How to hot update parameters in the NebulaGraph database?

Question

I want to enable authentication on my test host deployed with Nebula Graph, but I cannot find a way to do it without shutting the service down. I really don't want to do this.

Answer 1

• NebulaGraph leveraged the gflags as its configuration utils. And we exposed an HTTP interface per each process, which is configured with ws_http_port to listen on.
• Note, not all configurations could be changed on the fly in this "hot update" way.

Read in-memory Configurations

$ curl graphd:19669/flags | head

check_plan_killed_frequency=8
cluster_id_path="cluster.id"
expired_time_factor=5
failed_login_attempts=0
heartbeat_interval_secs=10
meta_client_retry_interval_secs=1
meta_client_retry_times=3
meta_client_timeout_ms=60000
password_lock_time_in_secs=0
storage_client_retry_interval_ms=1000

$ curl graphd:19669/flags?flags=ws_http_port
ws_http_port=19669

Update in-memory configuration

$ curl graphd:19669/flags?flags=system_memory_high_watermark_ratio
system_memory_high_watermark_ratio=0.8

$ curl -X PUT graphd:19669/flags \
  -H "Content-Type: application/json" \
  -d '{"system_memory_high_watermark_ratio":"0.9"}'

$ curl graphd:19669/flags?flags=system_memory_high_watermark_ratio
system_memory_high_watermark_ratio=0.9

Ref:

We could check all webservice endpoints here

Status WebService::start(uint16_t httpPort) {
  if (started_) {
    LOG(INFO) << "Web service has been started.";
    return Status::OK();
  }

  router().get("/flags").handler([](web::PathParams&& params) {
    DCHECK(params.empty());
    return new GetFlagsHandler();
  });
  router().put("/flags").handler([](web::PathParams&& params) {
    DCHECK(params.empty());
    return new SetFlagsHandler();
  });
  router().get("/stats").handler([](web::PathParams&& params) {
    DCHECK(params.empty());
    return new GetStatsHandler();
  });
  router().get("/status").handler([](web::PathParams&& params) {
    DCHECK(params.empty());
    return new StatusHandler();
  });
  router().get("/").handler([](web::PathParams&& params) {
    DCHECK(params.empty());
    return new StatusHandler();
  });