ES upgrade from 6.8.1 to 7.4.2

Elastic Stack Elasticsearch
1

Hello,
I am trying to upgrade my TST environment from Elasticsearch 6.8.1 to 7.4.2, I am getting the below error during the upgrade in logs.
Error:
master not discovered yet, this node has not previously joined a bootstrapped (v7+) cluster, and this node must discover master-eligible nodes [hostnamenode1, hostnamenode2, hostnamenode3] to bootstrap a cluster: have discovered

elasticsearch.yml
network.host: ipaddress of 1stvirtual

discovery.seed_hosts: ["ipaddress of 2ndvirtual", "ipaddress of 3rdvirtual"]

discovery.zen.minimum_master_nodes: 3

cluster.initial_master_nodes: ["hostnamenode1", "hostnamenode2", "hostnamenode3"]

on each virtual server we are running 3 nodes...
can you please help us with proper elasticsearch.yml configuration in this regard.

2

Does this note in the docs describe your problem, and its solution?

If not, you'll need to share some more detail. You haven't shared the full log message, and the bit that you have shared looks like it's been modified. Unfortunately the details of this message are important, and by modifying them you have likely lost the information that will help us solve your problem.

3

How did you configure the discovery.seed_hosts? With more than one node per physical server, these will listen on different ports. Try adding the transport protocol port (e.g. 9300, 9301, etc.) to each of the entries.