# MongoServerSelectionError: ReplicaSetNoPrimary

**URL:** <https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704>\
**Category:** Percona Operator for MongoDB\
**Created:** [April 27, 2023, 10:17am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704 "2023-04-27T10:17:36Z")\
**Posts on this page:** 13\
**Page:** 1

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [April 27, 2023, 10:17am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/1 "2023-04-27T10:17:36Z")

</div>

Hi friends,

I have created a mongodb instance and exposed it externally via “Loadbalancer” and im attempting to connect to mongodb using a node.js application and the ofifical mongodb driver, altough this problem is not specific to node.js and it also occurs in the official gui mongodb compass.

When connecting to mongodb if i add the option `directConnection:true` it then works.

> **[Connection Guide — Node.js](https://www.mongodb.com/docs/drivers/node/current/fundamentals/connection/connect/#direct-connection)**

With my current setup why does this occur? Have i misconfigured something that is forcing me to use `directConnection: true`

**error:**

```auto
MongoServerSelectionError: getaddrinfo EAI_AGAIN psmdb-db-rs0-0.psmdb-db-rs0.mongodb.svc.cluster.local
    at Timeout._onTimeout (/home/kay/checkpoint/example/example-api/node_modules/mongodb/src/sdam/topology.ts:564:30)
    at listOnTimeout (node:internal/timers:564:17)
    at processTimers (node:internal/timers:507:7) {
  reason: TopologyDescription {
    type: 'ReplicaSetNoPrimary',
    servers: Map(1) {
      'psmdb-db-rs0-0.psmdb-db-rs0.mongodb.svc.cluster.local:27017' => [ServerDescription]
    },
    stale: false,
    compatible: true,
    heartbeatFrequencyMS: 10000,
    localThresholdMS: 15,
    setName: 'rs0',
    maxElectionId: new ObjectId("7fffffff0000000000000001"),
    maxSetVersion: 3,
    commonWireVersion: 0,
    logicalSessionTimeoutMinutes: null
  },
  code: undefined,
  [Symbol(errorLabels)]: Set(0) {}
}

```

**rs.status()**

```auto
rs0:PRIMARY> rs.status()
{
        "set" : "rs0",
        "date" : ISODate("2023-04-27T10:21:01.518Z"),
        "myState" : 1,
        "term" : NumberLong(3),
        "syncSourceHost" : "",
        "syncSourceId" : -1,
        "heartbeatIntervalMillis" : NumberLong(2000),
        "majorityVoteCount" : 1,
        "writeMajorityCount" : 1,
        "votingMembersCount" : 1,
        "writableVotingMembersCount" : 1,
        "optimes" : {
                "lastCommittedOpTime" : {
                        "ts" : Timestamp(1682590858, 1),
                        "t" : NumberLong(3)
                },
                "lastCommittedWallTime" : ISODate("2023-04-27T10:20:58.192Z"),
                "readConcernMajorityOpTime" : {
                        "ts" : Timestamp(1682590858, 1),
                        "t" : NumberLong(3)
                },
                "appliedOpTime" : {
                        "ts" : Timestamp(1682590858, 1),
                        "t" : NumberLong(3)
                },
                "durableOpTime" : {
                        "ts" : Timestamp(1682590858, 1),
                        "t" : NumberLong(3)
                },
                "lastAppliedWallTime" : ISODate("2023-04-27T10:20:58.192Z"),
                "lastDurableWallTime" : ISODate("2023-04-27T10:20:58.192Z")
        },
        "lastStableRecoveryTimestamp" : Timestamp(1682590823, 1),
        "electionCandidateMetrics" : {
                "lastElectionReason" : "electionTimeout",
                "lastElectionDate" : ISODate("2023-04-27T10:09:27.983Z"),
                "electionTerm" : NumberLong(3),
                "lastCommittedOpTimeAtElection" : {
                        "ts" : Timestamp(0, 0),
                        "t" : NumberLong(-1)
                },
                "lastSeenOpTimeAtElection" : {
                        "ts" : Timestamp(1682590146, 1),
                        "t" : NumberLong(2)
                },
                "numVotesNeeded" : 1,
                "priorityAtElection" : 2,
                "electionTimeoutMillis" : NumberLong(10000),
                "newTermStartDate" : ISODate("2023-04-27T10:09:27.986Z"),
                "wMajorityWriteAvailabilityDate" : ISODate("2023-04-27T10:09:27.988Z")
        },
        "members" : [
                {
                        "_id" : 0,
                        "name" : "psmdb-db-rs0-0.psmdb-db-rs0.mongodb.svc.cluster.local:27017",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 697,
                        "optime" : {
                                "ts" : Timestamp(1682590858, 1),
                                "t" : NumberLong(3)
                        },
                        "optimeDate" : ISODate("2023-04-27T10:20:58Z"),
                        "lastAppliedWallTime" : ISODate("2023-04-27T10:20:58.192Z"),
                        "lastDurableWallTime" : ISODate("2023-04-27T10:20:58.192Z"),
                        "syncSourceHost" : "",
                        "syncSourceId" : -1,
                        "infoMessage" : "",
                        "electionTime" : Timestamp(1682590167, 1),
                        "electionDate" : ISODate("2023-04-27T10:09:27Z"),
                        "configVersion" : 5,
                        "configTerm" : 3,
                        "self" : true,
                        "lastHeartbeatMessage" : ""
                }
        ],
        "ok" : 1,
        "$clusterTime" : {
                "clusterTime" : Timestamp(1682590858, 1),
                "signature" : {
                        "hash" : BinData(0,"21SiIhjRT7Epx+N06OuODKfaV1k="),
                        "keyId" : NumberLong("7226631497447374854")
                }
        },
        "operationTime" : Timestamp(1682590858, 1)
}

```

**yaml**

```auto
# Default values for psmdb-cluster.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.

# Platform type: kubernetes, openshift
# platform: kubernetes

# Cluster DNS Suffix
# clusterServiceDNSSuffix: svc.cluster.local
# clusterServiceDNSMode: "Internal"

finalizers:
## Set this if you want that operator deletes the primary pod last
  - delete-psmdb-pods-in-order
## Set this if you want to delete database persistent volumes on cluster deletion
# - delete-psmdb-pvc

nameOverride: ""
fullnameOverride: ""

env:
  name: LOG_STRUCTURED
  value: 'false'
  name: LOG_LEVEL
  value: DEBUG

crVersion: 1.14.0
pause: false
unmanaged: false
allowUnsafeConfigurations: true
# ignoreAnnotations:
# - service.beta.kubernetes.io/aws-load-balancer-backend-protocol
# ignoreLabels:
# - rack
multiCluster:
  enabled: false
  # DNSSuffix: svc.clusterset.local
updateStrategy: SmartUpdate
upgradeOptions:
  versionServiceEndpoint: https://check.percona.com
  apply: disabled
  schedule: "0 2 * * *"
  setFCV: false

image:
  repository: percona/percona-server-mongodb
  tag: 6.0.4-3

imagePullPolicy: Always
# imagePullSecrets: []
# initImage:
# repository: percona/percona-server-mongodb-operator
# tag: 1.14.0
# initContainerSecurityContext: {}
# tls:
# # 90 days in hours
# certValidityDuration: 2160h
secrets: {}
  # If you set users secret here the operator will use existing one or generate random values
  # If not set the operator generates the default secret with name <cluster_name>-secrets
  # users: my-cluster-name-secrets
  # encryptionKey: my-cluster-name-mongodb-encryption-key

pmm:
  enabled: false
  image:
    repository: percona/pmm-client
    tag: 2.35.0
  serverHost: monitoring-service

replsets:
  - name: rs0
    size: 1
    # externalNodes:
    # - host: 34.124.76.90
    # - host: 34.124.76.91
    # port: 27017
    # votes: 0
    # priority: 0
    # - host: 34.124.76.92
    # configuration: |
    # operationProfiling:
    # mode: slowOp
    # systemLog:
    # verbosity: 1
    antiAffinityTopologyKey: "kubernetes.io/hostname"
    # tolerations: []
    # priorityClass: ""
    # annotations: {}
    # labels: {}
    nodeSelector:
      acme/node-type: "ops"
    # livenessProbe:
    # failureThreshold: 4
    # initialDelaySeconds: 60
    # periodSeconds: 30
    # timeoutSeconds: 10
    # startupDelaySeconds: 7200
    # readinessProbe:
    # failureThreshold: 8
    # initialDelaySeconds: 10
    # periodSeconds: 3
    # successThreshold: 1
    # timeoutSeconds: 2
    # runtimeClassName: image-rc
    # storage:
    # engine: wiredTiger
    # wiredTiger:
    # engineConfig:
    # cacheSizeRatio: 0.5
    # directoryForIndexes: false
    # journalCompressor: snappy
    # collectionConfig:
    # blockCompressor: snappy
    # indexConfig:
    # prefixCompression: true
    # inMemory:
    # engineConfig:
    # inMemorySizeRatio: 0.5
    sidecars:
    - image: percona/mongodb_exporter:0.36
      env:
      - name: EXPORTER_USER
        valueFrom:
          secretKeyRef:
            name: psmdb-db-secrets
            key: MONGODB_CLUSTER_MONITOR_USER
      - name: EXPORTER_PASS
        valueFrom:
          secretKeyRef:
            name: psmdb-db-secrets
            key: MONGODB_CLUSTER_MONITOR_PASSWORD
      - name: POD_IP
        valueFrom:
          fieldRef:
            fieldPath: status.podIP
      - name: MONGODB_URI
        value: "mongodb://$(EXPORTER_USER):$(EXPORTER_PASS)@$(POD_IP):27017"
      args: ["--discovering-mode", "--compatible-mode", "--collect-all", "--mongodb.uri=$(MONGODB_URI)"]
      name: metrics
    # volumeMounts:
    # - mountPath: /volume1
    # name: sidecar-volume-claim
    # - mountPath: /secret
    # name: sidecar-secret
    # - mountPath: /configmap
    # name: sidecar-config
    # sidecarVolumes:
    # - name: sidecar-secret
    # secret:
    # secretName: mysecret
    # - name: sidecar-config
    # configMap:
    # name: myconfigmap
    # sidecarPVCs:
    # - apiVersion: v1
    # kind: PersistentVolumeClaim
    # metadata:
    # name: sidecar-volume-claim
    # spec:
    # resources:
    # requests:
    # storage: 1Gi
    # volumeMode: Filesystem
    # accessModes:
    # - ReadWriteOnce
    podDisruptionBudget:
      maxUnavailable: 1
    expose:
      enabled: true
      exposeType: LoadBalancer
      # loadBalancerSourceRanges:
      # - 10.0.0.0/8
      # serviceAnnotations:
      # service.beta.kubernetes.io/aws-load-balancer-backend-protocol: http
      # serviceLabels: 
      # some-label: some-key
    nonvoting:
      enabled: false
      # podSecurityContext: {}
      # containerSecurityContext: {}
      size: 3
      # configuration: |
      # operationProfiling:
      # mode: slowOp
      # systemLog:
      # verbosity: 1
      antiAffinityTopologyKey: "kubernetes.io/hostname"
      # tolerations: []
      # priorityClass: ""
      # annotations: {}
      # labels: {}
      # nodeSelector: {}
      podDisruptionBudget:
        maxUnavailable: 1
      resources:
        limits:
          cpu: "300m"
          memory: "0.5G"
        requests:
          cpu: "300m"
          memory: "0.5G"
      volumeSpec:
        # emptyDir: {}
        # hostPath:
        # path: /data
        pvc:
          # annotations:
          # volume.beta.kubernetes.io/storage-class: example-hostpath
          # labels:
          # rack: rack-22
          # storageClassName: standard
          # accessModes: ["ReadWriteOnce"]
          resources:
            requests:
              storage: 3Gi
    arbiter:
      enabled: false
      size: 1
      antiAffinityTopologyKey: "kubernetes.io/hostname"
      # tolerations: []
      # priorityClass: ""
      # annotations: {}
      # labels: {}
      # nodeSelector: {}
    # schedulerName: ""
    resources:
      limits:
        cpu: "300m"
        memory: "0.5G"
      requests:
        cpu: "300m"
        memory: "0.5G"
    volumeSpec:
      # emptyDir: {}
      # hostPath:
      # path: /data
      pvc:
        # annotations:
        # volume.beta.kubernetes.io/storage-class: example-hostpath
        # labels:
        # rack: rack-22
        storageClassName: mongodb
        # accessModes: ["ReadWriteOnce"]
        resources:
          requests:
            storage: 250Gi

sharding:
  enabled: false 

backup:
  enabled: true
  image:
    repository: percona/percona-backup-mongodb
    tag: 2.0.5
  serviceAccountName: percona-server-mongodb-operator
  # annotations:
  # iam.amazonaws.com/role: 
  # resources:
  # limits:
  # cpu: "300m"
  # memory: "0.5G"
  # requests:
  # cpu: "300m"
  # memory: "0.5G"
  storages:
    s3-eu-west:
      type: s3
      s3:
        bucket: acme-test-mongodb-backup
        credentialsSecret: prod-aws-mongodb
        region: eu-west-2
        prefix: ""
        uploadPartSize: 10485760
        maxUploadParts: 10000
        storageClass: STANDARD
        insecureSkipTLSVerify: false
    # minio:
    # type: s3
    # s3:
    # bucket: MINIO-BACKUP-BUCKET-NAME-HERE
    # region: us-east-1
    # credentialsSecret: my-cluster-name-backup-minio
    # endpointUrl: http://minio.psmdb.svc.cluster.local:9000/minio/
    # prefix: ""
    # azure-blob:
    # type: azure
    # azure:
    # container: CONTAINER-NAME
    # prefix: PREFIX-NAME
    # credentialsSecret: SECRET-NAME
  pitr:
    enabled: false
    # oplogSpanMin: 10
    # compressionType: gzip
    # compressionLevel: 6
  tasks:
   - name: "every-hour-backup"
     enabled: true
     schedule: "0 * * * *"
     keep: 3
     type: logical
     storageName: s3-eu-west

  # - name: daily-s3-us-west
  # enabled: true
  # schedule: "0 0 * * *"
  # keep: 3
  # storageName: s3-us-west
  # compressionType: gzip
  # - name: weekly-s3-us-west
  # enabled: false
  # schedule: "0 0 * * 0"
  # keep: 5
  # storageName: s3-us-west
  # compressionType: gzip
  # - name: weekly-s3-us-west-physical
  # enabled: false
  # schedule: "0 5 * * 0"
  # keep: 5
  # type: physical
  # storageName: s3-us-west
  # compressionType: gzip
  # compressionLevel: 6

# If you set users here the secret will be constructed by helm with these values
# users:
# MONGODB_BACKUP_USER: backup
# MONGODB_BACKUP_PASSWORD: backup123456
# MONGODB_DATABASE_ADMIN_USER: databaseAdmin
# MONGODB_DATABASE_ADMIN_PASSWORD: databaseAdmin123456
# MONGODB_CLUSTER_ADMIN_USER: clusterAdmin
# MONGODB_CLUSTER_ADMIN_PASSWORD: clusterAdmin123456
# MONGODB_CLUSTER_MONITOR_USER: clusterMonitor
# MONGODB_CLUSTER_MONITOR_PASSWORD: clusterMonitor123456
# MONGODB_USER_ADMIN_USER: userAdmin
# MONGODB_USER_ADMIN_PASSWORD: userAdmin123456
# PMM_SERVER_API_KEY: apikey
# # PMM_SERVER_USER: admin
# # PMM_SERVER_PASSWORD: admin

```

---

<div class="post-metadata">

**Author:** ![Sergey\_Pronin](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/sergey_pronin/32/14887_2.png) [@Sergey\_Pronin](https://forums.percona.com/u/Sergey_Pronin)\
**Post date:** [April 28, 2023, 11:49am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/2 "2023-04-28T11:49:19Z")

</div>

Hello @Kay_Khan ,

seems you are doing all correctly.  
It is how mongodb works. [https://www.mongodb.com/docs/mongodb-shell/connect/](https://www.mongodb.com/docs/mongodb-shell/connect/)

You have just one node and you are connecting. This calls for directConnection parameter. Once you will connect to multiple nodes and have `?replicaSet` flag set in the URI, there should be no need to set directConnection param.  
At the same time, I’m a bit confused why if you use a LoadBalancer, you connect to `mongodb.svc.cluster.local` - which is a ClusterIP entity.

---

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [April 28, 2023, 12:16pm UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/3 "2023-04-28T12:16:51Z")

</div>

Hi thank you for replying. Is there some documentation you can point me to that implies we must use directConnection with a single node cluster?

> At the same time, I’m a bit confused why if you use a LoadBalancer, you connect to `mongodb.svc.cluster.local` - which is a ClusterIP entity.

I’m not sure, this is how it has been setup using this operator.

* * *

Im also not sure why, but i changed `clusterServiceDNSMode` to use the `External` value. This allows me to connect to this same cluster without the `directConnection` option. The differnece i can see between the original and the new version is the following.

1. members[0].name now points directly to the aws load balancer that was created

`clusterServiceDNSMode: External`

```auto
{
  set: 'rs0',
  date: ISODate("2023-04-28T12:14:17.160Z"),
  myState: 1,
  term: Long("14"),
  syncSourceHost: '',
  syncSourceId: -1,
  heartbeatIntervalMillis: Long("2000"),
  majorityVoteCount: 1,
  writeMajorityCount: 1,
  votingMembersCount: 1,
  writableVotingMembersCount: 1,
  optimes: {
    lastCommittedOpTime: { ts: Timestamp({ t: 1682684054, i: 1 }), t: Long("14") },
    lastCommittedWallTime: ISODate("2023-04-28T12:14:14.204Z"),
    readConcernMajorityOpTime: { ts: Timestamp({ t: 1682684054, i: 1 }), t: Long("14") },
    appliedOpTime: { ts: Timestamp({ t: 1682684054, i: 1 }), t: Long("14") },
    durableOpTime: { ts: Timestamp({ t: 1682684054, i: 1 }), t: Long("14") },
    lastAppliedWallTime: ISODate("2023-04-28T12:14:14.204Z"),
    lastDurableWallTime: ISODate("2023-04-28T12:14:14.204Z")
  },
  lastStableRecoveryTimestamp: Timestamp({ t: 1682684012, i: 1 }),
  electionCandidateMetrics: {
    lastElectionReason: 'electionTimeout',
    lastElectionDate: ISODate("2023-04-27T15:42:37.470Z"),
    electionTerm: Long("14"),
    lastCommittedOpTimeAtElection: { ts: Timestamp({ t: 0, i: 0 }), t: Long("-1") },
    lastSeenOpTimeAtElection: { ts: Timestamp({ t: 1682610067, i: 1 }), t: Long("13") },
    numVotesNeeded: 1,
    priorityAtElection: 2,
    electionTimeoutMillis: Long("10000"),
    newTermStartDate: ISODate("2023-04-27T15:42:37.474Z"),
    wMajorityWriteAvailabilityDate: ISODate("2023-04-27T15:42:37.476Z")
  },
  members: [
    {
      _id: 0,
      name: '<redacted>-1771644787.eu-west-2.elb.amazonaws.com:27017',
      health: 1,
      state: 1,
      stateStr: 'PRIMARY',
      uptime: 73914,
      optime: { ts: Timestamp({ t: 1682684054, i: 1 }), t: Long("14") },
      optimeDate: ISODate("2023-04-28T12:14:14.000Z"),
      lastAppliedWallTime: ISODate("2023-04-28T12:14:14.204Z"),
      lastDurableWallTime: ISODate("2023-04-28T12:14:14.204Z"),
      syncSourceHost: '',
      syncSourceId: -1,
      infoMessage: '',
      electionTime: Timestamp({ t: 1682610157, i: 1 }),
      electionDate: ISODate("2023-04-27T15:42:37.000Z"),
      configVersion: 6,
      configTerm: 14,
      self: true,
      lastHeartbeatMessage: ''
    }
  ],
  ok: 1,
  '$clusterTime': {
    clusterTime: Timestamp({ t: 1682684054, i: 1 }),
    signature: {
      hash: Binary(Buffer.from("535fbf62d30588efa00587e3fd4f1a56f9f41eba", "hex"), 0),
      keyId: Long("7226631497447374854")
    }
  },
  operationTime: Timestamp({ t: 1682684054, i: 1 })
}

```

Would really love help with understanding what is happening here.

My concern is we are pivoting away from bitnami mongodb to percona operator. We don’t want to have to update a bunch of applications that already have connection to mongodb to add this extra option `directConnection` if i don’t have to. and it seems like i should not need it ( open to being wrong about this ) but seems like there is a way when the members name is pointing to the load balancer ip directly via clusterServiceDNSMode=External.

---

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [April 28, 2023, 2:03pm UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/4 "2023-04-28T14:03:09Z")

</div>

You can see with the config in my OP under (yaml), that it creates both a `ClusterIP` and `Loadbalancer` is that expected?

```auto
NAME READY STATUS RESTARTS AGE
pod/psmdb-db-rs0-0 3/3 Running 0 3m47s
pod/psmdb-operator-584fc857f8-qxsj9 1/1 Running 0 28h

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/psmdb-db-rs0 ClusterIP None <none> 27017/TCP 28h
service/psmdb-db-rs0-0 LoadBalancer 172redacted138 <redacted>-redacted.eu-west-2.elb.amazonaws.com 27017:30608/TCP 28h
service/psmdb-metrics ClusterIP 172.20.130.58 <none> 9216/TCP 4d

NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/psmdb-operator 1/1 1 1 28h

NAME DESIRED CURRENT READY AGE
replicaset.apps/psmdb-operator-584fc857f8 1 1 1 28h

NAME READY AGE
statefulset.apps/psmdb-db-rs0 1/1 22h

```

---

<div class="post-metadata">

**Author:** ![Sergey\_Pronin](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/sergey_pronin/32/14887_2.png) [@Sergey\_Pronin](https://forums.percona.com/u/Sergey_Pronin)\
**Post date:** [April 28, 2023, 2:09pm UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/5 "2023-04-28T14:09:21Z")

</div>

Yeah, it is okay. The ClusterIP service is [headless](https://kubernetes.io/docs/concepts/services-networking/service/#headless-services). It is always there.

---

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [April 28, 2023, 2:40pm UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/6 "2023-04-28T14:40:20Z")

</div>

Okay i think we decided we are going to update our apps to include the `directConnection: true` as we’ve seen this mentioned else where. Which means we’ve also reverted the default `clusterServiceDNSMode` which is probably good as we were unsure in the first place what side effects that would have, its briefly mentioned in the documentation here [Exposing the cluster - Percona Operator for MongoDB](https://docs.percona.com/percona-operator-for-mongodb/expose.html#controlling-hostnames-in-replset-configuration)

> You should be careful with the clusterServiceDNSMode=External variant. Using IP addresses instead of DNS hostnames is discouraged in MongoDB. IP addresses make configuration changes and recovery more complicated. Also, they are particularly problematic in scenarios where IP addresses change (i.e., deleting and recreating the cluster).

So finally i think we are just confusd on whether we ought to be taking any action given your comment below

> At the same time, I’m a bit confused why if you use a LoadBalancer, you connect to `mongodb.svc.cluster.local` - which is a ClusterIP entity.

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<div class="post-metadata">

**Author:** ![Sergey\_Pronin](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/sergey_pronin/32/14887_2.png) [@Sergey\_Pronin](https://forums.percona.com/u/Sergey_Pronin)\
**Post date:** [May 1, 2023, 7:32am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/7 "2023-05-01T07:32:11Z")

</div>

Hey!  
Going deeper into ClusterIP comment that I made:  
If you expose the database through Loadbalancer and then connect to it through ClusterIP, I’m not sure if you really need a LoadBalancer.

---

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [May 1, 2023, 9:52am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/8 "2023-05-01T09:52:23Z")

</div>

Okay,

Just to clarify as im a little confused, the resources created in kubernetes and configuration of mongodb has been setup based on the yaml file using the percona mongodb operator. I have not made any extra configuration changes or added any additional resources ( other than service/psmdb-metrics) .

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<div class="post-metadata">

**Author:** ![jamoser](https://avatars.discourse-cdn.com/v4/letter/j/b2d939/32.png) [@jamoser](https://forums.percona.com/u/jamoser)\
**Post date:** [May 3, 2023, 10:03am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/9 "2023-05-03T10:03:03Z")

</div>

Most likely you are using the Operator in non-sharding aka Statefulset mode.

Then you have to provide the name of the replicaset in the connection string. And the Statefulset is handling to which pod the connection should go.

You never connect directly to a pod of the statefulset.

---

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [July 31, 2023, 1:12pm UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/10 "2023-07-31T13:12:28Z")

</div>

Sorry, how should i reconfigure my config to ensure that i dont need to connect directly to a pod? ( dont need to use directConnection=true)

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<div class="post-metadata">

**Author:** ![Sergey\_Pronin](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/sergey_pronin/32/14887_2.png) [@Sergey\_Pronin](https://forums.percona.com/u/Sergey_Pronin)\
**Post date:** [August 3, 2023, 9:14am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/11 "2023-08-03T09:14:14Z")

</div>

@Kay_Khan something like this:

```auto
mongo "mongodb+srv://databaseAdmin:databaseAdminPassword@my-cluster-name-rs0.<namespace name>.svc.cluster.local/admin?replicaSet=rs0&ssl=false"

```

note the `+srv` piece

Also you can just list all the endpoints of all your replica set nodes in a connection string.

```auto
mongodb://[username:password@]host1[:port1][,...hostN[:portN]][/[defaultauthdb][?options]]

```

---

<div class="post-metadata">

**Author:** ![Kay\_Khan](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/kay_khan/32/17023_2.png) [@Kay\_Khan](https://forums.percona.com/u/Kay_Khan)\
**Post date:** [October 5, 2023, 9:36am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/12 "2023-10-05T09:36:49Z")

</div>

This does not work when i substitute `my-cluster-name-rs0.<namespace name>.svc.cluster.local/` with my internal nlb address.

In mongodb compass

mongodb+srv://removed:removed@k8s-mongodb-psmdbdbi-1e0cbbc5c7-.elb.us-east-2.amazonaws.com/admin?replicaSet=rs0&ssl=false

 ![image](https://us1.discourse-cdn.com/flex019/uploads/percona1/original/2X/b/bd3d3081bc022447f02cc3c3cde5a426b3530654.png)

I am trying to connect to an internal mongodb instance from my local machine via VPN,

Local Machine → VPN Into VPC → NLB → Kubernetes Cluster → Percona Mongodb.

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<div class="post-metadata">

**Author:** ![Ivan\_Groenewold](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/ivan_groenewold/32/6299_2.png) [@Ivan\_Groenewold](https://forums.percona.com/u/Ivan_Groenewold)\
**Post date:** [November 7, 2025, 11:39am UTC](https://forums.percona.com/t/mongoserverselectionerror-replicasetnoprimary/21704/13 "2025-11-07T11:39:27Z")

</div>