Problem
Sometimes the post-upgrade Events Service can fail with this error:
"org.elasticsearch.indices.IndexClosedException: closed".
The cause for this can be the indexes that are left closed, which will look like this:
close default_c55c0f7e-fb9e-429a-a6a7-6732dbeb6b21___biz_txn_v1___2018-03-16_19-05-00
close default_c55c0f7e-fb9e-429a-a6a7-6732dbeb6b21___dbmon-wait-time___2018-03-21_05-05-01
close xxxxx_7626f743-d1da-4714-a186-de55193c73a9___dbmon-query-stat___2018-03-21_05-05-01
Solution
To open these indexes, manually run the following command for changing the close status to open status from Events Service host:
curl -XPOST 'localhost:9200/<my_index>/_open'
For three(n) indexes, run the command three(n) times to resolve the issue.