During review, it was decided to remove `LimitNOFILE` from `docker.service` to rely on the systemd v240 implicit default of `1024:524288`. On supported platforms with systemd prior to v240, packagers will patch the service with an explicit `LimitNOFILE=1024:524288`.
- `1024` soft limit is an implicit default, avoiding unexpected breakage. Software that needs a higher limit should request to raise the soft limit for its process.
- `524288` hard limit is an implicit default since systemd v240 and is adequate for most processes (_half of the historical limit from `fs.nr_open` of `1048576`_), while 4096 is the implicit default from the kernel (often too low). Individual containers can be started with `--ulimit` when a larger hard limit is required.
- The hard limit may not exceed `fs.nr_open` (_which a value of `infinity` will resolve to_). On most systems with systemd v240 or newer, this will resolve to an excessive size of 2^30 (over 1 billion).
- When set to `infinity` (usually as the soft limit) software may experience significantly increased resource usage, resulting in a performance regression or runtime failures that are difficult to troubleshoot.
- OpenRC current config approach lacks support for different soft/hard limits being set as it adjusts additional limits and `ulimit` does not support mixed usage of `-H` + `-S`. A soft limit of `524288` is not ideal, but 2^19 is much less overhead than 2^30, whilst a hard limit of 4096 would be problematic for Docker.
Signed-off-by: Brennan Kinney <5098581+polarathene@users.noreply.github.com>
c8930105bc