I Installed the ELK stacks as usual, but then I had to add nodes. A lot of google gave a lot of more og less usefull hints, so here is what i did:
First, I changed the name of the cluster and node elkserver1 (the only node) in /etc/elasticseach/elasticseach.yml
And restarted elasticsearch, tailed log - everything was ok
vi /etc/elasticseach/elasticseach.yml service eleaticsearch restart tail -f /var/log/elasticsearch/mos-eisley.log
Notice the logfilename follows the clustername 
Secondly, I changed the same on the next node (elkserver2) and added the IP on elkserver1 in the /etc/elasticseach/elasticseach.yml:
discovery.zen.ping.unicast.hosts: ["host1","host1"]
to
discovery.zen.ping.unicast.hosts: ["77.243.52.135"]
Then started ES with:
service eleaticsearch restart tail -f /var/log/elasticsearch/mos-eisley.log
But the node never connected to the clusted.
After a short part of troubleshooting, ES only listens on 127.0.0.0:9200, so in /etc/elasticseach/elasticseach.yml do change
#network.host: 127.0.0.1
to
network.host: 0.0.0.0
After successfull join, I changes
discovery.zen.ping.unicast.hosts: ["77.243.52.135"]
to
discovery.zen.ping.unicast.hosts: ["77.243.52.135","77.243.52.155"]
on both nodes