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Route Naming

You will use the following instructions in the
Pipelines
and
Deploy Distributed System
labs to create a unique routes
for your applications.
This will help avoid route naming collisions with others on the
same foundation.

Routes

Tanzu Application Service Routes
are domain name resolvable addresses used in the
Tanzu Application Service architecture to route network traffic to
mapped applications.

A route consists of two parts:

  1. domain:
    A
    domain
    with DNS configuration to resolve to a load balancer
    forwarding requests to Tanzu Application Service routers.
  2. hostname:
    A subdomain of the domain associated with the load
    balancer forwarding requests to Tanzu Application Service routers.

The route specification is as follows:

<hostname>.<domain>

For example, if the route is pal-tracker.apps.tas.example.com,
the hostname is pal-tracker and the domain is
apps.tas.example.com.

Route uniqueness

When you push an application to Tanzu Application Service,
if you do not explicitly tell the cf push command to exclude the route
via the --no-route options,
or map an automatically generated route via the --random-route option,
it will attempt to map a route with the application name as the
hostname component of the route.

This may result in collisions with other applications of the same name
running on the same foundation.

Remember that the route is a fully qualified domain name resolvable
address that must be unique.

You will need to map a route with a unique hostname component.

The following specify how to construct a unique route.

Determine the domain for your route

Run the cf domains command to find the value for the domain argument.

An example output will look like this,
but your domain will be specific to your foundation and/or organization:

Getting domains in org bill as bill...
name status type details
apps.tas.example.com shared
mesh.apps.tas.example.com shared
apps.internal shared internal

In this example,
the apps.tas.example.com is the desired domain.

Do not use the mesh or internal domains.

Determine a unique host

Try appending a unique string to the end of your application name.
You can use your initials,
the hex code of your favorite color,
or even a generated UUID
(try running uuid from the command line).

Here are some examples:

  1. pal-tracker-ben-smith

  2. pal-tracker-47BFE3

  3. pal-tracker-12E51872-1682-4E1B-97D2-55D0EB44432B

Verify your route is unique

Once you have decided on a route based from an existing domain,
use cf check-route to verify that it is unique for your foundation’s
domain.

Here is an example of checking that the route
pal-tracker-besmith is unique in the apps.tas.example.com
domain.

cf check-route pal-tracker-besmith apps.tas.example.com

The output will verify whether the route is already claimed on the
foundation.

If the route is available for use:

Checking for route...
OK
Route pal-tracker-besmith.apps.tas.example.com does not exist

If the route is not available for use:

Checking for route...
OK
Route pal-tracker-besmith.apps.tas.example.com does exist

Reserving routes

If the route is available for use,
you can also reserve a route in a space by running the
cf create-route command.
The route will exist,
but not be mapped to any application.

cf create-route <space> <domain> --hostname <hostname>

Example:

cf create-route sandbox apps.tas.example.com --hostname pal-tracker-besmith

Output:

Creating route pal-tracker-besmith.apps.tas.example.com for org <redacted> / space sandbox as <redacted>...
Route pal-tracker-besmith.apps.tas.example.com has been created.
OK

If you attempt to reserve a route already reserved or mapped to an
existing application on the Tanzu Application Service foundation,
you will get this message:

Creating route pal-tracker-besmith.apps.tas.example.com for org <redacted> / space sandbox as <redacted>...
Route pal-tracker-besmith.apps.tas.example.com already exists.
OK

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