Specifying Environment Variables

Explains how to set environment variables on a client node.

About this task

Some of the environment variables defined on the servers for the HPE Ezmeral Data Fabric cluster must be defined with the same values on the client. You can add environment variables directly to the startup script, or create a local env.sh file in /usr/local/mapr-loopbacknfs/conf. You cannot simply copy the env.sh file from a server node in the cluster because the MAPR_HOME setting would be different.

The loopbacknfs service can run either on file server nodes or external edge nodes.

loopbacknfs running on file server node:

  • If you want loopbacknfs to avoid using the internal IP address that has been set by using the MAPR_SUBNETS (usually set through env_override.sh/env.sh which is applied across all processes running in a machine), mark NFS_LOOPBACK_HONOUR_SUBNETS as false.

loopbacknfs running on edge node:

  • When MAPR_SUBNETS environment variable is set on edge nodes, the intention is to divert the traffic through the intended IP address, instead of all. Whether the given subnet is to be used or not is determined by the value of the NFS_LOOPBACK_HONOUR_SUBNETS environment variable.

Re-registration of loopbacknfs service

  • The process of re-registration of loopbacknfs with CLDB when using or honoring subnets is done as follows:
    • If there is change in device address, but device address is out of the subnet, loopbacknfs does not re-register.

    • If there is change in device address and if there are no subnets at all, loopbacknfs reregisters.

Complete the following steps to specify environment variables:

Procedure

  1. On a server node in the HPE Ezmeral Data Fabric cluster, locate the env.sh and env_override.sh files in the /opt/mapr/conf directory. If the env_override.sh file is not present, use the env.sh file. For more information about these files, see About env_override.sh.
  2. Retrieve the values for MAPR_SUBNETS and JAVA_HOME from the server files and clone them to /usr/local/mapr-loopbacknfs/conf/env.sh on the client node.
  3. (Optional) Set the NFS_LOOPBACK_HONOUR_SUBNETS environment variable to avoid re-registration whenever there is a change in any network interface. The value can be:
    • true to consider the MAPR_SUBNETS while registering with CLDB. If set to true, re-registration does not happen when there is a change in any network interface with IP that is not in the given MAPR_SUBNETS. If there is a change in the device address, but the device address is outside of subnet, the re-registration does not happen. Re-registration happens if there are no subnets at all and the device address has changed.
    • false to ignore the MAPR_SUBNETS. If set to false, re-registration happens when there is a change in any network interface.
    For example: 
    # export NFS_LOOPBACK_HONOUR_SUBNETS=true
# export MAPR_SUBNETS=10.10.104.0/24
                        
# env | grep SUBNET
NFS_LOOPBACK_HONOUR_SUBNETS=true
MAPR_SUBNETS=10.10.105.0/24,10.10.104.0/24
  4. Change the JAVA_HOME setting to point to the location where Java is installed on the client.
  5. Add the following lines to the client node env.sh file: 
    export MAPR_HOME=/usr/local/mapr-loopbacknfs 
export MAPR_TICKETFILE_LOCATION=<MAPR user ticket path>
    NOTE
    To allow impersonation, set the value for MAPR_TICKETFILE_LOCATION to the path to the mapr user ticket.
  6. Save and close the env.sh file.
  7. Restart the loopbacknfs service for the changes to take effect.