private Process startProcess() throws Exception {
        if (spec.command().isEmpty()) {
            throw new RuntimeException("No command specified");
        }
        ProcessBuilder bld = new ProcessBuilder(spec.command());
        return bld.start();
    }
The executor service for this worker.
trogdor/src/main/java/org/apache/kafka/trogdor/workload/ExternalCommandWorker.java