[petsc-users] osx error

Satish Balay balay at mcs.anl.gov
Fri Sep 18 10:42:40 CDT 2020 

Windows has neither host nor traceroute.

hostname is from cygwin [this is fine].

equivalent of traceroute is tracert

And for `host` recommendation is to use nslookup

https://stackoverflow.com/questions/21520191/unix-command-host-is-there-windows-equivalent

I think its best to:

- improve this test [with host - and fallback to traceroute/tracert - if host not found]
- make this a warning - instead of error.

[as the error case won't prevent any e-mails - it can increase due to false positives and negatives - if any]

Satish


On Fri, 18 Sep 2020, Satish Balay via petsc-users wrote:

> Its probably better to just run a test with gethostbyname()?
> 
> 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
> 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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