> On Квітень 11, 2016, 6:54 після полудня, Alejandro Fernandez wrote: > > ambari-common/src/main/python/resource_management/libraries/functions/fcntl_based_process_lock.py, > > line 29 > > <https://reviews.apache.org/r/45872/diff/3/?file=1339352#file1339352line29> > > > > Is this supported on all of the OS'es that Ambari runs on? > > > > If so, perhaps we can put a try around the "import fcntl" and just do a > > best approach at another locking method.
"import fcntl" should work on UNIX systems. The operation that can fail is fcntl.lockf(self.lock_file, fcntl.LOCK_EX) with an exception like "IOError: [Errno 45] Operation not supported". But fcntl is a part of POSIX (F_SETLKW is specified in POSIX.1-2001. Internally fcntl.lockf calls fcntl(fd, (code & LOCK_NB) ? F_SETLK : F_SETLKW, &l);) and POSIX compliant file systems should support it. It's probably an exotic case if fcntl.lockf fails (like when /var/lib/ambari-agent/tmp is mounted over NFSv2 or NFSv3 with rpc.lockd (nfslock service) not started). - Andrii ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://reviews.apache.org/r/45872/#review128204 ----------------------------------------------------------- On Квітень 11, 2016, 2:33 після полудня, Andrew Onischuk wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/45872/ > ----------------------------------------------------------- > > (Updated Квітень 11, 2016, 2:33 після полудня) > > > Review request for Ambari, Sumit Mohanty and Vitalyi Brodetskyi. > > > Bugs: AMBARI-15762 > https://issues.apache.org/jira/browse/AMBARI-15762 > > > Repository: ambari > > > Description > ------- > > **Problem** > Ambari executes component installs in parallel on a host. Each install process > in the post-install phase executes certain shared/common configuration > directory related steps (stacks/HDP/2.0.6/hooks/after- > INSTALL/scripts/shared_initialization.py:link_configs() -> ... -> /resource_ma > nagement/libraries/functions/conf_select.py:convert_conf_directories_to_symlin > ks() ) on the directories listed in conf_select.py:PACKAGE_DIRS > > The common configuration directory related processing fail in they are kicked > of in the same time for the same directory. > > In the case the following code snippet is executed in the same time by > multiple component installs > each will see the `backup_dir` as non existent and will try to execute the > "cp" command. One will succeed while the others fail. > > > > > Execute(("cp", "-R", "-p", old_conf, backup_dir), not_if = format("test > -e {backup_dir}"), sudo = True) > > > Similar behaviour is seen for the following code snippet: > > > > > Execute(as_sudo(["cp", "-R", "-p", os.path.join(old_conf, "*"), > versioned_conf], auto_escape=False), only_if = format("ls -d {old_conf}/*")) > > > **Possible solution** > Use the linux "lockfile" command or "mkdir /var/lock/mylock" (see example of > the mkdir solution here: <http://wiki.bash-hackers.org/howto/mutex>) > > > Diffs > ----- > > ambari-agent/src/main/python/ambari_agent/CustomServiceOrchestrator.py > 1bc045c > ambari-agent/src/test/python/ambari_agent/TestCustomServiceOrchestrator.py > 884612b > > ambari-agent/src/test/python/resource_management/TestFcntlBasedProcessLock.py > PRE-CREATION > > ambari-common/src/main/python/resource_management/libraries/functions/fcntl_based_process_lock.py > PRE-CREATION > > ambari-server/src/main/resources/stacks/HDP/2.0.6/hooks/after-INSTALL/scripts/params.py > 9f4971d > > ambari-server/src/main/resources/stacks/HDP/2.0.6/hooks/after-INSTALL/scripts/shared_initialization.py > c772ddb > > Diff: https://reviews.apache.org/r/45872/diff/ > > > Testing > ------- > > mvn clean test > > > Thanks, > > Andrew Onischuk > >
