How to change Jenkins mirror, when proxy forbids keyword ftp

Question

When I install a jenkins-plugin like the 'git-plugin', then jenkins redirects my requests to the mirror ftp.halifax.rwth-aachen.de. But I work behind a corporate proxy that forbid requests to URL containing the word 'ftp'.

Is there a way to choose or disable the mirror when downloading plugins for jenkins? Jenkins has no problems installing plugins from sites that do not contain 'ftp'.

Here is the error from jenkins log-view:

Dez 22, 2016 3:46:54 PM INFORMATION hudson.model.UpdateCenter$DownloadJob run
Starting the installation of Git client plugin on behalf of admin-ci
Dez 22, 2016 3:46:54 PM SCHWERWIEGEND hudson.model.UpdateCenter$DownloadJob run
Failed to install Git client plugin
hudson.util.IOException2: Failed to download from http://updates.jenkins-ci.org/download/plugins/git-client/2.1.0/git-client.hpi (redirected to: http://ftp.halifax.rwth-aachen.de/jenkins/plugins/git-client/2.1.0/git-client.hpi)
    at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1169)
    at hudson.model.UpdateCenter$DownloadJob._run(UpdateCenter.java:1666)
    at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:1864)
    at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1640)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:110)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.IOException: Server returned HTTP response code: 403 for URL: http://ftp.halifax.rwth-aachen.de/jenkins/plugins/git-client/2.1.0/git-client.hpi
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at sun.net.www.protocol.http.HttpURLConnection$10.run(HttpURLConnection.java:1926)
    at sun.net.www.protocol.http.HttpURLConnection$10.run(HttpURLConnection.java:1921)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.net.www.protocol.http.HttpURLConnection.getChainedException(HttpURLConnection.java:1920)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1490)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
    at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1121)
    ... 7 more
Caused by: java.io.IOException: Server returned HTTP response code: 403 for URL: http://ftp.halifax.rwth-aachen.de/jenkins/plugins/git-client/2.1.0/git-client.hpi
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1876)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1474)
    at sun.net.www.protocol.http.HttpURLConnection.getHeaderField(HttpURLConnection.java:2982)
    at java.net.URLConnection.getHeaderFieldLong(URLConnection.java:629)
    at java.net.URLConnection.getContentLengthLong(URLConnection.java:501)
    at java.net.URLConnection.getContentLength(URLConnection.java:485)
    at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1120)
    ... 7 more

    enter code here

Answer 1

By default Jenkins is using http://updates.jenkins-ci.org/update-center.json as a "load balancer" url which forwards you to the closest geographical mirror json (i.e. http://ftp-nyc.osuosl.org/pub/jenkins/updates/current/update-center.json for me). What you can do is use your own json file for that purpose by installing this plugin and host json file anywhere you want (i.e. internally):

https://wiki.jenkins.io/display/JENKINS/UpdateSites+Manager+plugin

Answer 2

I found a workaround:

1. Download the plugin direct from http://mirrors.jenkins-ci.org/plugins/gitlab-plugin/latest/

2. Upload the hpi-file into jenkins. There is an upload field in http://host:8080/pluginManager/advanced.

But this is only a workaround. I would like to get an answer to my question: "Is there a way to choose or disable the mirror when downloading plugins for jenkins?"