# How to port forward to Primary in Kubernetes Cluster

**URL:** https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294
**Category:** Percona Operator for MongoDB
**Created:** [December 24, 2022, 4:56pm UTC](https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294 "2022-12-24T16:56:39Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![anon17965173](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon17965173](https://forums.percona.com/u/anon17965173)
#### Post date: [December 24, 2022, 4:56pm UTC](https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294/1 "2022-12-24T16:56:39Z")

</div>

I want to port forward to my Primary in the ReplicaSet on my Kubernetes Cluster. This is how I am doing it now and it always connects to the secondary:

`kubectl port-forward svc/percona-db-psmdb-db-rs0 -n psmdb 27017:27017`

Then when I connect:

`mongosh 'mongodb://user:pass@localhost:27017/ms_user?ssl=false'`

```auto
Connecting to: mongodb://<credentials>@localhost:27017/user?ssl=false&directConnection=true&serverSelectionTimeoutMS=2000&appName=mongosh+1.5.4
Using MongoDB: 4.4.10-11
Using Mongosh: 1.5.4

```

Then when I want to do operations I get:

```auto
rs0 [direct: secondary] ms_user> db.users.drop()
MongoServerError: not primary

```

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<div class="post-metadata">

### Author: ![Agustin\_G](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/agustin_g/32/14111_2.png) [@Agustin\_G](https://forums.percona.com/u/Agustin_G)
#### Post date: [December 28, 2022, 10:49pm UTC](https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294/2 "2022-12-28T22:49:42Z")

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Hi,

I wonder if the namespace flag you are using should be before the subcommand, like:

`kubectl -n psmdb port-forward svc/percona-db-psmdb-db-rs0 27017:27017`

I don’t have a test instance at hand now, so please test this and let me know if it worked. Otherwise, I can spin something up and test.

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<div class="post-metadata">

### Author: ![Agustin\_G](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/agustin_g/32/14111_2.png) [@Agustin\_G](https://forums.percona.com/u/Agustin_G)
#### Post date: [December 28, 2022, 10:55pm UTC](https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294/3 "2022-12-28T22:55:37Z")

</div>

Also, what do you get from `kubectl -n namespace get services`?

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<div class="post-metadata">

### Author: ![Tomislav\_Plavcic](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/tomislav_plavcic/32/9717_2.png) [@Tomislav\_Plavcic](https://forums.percona.com/u/Tomislav_Plavcic)
#### Post date: [December 30, 2022, 11:06am UTC](https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294/4 "2022-12-30T11:06:39Z")

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Hi @anon17965173 ,  
How do you install database and which services do you have setup?  
I see you use helm if I’m not mistaking, this is what I did and it seems to work for me, but probably I did something different than in your setup.

Install DB:

```auto
helm install operator percona/psmdb-operator --namespace helm-test
helm install psmdb-db percona/psmdb-db --namespace helm-test --set sharding.enabled=false --set image.tag=4.4.16-16

```

so in my setup sharding is disabled and this is the service which is setup and to which I port-forward:

```auto
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
psmdb-db-rs0 ClusterIP None <none> 27017/TCP 7m51s

# port forwarding
$ kubectl port-forward svc/psmdb-db-rs0 -n helm-test 27017:27017
Forwarding from 127.0.0.1:27017 -> 27017
Forwarding from [::1]:27017 -> 27017

```

When I connect it seems to be always primary:

```auto
$ mongosh 'mongodb://<credentials>@localhost:27017/admin?ssl=false'
Current Mongosh Log ID: 63aec47a83658493db6015b4
Connecting to: mongodb://<credentials>@localhost:27017/admin?ssl=false&directConnection=true&serverSelectionTimeoutMS=2000&appName=mongosh+1.6.1
Using MongoDB: 4.4.16-16
Using Mongosh: 1.6.1

rs0 [direct: primary] admin> use test;
switched to db test

rs0 [direct: primary] test> db.korisnici.insert({ name: "Tomislav" })
{
  acknowledged: true,
  insertedIds: { '0': ObjectId("63aec48d83658493db6015b5") }
}

```

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<div class="post-metadata">

### Author: ![Gvidas\_Pranauskas](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/gvidas_pranauskas/32/13481_2.png) [@Gvidas\_Pranauskas](https://forums.percona.com/u/Gvidas_Pranauskas)
#### Post date: [February 13, 2024, 1:06pm UTC](https://forums.percona.com/t/how-to-port-forward-to-primary-in-kubernetes-cluster/19294/5 "2024-02-13T13:06:18Z")

</div>

Hello,  
It seems I have the same problem and I am not able to solve it with the methods you mentioned. Interestingly, when I create a pod in cluster and connect within it to mongodb, I connect to the primary node. When I port-forward locally, I get connected to the secondary node. Might this be related to the connection string and how mongodb resolves nodes?

How it goes locally:

```auto
$ kubectl get services -n perconamongodb
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
perconamongodbcluster-rs0 ClusterIP None <none> 27017/TCP 176m

$ kubectl port-forward service/perconamongodbcluster-rs0 27017:27017 -n perconamongodb
Forwarding from 127.0.0.1:27017 -> 27017
Forwarding from [::1]:27017 -> 27017

$ mongosh "mongodb://user:pass@localhost:27017/helloworld?ssl=false&replicaSet=rs0&directConnection=true"
Current Mongosh Log ID: 65cb6753f23d6c23d8e058c5
Connecting to: mongodb://<credentials>@localhost:27017/helloworld?ssl=false&replicaSet=rs0&directConnection=true&serverSelectionTimeoutMS=2000&appName=mongosh+2.1.4
Using MongoDB: 6.0.9-7
Using Mongosh: 2.1.4

For mongosh info see: https://docs.mongodb.com/mongodb-shell/

rs0 [direct: secondary] helloworld>

```

How it goes on the pod I have created in cluster (from the self: true you can see that the connection points to primary node):

```auto
[mongodb@percona-client /]$ mongo "mongodb://user:pass@perconamongodbcluster-rs0.perconamongodb.svc.cluster.local/helloworld?ssl=false&replicaSet=rs0&directConnection=true"
<min?ssl=false&replicaSet=rs0&directConnection=true"
Percona Server for MongoDB shell version v4.4.24-23
connecting to: mongodb://perconamongodbcluster-rs0.perconamongodb.svc.cluster.local:27017/helloworld?compressors=disabled&directConnection=true&gssapiServiceName=mongodb&replicaSet=rs0&ssl=false
Implicit session: session { "id" : UUID("05518a51-a1a5-47fd-933d-12d6804b1325") }
Percona Server for MongoDB server version: v6.0.9-7
WARNING: shell and server versions do not match

{
                        "_id" : 1,
                        "name" : "perconamongodbcluster-rs0-1.perconamongodbcluster-rs0.perconamongodb.svc.cluster.local:27017",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 8898,
                        "optime" : {
                                "ts" : Timestamp(1707829462, 2),
                                "t" : NumberLong(2)
                        },
                        "optimeDate" : ISODate("2024-02-13T13:04:22Z"),
                        "lastAppliedWallTime" : ISODate("2024-02-13T13:04:22.021Z"),
                        "lastDurableWallTime" : ISODate("2024-02-13T13:04:22.021Z"),
                        "syncSourceHost" : "",
                        "syncSourceId" : -1,
                        "infoMessage" : "",
                        "electionTime" : Timestamp(1707820581, 1),
                        "electionDate" : ISODate("2024-02-13T10:36:21Z"),
                        "configVersion" : 8,
                        "configTerm" : 2,
                        "self" : true,
                        "lastHeartbeatMessage" : ""
                }

```

What might be the reason to this? Otherwise, how to develop locally and test data insertion to the database?

I have deployed the Percona mongodb operator on Azure AKS, following this guide: [Install on Microsoft Azure Kubernetes Service (AKS) - Percona Operator for MongoDB](https://docs.percona.com/percona-operator-for-mongodb/aks.html#create-and-configure-the-aks-cluster)

Thanks.