[petsc-users] osx error

[Mark Adams]

On Fri, Sep 18, 2020 at 7:51 AM Matthew Knepley <knepley at gmail.com> wrote:

> On Fri, Sep 18, 2020 at 7:46 AM Mark Adams <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
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> wrote:
>>
>>> On Thu, 17 Sep 2020, Matthew Knepley wrote:
>>>
>>> > On Thu, Sep 17, 2020 at 8:33 PM Barry Smith <bsmith at petsc.dev> wrote:
>>> >
>>> > > > On Sep 17, 2020, at 4:59 PM, Satish Balay via petsc-users <
>>> > > 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] - 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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