10. Locators

10.1. Locators & locator list

A locator describes a TCP or UDP endpoint. It is an ip-address/port couple. In the configuration, a single locator is expressed like this:

ip-address:port

Example:

10.1.1.1:7400

Configuring a service or an application, we may need to specify several remote locators. This is called a locator list and is expressed like this:

ip-address:port,ip-address:port,...

Example:

10.1.1.1:7400,10.1.1.2:7400

When configured with a list of locators, the service or the application will try to connect them all.

10.2. Locators group

A locator group defines the locators of a fault-tolerant group of applications. An application configured with a locator group will try to connect to one and only one of those locators. During its lifetime, if the locator of the group to which it is connected dies, it will try to reconnect to another locator of the group so that it maintains a connection to one and only one of the locators of the group.

This is useful when pointing end-user applications to Vortex Link services as we may don’t want the application to be connected to all the services at the same time (unnecessary resources consumption), but we don’t want the service to which it is connected to to be a single point of failure.

In the configuration, a locator group is expressed in enclosing square brackets like this:

[ip-address:port,ip-address:port,...]

Example:

[10.1.1.1:7400,10.1.1.2:7400]

We may want to configure an application with a list of locators group. In the configuration, such a list is expressed like this:

[ip-address:port,ip-address:port,...],
[ip-address:port,ip-address:port,...],...

Example:

[10.1.1.1:7400,10.1.1.2:7400],[10.1.10.1:7405,10.1.10.2:7405]

We may also use a list of groups and single locators:

[10.1.1.1:7400,10.1.1.2:7400],10.1.10.1:7405,10.1.10.2:7405