I found this message in one of the HTTP requests when loading the metrics page.
[illegal_argument_exception] Fielddata is disabled on text fields by default. Set fielddata=true on [host.name] in order to load fielddata in memory by uninverting the inverted index. Note that this can however use significant memory. Alternatively use a keyword field instead.
But host.name in my case is already a keyword field so I don't know what to do next. Does anyone know how to solve this problem?
I have the index mapping here if it helps.