Error: No write index is defined for alias

When I click on start button in Maintenance submenu, I can see a new index with name fess.yyyyMMddHHmm gets created and update and search alias also being updated.
But when I start crawler next time, I get the below error-
java.lang.IllegalArgumentException: no write index is defined for alias [fess.update]. The write index may be explicitly disabled using is_write_index=false or the alias points to multiple indices without one being designated as a write index.

After checking all the indices, I noticed there were 2 indexes with name fess.yyyyMMddHHmm and fess.yyyyMMdd, both with search and update alias.
I Just wanted to know that does the crawler creates new index if it does not finds the index in format “fess.yyyyMMdd”?
Thanks in Advance!

Please remove fess.update and alias from the old fess index.

I did it, but every time I click Maintenance menu and then start crawler, issue came again. It would be really helpful if I got to know any code location in fess or fess-crawler where this index is being created during crawling so that i can try debugging it?

See AdminMaintenanceAction.

Okay. I’ll try this. Thank You!