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Secure Deployments using TLS

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The MongoDB Enterprise Kubernetes Operator can use TLS certificates to encrypt connections between:

  • MongoDB hosts in a replica set or sharded cluster
  • Client applications and MongoDB deployments

Note

You can’t secure a Standalone Instance of MongoDB in a Kubernetes cluster.

This guide instructs you on how to configure the Kubernetes Operator to use TLS for its MongoDB instances.

Deprecation Notice

Automatically generating TLS certificates with the Kubernetes Operator is deprecated and will be removed in a future release.

You must provide certificates from your own CA, as described in the following procedures, for production environments.

General Prerequisites

Before you secure your MongoDB deployment using TLS encryption, complete the following:

Configure TLS for a Replica Set

Prerequisites

Before you secure your replica set using TLS encryption, complete the following:

  • Create a PEM file for each of the following components:

    PEM file purpose Save File As…
    Your custom CA ca-pem
    Each member of your replica set <metadata.name>-<X>-pem

    To create the PEM file, concatenate the TLS certificate and the Private Key. An example of a PEM file would resemble:

    -----BEGIN CERTIFICATE-----
...
... your TLS certificate
...
-----END CERTIFICATE-----
-----BEGIN RSA PRIVATE KEY-----
...
... your private key
...
-----END RSA PRIVATE KEY----

    About the example filenames

    • Name these files the exact names provided, substituting the appropriate variables. If a filename doesn’t match, deployment errors occur.
      • Replace <metadata.name> with the value of metadata.name in your deployment resource.
      • Replace <Y> with a 0-based number for the sharded cluster.
      • Replace <X> with the member of a shard or replica set.
    • End the PEM files with -pem and not .pem. These files shouldn’t have a file extension.

    About the Domain Names in certificates

    Each certificate should include a valid Domain Name.

    For each replica set or sharded cluster member, the Common Name, also known as the Domain Name, for that member’s certificate must match the FQDN of the POD on which this cluster member is deployed.

    The FQDN name in each certificate has the following syntax: pod-name.service-name.namespace.svc.cluster.local. This name is different for each Pod hosting a member of the replica set or a sharded cluster.

    For example, for a member of a replica set deployed on a Pod with the name rs-mongos-0-0, in the Kubernetes Operator service named mongo-0 that is created in the default mongodb namespace, the FQDN is:

    copy 
    rs-mongos-0-0.mongo-0.mongodb.svc.cluster.local

Procedure

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:

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

Create the secret for your TLS certificates.

Run this kubectl command to create the secret that stores the replica set’s certificates:

copy 
kubectl create secret generic <metadata.name>-cert \
  --from-file=<metadata.name>-0-pem \
  --from-file=<metadata.name>-1-pem \
  --from-file=<metadata.name>-2-pem

This example covers a three-member replica set. If you have more than three members, you can add them to the certificate using the --from-file option.

3
4

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
copy 
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  security:
    tls:
      enabled: true
      ca: <custom-ca>
...
5

Paste the copied example section into your existing replica set resource.

Open your preferred text editor and paste the object specification at the end of your resource file in the spec section.

6

Configure the TLS settings for your replica set resource using a Custom Certificate Authority.

To enable TLS in your deployment, configure the following settings in your Kubernetes object:

Key Type Necessity Description Example
spec.security
.tls.enabled
 boolean Optional

If this value is true, TLS is enabled on the MongoDB deployment.

By default, Kubernetes Operator requires hosts to use and accept TLS encrypted connections.

 true
spec.security
.tls.ca
 string Optional If you use a custom CA and have created the ConfigMap that stores it, add the ConfigMap’s name. <custom-ca>
7

Save your replica set config file.

8

Apply your changes to your replica set deployment.

Invoke the following Kubernetes command to update your replica set:

copy 
kubectl apply -f <replica-set-conf>.yaml
9

Track the status of your deployment.

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

copy 
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.

Configure TLS for a Sharded Cluster

Prerequisites

Before you secure your replica set using TLS encryption, complete the following:

  • Create a PEM file for each of the following components:

    PEM file purpose Save File As…
    Your custom CA ca-pem
    Each shard in your sharded cluster <metadata.name>-<Y>-<X>-pem
    Each member of your config server replica set <metadata.name>-config-<X>-pem
    Each mongos <metadata.name>-mongos-<X>-pem

    About the example filenames

    • Name these files the exact names provided, substituting the appropriate variables. If a filename doesn’t match, deployment errors occur.
      • Replace <metadata.name> with the value of metadata.name in your deployment resource.
      • Replace <Y> with a 0-based number for the sharded cluster.
      • Replace <X> with the member of a shard or replica set.
    • End the PEM files with -pem and not .pem. These files shouldn’t have a file extension.

Procedure

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:

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

Create the secret for your Shards’ TLS certificates.

Run this kubectl command to create the secret that stores the sharded cluster shards’ certificates:

copy 
kubectl -n mongodb create secret generic <metadata.name>-0-cert \
       --from-file=<metadata.name>-0-0-pem \
       --from-file=<metadata.name>-0-1-pem \
       --from-file=<metadata.name>-0-2-pem \
       --from-file=<metadata.name>-0-3-pem \
       --from-file=<metadata.name>-0-4-pem

kubectl -n mongodb create secret generic <metadata.name>-1-cert \
       --from-file=<metadata.name>-1-0-pem \
       --from-file=<metadata.name>-1-1-pem \
       --from-file=<metadata.name>-1-2-pem \
       --from-file=<metadata.name>-1-3-pem \
       --from-file=<metadata.name>-1-4-pem

This example covers a two-shard sharded cluster with five members per shard. If you have more than two shards or five members per shard, you can add them to the certificate using the --from-file option.

3

Create the secret for your config server’s TLS certificates.

Run this kubectl command to create the secret that stores the sharded cluster config server’s certificates:

copy 
kubectl -n mongodb create secret generic <metadata.name>-config-cert \
       --from-file=<metadata.name>-config-0-pem \
       --from-file=<metadata.name>-config-1-pem \
       --from-file=<metadata.name>-config-2-pem
4

Create the secret for your mongos server’s TLS certificates.

Run this kubectl command to create the secret that stores the sharded cluster mongos certificates:

copy 
kubectl -n mongodb create secret generic <metadata.name>-mongos-cert \
       --from-file=<metadata.name>-mongos-0-pem \
       --from-file=<metadata.name>-mongos-1-pem \
       --from-file=<metadata.name>-mongos-2-pem
5

Create the ConfigMap to link your CA with your deployment.

Run this kubectl command to link your CA to your replica set:

copy 
kubectl create configmap custom-ca --from-file=ca-pem
6

Copy the highlighted section of this sharded cluster resource.

Change the highlighted settings of this YAML file to match your desired sharded cluster configuration.

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---
apiVersion: mongodb.com/v1
kind: MongoDB
metadata:
  name: <my-sharded-cluster>
spec:
  shardCount: 2
  mongodsPerShardCount: 3
  mongosCount: 2
  configServerCount: 3
  version: "4.2.2-ent"
  opsManager:
    configMapRef:
      name: <configMap.metadata.name>
            # Must match metadata.name in ConfigMap file
  credentials: <mycredentials>
  type: ShardedCluster
  persistent: true
copy 
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  security:
    tls:
      enabled: true
      ca: <custom-ca>
...
7

Paste the copied example section into your existing sharded cluster resource.

Open your preferred text editor and paste the object specification at the end of your resource file in the spec section.

8

Configure the TLS settings for your sharded cluster resource using a Custom Certificate Authority.

To enable TLS in your deployment, configure the following settings in your Kubernetes object:

Key Type Necessity Description Example
spec.security
.tls.enabled
 boolean Optional

If this value is true, TLS is enabled on the MongoDB deployment.

By default, Kubernetes Operator requires hosts to use and accept TLS encrypted connections.

 true
spec.security
.tls.ca
 string Optional If you use a custom CA and have created the ConfigMap that stores it, add the ConfigMap’s name. <custom-ca>
9

Save your sharded cluster config file.

10

Update and restart your sharded cluster deployment.

Invoke the following Kubernetes command to update and restart your sharded cluster:

copy 
kubectl apply -f <sharded-cluster-conf>.yaml
11

Track the status of your deployment.

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

copy 
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.

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