Documentation - Redise Pack

A guide to Redise Pack installation, operation and administration

open all | close all

How to set the cluster name (FQDN)

The Fully Qualified Domain Name (FQDN) is the unique cluster identifier that enables clients to connect to the different components that are part of the Redise Pack (RP). The FQDN is a crucial component of the high-availability mechanism in RP because it is used by the internal DNS to enable the automatic and transparent failover of nodes, databases shards, and endpoints, by automatically updating their IP addresses. For additional details on these components and their roles, refer to System architecture.

Note: Setting the cluster’s FQDN is a one-time operation. Once the FQDN is set it cannot be updated.

The FQDN must always comply with the IETF’s RFC 952 standard and section 2.1 of the RFC 1123 standard.

You have three options for naming the cluster FQDN:

1. DNS

Use this option if you already have your own domain, would like to make the cluster part of your domain, and are able to update the DNS.

Choosing this option requires you to ensure that the cluster and at least one node (preferably all nodes) in the cluster are correctly configured in the DNS with the appropriate NS entries.

For example:

  • Your domain is: mydomain.com
  • You would like to name the Redis Enterprise Pack cluster: redislabscluster
  • You have two nodes in the cluster:
    • node1 with IP 1.1.1.1
    • node2 with IP 2.2.2.2

Then

In the FQDN field, enter the value: redislabscluster.mydomain.com, and add the following records in the DNS for mydomain.com:

redislabscluster.mydomain.com NS node1.redislabscluster.mydomain.com
node2.redislabscluster.mydomain.com
node1.redislabscluster.mydomain.com A 1.1.1.1
node2.redislabscluster.mydomain.com A 2.2.2.2

2. Zero-configuration using mDNS (Development option only)

Note: mDNS is not supported for use with production environments and should only be used in dev/test environments.

mDNS (Multicast DNS) is a standard protocol that provides DNS-like name resolution and service discovery capabilities to machines on local networks with minimal to no configuration. Because not all clients support mDNS, ensure first that the clients that will be connecting to the cluster actually have mDNS support, and that the network infrastructure permits mDNS / multicasting between them and the cluster nodes.

Configuring the cluster to support mDNS requires you to assign the cluster a .local name.

For example:

  • You would like to name the Redise Pack cluster: redislabscluster

Then

In the FQDN field, enter the value redislabscluster.local

3. No DNS

Use this option only if you do not have a DNS or you have no way to configure DNS.

Note that when using this option, failover is not transparent to the client, meaning that when a failure occurs and the cluster promotes a slave to be a master, the IP used for connecting to the new master will change. When using the DNS or mDNS option, failover can be done transparently and the DNS is updated automatically to point to the IP of the new master.

When you use this option, the FQDN does not need to have any special format because clients will use IP addresses instead of hostnames to access the databases so you are free to choose whatever name you wish.