yum が失敗し ImportError: No module named cElementTree エラーが発生する

Issue

• 以下のエラーで yum に失敗します。

 yum update
Plugin "refresh-packagekit" can't be imported
Loaded plugins: rhnplugin, security
/usr/lib64/python2.6/xmlrpclib.py:612:DeprecationWarning:The xmllib module is obsolete.Use xml.sax instead.
  import xmllib # lazy subclassing (!)
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 285, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 136, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/cli.py", line 434, in doCommands
    self._getTs(needTsRemove)
  File "/usr/lib/python2.6/site-packages/yum/depsolve.py", line 99, in _getTs
    self._getTsInfo(remove_only)
  File "/usr/lib/python2.6/site-packages/yum/depsolve.py", line 110, in _getTsInfo
    pkgSack = self.pkgSack
  File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 897, in <lambda>
    pkgSack = property(fget=lambda self: self._getSacks(),
  File "/usr/lib/python2.6/site-packages/yum/__init__.py", line 682, in _getSacks
    self.repos.populateSack(which=repos)
  File "/usr/lib/python2.6/site-packages/yum/repos.py", line 294, in populateSack
    sack.populate(repo, mdtype, callback, cacheonly)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 165, in populate
    if self._check_db_version(repo, mydbtype):
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 223, in _check_db_version
    return repo._check_db_version(mdtype)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1256, in _check_db_version
    repoXML = self.repoXML
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1455, in <lambda>
    repoXML = property(fget=lambda self: self._getRepoXML(),
  File "/usr/share/yum-plugins/rhnplugin.py", line 525, in _getRepoXML
    return YumRepository._getRepoXML(self)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1447, in _getRepoXML
    self._loadRepoXML(text=self)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1437, in _loadRepoXML
    return self._groupLoadRepoXML(text, self._mdpolicy2mdtypes())
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1412, in _groupLoadRepoXML
    if self._commonLoadRepoXML(text):
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1240, in _commonLoadRepoXML
    self._repoXML = self._parseRepoXML(result)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1036, in _parseRepoXML
    return repoMDObject.RepoMD(self.id, local)
  File "/usr/lib/python2.6/site-packages/yum/repoMDObject.py", line 124, in __init__
    self.parse(srcfile)
  File "/usr/lib/python2.6/site-packages/yum/repoMDObject.py", line 140, in parse
    parser = iterparse(infile)
  File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1169, in cElementTree_iterparse
    _cElementTree_import()
  File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1164, in _cElementTree_import
    import cElementTree
ImportError:No module named cElementTree
You have new mail in /var/spool/mail/root
[root@vuwunicobandbd1 yum.repos.d]# yum repolist
Plugin "refresh-packagekit" can't be imported
Loaded plugins: rhnplugin, security
/usr/lib64/python2.6/xmlrpclib.py:612:DeprecationWarning:The xmllib module is obsolete.Use xml.sax instead.
  import xmllib # lazy subclassing (!)
Existing lock /var/run/yum.pid: another copy is running as pid 11892.
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :24 M RSS (328 MB VSZ)
    Started:Tue Mar  5 11:03:12 2013 - 00:02 ago
    State  :Running, pid:11892
Another app is currently holding the yum lock; waiting for it to exit...
  The other application is: yum
    Memory :26 M RSS (329 MB VSZ)
    Started:Tue Mar  5 11:03:12 2013 - 00:04 ago
    State  :Uninterruptible, pid:11892
Traceback (most recent call last):
  File "/usr/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 285, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 136, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/cli.py", line 438, in doCommands
    return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)
  File "/usr/share/yum-cli/yumcommands.py", line 851, in doCommand
    base.repos.populateSack()
  File "/usr/lib/python2.6/site-packages/yum/repos.py", line 294, in populateSack
    sack.populate(repo, mdtype, callback, cacheonly)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 165, in populate
    if self._check_db_version(repo, mydbtype):
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 223, in _check_db_version
    return repo._check_db_version(mdtype)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1256, in _check_db_version
    repoXML = self.repoXML
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1455, in <lambda>
    repoXML = property(fget=lambda self: self._getRepoXML(),
  File "/usr/share/yum-plugins/rhnplugin.py", line 525, in _getRepoXML
    return YumRepository._getRepoXML(self)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1447, in _getRepoXML
    self._loadRepoXML(text=self)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1437, in _loadRepoXML
    return self._groupLoadRepoXML(text, self._mdpolicy2mdtypes())
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1412, in _groupLoadRepoXML
    if self._commonLoadRepoXML(text):
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1240, in _commonLoadRepoXML
    self._repoXML = self._parseRepoXML(result)
  File "/usr/lib/python2.6/site-packages/yum/yumRepo.py", line 1036, in _parseRepoXML
    return repoMDObject.RepoMD(self.id, local)
  File "/usr/lib/python2.6/site-packages/yum/repoMDObject.py", line 124, in __init__
    self.parse(srcfile)
  File "/usr/lib/python2.6/site-packages/yum/repoMDObject.py", line 140, in parse
    parser = iterparse(infile)
  File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1169, in cElementTree_iterparse
    _cElementTree_import()
  File "/usr/lib/python2.6/site-packages/yum/misc.py", line 1164, in _cElementTree_import
    import cElementTree
ImportError:No module named cElementTree