This adds troubleshooting documentation for the case when the ShardsAvailabilityHealthIndicatorService
reports that there are not enough nodes in the data tier (user action "increase_node_capacity_for_allocations" or
"increase_tier_capacity_for_allocations_". This covers both the cloud and self-managed environments. For
cloud we first recommend increasing the number of availability zones (because you cannot directly add nodes), and
decreasing index.number_of_replicas if that is not possible. For self-managed, we first recommend adding nodes,
and decreasing index.number_of_replicas if that is not possible.
This adds a troubleshooting doc for indices that mix index filtering allocation
with data tiers routing.
Co-authored-by: Lee Hinman <dakrone@users.noreply.github.com>
