Commits on Oct 11, 2022

1. docker_logger: reorder imports to save memory …

   Nomad runs one logmon process and also one docker_logger process for each
   running allocation. A naive look at memory usage shows 10-30 MB of RSS, but a
   closer look shows that most of this memory (ex. all but ~2MB for logmon) is
   shared (`Shared_Clean` in Linux pmap).
   
   But a heap dump of docker_logger shows that it currently has an extra ~2500 KiB
   of heap (anonymously-mapped unshared memory) used for init blocks coming from
   the agent code (ex. mostly regexes from go-version, structs, and the Consul
   SDK). The packages for running logmon, docker_logger, and executor have an init
   block that parses `os.Args` to drop into their own logic, which prevents them
   from loading all the rest of the agent code and saves on memory, so this was
   unexpected.
   
   It looks like we accidentally reordered the imports in main to undo some of the
   work originally done in 404d2d4. This changeset
   restores the ordering. A follow-up heap dump shows this saves ~2MB of unshared
   RSS per docker_logger process.

   

   tgross committed Oct 11, 2022
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