I'm unable to pull docker images in my environment. I think it's blocked by company firewall, but I'm not sure why It gets layer info and later It prints that repository is not found.
sudo docker pull hello-world
latest: Pulling from hello-world
50a54e1f9180: Pulling fs layer
7a5a2d73abce: Pulling fs layer
Pulling repository hello-world
Repository not found
Docker version: (I cannot upgrade to newest docker on RHEL 6.9)
Docker version 1.7.1, build 786b29d/1.7.1
Could somebody explain me which protocols (https only?) are used during docker image pulling phase and what addresses are contacted ("https://registry-1.docker.io/v2" only?) ?
Problem was that firewall was blocking connections during pulling images. Docker registry uses CDN so more URLs need to be allowed and not only registry URL.
I requested to allow the following URLs on company firewall and it is working now.
dseasb33srnrn.cloudfront.net
auth.docker.io
elb-registry.us-east-1.aws.dckr.io.
us-east-1-elbregis-10fucsvj1tcgy-133821800.us-east-1.elb.amazonaws.com
registry-1.docker.io
registry-origin.docker.io
index.docker.io
elb-io.us-east-1.aws.dckr.io
us-east-1-elbio-rm5bon1qaeo4-623296237.us-east-1.elb.amazonaws.com
Docker log file (/var/log/docker) help me to identify root problem. There were the following errors:
level=error msg="Error from V2 registry: Get https://dseasb33srnrn.cloudfront.net/registry-v2/docker/registry/v2/blobs/sha256/78/78445dd45222097f5f8d5a16e48dc19c4ca162dcdb80010ab6f1ccfc7e2c0fa3/data?Expires=1493033299&Signature=DiEmffSxF1F9z-SRoGyX3NwzfeQY3BhE2Du3aPb1qy9VglXyn1mus7Xy9Y~DQnwaQ9IIN71FboK5lOAiN1Qj-x662qhioi72CJ-v02fiMHqC03FDb0l4LyULquU8GaalW3uZG4hdfuSqOBQ1qo9HEcxhMyQGqOqpfPUKjUlHqm8_&Key-Pair-Id=APKAJECH5M7VWIS5YZ6Q: read tcp 52.85.173.110:443: connection reset by peer"
The list of URLs which needs to be allowed I found here: https://forums.docker.com/t/list-of-docker-hub-mirror-sites-to-configure-proxy-whitelist/20845/2