I am now trying to implement the new system. My system will be divided into 2 clusters. First is for computing job. It will be heavily change by CI/CD very frequent. Then to prevent it from my juniors's accident and also save cost. Because on computer node does not need to use 100GB like database

Now. I am setting up my mongo-replicaset using helm. My configuration works fine. Here is my terminal log during the installation.

Install with 100GB per each node. They are 3 nodes.

$ gcloud container clusters create elmo --disk-size=100GB --enable-cloud-logging --enable-cloud-monitoring

I have changed username and password in the values.yaml

mongodbUsername: myuser
mongodbPassword: mypassword

However, when I jump in to the pod. It does not require me to do any authentication. I can execute show dbs

$ kubectl exec -it ipman-mongodb-replicaset-0 mongo

MongoDB shell version v4.0.6
connecting to: mongodb://127.0.0.1:27017/?gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("966e85fd-8857-46ac-a2a4-a8b560e37104") }
MongoDB server version: 4.0.6
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
    http://docs.mongodb.org/
Questions? Try the support group
    http://groups.google.com/group/mongodb-user
2019-03-20T12:15:51.266+0000 I STORAGE  [main] In File::open(), ::open for '//.mongorc.js' failed with Unknown error
Server has startup warnings:
2019-03-20T11:36:03.768+0000 I STORAGE  [initandlisten]
2019-03-20T11:36:03.768+0000 I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2019-03-20T11:36:03.768+0000 I STORAGE  [initandlisten] **          See http://dochub.mongodb.org/core/prodnotes-filesystem
2019-03-20T11:36:05.082+0000 I CONTROL  [initandlisten]
2019-03-20T11:36:05.082+0000 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2019-03-20T11:36:05.082+0000 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2019-03-20T11:36:05.083+0000 I CONTROL  [initandlisten]
---
Enable MongoDB's free cloud-based monitoring service, which will then receive and display
metrics about your deployment (disk utilization, CPU, operation statistics, etc).

The monitoring data will be available on a MongoDB website with a unique URL accessible to you
and anyone you share the URL with. MongoDB may use this information to make product
improvements and to suggest MongoDB products and deployment options to you.

To enable free monitoring, run the following command: db.enableFreeMonitoring()
To permanently disable this reminder, run the following command: db.disableFreeMonitoring()
---

rs0:PRIMARY> show dbs
admin   0.000GB
config  0.000GB
local   0.000GB

I can see 2 services running mongodb-replicaset

$ kubectl describe svc ipman-mongodb-replicaset

Name:              ipman-mongodb-replicaset
Namespace:         default
Labels:            app=mongodb-replicaset
                   chart=mongodb-replicaset-3.9.2
                   heritage=Tiller
                   release=ipman
Annotations:       service.alpha.kubernetes.io/tolerate-unready-endpoints: true
Selector:          app=mongodb-replicaset,release=ipman
Type:              ClusterIP
IP:                None
Port:              mongodb  27017/TCP
TargetPort:        27017/TCP
Endpoints:         10.60.1.5:27017,10.60.2.7:27017,10.60.2.8:27017
Session Affinity:  None
Events:            <none>

$ kubectl describe svc ipman-mongodb-replicaset-client

Name:              ipman-mongodb-replicaset-client
Namespace:         default
Labels:            app=mongodb-replicaset
                   chart=mongodb-replicaset-3.9.2
                   heritage=Tiller
                   release=ipman
Annotations:       <none>
Selector:          app=mongodb-replicaset,release=ipman
Type:              ClusterIP
IP:                None
Port:              mongodb  27017/TCP
TargetPort:        27017/TCP
Endpoints:         10.60.1.5:27017,10.60.2.7:27017,10.60.2.8:27017
Session Affinity:  None
Events:            <none>

I have seen here and here. I have 3 IP address. Which one should I use?

I think LoadBalancer might not fit to my need because it is normally use with backend service to balance load between nodes. For my case. It is master to do writing and replica to do reading.

$ gcloud compute instances list
NAME                                 ZONE               MACHINE_TYPE   PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP     STATUS
gke-elmo-default-pool-c5dc6e86-1j8v  asia-southeast1-a  n1-standard-1               10.148.0.59  35.197.148.201  RUNNING
gke-elmo-default-pool-c5dc6e86-5hs4  asia-southeast1-a  n1-standard-1               10.148.0.57  35.198.217.71   RUNNING
gke-elmo-default-pool-c5dc6e86-wh0l  asia-southeast1-a  n1-standard-1               10.148.0.58  35.197.128.107  RUNNING

Question:

1. Why my username:password does not take in to account when do authentication?

2. How can I expose my mongo shell and let client comes from internet use my database server by using

mongo -u <user> -p <pass> --host kluster.me.com --port 27017

I have checked with the helm chart document. I am worry that I am using k8s in the wrong way. Therefore I decided to ask in here.