Connecting opscenter but no data - cassandra

Question

I have deployed a datastax cassandra cluster on google cloud. The cluster size is 4 nodes on two different datacenters.
Servers are running fine and able to view opscenter but no data on it and getting the following errors.
This is a fresh deployment and all nodes are up and running. No tables were created yet.
Error Message from opscenter log:
[opscenterd] ERROR: Unhandled error in Deferred: com.datastax.driver.core.exceptions.UnavailableException: Not enough replicas available for query at consistency ONE (1 required but only 0 alive)
address.yaml from one of the node:
stomp_interface: 10.128.x.x [ ops center ip ]
agent_rpc_interface: 10.132.x.x [ one of the node ip]
agent_rpc_broadcast_address: 10.132.x.x
**cassandra.yaml from one of the node:**
cluster_name: 'Test Cluster'
num_tokens: 64
hinted_handoff_enabled: true
max_hint_window_in_ms: 10800000 # 3 hours
hinted_handoff_throttle_in_kb: 1024
max_hints_delivery_threads: 2
hints_directory: /var/lib/cassandra/hints
hints_flush_period_in_ms: 10000
max_hints_file_size_in_mb: 128
batchlog_replay_throttle_in_kb: 1024
authenticator: AllowAllAuthenticator
authorizer: AllowAllAuthorizer
role_manager: com.datastax.bdp.cassandra.auth.DseRoleManager
roles_validity_in_ms: 2000
permissions_validity_in_ms: 2000
partitioner: org.apache.cassandra.dht.Murmur3Partitioner
data_file_directories:
- /mnt/data
commitlog_directory: /mnt/commitlog
disk_failure_policy: stop
commit_failure_policy: stop
key_cache_size_in_mb:
key_cache_save_period: 14400
row_cache_size_in_mb: 0
row_cache_save_period: 0
counter_cache_size_in_mb:
counter_cache_save_period: 7200
saved_caches_directory: /mnt/saved_caches
commitlog_sync: periodic
commitlog_sync_period_in_ms: 10000
commitlog_segment_size_in_mb: 32
seed_provider:
# Addresses of hosts that are deemed contact points.
# Cassandra nodes use this list of hosts to find each other and learn
# the topology of the ring. You must change this if you are running
# multiple nodes!
- class_name: org.apache.cassandra.locator.SimpleSeedProvider
parameters:
# seeds is actually a comma-delimited list of addresses.
# Ex: "<ip1>,<ip2>,<ip3>"
- **seeds: "XX.XXX.X.X" [ The node IP from different Data Center]**
concurrent_reads: 32
concurrent_writes: 32
concurrent_counter_writes: 32
concurrent_materialized_view_writes: 32
memtable_allocation_type: heap_buffers
index_summary_capacity_in_mb:
index_summary_resize_interval_in_minutes: 60
trickle_fsync: true
trickle_fsync_interval_in_kb: 10240
storage_port: 7000
ssl_storage_port: 7001
listen_address: **SAME NODE IP**
broadcast_address: **SAME NODE IP**
start_native_transport: true
native_transport_port: 9042
start_rpc: true
rpc_address: 0.0.0.0
rpc_port: 9160
broadcast_rpc_address: SAME NODE IP
rpc_keepalive: true
rpc_server_type: sync
thrift_framed_transport_size_in_mb: 15
incremental_backups: false
snapshot_before_compaction: false
auto_snapshot: true
tombstone_warn_threshold: 1000
tombstone_failure_threshold: 100000
Opscenter.conf from opscenter:
[webserver]
port = 8888
interface = 0.0.0.0
[authentication]
enabled = False
[stat_reporter]
nodetool status:
Datacenter: europe-west1-b
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 10.XXX.0.2 220 KB 64 ? 5381a371-c532-4be7-a7f5-80162bef4541 europe-west1-b
UN 10.XXX.0.3 148.6 KB 64 ? e5b3dfec-f9bf-4952-b48f-b5a82749a9fe europe-west1-b
Datacenter: us-east1-b
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 10.XXX.0.2 158.72 KB 64 ? b93980e0-3c28-4bb0-9e49-220cb009d44c us-east1-b
UN 10.XXX.0.3 192.85 KB 64 ? af242b71-b7b4-4345-9888-5b89eb5e6199 us-east1-b
Note: Non-system keyspaces don't have the same replication settings, effective ownership information is meaningless

Answer 1

You have a DC in your replication factor ($dc) that doesnt exist, so when OpsCenter sends a request to read data the coordinator responds with an UnavailableException.
Try updating your keyspace like ALTER KEYSPACE "OpsCenter" WITH replication = {'class': 'NetworkTopologyStrategy', 'us-east1-b': '2'} and doing a full repair if you want to keep the data thats there.
If it hasnt run yet so you dont have data you want to save, just delete the opscenter keyspace (drop keyspace "OpsCenter") and restart opscenterd and the agents (after opscenter service has started back up).