>Learn how to use discovery selectors and how they intersect with Sidecar resources.</p></div><p class=post-author>Apr 30, 2021 <span>|</span> By Lin Sun - Solo.io, Christian Posta - Solo.io, Harvey Xia - Solo.io</p><div><p>As users move their services to run in the Istio service mesh, they are often surprised that the control plane watches and processes all of the Kubernetes resources, from all namespaces in the cluster, by default. This can be an issue for very large clusters with lots of namespaces and d