What could cause a server to be removed from the farm other than running PSConfig and removing it?

Question

Hi,
We had a strange issue today.  One of our two production WFE servers in our SP2010 farm had become disconnected from the farm. I noticed it because I had created a new site collection within an existing web site last week but it was only available on
one WFE. I didn't think for one second that the server had already been removed from the farm but I had decided I would remove it and re-add it to see if that would fix the issue.  When I ran PSConfig to remove it I found the following:
I checked the log:
Entering function WelcomeForm.TryToLoadTheFarm
Found a task by the name of initialize in the task collection
Entering function Farm.Farm
Leaving function Farm.Farm
Entering function Farm.TryIsJoinedToFarm
  Entering function get CommandCollection.this[string key]
    Entering function CommandCollectionBase.Get
      Found value in collection for key initialize
    Leaving function CommandCollectionBase.Get
    Found command initialize in collection
  Leaving function get CommandCollection.this[string key]
  Entering function Command.this[string key]
    Entering function CommandCollectionBase.Get
      Found value in collection for key B2B_UPGRADE
    Leaving function CommandCollectionBase.Get
    Found parameter B2B_UPGRADE in collection
  Leaving function Command.this[string key]
  Clearing cached Farm objects to reload
  Entering function Farm.Clear
    Entering function CentralAdminServiceInstance.Reset
    Leaving function CentralAdminServiceInstance.Reset
  Leaving function Farm.Clear
  My cached Farm object is null, so will load it
  Calling SPFarm.Local and SPServer.Local to get the local farm objects
  SPFarm.Local returned a local farm
  SPFarm.Local retuned a farm, but SPServer.Local returned null.  Failed to connect to the farm, except in B2B Upgrade.
  Entering function Farm.Clear
    Entering function CentralAdminServiceInstance.Reset
    Leaving function CentralAdminServiceInstance.Reset
  Leaving function Farm.Clear
Leaving function Farm.TryIsJoinedToFarm
Failed to successfully try to see if this server is joined to the server farm.  
The operation will continue so that you can force a disconnect from a server farm that cannot be contacted
Resource id to be retrieved is FarmIsJoinedFailureWhileUsingUICanOnlyDisconnect for language English (United States)
Resource retrieved id FarmIsJoinedFailureWhileUsingUICanOnlyDisconnect is Failed to detect if this server is joined to a server farm.
Possible reasons for this failure could be that you no longer have the appropriate permissions to the server farm, the database server hosting the server farm is unresponsive,
the configuration database is inaccessible or this server has been removed from the server farm.
To diagnose this problem further, review the extended error information located at {0}.
If this problem persists, choose to disconnect from the server farm. After disconnecting, run the wizard again to create or connect to an existing server farm.
Anyone know what this line means?
SPFarm.Local retuned a farm, but SPServer.Local returned null.  Failed to connect to the farm, except in B2B Upgrade.
Permissions were unchanged from before and I was running PSConfig elevated with the SharePoint admin account. So with this information along with the fact that the new site collection was not available on this server I concluded that it had been removed
somehow.
Has anyone seen this happen before?  As it is a production server I'm going to have to explain this to the customer.
Thanks! 

Answer 1

Hi Fridge,
In Sharepoint central admin,Manage servers in Farm,Does this show this WFE Server still?
Check if any ports(32843,32844) has been closed on the WFE server which got disconnected as these ports are used to communicate between WFE servers
Check if this is helpful
http://blogs.msdn.com/b/uksharepoint/archive/2013/01/21/sharepoint-2013-ports-proxies-and-protocols-an-overview-of-farm-communications.aspx