title: Neo4j embedded : Upgrade from 2.3.9 to 3.2.3 : initial_hosts are not communicating with each other
body: <p>I have upgraded my neo4j embedded DB from 2.3.9 to 3.2.3 in SINGLE mode, it has upgraded successfully. After upgrade, I have enabled "HA" mode. While running neo4j with 3 clusters, I am facing below issue.</p>
  
  <p>Individually servers are running fine in HA mode. (i.e. ha.initial_hosts = "ip_address_1:5101"), but if I add three servers under initial_hosts (as shown in the config), all three servers are stopping immediately. </p>
  
  <p>Am I missing any configuration? Please suggest.</p>
  
  <p><strong>Config:</strong></p>
  
  <pre><code>neo4j {
              # Enable these two options while upgrading neo4j database.
              # dbms.allow_format_migration=true
  
              # or weak or strong
      cache_type = "weak"
              # Reduce the default page cache memory allocation
              dbms.memory.pagecache.size="6G"
  
              # Port to listen to for incoming backup requests.
              dbms.backup.address = ${local.private-ip}":6367"
  
              # Unique server id for this Neo4j instance
              # can not be negative id and must be unique
              ha.server_id="1"
  
              # List of other known instances in this cluster
              ha.initial_hosts = "ip_1:5101,ip_2:5101,ip_3:5101"
  
              # ha.initial_hosts = "ip_1:5101"
              # ha.cluster_server = ${local.private-ip}":5101"
  
              # IP and port for this instance to bind to for communicating cluster information
              # with the other neo4j instances in the cluster.
              ha.host.coordination = ${local.private-ip}":5101"
  
              # IP and port for this instance to bind to for communicating data with the
              # other neo4j instances in the cluster.
              ha.host.data = ${local.private-ip}":6365"
  
              # HA - High Availability
              # SINGLE - Single mode, default.
              dbms.mode="HA"
  
              # HTTP Connector
              dbms.connector.http.enabled="true"
              dbms.connector.http.listen_address=":7474"
  
              # Bolt connector
              dbms.connector.bolt.enabled="true"
              dbms.connector.bolt.tls_level="OPTIONAL"
              dbms.connector.bolt.listen_address=":7689"
  }
  </code></pre>
  
  <p><strong>From the neo4j debug.log:</strong></p>
  
  <pre><code>2017-10-09 12:35:47.153+0000 ERROR [o.n.k.h.c.m.HighAvailabilityModeSwitcher] Error while trying to switch to slave Cannot find the master among [] with master serverId=1 and uri=ha://ip_address_1:6365?serverId=1
      java.lang.IllegalStateException: Cannot find the master among [] with master serverId=1 and uri=ha://ip_address_1:6365?serverId=1
              at org.neo4j.kernel.ha.cluster.SwitchToSlave.checkMyStoreIdAndMastersStoreId(SwitchToSlave.java:263)
              at org.neo4j.kernel.ha.cluster.SwitchToSlaveBranchThenCopy.checkDataConsistency(SwitchToSlaveBranchThenCopy.java:142)
              at org.neo4j.kernel.ha.cluster.SwitchToSlave.executeConsistencyChecks(SwitchToSlave.java:478)
              at org.neo4j.kernel.ha.cluster.SwitchToSlave.switchToSlave(SwitchToSlave.java:221)
              at org.neo4j.kernel.ha.cluster.modeswitch.HighAvailabilityModeSwitcher$1.run(HighAvailabilityModeSwitcher.java:355)
              at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
              at java.util.concurrent.FutureTask.run(FutureTask.java:266)
              at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
              at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
              at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
              at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
              at java.lang.Thread.run(Thread.java:745)
              at org.neo4j.helpers.NamedThreadFactory$2.run(NamedThreadFactory.java:109)
      2017-10-09 12:35:47.154+0000 INFO [o.n.k.h.c.m.HighAvailabilityModeSwitcher] Attempting to switch to slave in 300s
  </code></pre>