Configuring Cross-Cluster Trust

NOTE In this article, the term tenant refers to HPE Ezmeral Data Fabric tenants (formerly '"MapR tenants") and not to Kubernetes tenants unless explicitly noted otherwise on a case-by-case basis.

The edftool allows you to configure cross-cluster trust between either:

  • One HPE Ezmeral Data Fabric cluster on bare metal and one HPE Ezmeral Data Fabric on Kubernetes cluster.
  • Two HPE Ezmeral Data Fabric on Kubernetes clusters.

Trust allows mirroring between the two clusters and also allows tenants in one cluster to access data or tenants in the other cluster. All clusters listed in the mapr-clusters.conf file must have unique names in order to configure trust.


Cross-cluster operations are supported between HPE Ezmeral Runtime Enterprise clusters running the dataplatform operator with mapr-core-6.2.0 and other clusters running:

  • dataplatform operator with mapr-core-6.2
  • dataplatform operator with mapr-core-6.1
  • Bare-metal HPE Ezmeral Data Fabric clusters running release 6.1.0 or release 6.2.0

In this context, the term bare-metal means that HPE Ezmeral Data Fabric is deployed on either a Linux platform or a virtual machine.

About the edftool

The edftool simplifies complex security-related HPE Ezmeral Data Fabric tasks, including:

  • Setting up trust between two clusters.
  • Exporting the public certificates for each service.
  • Exporting the private keys for each service.
  • Generating certificate-signing requests for each service.
  • Importing new certificates.

The edftool tool resides in the admincli-0 pod, but the tool can also be run remotely from a Linux system with admin-level kubectl access to the cluster namespace. A client system running the edftool tool must have Keytool JDK utility, which is present if Java is installed. The tool uses SSH to log into both clusters and does the following:

  • Generates login and service tickets on both clusters.
  • Persists the cluster information for both clusters into the ssl_trustore and mapr-clusters.conf files.

    Each Data Fabric cluster has a configuration file, mapr-clusters.conf, that specifies the other Data Fabric clusters that this cluster can connect to. The file identifies the other clusters by specifying the cluster CLDB nodes.

    For more information about the mapr-clusters.conf configuration file, see mapr-clusters.conf in the HPE Ezmeral Data Fabric documentation.

  • For each instance of HPE Ezmeral Data Fabric on Kubernetes, edftool generates a kubectl patch. The kubectl patch enables secrets to persist the trust information after a pod restarts.

Accessing the edftool help

  1. Log into the admincli-0 pod by executing the following command:

    kubectl exec -it -n <pod-namespace> admincli-0 -- /bin/bash
  2. Execute the following command:


    The tool displays the command help:

    $ edftool
    Tool to help with some of the more complex tasks in the Data Fabric
    edftool [command]
    Available Commands:
    cluster-trust Setup trust between two clusters
    export-certs  Export the public certs of each serviceexport-keys    Export the private keys of each service
    gen-csrs      Generate certificate signing requests for each service
    help          Help about any command
    import-certs  Import new certs (newly signed?)
    -h, --help    help for edftool
    Use "edftool [command] --help" for more information about a command.
  3. You can display detailed information about each command by executing the following command:

    edftool <command> --help
  4. For example:

    edftool cluster-trust --help

Setting Up Cross-Cluster Trust

This illustration depicts the process of setting up cross-cluster trust:

To set up cross-cluster trust, do the following:

  1. Execute the following command on either the Kubernetes cluster or the Data Fabric client where the edftool is installed:

    kubectl exec -it -n <pod-namespace> admincli-0 -- /bin/bash
  2. Change to the /tmp directory to facilitate logging for the edftool:

    cd /tmp
  3. Execute the edftool cluster-trust command with the required parameters.

    The following example sets up cross-cluster trust between an HPE Ezmeral Data Fabric on Kubernetes and a bare-metal HPE Ezmeral Data Fabric cluster:

    edftool cluster-trust -a,, -p mapr
    -b,, -P mapr -S 5000

    In the example:

    • The first three IP addresses are used for the nodes that the CLDB pods are running on in the Kubernetes cluster, followed by the Kubernetes cluster password. The Kubernetes cluster contains the table to be replicated and is thus the “local” cluster.
    • The next three IP addresses are the IP addresses for the CLDB nodes in the bare-metal cluster, followed by the bare-metal cluster password. The table will be replicated to the bare-metal cluster, which is the “remote” cluster.
    • -S 5000 is the SSH port override for the local Kubernetes Data Fabric cluster.

      Port 5000 is the default port for containerized Data Fabric clusters. If both clusters were containerized Data Fabric clusters, then another parameter would be required for the remote cluster: -s 5000.

  4. When prompted by the edftool, run the script specified by the prompt. The script applies the patch that enables the secrets to persist the trust information after a pod restart. Patch script files are named k8_patch_cluster_<cluster-name>.sh, where <cluster-name> is the name of the cluster to which the patch should be applied.

    For example:

    Please run the script './' on a client with 
    kubectl access to it and rights to modify secrets and configmaps in the dataplatform namespace.

    If you are establishing trust between a Kubernetes Data Fabric cluster and a bare-metal HPE Ezmeral Data Fabric cluster, then a patch is created for the Kubernetes Data Fabric cluster only.

    If you are establishing trust between two Kubernetes Data Fabric clusters, then two patches are created. You must do the following:

    1. Run one of the scripts in the admincli pod on the local Kubernetes cluster.
    2. Copy the other script to a node that has client access to the remote Kubernetes cluster.
    3. Run the script on the remote Kubernetes cluster.
  5. Check the screen output for errors when the operation completes.
  6. Log in to the remote cluster:
    maprlogin password -cluster <cluster-name>
  7. Execute the following command to view files and directories on the remote cluster, thereby ensuring correct trust configuration:

    hadoop fs -ls /mapr/<cluster-name>

You should now be able log in to the remote cluster from the local cluster, set up a volume on one cluster and a mirror volume on the other cluster, and start replication. See Creating Remote Mirrors (link opens in a new browser tab/window).

Changes that require reconfiguration

You must reconfigure cross-cluster trust by running the edftool in the following circumstances:

  • The IP address of a CLDB pod on the Kubernetes cluster changes.
  • Additional CLDB pods are created.

To identify the full set of IP addresses for the CLDB nodes on the Kubernetes cluster, see the cldbLocations values for the <cluster-name>-external-cm in the hpe-externalclusterinfo namespace. The dataplatform operator automatically generates the external-cm ConfigMap to indicate the current values for various cluster parameters.