explain tag based pulls in README.md
@@ -119,6 +119,29 @@ make cluster-down
**Note:** Whenever you type `make cluster-down && make cluster-up`, you will
have a completely fresh cluster to play with.
+#### Sync specific components
+
+**Note:** The following is meant for allowing faster iteration on small changes to components that support it.
+Not every component is that simply exchangable without a full re-deploy. Always test with the final SHA based method in the end.
+
+In situations where you just want to work on a single component and rollout updates
+without re-deploying the whole environment, you can tell kubevirt to deploy using tags.
+
+```sh
+export KUBEVIRT_ONLY_USE_TAGS=true
+```
+
+After this any `make cluster-sync` will use the `DOCKER_TAG` for pulling images instead of SHAs.
+This means you can simply rebuild the component that changed and then kill the respective pods to
+cause a fresh pull:
+
+```sh
+PUSH_TARGETS='virt-api' ./hack/bazel-push-images.sh
+kubectl delete po -n kubevirt -l kubevirt.io=virt-api
+```
+
+Once the respective component is back, it should be using your new build.
+
### Accessing the containerized nodes via ssh
Based on the used cluster, node names might be different.
