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 Minikube.
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 demo throughout this tutorial. Run the following command to prepare your cluster for this tutorial:
$ kubectl create -f https://raw.githubusercontent.com/kubedb/cli/0.8.0-beta.2/docs/examples/mongodb/demo-0.yaml
namespace "demo" created
$ kubectl get ns
NAME STATUS AGE
default Active 45m
demo Active 10s
kube-public Active 45m
kube-system Active 45m
In this tutorial we will use .js script stored in GitHub repository kubedb/mongodb-init-scripts.
Note that the yaml files that are used in this tutorial, stored in docs/examples folder in GitHub repository kubedb/cli.
Create a MongoDB database with Init-Script
Below is the MongoDB object created in this tutorial.
apiVersion: kubedb.com/v1alpha1
kind: MongoDB
metadata:
name: mgo-init-script
namespace: demo
spec:
version: 3.4
doNotPause: true
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 50Mi
init:
scriptSource:
gitRepo:
repository: "https://github.com/kubedb/mongodb-init-scripts.git"
directory: .
$ kubedb create -f https://raw.githubusercontent.com/kubedb/cli/0.8.0-beta.2/docs/examples/mongodb/Initialization/demo-1.yaml
validating "https://raw.githubusercontent.com/kubedb/cli/0.8.0-beta.2/docs/examples/mongodb/Initialization/demo-1.yaml"
mongodb "mgo-init-script" created
Here,
spec.version is the version of MongoDB database. In this tutorial, a MongoDB 3.4 database is going to be created.
spec.storage specifies the StorageClass of PVC dynamically allocated to store data for this database. This storage spec will be passed to the StatefulSet created by KubeDB operator to run database pods. You can specify any StorageClass available in your cluster with appropriate resource requests. If no storage spec is given, an emptyDir is used.
spec.init.scriptSource specifies 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 repository https://github.com/kubedb/mongodb-init-scripts.git is used to create a test database. You can use other volume sources instead of gitrepo. 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 StatefulSet and a ClusterIP Service with the matching MongoDB object name. KubeDB operator will also create a governing service for StatefulSets with the name kubedb, if one is not already present. No MongoDB specific RBAC roles are required for RBAC enabled clusters.
$ kubedb describe mg -n demo mgo-init-script
Name: mgo-init-script
Namespace: demo
StartTimestamp: Tue, 06 Feb 2018 09:56:07 +0600
Status: Running
Volume:
StorageClass: standard
Capacity: 50Mi
Access Modes: RWO
StatefulSet:
Name: mgo-init-script
Replicas: 1 current / 1 desired
CreationTimestamp: Tue, 06 Feb 2018 09:56:12 +0600
Pods Status: 1 Running / 0 Waiting / 0 Succeeded / 0 Failed
Service:
Name: mgo-init-script
Type: ClusterIP
IP: 10.106.175.209
Port: db 27017/TCP
Database Secret:
Name: mgo-init-script-auth
Type: Opaque
Data
====
password: 16 bytes
user: 4 bytes
No Snapshots.
Events:
FirstSeen LastSeen Count From Type Reason Message
--------- -------- ----- ---- -------- ------ -------
6s 6s 1 MongoDB operator Normal Successful Successfully patched StatefulSet
6s 6s 1 MongoDB operator Normal Successful Successfully patched MongoDB
9s 9s 1 MongoDB operator Normal Successful Successfully created StatefulSet
9s 9s 1 MongoDB operator Normal Successful Successfully created MongoDB
18s 18s 1 MongoDB operator Normal Successful Successfully created Service
$ kubectl get statefulset -n demo
NAME DESIRED CURRENT AGE
mgo-init-script 1 1 46s
$ kubectl get pvc -n demo
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
data-mgo-init-script-0 Bound pvc-ac84fbb9-0af1-11e8-a107-080027869227 50Mi RWO standard 1m
$ kubectl get pv -n demo
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-ac84fbb9-0af1-11e8-a107-080027869227 50Mi RWO Delete Bound demo/data-mgo-init-script-0 standard
$ kubectl get service -n demo
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubedb ClusterIP None <none> <none> 2m
mgo-init-script ClusterIP 10.106.175.209 <none> 27017/TCP 2m
KubeDB operator sets the status.phase to Running once the database is successfully created. Run the following command to see the modified MongoDB object:
$ kubedb get mg -n demo mgo-init-script -o yaml
apiVersion: kubedb.com/v1alpha1
kind: MongoDB
metadata:
clusterName: ""
creationTimestamp: 2018-02-06T03:56:07Z
finalizers:
- kubedb.com
generation: 0
name: mgo-init-script
namespace: demo
resourceVersion: "4827"
selfLink: /apis/kubedb.com/v1alpha1/namespaces/demo/mongodbs/mgo-init-script
uid: a9348cad-0af1-11e8-a107-080027869227
spec:
databaseSecret:
secretName: mgo-init-script-auth
doNotPause: true
init:
scriptSource:
gitRepo:
directory: .
repository: https://github.com/kubedb/mongodb-init-scripts.git
storage:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 50Mi
storageClassName: standard
version: 3.4
status:
creationTime: 2018-02-06T03:56:12Z
phase: Running
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 user 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.databaseSecret.secretName. While creating this secret manually, make sure the secret contains these two keys containing data user and password.
$ kubectl get secrets -n demo mgo-init-script-auth -o json
apiVersion: v1
data:
password: STJ1YnNiU3BUNzFOZUhXSA==
user: cm9vdA==
kind: Secret
metadata:
creationTimestamp: 2018-02-06T03:56:12Z
labels:
kubedb.com/kind: MongoDB
kubedb.com/name: mgo-init-script
name: mgo-init-script-auth
namespace: demo
resourceVersion: "4789"
selfLink: /api/v1/namespaces/demo/secrets/mgo-init-script-auth
uid: ac33c72d-0af1-11e8-a107-080027869227
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.\user}' | base64 -d
root
$ kubectl get secrets -n demo mgo-init-script-auth -o jsonpath='{.data.\password}' | base64 -d
I2ubsbSpT71NeHWH
$ 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","I2ubsbSpT71NeHWH")
1
> show dbs
admin 0.000GB
local 0.000GB
mydb 0.000GB
> use mydb
switched to db mydb
> db.movie.find()
{ "_id" : ObjectId("5a72b2b1e1a0770e3bdb56f1"), "name" : "batman" }
> exit
bye
As you can see here, the initial script has successfully created a database named mydb and inserted data into that database successfully.
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
$ kubedb delete mg,drmn,snap -n demo --all --force
$ kubectl delete ns demo
namespace "demo" deleted
Next Steps
