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Deploy a Replica Set

Note

At any place on this page that says Ops Manager, you can substitute Cloud Manager.

Important

  • You can use the Kubernetes Operator to deploy MongoDB resources with Ops Manager version 4.0.11 or later and Cloud Manager.
  • You can’t use the Kubernetes Operator to deploy MongoDB resources to Atlas.

A replica set is a group of MongoDB deployments that maintain the same data set. Replica sets provide redundancy and high availability and are the basis for all production deployments.

To learn more about replica sets, see the Replication Introduction in the MongoDB manual.

Use this procedure to deploy a new replica set that Ops Manager manages. After deployment, use Ops Manager to manage the replica set, including such operations as adding, removing, and reconfiguring members.

Prerequisites

To deploy a replica set using an object, you need to complete the following procedures:

Alternatively, for MongoDB Cloud Manager, after installing the Kubernetes Operator, you can use the Cloud Manager UI to automatically generate the ConfigMap and Kubernetes secret YAML files, which you can then apply to your Kubernetes environment.

Considerations

Starting in Kubernetes Operator version 1.11.0, you must migrate all deployed MongoDBOpsManager custom resources to a specified MongoDB version.

Deploy a Replica Set

1

Configure kubectl to default to your namespace.

If you have not already, run the following command to execute all kubectl commands in the namespace you created:

kubectl config set-context $(kubectl config current-context) --namespace=<namespace>
2

Copy the highlighted section of this replica set resource.

Change the highlighted settings of this YAML file to match your desired replica set configuration.

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---
apiVersion: mongodb.com/v1
kind: MongoDB
metadata:
  name: <my-replica-set>
spec:
  members: 3
  version: "4.2.2-ent"
  opsManager:
    configMapRef:
      name: <configMap.metadata.name>
            # Must match metadata.name in ConfigMap file
  credentials: <mycredentials>
  type: ReplicaSet
  persistent: true
...
3

Paste the copied example to create a new replica set resource.

Open your preferred text editor and paste the object specification into a new text file.

4

Change the highlighted settings to your preferred values.

Key Type Description Example
metadata.name string

Label for this Kubernetes replica set object.

Resource names must be 44 characters or less.

See also

myproject
spec.members integer Number of members of the replica set. 3
spec.version string

Version of MongoDB that this replica set should run.

The format should be X.Y.Z for the Community edition and X.Y.Z-ent for the Enterprise edition.

Important

Ensure that you choose a compatible MongoDB Server version.

Compatible versions differ depending on the base image that the MongoDB database resource uses.

To learn more about MongoDB versioning, see MongoDB Versioning in the MongoDB Manual.

3.6.7
spec
.opsManager
.configMapRef
string

Name of the ConfigMap with the Ops Manager connection configuration. The spec.cloudManager.configMapRef.name setting is an alias for this setting and can be used in its place.

Note

This value must exist on the same namespace as the resource you want to create.

Operator manages changes to the ConfigMap

The Kubernetes Operator tracks any changes to the ConfigMap and reconciles the state of the MongoDB Kubernetes resource.

<myconfigmap>
spec.credentials string

Name of the Kubernetes secret you created as Ops Manager API authentication credentials for the Kubernetes Operator to communicate with Ops Manager.

The Ops Manager Kubernetes Secret object holding the Credentials must exist on the same Namespace as the resource you want to create.

Operator manages changes to the Secret

The Kubernetes Operator tracks any changes to the Secret and reconciles the state of the MongoDB Kubernetes resource.

<mycredentials>
spec.type string Type of MongoDB Kubernetes resource to create. ReplicaSet
spec.persistent string

Optional.

Flag indicating if this MongoDB Kubernetes resource should use Persistent Volumes for storage. Persistent volumes are not deleted when the MongoDB Kubernetes resource is stopped or restarted.

If this value is true, then spec.podSpec.persistence.single is set to its default value of 16Gi.

To change your Persistent Volume Claims configuration, configure the following collections to meet your deployment requirements:

Warning

Your containers must have permissions to write to your Persistent Volume. The Kubernetes Operator sets fsGroup = 2000 in securityContext This makes Kubernetes try to fix write permissions for the Persistent Volume. If redeploying the deployment item does not fix issues with your Persistent Volumes, contact MongoDB Support.

Note

If you do not use Persistent Volumes, the Disk Usage and Disk IOPS charts cannot be displayed in either the Processes tab on the Deployment page or in the Metrics page when reviewing the data for this deployment.

true
5

Add any additional accepted settings for a replica set deployment.

You can also add any of the following optional settings to the object specification file for a replica set deployment:

Warning

You must set spec.clusterDomain if your Kubernetes cluster has a default domain other than the default cluster.local. If you neither use the default nor set the spec.clusterDomain option, the Kubernetes Operator might not function as expected.

6

Save this replica set config file with a .yaml extension.

7

Start your replica set deployment.

Invoke the following Kubernetes command to create your replica set:

kubectl apply -f <replica-set-conf>.yaml
8

Track the status of your replica set deployment.

To check the status of your MongoDB Kubernetes resource, invoke the following command:

kubectl get mdb <resource-name> -o yaml -w

The -w flag means “watch”. With the “watch” flag set, the output refreshes immediately when the configuration changes until the status phase achieves the Running state.

See Troubleshoot the Kubernetes Operator for information about the resource deployment statuses.