature like Role-based access control for controlling user access which include in later version like Elasticsearch 6.8 or later.
So we want to upgrade our elasticsaerch as well as all the other stack part also.
Can we upgrade directly to version 7.9 without lossing the existing data?
Can you please give us some idea/steps how we can upgrade our 3 node cluster?
Any help or guidance will be appriciated.