Nathan Kinder wrote: > > > On 02/28/2015 01:13 PM, Nathan Kinder wrote: >> >> >> On 02/28/2015 01:07 PM, Rob Crittenden wrote: >>> Nathan Kinder wrote: >>>> >>>> >>>> On 02/27/2015 01:18 PM, Nathan Kinder wrote: >>>>> >>>>> >>>>> On 02/27/2015 01:08 PM, Rob Crittenden wrote: >>>>>> Nathan Kinder wrote: >>>>>>> >>>>>>> >>>>>>> On 02/27/2015 12:20 PM, Rob Crittenden wrote: >>>>>>>> Nathan Kinder wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> On 02/26/2015 12:55 AM, Martin Kosek wrote: >>>>>>>>>> On 02/26/2015 03:28 AM, Nathan Kinder wrote: >>>>>>>>>>> Hi, >>>>>>>>>>> >>>>>>>>>>> The two attached patches address some issues that affect >>>>>>>>>>> ipa-client-install when syncing time from the NTP server. Now that >>>>>>>>>>> we >>>>>>>>>>> use ntpd to perform the time sync, the client install can end up >>>>>>>>>>> hanging >>>>>>>>>>> forever when the server is not reachable (firewall issues, etc.). >>>>>>>>>>> These >>>>>>>>>>> patches address the issues in two different ways: >>>>>>>>>>> >>>>>>>>>>> 1 - Don't attempt to sync time when --no-ntp is specified. >>>>>>>>>>> >>>>>>>>>>> 2 - Implement a timeout capability that is used when we run ntpd to >>>>>>>>>>> perform the time sync to prevent indefinite hanging. >>>>>>>>>>> >>>>>>>>>>> The one potentially contentious issue is that this introduces a new >>>>>>>>>>> dependency on python-subprocess32 to allow us to have timeout >>>>>>>>>>> support >>>>>>>>>>> when using Python 2.x. This is packaged for Fedora, but I don't >>>>>>>>>>> see it >>>>>>>>>>> on RHEL or CentOS currently. It would need to be packaged there. >>>>>>>>>>> >>>>>>>>>>> https://fedorahosted.org/freeipa/ticket/4842 >>>>>>>>>>> >>>>>>>>>>> Thanks, >>>>>>>>>>> -NGK >>>>>>>>>> >>>>>>>>>> Thanks for Patches. For the second patch, I would really prefer to >>>>>>>>>> avoid new >>>>>>>>>> dependency, especially if it's not packaged in RHEL/CentOS. Maybe we >>>>>>>>>> could use >>>>>>>>>> some workaround instead, as in: >>>>>>>>>> >>>>>>>>>> http://stackoverflow.com/questions/3733270/python-subprocess-timeout >>>>>>>>> >>>>>>>>> I don't like having to add an additional dependency either, but the >>>>>>>>> alternative seems more risky. Utilizing the subprocess32 module >>>>>>>>> (which >>>>>>>>> is really just a backport of the normal subprocess module from Python >>>>>>>>> 3.x) is not invasive for our code in ipautil.run(). Adding some sort >>>>>>>>> of >>>>>>>>> a thread that has to kill the spawned subprocess seems more risky (see >>>>>>>>> the discussion about a race condition in the stackoverflow thread >>>>>>>>> above). That said, I'm sure the thread/poll method can be made to >>>>>>>>> work >>>>>>>>> if you and others feel strongly that this is a better approach than >>>>>>>>> adding a new dependency. >>>>>>>> >>>>>>>> Why not use /usr/bin/timeout from coreutils? >>>>>>> >>>>>>> That sounds like a perfectly good idea. I wasn't aware of it's >>>>>>> existence (or it's possible that I forgot about it). Thanks for the >>>>>>> suggestion! I'll test out a reworked version of the patch. >>>>>>> >>>>>>> Do you think that there is value in leaving the timeout capability >>>>>>> centrally in ipautil.run()? We only need it for the call to 'ntpd' >>>>>>> right now, but there might be a need for using a timeout for other >>>>>>> commands in the future. The alternative is to just modify >>>>>>> synconce_ntp() to use /usr/bin/timeout and leave ipautil.run() alone. >>>>>> >>>>>> I think it would require a lot of research. One of the programs spawned >>>>>> by this is pkicreate which could take quite some time, and spawning a >>>>>> clone in particular. >>>>>> >>>>>> It is definitely an interesting idea but I think it is safest for now to >>>>>> limit it to just NTP for now. >>>>> >>>>> What I meant was that we would have an optional keyword "timeout" >>>>> parameter to ipautil.run() that defaults to None, just like my >>>>> subprocess32 approach. If a timeout is not passed in, we would use >>>>> subprocess.Popen() to run the specified command just like we do today. >>>>> We would only actually pass the timeout parameter to ipautil.run() in >>>>> synconce_ntp() for now, so no other commands would have a timeout in >>>>> effect. The capability would be available for other commands this way >>>>> though. >>>>> >>>>> Let me propose a patch with this implementation, and if you don't like >>>>> it, we can leave ipautil.run() alone and restrict the changes to >>>>> synconce_ntp(). >>>> >>>> An updated patch 0002 is attached that uses the approach mentioned above. >>> >>> Looks good. Not to nitpick to death but... >>> >>> Can you add timeout to ipaplatform/base/paths.py as BIN_TIMEOUT = >>> "/usr/bin/timeout" and reference that instead? It's for portability. >> >> Sure. I was wondering if we should do something around a full path. >> >>> >>> And a question. I'm impatient. Should there be a notice that it will >>> timeout after n seconds somewhere so people like me don't ^C after 2 >>> seconds? Or is that just overkill and I need to learn patience? >> >> Probably both. :) There's always going to be someone out there who will >> do ctrl-C, so I think printing out a notice is a good idea. I'll add this. >> >>> >>> Stylistically, should we prefer p.returncode is 15 or p.returncode == 15? >> >> After some reading, it seems that '==' should be used. Small integers >> work with 'is', but '==' is the consistent way that equality of integers >> should be checked. I'll modify this. > > Another updated patch 0002 is attached that addresses Rob's review comments. > > Thanks, > -NGK >
LGTM. Does someone else have time to test this? I also don't know if there is a policy on placement of new items in paths.py. Things are all over the place and some have BIN_ prefix and some don't. rob _______________________________________________ Freeipa-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/freeipa-devel
