[SOLVED] Docker on Centos7 : connection refused

Issue

I know there has been a few questions posted on similar issues already but unfortunately I still can't manage to get the following command working :

$sudo docker run hello-world

Unable to find image 'hello-world:latest' locally docker: Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp 52.54.216.153:443: getsockopt: connection refused. See 'docker run --help'.

I am using CentOS7 virtual machine on VirtualBox with HTTP/HTTPS/FTP proxy settings configured at system level. This proxy configuration has been working fine for Chrome and other applications.

After browsing this forum, I tried to create explicit proxy settings for the Docker application by:

• creating a ~/.docker/config.json file as mentioned at https://docs.docker.com/network/proxy/ and then do "systemctl restart docker"

• creating a /etc/systemd/system/docker.service.d/http-proxy.conf and then do "systemctl daemon-reload" and "systemctl restart docker"

Here is the version of Docker on my virtual machine:

$sudo docker version

Client:
 Version:      18.03.1-ce
 API version:  1.37
 Go version:   go1.9.5
 Git commit:   9ee9f40
 Built:        Thu Apr 26 07:20:16 2018
 OS/Arch:      linux/amd64
 Experimental: false
 Orchestrator: swarm

Server:
 Engine:
  Version:      18.03.1-ce
  API version:  1.37 (minimum version 1.12)
  Go version:   go1.9.5
  Git commit:   9ee9f40
  Built:        Thu Apr 26 07:23:58 2018
  OS/Arch:      linux/amd64
  Experimental: false

$curl -v https://registry-1.docker.io/v2/

* About to connect() to proxy XXX port 8012 (#0)
...
> 
< HTTP/1.1 200 Connection established
< 
* Proxy replied OK to CONNECT request
* Initializing NSS with certpath: sql:/etc/pki/nssdb
*   CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none
* SSL connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
* Server certificate:
*   subject: CN=*.docker.io
*   start date: Aug 02 00:00:00 2017 GMT
*   expire date: Sep 02 12:00:00 2018 GMT
*   common name: *.docker.io
*   issuer: CN=Amazon,OU=Server CA 1B,O=Amazon,C=US
> GET /v2/ HTTP/1.1
> User-Agent: curl/7.29.0
> Host: registry-1.docker.io
> Accept: */*
> 
< HTTP/1.1 401 Unauthorized
< Content-Type: application/json; charset=utf-8
< Docker-Distribution-Api-Version: registry/2.0
< Www-Authenticate: Bearer realm="https://auth.docker.io/token",service="registry.docker.io"
< Date: Fri, 08 Jun 2018 16:00:17 GMT
< Content-Length: 87
< Strict-Transport-Security: max-age=31536000
< 
{"errors":[{"code":"UNAUTHORIZED","message":"authentication required","detail":null}]}
* Connection #0 to host XXX left intact

$curl -v https://54.152.209.167

   ...
   ...
< HTTP/1.1 200 Connection established
< 
* Proxy replied OK to CONNECT request
* Initializing NSS with certpath: sql:/etc/pki/nssdb
*   CAfile: /etc/pki/tls/certs/ca-bundle.crt
  CApath: none
* Server certificate:
*   subject: CN=*.docker.io
*   start date: Aug 02 00:00:00 2017 GMT
*   expire date: Sep 02 12:00:00 2018 GMT
*   common name: *.docker.io
*   issuer: CN=Amazon,OU=Server CA 1B,O=Amazon,C=US
* NSS error -12276 (SSL_ERROR_BAD_CERT_DOMAIN)
* Unable to communicate securely with peer: requested domain name does not match the server's certificate.
* Closing connection 0
curl: (51) Unable to communicate securely with peer: requested domain name does not match the server's certificate.

Solution

As mentioned in https://docs.docker.com/config/daemon/systemd/#httphttps-proxy, the following commands solved my problem. It was kind of lost in the doc, IMO.

$ sudo mkdir -p /etc/systemd/system/docker.service.d

vi /etc/systemd/system/docker.service.d/http-proxy.conf 
[Service]
Environment="http://IP:PORT/"

vi /etc/systemd/system/docker.service.d/https-proxy.conf 
[Service]
Environment="http://IP:PORT/"

$ sudo systemctl daemon-reload
$ sudo systemctl restart docker
$ systemctl show --property=Environment docker
Environment=HTTP_PROXY=http://"http://IP:PORT/"

Answered By - Pierric