Setting up a HyperServer Server Farm

Configuring and setting up a server farm is straightforward. For example, to build a farm with three servers you run three HyperServer instances: one acting as the master and two as slaves (ServerNodes). The master HyperServer handles incoming requests and relays them to its local Nodes and the ServerNodes in the cluster.

Configuring Master HyperServer

To convert a regular HyperServer into a master, add one or more ServerNodes to the master HyperServer CFG file.

Example: adding two ServerNodes to the master CFG file

[server-0]
enabled=1
url=http://192.168.1.32:8077
name=HP-ML150
token=gmvsek210828175924563

[server-1]
enabled=1
url=http://192.168.1.33:8077
name=DELL-7080
token=eftrgj210828180420097

Details:

[server-0]

Each ServerNode configuration begins with a section named server- plus a unique number (e.g., server-0).

enabled=1

Determines if the ServerNode is enabled. When enabled, traffic is redirected to this ServerNode; otherwise it is ignored.

url=http://192.168.1.33:8077

The HTTP address used to communicate with this ServerNode.

Examples:

• http://192.168.1.33:8077 — URL with physical IP address

• http://webserver-1:8077 — URL with network name of a local server

• http://mycompanydomain.com:8077 — Global URL with a domain name

name=DELL-7080

Optional name to help identify the ServerNode.

token=eftrgj210828180420097

A token is a unique identifier required to authorize the master HyperServer to remotely access the Server Control Panel of the ServerNode. The token is automatically generated in the ServerNode's CFG file the first time you run the ServerNode executable; copy it into the master CFG.

You must restart HyperServer after adding or modifying these parameters. (Future releases will allow changing server farm parameters from the Control Panel without restarting.)

Additional parameters related to Cluster Operation Modes

For default cluster mode (0 - PassThrough) you don't need to change these. See Cluster Operation Modes for more details.

cluster_mode=0
global_url=
avoid_direct_access=0
error_redirect_master=0
url_timeout_secs=300

(Links retained as in original:) https://unigui.com/doc/online_help/cluster-operation-modes.htm

Configuring Slave HyperServer Instances (ServerNodes)

Configuring a slave HyperServer is similar to a standard HyperServer instance. Configure required HyperServer parameters, test the instance locally, and deploy in Service mode for production (Standalone mode is for testing/debugging). For the master you may use any deployment method (ISAPI, Apache module, Windows/Linux Service, or Standalone EXE for testing).

When running a ServerNode, a token parameter is automatically created in its CFG file. Example snippet:

...
server_title=Slave-8078
server_build=1.90.0.1552
dont_create_backup=0
allow_remote_config=1
token=gmvsek210828175924563
http_max_pool=1000
max_connections=1000
...

Copy this token string into the ServerNode configuration section of the master CFG file:

[server-0]
enabled=1
url=http://192.168.1.16:8077
name=DELL-7080
token=gmvsek210828175924563

Testing Your Server Farm

Run the slave HyperServer instance first, then the master. Example test: one slave and the master on the same PC using different ports. Master runs on port 8077 and slave on port 8078.

Open the master Server Control Panel:

http://127.0.0.1:8077/server

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In the Server Control Panel open the ServerNodes page. You should see the configured ServerNodes. If communication is working, the ServerNode at http://127.0.0.1:8078 should be shown as Online.

You can access the Control Panel of the slave from the master's Control Panel by clicking the search icon in the Actions column.

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Clicking the icon opens a page titled with the ServerNode name configured:

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From this page you can monitor and manage the ServerNode (Nodes, sessions, configuration) from the master Control Panel.

Running Web Application Sessions in a Server Farm

Open the master HyperServer root URL and the web application will display in the browser.

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On the ServerNode you will see a Node created (e.g., LocalNode-0).

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On the ServerNodes page you will see Node and session info. ServerNodes receive IDs starting from 1024 (e.g., ServerNode with Node Id 1024 has one active Node and one running session).

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Master HyperServer can serve two roles:

• Load balancer for ServerNodes (redirects traffic), and optionally

• A regular HyperServer owning local Nodes and web sessions.

To make the master act only as a load balancer (no local Nodes), set in the master CFG:

max_nodes=0

This prevents the master from creating local Nodes; all incoming traffic will be redirected to ServerNodes.

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Persistent Node in a Server Cluster

To ensure certain tasks run in a specific Node, set persistent_node=1 in that ServerNode's CFG file.

In your application code ensure the task runs only on the Persistent Node:

procedure TUniServerModule.UniThreadTimer1Timer(Sender: TObject);
begin
  if PersistentNode then // run code if I'm a persistent Node
  begin
    // Your task here
  end;
end;

You can also configure the master HyperServer to be the Persistent Node by setting in the master CFG:

[hyper_server]
binary_name=dbdemo.exe
persistent_node=1

HyperServer Applications can own Persistent Nodes by setting persistent_node=1 in the application configuration:

[application-0]
enabled=1
alias=fishfacts
binary_name=fishfacts.exe
max_nodes=4
persistent_node=1

See Terminology for more information: https://unigui.com/doc/online_help/terminology.htm

Below section only applies to HyperServer versions prior to 1.95 and is provided here for reference only. For version 1.95 and later use the new "Persistent Node" feature.

Persistent Node Zero in a Server Cluster

To run tasks in Node Zero of a selected ServerNode, set persistent_node_zero=1 in that ServerNode's CFG file.

Example code to ensure only Node Zero of the selected ServerNode runs the code:

procedure TUniServerModule.UniThreadTimer1Timer(Sender: TObject);
var
  ExecIt : Boolean;
begin
  ExecIt := NodeZero and (ServerNodeId = 1024); // My owner is first ServerNode with ID = 1024
  if ExecIt or (not NodeMode) then // run code either if I'm Node #0 or I'm not a Node!
  begin
    // Your task here
  end;
end;

To run code in Node Zero of the master HyperServer replace 1024 with -1 and set persistent_node_zero=1.

procedure TUniServerModule.UniThreadTimer1Timer(Sender: TObject);
var
  ExecIt : Boolean;
begin
  ExecIt := NodeZero and (ServerNodeId = -1); // My owner is not a ServerNode (it is either a standard HyperServer or a master HyperServer instance)
  if ExecIt or (not NodeMode) then // run code either if I'm Node #0 or I'm not a Node!
  begin
    // Your task here
  end;
end;

Starting from uniGUI build 1566 a new property simplifies this: ClusterNodeZero. The prior handlers can be replaced with:

procedure TUniServerModule.UniThreadTimer1Timer(Sender: TObject);
begin
  if ClusterNodeZero then
  begin
    // Your task here
  end;
end;

ClusterNodeZero returns True if Node Id is zero and, when running in a server farm cluster, the ServerNode is also 1024. If the running application is not a Node and not part of a cluster, ClusterNodeZero returns True.

Implementation (from uniGUIServer.pas):

function TUniGUIServerModule.GetClusterNodeZero: Boolean;
begin
  if NodeMode then
  begin
    Result := NodeZero;
    if Result and ServerNode then
      Result := (ServerNodeId = SERVER_NODE_BASE_ID);
  end
  else
    Result := True;
end;

This ensures your thread task runs on only one Node regardless of total Nodes in the cluster.

While the above works, it's better to enable a Timer only when the Node is Node Zero. Because ServerNodeId may be populated after Node creation, enabling a timer in OnCreate may be unreliable. uniGUI provides the OnClusterNodeIdChange event which fires initially when the Server Module is created and whenever ServerNodeId changes.

Recommended pattern (build 1566 and later):

procedure TUniServerModule.UniGUIServerModuleClusterNodeIdChange(Sender: TObject);
begin
  UniThreadTimer1.Enabled := ClusterNodeZero;
end;

procedure TUniServerModule.UniThreadTimer1Timer(Sender: TObject);
begin
  // Your task here
end;

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References (kept as in original):

• https://unigui.com/doc/online_help/index.html?setting-up-a-hyperserver-serve.htm

• https://unigui.com/doc/online_help/hyperserver.htm

• https://unigui.com/doc/online_help/hyperserver-server-farm.htm

• https://unigui.com/doc/online_help/distributing-traffic-in-a-hype.htm

• https://unigui.com/doc/online_help/cluster-operation-modes.htm

• https://unigui.com/doc/online_help/hyperserver-applications.htm

• https://unigui.com/doc/online_help/terminology.htm