Elasticsearch client node in Docker unable to join non Docker cluster

Hello All,

We have an 1.7.5 Elasticsearch cluster of 6 nodes.

I am trying to join a client only node that is on Docker and have been unable to apart from one time.

The Docker host is on the same network with the Elasticsearch cluster.

The ES client node did join once and it was then stopped the restarted out of curiosity and it was unable to rejoin the cluster after that.

Also tried deleting the container and launching a new one but it made no difference.

What could be causing this?

The ES related config looks like this:

es.cluster.name=ClusterName
es.network.publish_host=10.x.6.90
es.http.port=9200-9300
es.transport.tcp.port=9300-9400
es.index.action.destructive_requires_name=true
es.index.query.bool.max_clause_count=1000000
es.indices.breaker.total.limit=75%
es.threadpool.bulk.queue_size=1000
es.node.client=true
es.node.data=false
es.node.master=false
es.http.enabled=false
es.discovery.zen.ping.multicast.enabled=false
es.discovery.zen.ping.unicast.hosts="10.x.6.80,10.x.6.81,10.x.6.82,10.x.7.80,10.x.7.81,10.x.7.82"

The error:
17:03:50.859 [main] INFO org.elasticsearch.node - [Mangle] starting ...
17:03:50.943 [main] INFO org.elasticsearch.transport - [Mangle] bound_address {inet[/0:0:0:0:0:0:0:0:9300]}, publish_address {inet[/10.x.6.90:9300]}
17:03:50.958 [main] INFO org.elasticsearch.discovery - [Mangle] ClusterName/zj62_vPpQYWNzV6kuJbrFg
17:03:54.043 [elasticsearch[Mangle][generic][T#1]] INFO org.elasticsearch.discovery.zen - [Mangle] failed to send join request to master [[MasterNode3][2fq2A98lR9qnkS37WPyA5g][MasterNode3][inet[/10.x.6.82:9300]]{master=true}], reason [RemoteTransportException[[MasterNode3][inet[/10.x.6.82:9300]][internal:discovery/zen/join]]; nested: ConnectTransportException[[Mangle][inet[/10.x.6.90:9300]] connect_timeout[30s]]; nested: ConnectException[Connection refused: /10.x.6.90:9300]; ]
17:03:57.079 [elasticsearch[Mangle][generic][T#1]] INFO org.elasticsearch.discovery.zen - [Mangle] failed to send join request to master [[MasterNode3][2fq2A98lR9qnkS37WPyA5g][MasterNode3][inet[/10.x.6.82:9300]]{master=true}], reason [RemoteTransportException[[MasterNode3][inet[/10.x.6.82:9300]][internal:discovery/zen/join]]; nested: ConnectTransportException[[Mangle][inet[/10.x.6.90:9300]] connect_timeout[30s]]; nested: ConnectException[Connection refused: /10.x.6.90:9300]; ]

Some additional information on this.
If the transport port is directly mapped (-p 9300:9300), it can join.