[petsc-users] osx error
Barry Smith
bsmith at petsc.dev
Fri Sep 18 09:23:10 CDT 2020
This email thread doesn't seem to have clear communication. Can we start at the beginning again please? Please answer my questions directly in the appropriate lines below in your email response so we know what answer goes with what question. I know you have done some of these things but it is unclear what order you did them and the order is important.
Background: In order to decide if the test in MPI.py works, or needs to be modified or removed we need clear information about your system BEFORE you made changes to get things to work.
1) Did you add the
127.0.0.1 MarksMac-5.local
to the /etc/hosts yesterday because Satish suggested it, or have you had it there for a long time? (You should not need it)
2) Please run
ping -c 2 `hostname`
3) Please remove the line 127.0.0.1 MarksMac-5.local in /etc/hosts and follow the directions in
https://stackoverflow.com/questions/37951379/etc-hosts-ignored-in-mac-el-capitan-10-11-5 <https://stackoverflow.com/questions/37951379/etc-hosts-ignored-in-mac-el-capitan-10-11-5>
to flush the DNS cache (note for different versions of MacOS the command is different).
4) Please run
ping -c 2 `hostname`
5) Please run a MPI program (doesn't matter which and I don't care how you installed MPICH or OpenMPI) with
mpiexec -n 2 ./programname
does it run, hang or ?
Based on this information we can decide what needs to be done next.
Thanks
Barry
As a side note on my Mac
$ hostname
Barrys-MacBook-Pro-3.local
~/Src/petsc (barry/2020-07-07/docs-no-makefiles *>) arch-docs-no-makefiles
$ /sbin/ping -c 2 `hostname`
PING barrys-macbook-pro-3.local (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.077 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.112 ms
--- barrys-macbook-pro-3.local ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.077/0.095/0.112/0.018 ms
~/Src/petsc (barry/2020-07-07/docs-no-makefiles *>) arch-docs-no-makefiles
$
We are trying to understand if/why your machine is behaving differently.
My theory is that if ping -c 2 `hostname` fails then MPICH and OpenMP mpiexec -n 2 will fail. We need to determine if this theory is correct or if you have a counter-example.
> On Sep 18, 2020, at 8:09 AM, Mark Adams <mfadams at lbl.gov> 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/ <http://www.cse.buffalo.edu/~knepley/>
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