Basic Configuration

This section will cover a basic LiteSpeed Web ADC configuration using a LiteSpeed Web ADC server as well as 2 (or more) web servers running on separate machines from one another. For simplicity, we will be assuming 2 web servers with LiteSpeed Web ADC configured to handle HTTP traffic to a single site being hosted on both of these servers. If you would like to use LiteSpeed Web ADC for a different application, simply replace “clusterHTTP” in this guide with the appropriate cluster type (AJP,LSAPI,FCGI,MIX).

Configuration

To start, log in to your LiteSpeed Web ADC WebAdmin Console using the IP address of your LiteSpeed Web ADC server and the port number you assigned the LiteSpeed Web ADC WebAdmin Console during installation. We will be using “192.168.0.10” as our LiteSpeed Web ADC IP address and the default port “7090” for the LiteSpeed Web ADC WebAdmin Console.

http://192.168.0.10:7090

Once you have logged in, navigate to Configuration » Clusters and click “Add” at the top right of “Clusters List”.

Here we will be defining a new cluster as follows:

Click “Save” at the top right.

Now that we have our cluster defined, let's define a worker group for this cluster where we will be adding in our two web servers as nodes. We will be using “192.168.0.15:81” and “192.168.0.16:82” as our two web servers and ports. Replace these values the IP addresses and ports of your own web servers.

While still viewing the “clusterXYZ” cluster, click the tab for “Worker Group”, and then click “Add”. Define the worker group as follows:

Where “Node Address List” is a comma separated list in the form:

(Node_Tag)LSLB_IP_Address->Destination_IP_Address:Destination_Port

Click “Save” at the top right.

With our cluster fully configured and our web servers added as nodes to a worker group in said cluster, let's create our LiteSpeed Web ADC virtual host.

Navigate to Configuration » Virtual Hosts.

Since we will now be creating our own virtual host, we no longer need the “Example” host. Delete “Example” by clicking “Delete” in the “Action” section for this host and then clicking “Yes” to the confirmation message on the resulting page.

Back in Configuration » Virtual Hosts, click “Add” at the top right of “Virtual Host List”.

Choose a “Virtual Host Name”, select “clusterXYZ” for “Default Cluster” to specify that this virtual host will be handling HTTP traffic, enter a location for this virtual host's configuration file. For example:

Click “Save” at the top right.

Now that we have a LiteSpeed Web ADC virtual host configured, the final step is to set a listener for the LiteSpeed Web ADC virtual host. The “Default” listener should already be configured for the port you specified during installation, so lets check that by clicking “View/Edit”.

Here you should see that under “Virtual Host Mappings”, the “Example” virtual host is still mapped to this listener.

Because we deleted this virtual host earlier, we should also delete the mapping by again clicking “Delete” under the “Action” section and then clicking “Yes” to the confirmation message on the resulting page.

Since we created our own LiteSpeed Web ADC Virtual host earlier, we can now add it to “Virtual Host Mappings” by clicking “Add” and selecting it as well as entering your sites domains in the comma seperated “Domains” list.

Click “Save” at the top right and apply changes with a “Graceful Restart”.

Before:

After:

Your LiteSpeed Web ADC should now be working and ready to handle all incoming HTTP traffic to your specified port/site!

Testing

Below are 2 methods of testing that LiteSpeed Web ADC is configured correctly and working. We will again be assuming 2 web servers with LiteSpeed Web ADC handling HTTP requests to a web site hosted on both of these servers, but these tests can me modified to test other applications of LiteSpeed Web ADC as well.

For both tests: Run your servers in an isolated environment (no outside traffic) and make a small but noticeable change to the home page of one of your web servers.

Test 1: Disabling One Of Two Web Servers

Aside from balancing your servers traffic as to not cause a crash, one of the main features of a load balancer is to appropriately redirect traffic to an available server if one should experience a failure. With two servers running this is an easy thing to check.

To begin, visit your site through a browser and make note of which server you are being directed to with respect to the small change you made earlier, we will call this server “Server 1”. If your “Mode” is set to “Stateful” under “Load Balancer Definition” in Configuration » Clusters » < your_HTTP_cluster >, then this server (Server 1) will be the preferred server for LiteSpeed Web ADC to direct your IP address to. This is also known as “Session Affinity”.

Now that we know which server you are being directed to, either stop Server 1 or change Server 1's port to a number LiteSpeed Web ADC is not aware of and restart it to have this change take affect. If everything is working correctly, the next time you attempt to visit your site, LiteSpeed Web ADC will instead redirect your request to Server 2, which you can again confirm with respect to the small change made earlier.

Test 2: Round Robin

From the LiteSpeed Web ADC WebAdmin Console, navigate to Configuration » Clusters. Select the cluster you are using to direct HTTP traffic to your site, in our cause this is “clusterXYZ”. Click “Edit” at the top right of the “Load Balancer Definition” section.

Change “Mode” to “Stateless” and “Strategy” to “Round Robin”.

Click “Save” at the top right.

By choosing “Stateless”, you have told LiteSpeed Web ADC to ignore “Session Affinity” for this cluster. Meaning that you are equally likely to be sent to Server 1 or Server 2 on an HTTP request for your site. By choosing “Round Robin”, you have told LiteSpeed Web ADC to rotate back and forth between Server 1 and Server 2 when receiving HTTP requests for your site.

Perform a “Graceful Restart” of LSLB.

Because of possible browser caching, this next part is best done through the terminal.

Use the following terminal command to request your web page. For this example our domain name is yoursitename.com, replace this with your own domain name or the IP address and port of your LSLB server.

curl -i yoursitename.com

or

curl -i 192.168.0.10:80

Run this command a few times to check if LiteSpeed Web ADC is correctly swapping back and forth between Server 1 and Server 2 by checking for the small change made earlier. The output should be similar to Server 1 → Server 2 → Server 1 → Server 2… and so on.

Note: It is recommended to set “Mode” and “Strategy” back to your previous settings when done performing this test. The default settings are “Stateful” and “Least Load” respectively.

 
litespeed_wiki/lslb/basic_config.txt · Last modified: 2017/10/20 16:24 by Johathan Kagan