@Override
                public void onError(Throwable throwable) {
                    status.done();
                    if (log.isDebugEnabled()) {
                        log.debug("Send alarm message failed: {}", throwable.getMessage());
                    }
                }
Use SkyWalking alarm grpc API call a remote methods.
oap-server/server-alarm-plugin/src/main/java/org/apache/skywalking/oap/server/core/alarm/provider/grpc/GRPCCallback.java