KB-XXXX Patch not available

Symptoms

The following error is seen when trying to add objects to a patch:

The following error is also seen in the application server logs:

16:29:55,598 INFO  [stdout] (ServerService Thread Pool -- 83) 2018-04-04 16:29:55,598 [ServerService Thread Pool -- 83] ERROR com.appiancorp.applicationpatch.PatchSchemaSpringContextListener - APNX-1-4506-001 - Failed to connect to data server. The ability to store and retrieve application patches will not be available until the connection is reestablished. Check the status of the data server.

Cause

The Appian data server is not running or is not available. 

Action

To correct this issue, perform the following:

1. Check the status of the data server by executing <APPIAN_HOME>/data-server/bin/status.sh (status.bat on Windows). 
   • Green: Reads and writes can be performed. The writer(hs/hs-gw) and the reader(rts-0/rts-gw-0) are both up and running.
   • Red: Reads and/or writes can no longer be performed. This means either the writer (hs/hs-gw) is down or the reader(rts-0/rts-gw-0) is down.
2. If the status is Red, start the data server by executing <APPIAN_HOME>/data-server/bin/start.sh (start.bat on Windows)

Affected Versions

This only affects Appian 18.1.