Considering that the OP stated that this'll be in a High Availablity Group, it might be worth noting there is a known issue with it on Linux. Not sure if it'll affect them, however:
Certain algorithms (cipher suites) for Transport Layer Security (TLS) do not work properly with SQL Server on Linux. This results in connection failures when attempting to connect to SQL Server, as well as problems establishing connections between replicas in high availability groups.
Details of a "resolution" can be found on the same page that Anthony linked to.
Excuse my typos and sometimes awful grammar. My fingers work faster than my brain does :-P
Please always remember to encapsulate your code in IFCode Markup. For example [code=sql] [/code]
to read Jeffs Guide on how to post SQL questions, and get swift and helpful answers from the community