| package opts // import "github.com/docker/docker/opts" |
| |
| // TODO Windows. Identify bug in GOLang 1.5.1+ and/or Windows Server 2016 TP5. |
| // @jhowardmsft, @swernli. |
| // |
| // On Windows, this mitigates a problem with the default options of running |
| // a docker client against a local docker daemon on TP5. |
| // |
| // What was found that if the default host is "localhost", even if the client |
| // (and daemon as this is local) is not physically on a network, and the DNS |
| // cache is flushed (ipconfig /flushdns), then the client will pause for |
| // exactly one second when connecting to the daemon for calls. For example |
| // using docker run windowsservercore cmd, the CLI will send a create followed |
| // by an attach. You see the delay between the attach finishing and the attach |
| // being seen by the daemon. |
| // |
| // Here's some daemon debug logs with additional debug spew put in. The |
| // AfterWriteJSON log is the very last thing the daemon does as part of the |
| // create call. The POST /attach is the second CLI call. Notice the second |
| // time gap. |
| // |
| // time="2015-11-06T13:38:37.259627400-08:00" level=debug msg="After createRootfs" |
| // time="2015-11-06T13:38:37.263626300-08:00" level=debug msg="After setHostConfig" |
| // time="2015-11-06T13:38:37.267631200-08:00" level=debug msg="before createContainerPl...." |
| // time="2015-11-06T13:38:37.271629500-08:00" level=debug msg=ToDiskLocking.... |
| // time="2015-11-06T13:38:37.275643200-08:00" level=debug msg="loggin event...." |
| // time="2015-11-06T13:38:37.277627600-08:00" level=debug msg="logged event...." |
| // time="2015-11-06T13:38:37.279631800-08:00" level=debug msg="In defer func" |
| // time="2015-11-06T13:38:37.282628100-08:00" level=debug msg="After daemon.create" |
| // time="2015-11-06T13:38:37.286651700-08:00" level=debug msg="return 2" |
| // time="2015-11-06T13:38:37.289629500-08:00" level=debug msg="Returned from daemon.ContainerCreate" |
| // time="2015-11-06T13:38:37.311629100-08:00" level=debug msg="After WriteJSON" |
| // ... 1 second gap here.... |
| // time="2015-11-06T13:38:38.317866200-08:00" level=debug msg="Calling POST /v1.22/containers/984758282b842f779e805664b2c95d563adc9a979c8a3973e68c807843ee4757/attach" |
| // time="2015-11-06T13:38:38.326882500-08:00" level=info msg="POST /v1.22/containers/984758282b842f779e805664b2c95d563adc9a979c8a3973e68c807843ee4757/attach?stderr=1&stdin=1&stdout=1&stream=1" |
| // |
| // We suspect this is either a bug introduced in GOLang 1.5.1, or that a change |
| // in GOLang 1.5.1 (from 1.4.3) is exposing a bug in Windows. In theory, |
| // the Windows networking stack is supposed to resolve "localhost" internally, |
| // without hitting DNS, or even reading the hosts file (which is why localhost |
| // is commented out in the hosts file on Windows). |
| // |
| // We have validated that working around this using the actual IPv4 localhost |
| // address does not cause the delay. |
| // |
| // This does not occur with the docker client built with 1.4.3 on the same |
| // Windows build, regardless of whether the daemon is built using 1.5.1 |
| // or 1.4.3. It does not occur on Linux. We also verified we see the same thing |
| // on a cross-compiled Windows binary (from Linux). |
| // |
| // Final note: This is a mitigation, not a 'real' fix. It is still susceptible |
| // to the delay if a user were to do 'docker run -H=tcp://localhost:2375...' |
| // explicitly. |
| |
| // DefaultHTTPHost Default HTTP Host used if only port is provided to -H flag e.g. dockerd -H tcp://:8080 |
| const DefaultHTTPHost = "127.0.0.1" |