This fix tries to address issues raised in #20936 and #22443
where `docker pull` or `docker push` fails because of the
concurrent connection failing.
Currently, the number of maximum concurrent connections is
controlled by `maxDownloadConcurrency` and `maxUploadConcurrency`
which are hardcoded to 3 and 5 respectively. Therefore, in
situations where network connections don't support multiple
downloads/uploads, failures may encounter for `docker push`
or `docker pull`.
This fix tries changes `maxDownloadConcurrency` and
`maxUploadConcurrency` to adjustable by passing
`--max-concurrent-uploads` and `--max-concurrent-downloads` to
`docker daemon` command.
The documentation related to docker daemon has been updated.
Additional test case have been added to cover the changes in this fix.
This fix fixes#20936. This fix fixes#22443.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>