Two nodes not joining Elasticsearch cluster - elasticsearch

Question

I have an elasticsearch cluster in google cloud consisting of 3 nodes in which one is a master node. Now i don't know why my two nodes are not joining cluster only one node is in cluster right now. I used below command to start/stop/restart the other two nodes
sudo service elasticsearch start
when i ran above command for the two nodes there were no error shown but now when i try to use below command to retrieve my indexed data i got error on both of the nodes.
curl 'http://localhost:9200/merchants/_search?pretty=true' -d '{
"query" : {
"match_all" : { }
}
}'
**curl: (7) Failed to connect to localhost port 9200: Connection refused**
my elasticsearch.yml file is given below
script.inline: on
script.indexed: on
script.engine.groovy.inline.aggs: on
script.groovy.sandbox.enabled: false
# ======================== Elasticsearch Configuration =========================
#
# NOTE: Elasticsearch comes with reasonable defaults for most settings.
# Before you set out to tweak and tune the configuration, make sure you
# understand what are you trying to accomplish and the consequences.
#
# The primary way of configuring a node is via this file. This template lists
# the most important settings you may want to configure for a production cluster.
#
# Please see the documentation for further information on configuration options:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/setup-configuration.html>
#
# ---------------------------------- Cluster -----------------------------------
#
# Use a descriptive name for your cluster:
#
cluster.name: elasticsearch-cluster
#
# ------------------------------------ Node ------------------------------------
#
# Use a descriptive name for the node:
#
node.name: "elasticsearch-1-1-vm"
#
# Add custom attributes to the node:
#
# node.rack: r1
#
# ----------------------------------- Paths ------------------------------------
#
# Path to directory where to store the data (separate multiple locations by comma):
#
path.data: /var/lib/elasticsearch/data
#
# Path to log files:
#
# path.logs: /path/to/logs
#
# ----------------------------------- Memory -----------------------------------
#
# Lock the memory on startup:
#
# bootstrap.mlockall: true
#
# Make sure that the `ES_HEAP_SIZE` environment variable is set to about half the memory
# available on the system and that the owner of the process is allowed to use this limit.
#
# Elasticsearch performs poorly when the system is swapping the memory.
#
# ---------------------------------- Network -----------------------------------
#
# Set the bind address to a specific IP (IPv4 or IPv6):
#
network.host: 0.0.0.0
#
# Set a custom port for HTTP:
#
# http.port: 9200
#
# For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-network.html>
#
# --------------------------------- Discovery ----------------------------------
#
# Pass an initial list of hosts to perform discovery when new node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"]
#
discovery.zen.ping.unicast.hosts: ["10.128.0.5", "10.128.0.6", "10.128.0.4"]
#
# Prevent the "split brain" by configuring the majority of nodes (total number of nodes / 2 + 1):
#
# discovery.zen.minimum_master_nodes: 3
#
# For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-discovery.html>
#
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
# gateway.recover_after_nodes: 3
#
# For more information, see the documentation at:
# <http://www.elastic.co/guide/en/elasticsearch/reference/current/modules-gateway.html>
#
# ---------------------------------- Various -----------------------------------
#
# Disable starting multiple nodes on a single system:
#
# node.max_local_storage_nodes: 1
#
# Require explicit names when deleting indices:
#
# action.destructive_requires_name: true
Can anyone please tell me what can be the best way to restart the elasticsearch cluster, i think my sudo elasticsearch start command is not working properly otherwise i must not have gotten connection refused error. Please if anyone know anything about ES cluster please help me i am stuck in this problem from past one week and havn't gotten anything useful till know.