New to KubeDB? Please start here.
Restart MongoDB
KubeDB supports restarting the MongoDB database via a MongoDBOpsRequest. Restarting is useful if some pods are got stuck in some phase, or they are not working correctly. This tutorial will show you how to use that.
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 created
Note: YAML files used in this tutorial are stored in docs/examples/mongodb folder in GitHub repository kubedb/docs.
Deploy MongoDB
In this section, we are going to deploy a MongoDB database using KubeDB.
apiVersion: kubedb.com/v1
kind: MongoDB
metadata:
name: mongo
namespace: demo
spec:
version: "4.4.26"
replicaSet:
name: "replicaset"
podTemplate:
spec:
containers:
- name: mongo
resources:
requests:
cpu: "300m"
memory: "300Mi"
replicas: 2
storageType: Durable
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
deletionPolicy: WipeOut
arbiter: {}
hidden:
replicas: 2
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2Gi
spec.replicaSetrepresents the configuration for replicaset.namedenotes the name of mongodb replicaset.
spec.replicasdenotes the number of general members inrs0mongodb replicaset.spec.podTemplatedenotes specifications of all the 3 general replicaset members.spec.ephemeralStorageholds the emptyDir volume specifications. This storage spec will be passed to the PetSet created by KubeDB operator to run database pods. So, each members will have a pod of this ephemeral storage configuration.spec.arbiterdenotes arbiter-node spec of the deployed MongoDB CRD.spec.hiddendenotes hidden-node spec of the deployed MongoDB CRD.
Let’s create the MongoDB CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/mongodb/restart/mongo.yaml
mongodb.kubedb.com/mongo created
Apply Restart opsRequest
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
name: restart
namespace: demo
spec:
type: Restart
databaseRef:
name: mongo
readinessCriteria:
oplogMaxLagSeconds: 10
objectsCountDiffPercentage: 15
timeout: 3m
apply: Always
spec.typespecifies the Type of the ops Requestspec.databaseRefholds the name of the MongoDB database. The db should be available in the same namespace as the opsRequest- The meaning of
spec.readinessCriteria,spec.timeout&spec.applyfields will be found here
Note: The method of restarting the standalone & sharded db is exactly same as above. All you need, is to specify the corresponding MongoDB name in
spec.databaseRef.namesection.
Let’s create the MongoDBOpsRequest CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/mongodb/restart/ops.yaml
mongodbopsrequest.ops.kubedb.com/restart created
Now the Ops-manager operator will first restart the general secondary pods, then serially the arbiters, the hidden nodes, & lastly will restart the Primary of the database.
$ kubectl get mgops -n demo
NAME TYPE STATUS AGE
restart Restart Successful 10m
$ kubectl get mgops -n demo -oyaml restart
apiVersion: ops.kubedb.com/v1alpha1
kind: MongoDBOpsRequest
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"ops.kubedb.com/v1alpha1","kind":"MongoDBOpsRequest","metadata":{"annotations":{},"name":"restart","namespace":"demo"},"spec":{"apply":"Always","databaseRef":{"name":"mongo"},"readinessCriteria":{"objectsCountDiffPercentage":15,"oplogMaxLagSeconds":10},"timeout":"3m","type":"Restart"}}
creationTimestamp: "2022-10-31T08:54:45Z"
generation: 1
name: restart
namespace: demo
resourceVersion: "738625"
uid: 32f6c52f-6114-4e25-b3a1-877223cf7145
spec:
apply: Always
databaseRef:
name: mongo
readinessCriteria:
objectsCountDiffPercentage: 15
oplogMaxLagSeconds: 10
timeout: 3m
type: Restart
status:
conditions:
- lastTransitionTime: "2022-10-31T08:54:45Z"
message: MongoDB ops request is restarting the database nodes
observedGeneration: 1
reason: Restart
status: "True"
type: Restart
- lastTransitionTime: "2022-10-31T08:57:05Z"
message: Successfully Restarted ReplicaSet nodes
observedGeneration: 1
reason: RestartReplicaSet
status: "True"
type: RestartReplicaSet
- lastTransitionTime: "2022-10-31T08:57:05Z"
message: Successfully restarted all nodes of MongoDB
observedGeneration: 1
reason: Successful
status: "True"
type: Successful
observedGeneration: 1
phase: Successful
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
kubectl delete mongodbopsrequest -n demo restart
kubectl delete mongodb -n demo mongo
kubectl delete ns demo
Next Steps
- Detail concepts of MongoDB object.
- 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.
- Use kubedb cli to manage databases like kubectl for Kubernetes.
- Detail concepts of MongoDB object.
- Want to hack on KubeDB? Check our contribution guidelines.