[ale] After 15 years, Nohup is sttll broken???

[neal at mnopltd.com]

Thank you for the reply.  Additional response inline below.

On 2019-07-31 09:19, Chris Fowler wrote:
> -------------------------
> 
>> FROM: "Neal Rhodes via Ale" <ale at ale.org>
>> TO: "Jim Kinney" <jim.kinney at gmail.com>
>> CC: "Atlanta Linux Enthusiasts" <ale at ale.org>
>> SENT: Wednesday, July 31, 2019 10:10:41 AM
>> SUBJECT: Re: [ale] After 15 years, Nohup is sttll broken???
> 
>> Well, indirectly - if the ssh session didn't die, it probably
>> wouldn't
>> happen.
>  I've been using keepalive SSH options for years to keep session up.
> I had system that did dialout ppp to servers with an idle timeout set
> for pppd.  SSH session would drop so I used the keep alive out of band
> SSH messages to keep those connections up.  I now use the same options
> for standard networks (real speeds).

Hmm.  I forgot about that.   However, the man page for ssh_config states 
that tcpkeepalive is  on by default.  So...

I think we're seeing the ssh sessions die because the Sonicwall VPN is 
configured to kill any connections after xx time.   I cannot get that 
changed.



>> BUT - isn't that the whole freaking point of nohup?   No-Hang-Up?
>> 
>> Wasn't the original point of nohup that I didn't want a modem
>> disconnect, or accidently hitting CTRL-C on the keyboard, to kill a
>> background job I had started?
> 
> I've always thrown nohup in the background on exection
> 
> nohup ./script.sh &

Hmm. That IS an interesting point, and worth experimentation.  Thanks.


> 
>> What if I needed to start something via nohup, then shutdown my
>> notebook, and drive home?   My ssh session is gonna die.
> 
> tmux.  Start the tmux session and run the job in a tmux pane.  When
> you get home SSH back to the server and attach to the tmux session.  I
> use this in development so I can occasionally check up on build status
> via JuiceSSH on Android.
> 
>> Regards,
>> 
>> Neal
>> 
>> On 2019-07-31 09:05, Jim Kinney wrote:
>>> Sounds like an ssh problem. Is keepalive set on?
>>> 
>>> On July 31, 2019 10:03:53 AM EDT, Neal Rhodes via Ale
>> <ale at ale.org>
>>> wrote:
>>> 
>>>> So, about 15 years ago, when we were transitioning from SCO Unix
>> to
>>>> Linux, we noticed that nohup didn't work on long running Progress
>>>> Database jobs.
>>>> 
>>>> We would start an update job via nohup, leave, several hours
>> later
>>>> the
>>>> ssh session would timeout, and at some point the job would get a
>>>> hangup
>>>> signal and die.  Which is sometimes really annoying if it's a 15
>>>> hour
>>>> job.
>>>> 
>>>> Our workaround at the time was a script, "mynohup":
>>>> 
>>>> #!/bin/bash
>>>> set -x
>>>> echo "at `date` Starting: $* " >> mynohup.out
>>>> echo "$*  >> mynohup.out " | at now
>>>> set +x
>>>> 
>>>> Which has worked flawlessly for 14.9 years.
>>>> 
>>>> Now we are transitioning to new servers, running
>>>> 2.6.32-696.30.1.el6.x86_64 #1 SMP Tue May 22 03:28:18 UTC 2018
>>>> x86_64
>>>> x86_64 x86_64 GNU/Linux
>>>> 
>>>> inside VMs, and we experienced some awkwardness with some admin
>> UI
>>>> which
>>>> had Apache -> PHP -> sh -> sudo - adminuser -> mynohup something.
>>>> Barfing up some messages about tty devices.   I thought of at
>> least
>>>> unwinding the old kluge.
>>>> 
>>>> So, I thought, surely this has been fixed now, and tried running
>> a
>>>> job
>>>> via nohup from an ssh session.
>>>> 
>>>> Sure enough, at some point after leaving the office, the DB log
>>>> shows....
>>>> 
>>>> [2019/07/30 at 22:07:25.844-0500] P-28382  7: (562)   HANGUP signal
>>>> received.
>>>> [2019/07/30 at 22:07:25.847-0500] P-28382  7: (453)   Logout by neal
>> on
>>>> 
>>>> /dev/pts/4.
>>>> [2019/07/30 at 22:07:28.241-0500] P-28439  8: (562)   HANGUP signal
>>>> received.
>>>> [2019/07/30 at 22:07:28.241-0500] P-28439  8: (453)   Logout by
>>>> tdiadmin on
>>>> batch.
>>>> 
>>>> Wuh? The sole point of nohup is to not get a hangup, and ....????
>>>> 
>>>> regards,
>>>> 
>>>> Neal
>>>> -------------------------
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>>> 
>>> --
>>> Sent from my Android device with K-9 Mail. All tyopes are thumb
>>> related and reflect authenticity.
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