VB
Vyacheslav Breus
August 23, 2022
Updated September 11, 2022

MongoDB on Kubernetes

Kubernetes MongoDB

Introduction

In the Serverspace you can create a server with already installed app "MongoDB".
MongoDB is one of most popular NoSQL database management solution. In combination with Kubernetes orchestrator it could be easy-to-scale, multipurpose solution.

Requirements

To work with MongoDB in Kubernetes you need one server under any operation system (Linux with root access or sudo membership preferred) to manage and Kubernetes cluster (see next step).

Kubernetes instance creation

Before deploy MongoDB you need to have Kubernetes. To create it in ServerSpace infrastructure, just login into your client area, then click to Kubernetes link and create an instance:

pic1

pic2

Process may take a time, please be patient. When finished, you will see cluster parameters and should download access credentions file:

pic3

Instance setup

To install database service on your Kubernetes cluster please do follow:

  • Login to your management server as privileged user and install necessary tools:
sudo -s
apt-get update && apt install curl apt-transport-https -y && curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - && echo "deb https://apt.kubernetes.io/ kubernetes-xenial main" | tee -a /etc/apt/sources.list.d/kubernetes.list && apt-get update && apt install kubectl -y

pic4

  • Make a file which stores cluster access data and set this as system variable:
mkdir /usr/local/etc/mongo && cd /usr/local/etc/mongo
cat << EOF > testcluster.conf
<PASTE CONFIGURATION DATA HERE>
EOF
echo "export KUBECONFIG=testcluster.conf" >> ~/.bashrc

pic5

  • To check connection just run:
kubectl cluster-info

If output looks like picture below - connection is successful

pic6

    • MongoDB needs storage to save it's data. Storage creating process describes in special configuration files. You can customize it by your needs:
    cat << EOF > PersistVolClaim.yaml
    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
    name: mongodatapv # Should be the same with name in previous file
    spec:
    accessModes:
    - ReadWriteOnce
    resources:
    requests:
    storage: 1Gi # Should be the same with capacity in previous file
    EOF

    pic8

      Next step is creating credentials file, which stores access to MongoDB:

      cat << EOF > Creds.yaml
      apiVersion: v1
      data:
      username: <BASE64_ENCODED_LOGIN>
      password: <BASE64_ENCODED_PASSWORD>
      kind: Secret
      metadata:
      creationTimestamp: null
      name: creds
      EOF

      pic9

      Tip: To encode and decode data you can use simple commands:

      echo <DATA> | base64 # to crypt data via base64 tool
      echo <BASE64_ENCRYPTED_DATA> | base64 -d # to decrypt it

      pic10

      • Then create an instance deployment file:

        cat << EOF > Deploy.yaml
        apiVersion: apps/v1
        kind: Deployment
        metadata:
        labels:
        app: mongo
        name: mongo
        spec:
        replicas: 1
        selector:
        matchLabels:
        app: mongo
        strategy: {}
        template:
        metadata:
        labels:
        app: mongo
        spec:
        containers:
        - image: mongo
        name: mongo
        args: ["--dbpath","/data/db"]
        livenessProbe:
        exec:
        command:
        - mongo
        - --disableImplicitSessions
        - --eval
        readinessProbe:
        exec:
        command:
        - mongo
        - --disableImplicitSessions
        - --eval
        env:
        - name: MONGO_INITDB_ROOT_USERNAME
        valueFrom:
        secretKeyRef:
        name: creds
        key: username
        - name: MONGO_INITDB_ROOT_PASSWORD
        valueFrom:
        secretKeyRef:
        name: creds
        key: password
        volumeMounts:
        - name: "datadir"
        mountPath: "/data/db"
        volumes:
        - name: "datadir"
        persistentVolumeClaim:
        claimName: "mongopvc"
        EOF

      pic11

      • To launch MongoDB please run command:
      kubectl apply -f

      Successful output looks like at picture below:

      pic12

      Connection check

      • Now instances is deployed, so you should check connection. Just run:
      kubectl exec deployment/client -it -- /bin/bash
      mongo

      In case you see MongoDB prompt, connect is succesful:

      pic14

       

      • To create new database just "switch" to the new database. NOTE: Data will not be saved until you add something into the database:
      use NEW_DATABASE_NAME
      db.createCollection("newdata") # example to add data
      show dbs # check is database exist

      pic15

      Conclusion

      After this article reading you knew how to create Kubernetes via ServerSpace client area, deploy MongoDB into it, create new database and insert new data to this base.

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