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Secure Client Authentication with LDAP in Multi-Cluster Deployments

MongoDB Enterprise supports:

  • Proxying authentication requests to a Lightweight Directory Access Protocol (LDAP) service.
  • Simple and SASL binding to LDAP servers. MongoDB Enterprise can bind to an LDAP server via saslauthd or through the operating system libraries.

To learn more, see the LDAP Proxy Authentication and LDAP Authorization sections in the MongoDB Server documentation.

You can use the Kubernetes Operator to configure LDAP to authenticate your client applications that connect to your multi-cluster deployments. This guide describes how to configure LDAP authentication from client applications to your multi-cluster deployments.

Considerations

  • To configure LDAP in CustomResourceDefinitions, use the parameters under the spec.security.authentication.ldap and other security LDAP settings specific to the MongoDB Agent, from the Kubernetes Operator MongoDB resource specification. The procedures in this section describe the required settings and provide examples of LDAP configuration.
  • To improve security, consider configuring TLS. Encryption with TLS is optional. By default, LDAP traffic is sent as plain text. This means that username and password are exposed to network threats. Many modern directory services, such as Microsoft Active Directory, require encrypted connections. Consider using LDAP over TLS/SSL to encrypt vauthentication requests in your Kubernetes Operator MongoDB deployments.

General Prerequisites

Before you secure your multi-cluster deployment using TLS encryption, complete the following tasks:

Configure LDAP Client Authentication for a Multi-Cluster Replica Set

1

Create the secret for the TLS certificate of your MongoDBMulti custom resource.

Run the kubectl command to create a new secret that stores the MongoDB multi-cluster resource’s certificate:

kubectl --context $MDB_CENTRAL_CLUSTER_FULL_NAME \
  --namespace=<metadata.namespace> \
  create secret tls <prefix>-<metadata.name>-cert \
  --cert=<resource-tls-cert> \
  --key=<resource-tls-key>

Note

You must prefix your secrets with <prefix>-<metadata.name>.

Example

If you call your deployment my-deployment and you set the prefix to mdb, you must name the TLS secret for the client TLS communications mdb-my-deployment-cert. Also, you must name the TLS secret for internal cluster authentication (if enabled) mdb-my-deployment-clusterfile.

If you’re using HashiCorp Vault as your secret storage tool, you can Create a Vault Secret instead.

To learn about your options for secret storage, see Configure Secret Storage.

2
3

Update your MongoDBMulti custom resource to enable LDAP authentication.

Update your MongoDBMulti custom resource with security settings from the Kubernetes Operator MongoDB resource specification.

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

Key Type and necessity Description Example
spec.security
boolean,
required
Set to true to enable LDAP authentication. true
string,
required
Specify the LDAP Distinguished Name to which MongoDB binds when connecting to the LDAP server. cn=admin,dc=example,dc=org
string,
required
Specify the name of the secret that contains the LDAP Bind Distinguished Name’s password with which MongoDB binds when connecting to an LDAP server. <secret-name>
string,
optional
Add the ConfigMap’s name that stores the custom CA that you used to sign your deployment’s TLS certificates. <configmap-name>
string,
optional
Add the field name that stores the CA which validates the LDAP server’s TLS certificate. <configmap-key>
array of strings,
required
Specify the list of hostname:port combinations of one or more LDAP servers. For each server, use a separate line. <example.com:636>
string,
optional
Set to tls to use LDAPS (LDAP over TLS). Leave blank if your LDAP server doesn’t accept TLS. tls
string,
required

Specify the mapping that maps the username provided to mongod or mongos for authentication to an LDAP Distinguished Name (DN).

To learn more, see security.ldap.userToDNMapping and LDAP Query Templates in the MongoDB Server documentation.

<match: "(.+)",substitution: "uid={0},ou=groups,dc=example,dc=org">
spec.security
string,
required
Set to LDAP to enable authentication through LDAP. LDAP
spec.security
string,
optional

Add the <prefix> of the secret name that contains your MongoDB deployment’s TLS certificates.

Example

If you call your deployment my-deployment and you set the prefix to mdb, you must name the TLS secret for the client TLS communications mdb-my-deployment-cert. Also, you must name the TLS secret for internal cluster authentication (if enabled) mdb-my-deployment-clusterfile.

devDb
spec.security
string,
optional
Add the ConfigMap’s name that stores the custom CA that you used to sign your deployment’s TLS certificates. <custom-ca>

The resulting configuration may look similar to the following example:

security:
 authentication:
   enabled: true
   # Enabled LDAP Authentication Mode
   modes:
     - "LDAP"
     - "SCRAM"
     # LDAP related configuration
   ldap:
   # Specify the hostname:port combination of one or
   # more LDAP servers
     servers:
       - "ldap1.example.com:636"
       - "ldap2.example.com:636"

   # Set to "tls" to use LDAP over TLS. Leave blank if
   # the LDAP server doesn't accept TLS.
   transportSecurity: "tls"

   # If TLS is enabled, add a reference to a ConfigMap that
   # contains a CA certificate that validates the LDAP server's
   # TLS certificate.
   caConfigMapRef:
     name: "<configmap-name>"
     key: "<configmap-entry-key>"

   # Specify the LDAP Distinguished Name to which
   # MongoDB binds when connecting to the LDAP server
   bindQueryUser: "cn=admin,dc=example,dc=org"

   # Specify the password with which MongoDB binds
   # when connecting to an LDAP server. This is a
   # reference to a Secret Kubernetes Object containing
   # one "password" key.
   bindQueryPasswordSecretRef:
     name: "<secret-name>"

For a full list of LDAP settings, see security settings in the Kubernetes Operator MongoDB resource specification. Also see the spec.security.authentication.agents.automationUserName setting for the MongoDB Agent user in your LDAP-enabled Kubernetes Operator deployment.

4

Verify that the MDB resources are running.

  1. For member clusters, run the following commands to verify that the MongoDB Pods are in the running state:

    kubectl get pods \
     --context=$MDB_CLUSTER_1_FULL_NAME \
     --namespace mongodb
    
    kubectl get pods \
     --context=$MDB_CLUSTER_2_FULL_NAME \
     --namespace mongodb
    
    kubectl get pods \
     --context=$MDB_CLUSTER_3_FULL_NAME \
     --namespace mongodb
    
  2. In the central cluster, run the following commands to verify that the MongoDBMulti custom resource is in the running state:

    kubectl --context=$MDB_CENTRAL_CLUSTER_FULL_NAME \
      --namespace mongodb \
      get mdbm multi-replica-set -o yaml -w