Hi.

I am having an issue with published content not replicating across to web servers in a load balanced environment and wondered if anyone can assist.

We are on Umbraco version 7.10.2. I have 1 x CMS server and 2 x web servers sitting behind a load balancer.

I am using flexible load balancing as described in this documentation and have implemented the recommended master/slave server configuration from this document.

The problem I am seeing is that the CMS is correctly updating the umbracoCacheInstruction table when a publish is done but the web servers are not picking this up and refreshing their content so I have to manually delete umbraco.config and recycle the app pool in IIS to get it to show up.

The implementation of the master server registrar class is:

public class MasterServerRegistrar : IServerRegistrar2
{
    public IEnumerable<IServerAddress> Registrations => Enumerable.Empty<IServerAddress>();

    public ServerRole GetCurrentServerRole()
    {
        return ServerRole.Master;
    }

    public string GetCurrentServerUmbracoApplicationUrl()
    {
        var currentServerUrl = ConfigurationManager.AppSettings[GeneralKeys.CurrentServerUrl];

        return !string.IsNullOrWhiteSpace(currentServerUrl) ? currentServerUrl : null;
    }
}

and the slave server class:

public class FrontEndReadOnlyServerRegistrar : IServerRegistrar2
{
    public IEnumerable<IServerAddress> Registrations => Enumerable.Empty<IServerAddress>();

    public ServerRole GetCurrentServerRole()
    {
        return ServerRole.Slave;
    }

    public string GetCurrentServerUmbracoApplicationUrl()
    {
        var currentServerUrl = ConfigurationManager.AppSettings[GeneralKeys.CurrentServerUrl];

        return !string.IsNullOrWhiteSpace(currentServerUrl) ? currentServerUrl : null;
    }
}

Where the current server URL value is the full URL to the /umbraco path for each server. When testing this we've noticed that the umbracoServer table does not update with the registered server details, which I assume is how the CMS server knows about the web servers to be able to notify them to refresh their content.

One thing I wasn't sure about is the Registrations property return an empty list of IServerAddress objects. Should this be the actual address of each server (IP or URL)? What should we return for this?

I would be grateful for any assistance. Thanks.