nning in a <a href="/docs/reference/glossary/#primary-cluster">primary cluster</a>
or to an <a href="/docs/reference/glossary/#external-control-plane">external control plane</a>.</p>'>remote clusters</span>. However, one of them also serves as the Istio configuration cluster, in addition to running services. The external control plane reads Istio configurations from the <code>config cluster</code> and Istiod pushes configuration to the data plane running in both the config cluster and other remote clusters 