Teracloud® Streams name resolution requirements for resources

All resources must satisfy the product network configuration requirements or Teracloud® Streams fails to start on the resource.

Restriction: When you create a Teracloud® Streams instance or add resources to an instance, you cannot use localhost or any other host name or address that resolves to a loopback address (127.*.*.*).

Configured with the Teracloud® Streams application network properties

Each resource can have several interfaces. You can separate the application and management services network usage for Teracloud® Streams by using the domain.applicationNetwork and instance.applicationNetwork properties.

For more information, see Application network properties for Teracloud® Streams domains and instances.

Configured without the Teracloud® Streams application network properties

Each resource can have several interfaces, as long as the IP address of one interface matches an entry in the Linux™ name resolver. Teracloud® Streams uses the matching interface for all communication and ignores the other interfaces.

Ensure that all resources satisfy the following network configuration requirements:
  • The name of the configured resource must match an entry in the Linux™ name resolver, for example: DNS, LDAP, Network Information Service (NIS), or /etc/hosts. The Linux™ name resolver entry is configured in the /etc/nsswitch.conf file. For configuration information, see your Linux™ documentation.

  • The Linux™ name resolver result must match an ipv4 IP address of one of the local non-loopback interfaces.

  • The host name to IP address resolution must be global. That is, for each resource in a domain, the Linux™ name resolver on the other domain resources must return the same host name to IP address mapping for the resource. For example, the host name hostA must map to the same IP address from every resource in a domain.

Note: With these requirements met, the Teracloud® Streams runtime system exclusively uses the IP address from the instance configuration for all communication. The runtime system's TCP and LLM_RUM_TCP PE transports also use that same IP address.

Verifying local host name to IP address requirements

Teracloud® Streams provides tools that help you to verify this requirement on single and multiple resources:
  • Before installation, run the dependency checker script to verify requirements on the resources that you plan to install Teracloud® Streams on. If you are installing the product on a cluster of resources, run the dependency checker script on each resource in the cluster. For more information about this tool, see Teracloud® Streams dependency checker script.
  • After installation, you can use the streamtool checkhosts, checkdomainhosts, and checkinstancehosts commands to verify requirements on single or multiple resources. For more information about these commands, see Verifying requirements for Teracloud® Streams resources.