New to KubeDB? Please start here.
Initialize MongoDB using Script
This tutorial will show you how to use KubeDB to initialize a MongoDB database with .js and/or .sh script.
Before You Begin
At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.
Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.
To keep things isolated, this tutorial uses a separate namespace called
demothroughout this tutorial.$ kubectl create ns demo namespace/demo createdIn this tutorial we will use .js script stored in GitHub repository kubedb/mongodb-init-scripts.
Note: The yaml files used in this tutorial are stored in docs/examples/mongodb folder in GitHub repository kubedb/docs.
Prepare Initialization Scripts
MongoDB supports initialization with .sh and .js files. In this tutorial, we will use init.js script from mongodb-init-scripts git repository to insert data inside kubedb DB.
We will use a ConfigMap as script source. You can use any Kubernetes supported volume as script source.
At first, we will create a ConfigMap from init.js file. Then, we will provide this ConfigMap as script source in init.script of MongoDB crd spec.
Let’s create a ConfigMap with initialization script,
$ kubectl create configmap -n demo mg-init-script \
--from-literal=init.js="$(curl -fsSL https://github.com/kubedb/mongodb-init-scripts/raw/master/init.js)"
configmap/mg-init-script created
Create a MongoDB database with Init-Script
Below is the MongoDB object created in this tutorial.
apiVersion: kubedb.com/v1
kind: MongoDB
metadata:
name: mgo-init-script
namespace: demo
spec:
version: "4.4.26"
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
init:
script:
configMap:
name: mg-init-script
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.12.18/docs/examples/mongodb/Initialization/replicaset.yaml
mongodb.kubedb.com/mgo-init-script created
Here,
spec.init.scriptspecifies a script source used to initialize the database before database server starts. The scripts will be executed alphabatically. In this tutorial, a sample .js script from the git repositoryhttps://github.com/kubedb/mongodb-init-scripts.gitis used to create a test database. You can use other volume sources. The *.js and/or *.sh sripts that are stored inside the root folder will be executed alphabatically. The scripts inside child folders will be skipped.
KubeDB operator watches for MongoDB objects using Kubernetes api. When a MongoDB object is created, KubeDB operator will create a new PetSet and a Service with the matching MongoDB object name. KubeDB operator will also create a governing service for PetSets with the name <mongodb-crd-name>-gvr, if one is not already present. No MongoDB specific RBAC roles are required for RBAC enabled clusters.
$ kubectl dba describe mg -n demo mgo-init-script
Name: mgo-init-script
Namespace: demo
CreationTimestamp: Thu, 11 Feb 2021 10:58:22 +0600
Labels: <none>
Annotations: kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"kubedb.com/v1","kind":"MongoDB","metadata":{"annotations":{},"name":"mgo-init-script","namespace":"demo"},"spec":{"init":{"script"...
Replicas: 1 total
Status: Ready
StorageType: Durable
Volume:
StorageClass: standard
Capacity: 1Gi
Access Modes: RWO
Paused: false
Halted: false
Termination Policy: Delete
PetSet:
Name: mgo-init-script
CreationTimestamp: Thu, 11 Feb 2021 10:58:23 +0600
Labels: app.kubernetes.io/component=database
app.kubernetes.io/instance=mgo-init-script
app.kubernetes.io/managed-by=kubedb.com
app.kubernetes.io/name=mongodbs.kubedb.com
Annotations: <none>
Replicas: 824638316568 desired | 1 total
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Service:
Name: mgo-init-script
Labels: app.kubernetes.io/component=database
app.kubernetes.io/instance=mgo-init-script
app.kubernetes.io/managed-by=kubedb.com
app.kubernetes.io/name=mongodbs.kubedb.com
Annotations: <none>
Type: ClusterIP
IP: 10.107.34.91
Port: primary 27017/TCP
TargetPort: db/TCP
Endpoints: [10.107.34.91]:27017
Service:
Name: mgo-init-script-pods
Labels: app.kubernetes.io/component=database
app.kubernetes.io/instance=mgo-init-script
app.kubernetes.io/managed-by=kubedb.com
app.kubernetes.io/name=mongodbs.kubedb.com
Annotations: <none>
Type: ClusterIP
IP: None
Port: db 27017/TCP
TargetPort: db/TCP
Endpoints: [10.107.34.91]:27017
Auth Secret:
Name: mgo-init-script-auth
Labels: app.kubernetes.io/component=database
app.kubernetes.io/instance=mgo-init-script
app.kubernetes.io/managed-by=kubedb.com
app.kubernetes.io/name=mongodbs.kubedb.com
Annotations: <none>
Type: Opaque
Data:
password: 16 bytes
username: 4 bytes
Init:
Script Source:
Volume:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: mg-init-script
Optional: false
AppBinding:
Metadata:
Annotations:
kubectl.kubernetes.io/last-applied-configuration: {"apiVersion":"kubedb.com/v1","kind":"MongoDB","metadata":{"annotations":{},"name":"mgo-init-script","namespace":"demo"},"spec":{"init":{"script":{"configMap":{"name":"mg-init-script"}}},"storage":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"1Gi"}},"storageClassName":"standard"},"version":"4.4.26"}}
Creation Timestamp: 2021-02-11T04:58:42Z
Labels:
app.kubernetes.io/component: database
app.kubernetes.io/instance: mgo-init-script
app.kubernetes.io/managed-by: kubedb.com
app.kubernetes.io/name: mongodbs.kubedb.com
Name: mgo-init-script
Namespace: demo
Spec:
Client Config:
Service:
Name: mgo-init-script
Port: 27017
Scheme: mongodb
Secret:
Name: mgo-init-script-auth
Type: kubedb.com/mongodb
Version: 4.4.26
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Successful 47s MongoDB operator Successfully created stats service
Normal Successful 47s MongoDB operator Successfully created Service
Normal Successful 46s MongoDB operator Successfully stats service
Normal Successful 46s MongoDB operator Successfully stats service
Normal Successful 27s MongoDB operator Successfully created appbinding
Normal Successful 27s MongoDB operator Successfully patched PetSet demo/mgo-init-script
Normal Successful 27s MongoDB operator Successfully patched MongoDB
$ kubectl get petset -n demo
NAME READY AGE
mgo-init-script 1/1 30s
$ kubectl get pvc -n demo
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
datadir-mgo-init-script-0 Bound pvc-a10d636b-c08c-11e8-b4a9-0800272618ed 1Gi RWO standard 11m
$ kubectl get pv -n demo
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-a10d636b-c08c-11e8-b4a9-0800272618ed 1Gi RWO Delete Bound demo/datadir-mgo-init-script-0 standard 12m
$ kubectl get service -n demo
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
mgo-init-script ClusterIP 10.107.34.91 <none> 27017/TCP 52s
mgo-init-script-pods ClusterIP None <none> 27017/TCP 52s
KubeDB operator sets the status.phase to Ready once the database is successfully created. Run the following command to see the modified MongoDB object:
$ kubectl get mg -n demo mgo-init-script -o yaml
apiVersion: kubedb.com/v1
kind: MongoDB
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"kubedb.com/v1","kind":"MongoDB","metadata":{"annotations":{},"name":"mgo-init-script","namespace":"demo"},"spec":{"init":{"script":{"configMap":{"name":"mg-init-script"}}},"storage":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"1Gi"}},"storageClassName":"standard"},"version":"4.4.26"}}
creationTimestamp: "2021-02-10T04:38:52Z"
finalizers:
- kubedb.com
generation: 3
managedFields:
- apiVersion: kubedb.com/v1
fieldsType: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.: {}
f:kubectl.kubernetes.io/last-applied-configuration: {}
f:spec:
.: {}
f:init:
.: {}
f:script:
.: {}
f:configMap:
.: {}
f:name: {}
f:storage:
.: {}
f:accessModes: {}
f:resources:
.: {}
f:requests:
.: {}
f:storage: {}
f:storageClassName: {}
f:version: {}
manager: kubectl-client-side-apply
operation: Update
time: "2021-02-10T04:38:52Z"
- apiVersion: kubedb.com/v1
fieldsType: FieldsV1
fieldsV1:
f:metadata:
f:finalizers: {}
f:spec:
f:authSecret:
.: {}
f:name: {}
f:init:
f:initialized: {}
f:status:
.: {}
f:conditions: {}
f:observedGeneration: {}
f:phase: {}
manager: mg-operator
operation: Update
time: "2021-02-10T04:39:16Z"
name: mgo-init-script
namespace: demo
resourceVersion: "98944"
uid: 5f13be2a-9a47-4b7e-9b83-a00b9bc89438
spec:
authSecret:
name: mgo-init-script-auth
init:
initialized: true
script:
configMap:
name: mg-init-script
podTemplate:
controller: {}
metadata: {}
spec:
resources:
limits:
cpu: 500m
memory: 1Gi
requests:
cpu: 500m
memory: 1Gi
serviceAccountName: mgo-init-script
replicas: 1
sslMode: disabled
storage:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
storageClassName: standard
storageEngine: wiredTiger
storageType: Durable
deletionPolicy: Delete
version: 4.4.26
status:
conditions:
- lastTransitionTime: "2021-02-10T04:38:53Z"
message: 'The KubeDB operator has started the provisioning of MongoDB: demo/mgo-init-script'
reason: DatabaseProvisioningStartedSuccessfully
status: "True"
type: ProvisioningStarted
- lastTransitionTime: "2021-02-10T04:39:16Z"
message: All desired replicas are ready.
reason: AllReplicasReady
status: "True"
type: ReplicaReady
- lastTransitionTime: "2021-02-10T04:39:33Z"
message: 'The MongoDB: demo/mgo-init-script is accepting client requests.'
observedGeneration: 3
reason: DatabaseAcceptingConnectionRequest
status: "True"
type: AcceptingConnection
- lastTransitionTime: "2021-02-10T04:39:33Z"
message: 'The MongoDB: demo/mgo-init-script is ready.'
observedGeneration: 3
reason: ReadinessCheckSucceeded
status: "True"
type: Ready
- lastTransitionTime: "2021-02-10T04:39:16Z"
message: 'The MongoDB: demo/mgo-init-script is successfully provisioned.'
observedGeneration: 2
reason: DatabaseSuccessfullyProvisioned
status: "True"
type: Provisioned
observedGeneration: 3
phase: Ready
Please note that KubeDB operator has created a new Secret called mgo-init-script-auth (format: {mongodb-object-name}-auth) for storing the password for MongoDB superuser. This secret contains a username key which contains the username for MongoDB superuser and a password key which contains the password for MongoDB superuser.
If you want to use an existing secret please specify that when creating the MongoDB object using spec.authSecret.name. While creating this secret manually, make sure the secret contains these two keys containing data username and password.
$ kubectl get secrets -n demo mgo-init-script-auth -o yaml
apiVersion: v1
data:
password: eGtBaTRmRVpmSVFrNmczVw==
user: cm9vdA==
kind: Secret
metadata:
creationTimestamp: "2019-02-06T09:43:54Z"
labels:
app.kubernetes.io/name: mongodbs.kubedb.com
app.kubernetes.io/instance: mgo-init-script
name: mgo-init-script-auth
namespace: demo
resourceVersion: "89594"
selfLink: /api/v1/namespaces/demo/secrets/mgo-init-script-auth
uid: b7cf2369-29f3-11e9-aebf-080027875192
type: Opaque
Now, you can connect to this database through mongo-shell. In this tutorial, we are connecting to the MongoDB server from inside the pod.
$ kubectl get secrets -n demo mgo-init-script-auth -o jsonpath='{.data.\username}' | base64 -d
root
$ kubectl get secrets -n demo mgo-init-script-auth -o jsonpath='{.data.\password}' | base64 -d
oEwk7IGxCPM5OWo5
$ kubectl exec -it mgo-init-script-0 -n demo sh
> mongo admin
MongoDB shell version v3.4.10
connecting to: mongodb://127.0.0.1:27017/admin
MongoDB server version: 3.4.10
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
> db.auth("root","oEwk7IGxCPM5OWo5")
1
> show dbs
admin 0.000GB
config 0.000GB
kubedb 0.000GB
local 0.000GB
> use kubedb
switched to db kubedb
> db.people.find()
{ "_id" : ObjectId("5ba9d667981f02e927b6788e"), "firstname" : "kubernetes", "lastname" : "database" }
> exit
bye
As you can see here, the initial script has successfully created a database named kubedb and inserted data into that database successfully.
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
kubectl patch -n demo mg/mgo-init-script -p '{"spec":{"deletionPolicy":"WipeOut"}}' --type="merge"
kubectl delete -n demo mg/mgo-init-script
kubectl delete ns demo
Next Steps
- Backup and Restore MongoDB databases using Stash.
- Initialize MongoDB with Script.
- Monitor your MongoDB database with KubeDB using out-of-the-box Prometheus operator.
- Monitor your MongoDB database with KubeDB using out-of-the-box builtin-Prometheus.
- Use private Docker registry to deploy MongoDB with KubeDB.
- Detail concepts of MongoDB object.
- Detail concepts of MongoDBVersion object.
- Want to hack on KubeDB? Check our contribution guidelines.