String sentinelLs() {
        String servicelist = "";
        synchronized (this) {
            if (connection == null || ! connection.isValid()) {
                connection = supervisor.connect(SPEC);
            }
        }
        if (connection.isValid()) {
            Request req = new Request("sentinel.ls");
            connection.invokeSync(req, Duration.ofSeconds(5));
            if (req.errorCode() == ErrorCode.NONE &&
                req.checkReturnTypes("s"))
            {
                servicelist = req.returnValues().get(0).asString();
            } else {
                log.log(Level.WARNING, "Bad answer to RPC request: " + req.errorMessage());
            }
        } else {
            log.log(Level.WARNING, "Could not connect to sentinel at: " + SPEC);
        }
        return servicelist;
    }
Update the status (pid check etc)

@param services list of services
@throws Exception if something went wrong
metrics-proxy/src/main/java/ai/vespa/metricsproxy/service/ConfigSentinelClient.java