[petsc-users] osx error

Satish Balay balay at mcs.anl.gov
Fri Sep 18 10:48:12 CDT 2020 

On Fri, 18 Sep 2020, Barry Smith wrote:

> 
> 
> > On Sep 18, 2020, at 10:14 AM, Satish Balay <balay at mcs.anl.gov> wrote:
> > 
> > Its probably better to just run a test with gethostbyname()?
> 
>   I had hoped to avoid building C code and running it. The Apple manual page for gethostbyname() states: The getaddrinfo(3) and getnameinfo(3) functions are preferred over the gethostbyname(), gethostbyname2(), and
>      gethostbyaddr() functions.
> 
> 
>   I do not know what MPICH and OpenMPI use. 
> 
>   On the Mac 
> 
> > 
> > The closest thing I can think off is:
> > 
> > 
> > I don't know if 'traceroute' or 'host' commands are universally available.
> > 
> >>>>>>> 
> > balay at sb /home/balay
> > $ host `hostname`
> > sb has address 192.168.0.144
> 
> $ host `hostname`
> Host Barrys-MacBook-Pro-3.local not found: 3(NXDOMAIN)
> 
> Also on the Apple `hostname` is associated with multiple addresses and it seems different utilities may use different addresses produced. Some addresses may work, others may not.

If its bound to multiple adresses nslookup should list all adressed

If host doesn't work - how is tracroute able to resolve it?

What do you get for:

nslookup `hostname`
traceroute `hostname`

dig `hostname`

Satish

> 
> 
>  I will make one more MR adding traceroute first and if any of the tests succeed continue. If that fails for users then we will likely need to drop the test.
> 
>  I don't like just using a mpiexec -n 2 test because that can fail for so many reasons it is difficult to provide diagnostics to the users.
> 
> Barry
> 
> 
> 
> > balay at sb /home/balay
> > $ echo $?
> > 0
> > balay at sb /home/balay
> > $ host foobar
> > Host foobar not found: 3(NXDOMAIN)
> > balay at sb /home/balay
> > $ echo $?
> > 1
> > balay at sb /home/balay
> > $ 
> > <<<<<<
> > 
> > However - I fear if there are *any* false positives - or false negatives - this test will generate more e-mail than the actual issue [of misbehaving MPI]
> > 
> > Satish
> > 
> > On Fri, 18 Sep 2020, Barry Smith wrote:
> > 
> >> 
> >>   try 
> >> 
> >>   /usr/sbin/traceroute  `hostname`
> >> 
> >> 
> >>> On Sep 18, 2020, at 10:07 AM, Mark Adams <mfadams at lbl.gov> wrote:
> >>> 
> >>> Let me know if you want anything else.
> >>> Thanks,
> >>> Mark
> >>> 
> >>> On Fri, Sep 18, 2020 at 11:05 AM Mark Adams <mfadams at lbl.gov <mailto:mfadams at lbl.gov>> wrote:
> >>> 
> >>> 
> >>> On Fri, Sep 18, 2020 at 11:04 AM Satish Balay <balay at mcs.anl.gov <mailto:balay at mcs.anl.gov>> wrote:
> >>> On Fri, 18 Sep 2020, Satish Balay via petsc-users wrote:
> >>> 
> >>>>>>> 07:41 master *= ~/Codes/petsc$ ping -c 2 MarksMac-302.local
> >>>>>>> PING marksmac-302.local (127.0.0.1): 56 data bytes
> >>>> 
> >>>> So it is resolving MarksMac-302.local as 127.0.0.1 - but ping is not responding?
> >>>> 
> >>>> I know some machines don't respond to external ping [and firewalls can block it] but don't really know if they always respond to internal ping or not.
> >>>> 
> >>>> If some machines don't respond to internal ping  - then we can't use ping test in configure [it will create false negatives - as in this case]
> >>> 
> >>> BTW: To confirm, please try:
> >>> 
> >>> ping 127.0.0.1
> >>> 
> >>> 
> >>> 11:02 master *= ~/Codes/petsc$ sudo vi /etc/hosts
> >>> 11:02 master *= ~/Codes/petsc$ ping 127.0.0.1
> >>> PING 127.0.0.1 (127.0.0.1): 56 data bytes
> >>> Request timeout for icmp_seq 0
> >>> Request timeout for icmp_seq 1
> >>> Request timeout for icmp_seq 2
> >>> Request timeout for icmp_seq 3
> >>> Request timeout for icmp_seq 4
> >>> Request timeout for icmp_seq 5
> >>> Request timeout for icmp_seq 6
> >>> Request timeout for icmp_seq 7
> >>> Request timeout for icmp_seq 8
> >>> Request timeout for icmp_seq 9
> >>> Request timeout for icmp_seq 10
> >>> Request timeout for icmp_seq 11
> >>> Request timeout for icmp_seq 12
> >>> Request timeout for icmp_seq 13
> >>> Request timeout for icmp_seq 14
> >>> Request timeout for icmp_seq 15
> >>> Request timeout for icmp_seq 16
> >>> Request timeout for icmp_seq 17
> >>> Request timeout for icmp_seq 18
> >>> Request timeout for icmp_seq 19
> >>> Request timeout for icmp_seq 20
> >>> Request timeout for icmp_seq 21
> >>> 
> >>> still going ......
> >>> 
> >>> 
> >>> Satish
> >>> 
> >>>> 
> >>>> 
> >>>> Mark, can you remove the line that you added to /etc/hosts - i.e:
> >>>> 
> >>>> 127.0.0.1 MarksMac-302.local
> >>>> 
> >>>> And now rerun MPI tests. Do they work or fail?
> >>>> 
> >>>> [this is to check if this test is a false positive on your machine]
> >>>> 
> >>>> Satish
> >>>> 
> >>>> 
> >>>> On Fri, 18 Sep 2020, Mark Adams wrote:
> >>>> 
> >>>>> On Fri, Sep 18, 2020 at 7:51 AM Matthew Knepley <knepley at gmail.com <mailto:knepley at gmail.com>> wrote:
> >>>>> 
> >>>>>> On Fri, Sep 18, 2020 at 7:46 AM Mark Adams <mfadams at lbl.gov <mailto:mfadams at lbl.gov>> wrote:
> >>>>>> 
> >>>>>>> Oh you did not change my hostname:
> >>>>>>> 
> >>>>>>> 07:37 master *= ~/Codes/petsc$ hostname
> >>>>>>> MarksMac-302.local
> >>>>>>> 07:41 master *= ~/Codes/petsc$ ping -c 2 MarksMac-302.local
> >>>>>>> PING marksmac-302.local (127.0.0.1): 56 data bytes
> >>>>>>> Request timeout for icmp_seq 0
> >>>>>>> 
> >>>>>>> --- marksmac-302.local ping statistics ---
> >>>>>>> 2 packets transmitted, 0 packets received, 100.0% packet loss
> >>>>>>> 07:42 2 master *= ~/Codes/petsc$
> >>>>>>> 
> >>>>>> 
> >>>>>> This does not make sense to me. You have
> >>>>>> 
> >>>>>>  127.0.0.1 MarksMac-302.local
> >>>>>> 
> >>>>>> in /etc/hosts,
> >>>>>> 
> >>>>> 
> >>>>> 09:07  ~/.ssh$ cat /etc/hosts
> >>>>> ##
> >>>>> # Host Database
> >>>>> #
> >>>>> # localhost is used to configure the loopback interface
> >>>>> # when the system is booting.  Do not change this entry.
> >>>>> ##
> >>>>> 127.0.0.1 localhost
> >>>>> 255.255.255.255 broadcasthost
> >>>>> 127.0.0.1    MarksMac-5.local
> >>>>> 127.0.0.1 243.124.240.10.in-addr.arpa.private.cam.ac.uk <http://243.124.240.10.in-addr.arpa.private.cam.ac.uk/>
> >>>>> 127.0.0.1 MarksMac-302.local
> >>>>> 09:07  ~/.ssh$
> >>>>> 
> >>>>> 
> >>>>> 
> >>>>> 
> >>>>> 
> >>>>>> but you cannot resolve that name?
> >>>>>> 
> >>>>>>  Matt
> >>>>>> 
> >>>>>> 
> >>>>>>> BTW, I used to get messages about some network issue and 'changing host
> >>>>>>> name to MarksMac-[x+1].local'. That is, the original hostname
> >>>>>>> was MarksMac.local, then I got a message about changing
> >>>>>>> to MarksMac-1.local, etc. I have not seen these messages for months but
> >>>>>>> apparently this process has continued unabated.
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> 
> >>>>>>> On Thu, Sep 17, 2020 at 11:10 PM Satish Balay via petsc-users <
> >>>>>>> petsc-users at mcs.anl.gov <mailto:petsc-users at mcs.anl.gov>> wrote:
> >>>>>>> 
> >>>>>>>> On Thu, 17 Sep 2020, Matthew Knepley wrote:
> >>>>>>>> 
> >>>>>>>>> On Thu, Sep 17, 2020 at 8:33 PM Barry Smith <bsmith at petsc.dev <mailto:bsmith at petsc.dev>> wrote:
> >>>>>>>>> 
> >>>>>>>>>>> On Sep 17, 2020, at 4:59 PM, Satish Balay via petsc-users <
> >>>>>>>>>> petsc-users at mcs.anl.gov <mailto:petsc-users at mcs.anl.gov>> wrote:
> >>>>>>>>>>> 
> >>>>>>>>>>> Here is a fix:
> >>>>>>>>>>> 
> >>>>>>>>>>> echo 127.0.0.1 `hostname` | sudo tee -a /etc/hosts
> >>>>>>>>>> 
> >>>>>>>>>> Satish,
> >>>>>>>>>> 
> >>>>>>>>>>   I don't think you want to be doing this on a Mac (on anything?)
> >>>>>>>> On a
> >>>>>>>>>> Mac based on the network configuration etc as it boots up and as
> >>>>>>>> networks
> >>>>>>>>>> are accessible or not (wi-fi) it determines what hostname should be,
> >>>>>>>> one
> >>>>>>>>>> should never being hardwiring it to some value.
> >>>>>>>>>> 
> >>>>>>>>> 
> >>>>>>>>> Satish is just naming the loopback interface. I did this on all my
> >>>>>>>> former
> >>>>>>>>> Macs.
> >>>>>>>> 
> >>>>>>>> 
> >>>>>>>> Yes - this doesn't change the hostname. Its just adding an entry for
> >>>>>>>> gethostbyname - for current hostname.
> >>>>>>>> 
> >>>>>>>>>>> 
> >>>>>>>> 127.0.0.1 MarksMac-302.local
> >>>>>>>> <<<
> >>>>>>>> 
> >>>>>>>> Sure - its best to not do this when one has a proper IP name [like
> >>>>>>>> foo.mcs.anl.gov <http://foo.mcs.anl.gov/>] - but its useful when one has a hostname like
> >>>>>>>> "MarksMac-302.local" -that is not DNS resolvable
> >>>>>>>> 
> >>>>>>>> Even if the machine is moved to a different network with a different
> >>>>>>>> name - the current entry won't cause problems [but will need another entry
> >>>>>>>> for the new host name - if this new name is also not DNS resolvable]
> >>>>>>>> 
> >>>>>>>> Its likely this file is a generated file on  macos  - so might get reset
> >>>>>>>> on reboot - or some network change? [if this is the case - the change won't
> >>>>>>>> be permanent]
> >>>>>>>> 
> >>>>>>>> 
> >>>>>>>> Satish
> >>>>>>>> 
> >>>>>>> 
> >>>>>> 
> >>>>>> --
> >>>>>> What most experimenters take for granted before they begin their
> >>>>>> experiments is infinitely more interesting than any results to which their
> >>>>>> experiments lead.
> >>>>>> -- Norbert Wiener
> >>>>>> 
> >>>>>> https://www.cse.buffalo.edu/~knepley/ <https://www.cse.buffalo.edu/~knepley/>
> >>>>>> <http://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>>
> >>>>>> 
> >>>>> 
> >>>> 
> >>> 
> >> 
> >> 
> > 
> 
>

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