Linking sites on local systems using YAML

Using a link resource YAML file allows you to create links between sites. The link direction is not significant, and is typically determined by ease of connectivity. For example, if east is behind a firewall, linking from east to west is the easiest option.

Once sites are linked, services can be exposed and consumed across the application network without the need to open ports or manage inter-site connectivity.

The procedures below describe linking an existing site. Typically, it is easier to configure a site, links and services in a set of files and then create a configured site by placing all the YAML files in a directory, for example local and then using the following command to

Linking sites using a `link` resource

An alternative approach to linking sites using tokens is to create a link resource YAML file using the CLI, and to apply that resource to another site.

Prerequisites

A local system site
A Kubernetes site with enable-link-access enabled.

To link sites, you create a link resource YAML file on one site and apply that resource on the other site to create the link.

Procedure

On the site where you want to create a link , make sure link access is enabled:
```
skupper site update --enable-link-access
```
Create a link resource YAML file:
```
skupper link generate > <filename>
```
where <filename> is the name of a YAML file that is saved on your local filesystem.

Apply the link resource YAML file on a local system site to create a link:

mv <filename> ~/.local/share/skupper/namespaces/default/input/resources/
skupper system setup --force

where <filename> is the name of a YAML file that is saved on your local filesystem.

The path shown is specific to the default namespace. If you are configuring a different namespace, use that name instead.

The site is recreated and you see some of the internal resources that are not affected, for example:

Sources will be consumed from namespace "default"
2025/03/09 22:43:14 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-local-ca/tls.crt
2025/03/09 22:43:14 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-local-ca/tls.key
2025/03/09 22:43:14 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-local-ca/ca.crt
2025/03/09 22:43:14 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-site-ca/tls.crt
2025/03/09 22:43:14 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-site-ca/tls.key
2025/03/09 22:43:14 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-site-ca/ca.crt
2025/03/09 22:43:15 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-service-ca/tls.crt
2025/03/09 22:43:15 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-service-ca/tls.key
2025/03/09 22:43:15 WARN certificate will not be overwritten path=~/.local/share/skupper/namespaces/default/runtime/issuers/skupper-service-ca/ca.crt

Check the status of the link:
```
skupper link status
```
The output shows the link name:
```
$ skupper link status
NAME            STATUS
link-west       Ok
```
You can now expose services on the application network.

Linking sites on local systems using YAML

Linking sites using a link resource

Linking sites using a `link` resource