14-Sep-2016 21:43:58.241 INFO [Download metadata thread] hudson.model.AsyncPeriodicWork$1.run Finished Download metadata. 2,388 ms14-Sep-2016 21:43:59.070 WARNING [Jenkins initialization thread] hudson.model.UpdateCenter.updateDefaultSite Upgrading Jenkins. Failed to update the default Update Site ‘default‘. Plugin upgrades may fail. java.io.IOException: Could not find JSON in http://updates.jenkins-ci.org/update-center.json?id=default&version=2.7.4        at hudson.model.DownloadService.loadJSON(DownloadService.java:174)        at hudson.model.UpdateSite.updateDirectlyNow(UpdateSite.java:176)        at hudson.model.UpdateCenter.updateDefaultSite(UpdateCenter.java:2181)        at jenkins.install.SetupWizard.init(SetupWizard.java:170)        at jenkins.install.InstallState$3.initializeState(InstallState.java:105)        at jenkins.model.Jenkins.setInstallState(Jenkins.java:970)        at jenkins.install.InstallUtil.proceedToNextStateFrom(InstallUtil.java:94)        at jenkins.model.Jenkins.<init>(Jenkins.java:887)        at hudson.model.Hudson.<init>(Hudson.java:85)        at hudson.model.Hudson.<init>(Hudson.java:81)        at hudson.WebAppMain$3.run(WebAppMain.java:227)14-Sep-2016 21:43:59.097 INFO [Jenkins initialization thread] hudson.WebAppMain$3.run Jenkins is fully up and running