Nodes not syncing due to: master not discovered or elected yet

Elastic Stack Elasticsearch
2

The cluster is operational and green. Here is the current discovery set in the elasticsearch.yml

Primary node:

# --------------------------------- Discovery ----------------------------------
#
# Pass an initial list of hosts to perform discovery when this node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"]
#
#discovery.seed_hosts: ["host1", "host2"]
#discovery.seed_hosts: ["primarynode", "secondarynode"]
#discovery.seed_hosts: ["primarynode", "secondarynode", "votingonlynode"]
discovery.seed_hosts: ["192.168.0.235", "192.168.0.236", "192.168.0.237"]
#
# Bootstrap the cluster using an initial set of master-eligible nodes:
#
#cluster.initial_master_nodes: ["node-1", "node-2"]
#cluster.initial_master_nodes: ["primarynode", "secondarynode"]

#30-05-2021: Commented as part of diagnostic since the sync was failing. That restore did not work.
#30-05-2021: Removing the comment
#30-05-2021: Needs review - added to tasks
#31-05-2021: Commenting based on: https://www.elastic.co/guide/en/elasticsearch/reference/master/modules-discovery-bootstrap-cluster.html
#-> This setting is only needed to form a cluster.
#cluster.initial_master_nodes: ["192.168.0.235", "192.168.0.236"]

#

Secondary node

# --------------------------------- Discovery ----------------------------------
#
# Pass an initial list of hosts to perform discovery when this node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"]
#
#discovery.seed_hosts: ["host1", "host2"]
#discovery.seed_hosts: ["primarynode", "secondarynode"]
#discovery.seed_hosts: ["primarynode", "secondarynode", "votingonlynode"]
discovery.seed_hosts: ["192.168.0.235", "192.168.0.236", "192.168.0.237"]
# Bootstrap the cluster using an initial set of master-eligible nodes:
#
#cluster.initial_master_nodes: ["node-1", "node-2"]
#cluster.initial_master_nodes: ["primarynode", "secondarynode"]


#30-05-2021: Commented as part of diagnostic since the sync was failing. That restore did not work.
#30-05-2021: Removing the comment
#30-05-2021: Needs review - added to tasks
#31-05-2021: Commenting based on: https://www.elastic.co/guide/en/elasticsearch/reference/master/modules-discovery-bootstrap-cluster.html
#-> This setting is only needed to form a cluster.
#cluster.initial_master_nodes: ["192.168.0.235", "192.168.0.236"]


#
# For more information, consult the discovery and cluster formation module documentation.
#

Tertiary node (voting only)

# --------------------------------- Discovery ----------------------------------
#
# Pass an initial list of hosts to perform discovery when this node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"]
#
#discovery.seed_hosts: ["host1", "host2"]
#discovery.seed_hosts: ["primarynode", "secondarynode", "votingonlynode"]
discovery.seed_hosts: ["192.168.0.235", "192.168.0.236", "192.168.0.237"]
#
# Bootstrap the cluster using an initial set of master-eligible nodes:
#
#cluster.initial_master_nodes: ["node-1", "node-2"]
#cluster.initial_master_nodes: ["primarynode", "secondarynode"]

#Commented on 30-05-2021 as part of diagnosing cluster sync failure
#cluster.initial_master_nodes: ["192.168.0.235", "192.168.0.236"]
#
# For more information, consult the discovery and cluster formation module documentation.
#