This problem occurs when you have a datafeed that contains search or query domain specific language (DSL) that was discontinued. For example, if you created a datafeed query in 5.x using search syntax that was deprecated in 5.x and removed in 6.0, you must fix the datafeed before you upgrade to 6.0.
- If deprecation logging is enabled before the upgrade, deprecation messages are generated when the datafeeds attempt to retrieve data.
- After the upgrade, nodes fail to start and the error indicates that they failed to read the local state.
Before you upgrade, identify the problematic search or query DSL. In 5.6.5 and later, the Upgrade Assistant detects these scenarios. If you cannot fix the DSL before the upgrade, you must delete the datafeed then re-create it with valid DSL after the upgrade.
If you do not fix or delete the datafeed before the upgrade, in order to successfully start the failing nodes you must downgrade the nodes then fix the problem per above.
See also Upgrading the Elastic Stack.