mapr-clusters.conf

You can define one or more clusters in the /opt/mapr/conf/mapr-clusters.conf file on a node or client. To define a cluster, you specify the CLDB nodes in the cluster. Defining a cluster creates the global namespace. Note that the mapr-clusters.conf file on each node or client must have the same cluster configuration and naming convention to create the global namespace.

The following section describes the configuration format of the mapr-clusters.conf file:

Format:

<cluster-name1> secure=false  <CLDB> <CLDB> ... <CLDB>
[ clustername2  <CLDB> <CLDB> <CLDB> ]
[ ... ]

The <CLDB> string format can contain multiple space-separated instances of the following:

host;ip:port - Host, IP, and port (uses DNS to resolve hostnames, or provided IP if DNS is down)
host:port - Hostname and IP (uses DNS to resolve host, specifies port)
ip:port - IP and port (avoids using DNS to resolve hosts, specifies port)
host - Hostname only (default, uses DNS to resolve host, uses default port)
ip - IP only (avoids using DNS to resolve hosts, uses default port)

You can edit mapr-clusters.conf manually to add more clusters. For example:

<cluster-name3>  <CLDB> <CLDB> <CLDB>

Security enabled, with and without Kerberos

With security enabled, without Kerberos, the format for the mapr-clusters.conf file is:

<clustername1> secure=true  <CLDB> <CLDB> ... <CLDB>
            [ <clustername2>  <CLDB> <CLDB> ... <CLDB> ]
            [ ... ]

With Kerberos enabled, the format for the mapr-clusters.conf file is:

<clustername1> secure=true kerberosEnable=true <CLDB> <CLDB> ... <CLDB>
            [ <clustername2>  <CLDB> <CLDB> ... <CLDB> ]
            [ ... ]

Note: Before renaming a cluster using the mapr-clusters.conf file, stop the warden on all the nodes.

Adding multihomed CLDB entries to mapr-clusters.conf with configure.sh

In this example, the cluster my.cluster.com has CLDB servers at nodeA, nodeB, nodeC, and nodeD. The CLDB servers nodeB and nodeD have two NICs each at eth0 and eth1. The entries in mapr-clusters.conf are separated by spaces for each server's entry. Within a server's entry, individual interfaces are separated by semicolons (;).

The command

configure.sh -N my.cluster.com -C nodeAeth0,nodeCeth0 -M nodeBeth0,nodeBeth1 -M nodeDeth0,nodeDeth1 -Z zknodeA

generates the following entry in mapr-clusters.conf:

my.cluster.com nodeAeth0 nodeBeth0;nodeBeth1 nodeCeth0 nodeDeth0;nodeDeth1

Cluster Limits

There is no limit for the number of clusters for HDFS and NFSv3. However, the maximum number of clusters for FUSE is 16.