private static ShellExecResponse masterExec(final AsyncAdmin admin, final ShellExecRequest req) {
    // TODO: Admin API provides no means of sending exec to a backup master.
    return admin.<ShellExecService.Stub, ShellExecResponse> coprocessorService(
      ShellExecService::newStub,
      (stub, controller, callback) -> stub.shellExec(controller, req, callback)).join();
  }
Overrides commands to make use of coprocessor where possible. Only supports actions taken against
Master and Region Server hosts.
hbase-it/src/test/java/org/apache/hadoop/hbase/CoprocClusterManager.java