I am currently using ES 6.6.1 (3 nodes), all running on centos 7.
I am planning an upgrade to 6.8 and then 7.1
The upgrade assistent says this:
Number of open shards exceeds cluster soft limit
There are  open shards in this cluster, but the cluster is limited to  per data node, for  maximum.
The upgrade assistant links to this documentation which gives me 404 error upon opening it:
How should I fix those on centos?
Does this related to max open file in linux?