Here's an example [1]

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2017-08-09 03:31:00.821 |     protobuf===3.3.0 from http://mirror.ord.rax.openstack.org/pypi/packages/d0/60/35ed2bb392a7845ba316a66ea1f6cc2f3acaf95e7905deca17d46430452b/protobuf-3.3.0-cp27-cp27mu-manylinux1_x86_64.whl#md5=fa09b90d290bb63aa075e4a5a7965001 (from -c /opt/stack/new/requirements/upper-constraints.txt (line 330)):
2017-08-09 03:31:00.821 |         Expected md5 fa09b90d290bb63aa075e4a5a7965001
2017-08-09 03:31:00.821 |              Got        c7a6afd624e1c302ad0cd793447be780
---

The download happened before that

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2017-08-09 03:30:58.365 | Collecting protobuf===3.3.0 (from -c /opt/stack/new/requirements/upper-constraints.txt (line 330))
2017-08-09 03:30:58.524 |   Downloading http://mirror.ord.rax.openstack.org/pypi/packages/d0/60/35ed2bb392a7845ba316a66ea1f6cc2f3acaf95e7905deca17d46430452b/protobuf-3.3.0-cp27-cp27mu-manylinux1_x86_64.whl (5.7MB)
---

going to the mirror logs, we have the following (removed everything after the pip UA string, which is very long).  this test is 2001:4801:7828:104:be76:4eff:fe10:22e3

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2001:4801:7828:104:be76:4eff:fe10:284c - - [09/Aug/2017:03:30:58 +0000] "GET /pypi/simple/protobuf/ HTTP/1.1" 200 5872 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:22e3 - - [09/Aug/2017:03:30:58 +0000] "GET /pypi/simple/protobuf/ HTTP/1.1" 200 5872 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:284c - - [09/Aug/2017:03:30:58 +0000] "GET /wheel/ubuntu-16.04-x86_64/protobuf/ HTTP/1.1" 200 763 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:22e3 - - [09/Aug/2017:03:30:58 +0000] "GET /wheel/ubuntu-16.04-x86_64/protobuf/ HTTP/1.1" 200 763 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:284c - - [09/Aug/2017:03:30:58 +0000] "GET /pypi/packages/d0/60/35ed2bb392a7845ba316a66ea1f6cc2f3acaf95e7905deca17d46430452b/protobuf-3.3.0-cp27-cp27mu-manylinux1_x86_64.whl HTTP/1.1" 200 5724653 "-" "pip/9.0.1 ... 
---

Werid ... two addresses at the same time, only one seems to actually download.  here's the entire logs for that IP available

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root@mirror:/var/log/apache2# cat mirror.ord.rax.openstack.org_access.log.1 | grep 'fe10:22e3' | grep protobuf
2001:4801:7828:104:be76:4eff:fe10:22e3 - - [09/Aug/2017:03:30:58 +0000] "GET /pypi/simple/protobuf/ HTTP/1.1" 200 5872 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:22e3 - - [09/Aug/2017:03:30:58 +0000] "GET /wheel/ubuntu-16.04-x86_64/protobuf/ HTTP/1.1" 200 763 "-" "pip/9.0.1 ... 
2001:4801:7828:101:be76:4eff:fe10:22e3 - - [09/Aug/2017:04:11:34 +0000] "GET /pypi/simple/protobuf/ HTTP/1.1" 200 5872 "-" "pip/9.0.1 ... 
2001:4801:7828:101:be76:4eff:fe10:22e3 - - [09/Aug/2017:04:11:35 +0000] "GET /wheel/ubuntu-16.04-x86_64/protobuf/ HTTP/1.1" 200 763 "-" "pip/9.0.1 ...
2001:4801:7828:101:be76:4eff:fe10:22e3 - - [09/Aug/2017:04:11:36 +0000] "GET /pypi/packages/d0/60/35ed2bb392a7845ba316a66ea1f6cc2f3acaf95e7905deca17d46430452b/protobuf-3.3.0-cp27-cp27mu-manylinux1_x86_64.whl HTTP/1.1" 200 5724653 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:22e3 - - [09/Aug/2017:06:28:44 +0000] "GET /pypi/simple/protobuf/ HTTP/1.1" 200 5872 "-" "pip/9.0.1 ... 
2001:4801:7828:104:be76:4eff:fe10:22e3 - - [09/Aug/2017:06:28:44 +0000] "GET /wheel/ubuntu-16.04-x86_64/protobuf/ HTTP/1.1" 200 727 "-" "pip/9.0.1 ... 
---



[1] http://logs.openstack.org/71/491971/1/check/gate-dsvm-nodepool-ubuntu-src/7d94fa8/logs/devstacklog.txt.gz#_2017-08-09_03_31_00_820