identify live spark master at the time of spark-submit - spark-streaming

Question

I have 5 node spark cluster where 2 node are running master. in HA(by Zookeeper) scenario any one will be elected as master.
at the time of submitting application using command
/bin/spark-submit --class SparkAggregator.java --deploy-mode cluster --supervise --master spark://host1:7077
getting error
Can only accept driver submissions in ALIVE state. Current state: STANDBY.
spark-submit doe not allow multiple master name in --master.
Question:
How to identify the elected master at the time of spark-submit.
Thanks
Pankaj

Answer 1

The master option can take multiple spark masters, so if you have more than one list them with a comma between them. e.g.
/bin/spark-submit --class SparkAggregator.java --deploy-mode cluster --supervise --master spark://host1:7077,host2:7077,host3:7077
If will try to connect to all of them, the first that responds is used, this allow you to use multiple masters in a cluster where only one is active and the rest are in standby.

Answer 2

Spark has a hidden API which tell you about the status of the Spark Cluster
API Request- http://SPARK_MASTER_IP:8080/json/
Output -
{
"url" : "spark://10.204.216.233:7077",
"workers" : [ {
"id" : "worker-20170606104140-10.204.217.96-40047",
"host" : "10.204.217.96",
"port" : 40047,
"webuiaddress" : "http://10.204.217.96:8081",
"cores" : 4,
"coresused" : 0,
"coresfree" : 4,
"memory" : 29713,
"memoryused" : 0,
"memoryfree" : 29713,
"state" : "ALIVE",
"lastheartbeat" : 1496760671542
}, {
"id" : "worker-20170606104144-10.204.219.15-42749",
"host" : "10.204.219.15",
"port" : 42749,
"webuiaddress" : "http://10.204.219.15:8081",
"cores" : 4,
"coresused" : 0,
"coresfree" : 4,
"memory" : 29713,
"memoryused" : 0,
"memoryfree" : 29713,
"state" : "ALIVE",
"lastheartbeat" : 1496760675649
}, {
"id" : "worker-20170606104151-10.204.217.249-35869",
"host" : "10.204.217.249",
"port" : 35869,
"webuiaddress" : "http://10.204.217.249:8081",
"cores" : 4,
"coresused" : 0,
"coresfree" : 4,
"memory" : 29713,
"memoryused" : 0,
"memoryfree" : 29713,
"state" : "ALIVE",
"lastheartbeat" : 1496760682270
} ],
"cores" : 12,
"coresused" : 0,
"memory" : 89139,
"memoryused" : 0,
"activeapps" : [ ],
"completedapps" : [ ],
"activedrivers" : [ ],
"status" : "ALIVE"
}