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9b12e4fe JC |
1 | package opts |
2 | ||
3 | // TODO Windows. Identify bug in GOLang 1.5.1 and/or Windows Server 2016 TP4. | |
4 | // @jhowardmsft, @swernli. | |
5 | // | |
6 | // On Windows, this mitigates a problem with the default options of running | |
7 | // a docker client against a local docker daemon on TP4. | |
8 | // | |
9 | // What was found that if the default host is "localhost", even if the client | |
10 | // (and daemon as this is local) is not physically on a network, and the DNS | |
11 | // cache is flushed (ipconfig /flushdns), then the client will pause for | |
12 | // exactly one second when connecting to the daemon for calls. For example | |
13 | // using docker run windowsservercore cmd, the CLI will send a create followed | |
14 | // by an attach. You see the delay between the attach finishing and the attach | |
15 | // being seen by the daemon. | |
16 | // | |
17 | // Here's some daemon debug logs with additional debug spew put in. The | |
18 | // AfterWriteJSON log is the very last thing the daemon does as part of the | |
19 | // create call. The POST /attach is the second CLI call. Notice the second | |
20 | // time gap. | |
21 | // | |
22 | // time="2015-11-06T13:38:37.259627400-08:00" level=debug msg="After createRootfs" | |
23 | // time="2015-11-06T13:38:37.263626300-08:00" level=debug msg="After setHostConfig" | |
24 | // time="2015-11-06T13:38:37.267631200-08:00" level=debug msg="before createContainerPl...." | |
25 | // time="2015-11-06T13:38:37.271629500-08:00" level=debug msg=ToDiskLocking.... | |
26 | // time="2015-11-06T13:38:37.275643200-08:00" level=debug msg="loggin event...." | |
27 | // time="2015-11-06T13:38:37.277627600-08:00" level=debug msg="logged event...." | |
28 | // time="2015-11-06T13:38:37.279631800-08:00" level=debug msg="In defer func" | |
29 | // time="2015-11-06T13:38:37.282628100-08:00" level=debug msg="After daemon.create" | |
30 | // time="2015-11-06T13:38:37.286651700-08:00" level=debug msg="return 2" | |
31 | // time="2015-11-06T13:38:37.289629500-08:00" level=debug msg="Returned from daemon.ContainerCreate" | |
32 | // time="2015-11-06T13:38:37.311629100-08:00" level=debug msg="After WriteJSON" | |
33 | // ... 1 second gap here.... | |
34 | // time="2015-11-06T13:38:38.317866200-08:00" level=debug msg="Calling POST /v1.22/containers/984758282b842f779e805664b2c95d563adc9a979c8a3973e68c807843ee4757/attach" | |
35 | // 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" | |
36 | // | |
37 | // We suspect this is either a bug introduced in GOLang 1.5.1, or that a change | |
38 | // in GOLang 1.5.1 (from 1.4.3) is exposing a bug in Windows TP4. In theory, | |
39 | // the Windows networking stack is supposed to resolve "localhost" internally, | |
40 | // without hitting DNS, or even reading the hosts file (which is why localhost | |
41 | // is commented out in the hosts file on Windows). | |
42 | // | |
43 | // We have validated that working around this using the actual IPv4 localhost | |
44 | // address does not cause the delay. | |
45 | // | |
46 | // This does not occur with the docker client built with 1.4.3 on the same | |
47 | // Windows TP4 build, regardless of whether the daemon is built using 1.5.1 | |
48 | // or 1.4.3. It does not occur on Linux. We also verified we see the same thing | |
49 | // on a cross-compiled Windows binary (from Linux). | |
50 | // | |
51 | // Final note: This is a mitigation, not a 'real' fix. It is still susceptible | |
52 | // to the delay in TP4 if a user were to do 'docker run -H=tcp://localhost:2375...' | |
53 | // explicitly. | |
54 | ||
55 | // DefaultHTTPHost Default HTTP Host used if only port is provided to -H flag e.g. docker daemon -H tcp://:8080 | |
56 | const DefaultHTTPHost = "127.0.0.1" |