[mesos] branch master updated: Windows: Add comment about V2S2 Docker image Manifest.

[ji...@apache.org]

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jieyu pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mesos.git


The following commit(s) were added to refs/heads/master by this push:
     new e8dcb96  Windows: Add comment about V2S2 Docker image Manifest.
e8dcb96 is described below

commit e8dcb96bc64e6909dff4e98485944f739dfc49f7
Author: Liangyu Zhao <t-...@microsoft.com>
AuthorDate: Wed Aug 29 13:52:18 2018 -0700

    Windows: Add comment about V2S2 Docker image Manifest.
    
    Review: https://reviews.apache.org/r/68562/
---
 src/uri/fetchers/docker.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/uri/fetchers/docker.cpp b/src/uri/fetchers/docker.cpp
index 656f097..6b1277f 100644
--- a/src/uri/fetchers/docker.cpp
+++ b/src/uri/fetchers/docker.cpp
@@ -726,6 +726,11 @@ Future<Nothing> DockerFetcherPluginProcess::__fetch(
   // https://docs.docker.com/registry/spec/manifest-v2-2/
   //
   // If fetch is failed, program continues without schema 2 manifest.
+  //
+  // Schema 2 manifest may have foreign URLs to fetch blobs from servers
+  // other than Docker Hub. Some file layers, for example, Windows OS
+  // layers are only stored on Microsoft servers, so only with schema 2
+  // manifest, such layers can be successfully fetched.
   http::Headers s2ManifestHeaders = {
     {"Accept", "application/vnd.docker.distribution.manifest.v2+json"}
   };