Upon trying to update a host to the latest Patch version using VMware Update Manager , an error message was displayed in the GUI :

Scan entity x.x.x.x Host cannot download files from VMware vSphere Update Manager patch store.  Check the network connectivity and firewall setup, and check esxupdate logs for details

SSH’ing into the host and looking at /vars/logs/esxupdate.log using VI , I saw the errors below with IP’s removed

Options: {‘nosigcheck’: None, ‘retry’: 5, ‘loglevel’: None, ‘cleancache’: None, ‘viburls’: None, ‘meta’: [‘http://x.x.x.x:9084/vum/repository/hostupdate/csco/csco-VEM-5.1.0-metadata.zip‘, ‘http://x.x.x.x:9084/vum/repository/hostupdate/vmw/vmw-ESXi-5.1.0-metadata.zip‘], ‘proxyurl’: None, ‘timeout’: 30.0, ‘cachesize’: None, ‘hamode’: True, ‘maintenancemode’: None}
2014-03-10T13:11:58Z esxupdate: BootBankInstaller.pyc: INFO: Unrecognized value “title=Loading VMware ESXi” in boot.cfg
2014-03-10T13:11:58Z esxupdate: BootBankInstaller.pyc: INFO: Unrecognized value “title=Loading VMware ESXi” in boot.cfg
2014-03-10T13:11:59Z esxupdate: vmware.runcommand: INFO: runcommand called with: args = ‘[‘/sbin/bootOption’, ‘-rp’]’, outfile = ‘None’, returnoutput = ‘True’, timeout = ‘0.0’.
2014-03-10T13:11:59Z esxupdate: vmware.runcommand: INFO: runcommand called with: args = ‘[‘/sbin/bootOption’, ‘-ro’]’, outfile = ‘None’, returnoutput = ‘True’, timeout = ‘0.0’.
2014-03-10T13:11:59Z esxupdate: downloader: DEBUG: Downloading http://x.x.x.x:9084/vum/repository/hostupdate/csco/csco-VEM-5.1.0-metadata.zip to /tmp/tmp6mJvD9…
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR: An esxupdate error exception was caught:
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR: Traceback (most recent call last):
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR:   File “/usr/sbin/esxupdate”, line 216, in main
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR:     cmd.Run()
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR:   File “/build/mts/release/bora-799733/bora/build/esx/release/vmvisor/sys/lib/python2.6/site-packages/vmware/esx5update/Cmdline.py”, line 106, in Run
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR:   File “/build/mts/release/bora-799733/bora/build/esx/release/vmvisor/sys/lib/python2.6/site-packages/vmware/esximage/Transaction.py”, line 71, in DownloadMetadatas
2014-03-10T13:14:29Z esxupdate: esxupdate: ERROR: MetadataDownloadError: (‘http://x.x.x.x:9084/vum/repository/hostupdate/csco/csco-VEM-5.1.0-metadata.zip‘, None, “(‘http://x.x.x.x:9084/vum/repository/hostupdate/csco/csco-VEM-5.1.0-metadata.zip‘, ‘/tmp/tmp6mJvD9’, ‘[Errno 12] Timeout: <urlopen error timed out>’)”)
2014-03-10T13:14:29Z esxupdate: esxupdate: DEBUG: <<<

Googling around pointed at the issue being firewall related however telneting to the port 9084 worked fine. I then tried to access this link on my computer : http://x.x.x.x:9084/vum/repository/hostupdate/csco/csco-VEM-5.1.0-metadata.zip. it eventually downloaded however seemed to take a while. In the end I rebooted the VCenter Server which fixed the problem , it was just timing out! It looks like TomCat can randomly start to leak memory which can be fixed if neede