How to run script (sleep360) without delaying bootup

[Kam Leo]

On 4/22/07, Nigel Henry <cave.dnb at tiscali.fr> wrote:
> On Sunday 22 April 2007 19:16, Steve Siegfried wrote:
> > Nigel Henry wrote:
> > > On Sunday 22 April 2007 18:19, Scott Berry wrote:
> > > > Nigel, what would you want to ping?  I think you could put a line in
> > > > that script to do that.
> > > >
> > > > Scott
> > >
> > > Pinging a server on the Internet isn't really the problem, as long as
> > > nobody get's T'd off on getting a ping on a daily basis. All I want is a
> > > script that will continually send a ping to <some server>, then when the
> > > Internet connection is up, and it gets a positive response from the
> > > server, will then run /usr/local/bin/ntp-restart, and terminate the ping.
> > > This will then restart the ntp daemon, and all of the servers listed in
> > > /etc/ntp.conf will be polled.
> > >
> > > At the moment when the ntp daemon is started at bootup on FC2, I get
> > > varying results. Post bootup I connect to the Internet, and sometimes
> > > just one of the six timeservers is listed when running ntpq> pe, and
> > > sometimes 4 of the timeservers are listed, but never the 6. If I do an
> > > /etc/init.d/ntpd stop, followed by an /etc/init.d start, then run ntpq, I
> > > see all 6 Internet timeservers listed.
> > >
> > > There is a problem with the ntp daemon, at least on FC2, when no Internet
> > > connection is available at bootup.
> > >
> > > Nigel.
> >
> > You can probably do this without pinging.
> >
> > Assuming you talk to the outside internet via eth0, then "ifconfig eth0"
> > won't tell you what your ip-address is until eth0 is all the way up.
> >
> > Thus, the following script will either:
> >  - print your ip-address and return 0 (success),
> > or
> >  - print "eth0 not active." and return 1 (failure).
> >
> >     > #!/bin/ksh
> >     > DEVICE=${1:-eth0}
> >     > if [ `/sbin/ifconfig | grep ^$DEVICE | wc -l` = 0 ]
> >     > then echo "$DEVICE not active."
> >     >      exit 1
> >     > else mungeline=`/sbin/ifconfig $DEVICE | grep "inet addr" | tr -s ":"
> >     > " " | cut -d' ' -f4` echo $mungeline
> >     >      exit 0
> >     > fi
> >
> > Hope this helps,
> >
> > -S
>
> This is my setup. I have 2 machines on a LAN. These access the Internet
> through a Smoothwall firewall, which is installed on an old machine. The
> Smoothwall accesses the Internet through a serial modem. To connect to
> Internet I have to have one of the machines on the LAN booted up, so as
> access the web interface to the Smoothwall.
>
> So this is the way it goes. The Smoothwall is left running continually, but I
> shut down the dialup connection, and the 2 machines on the LAN last thing at
> night, unless I'm doing updates.
>
> Next day. Smoothwall is still running, but no connection to the Internet. Next
> I boot the machine on the LAN that has the Internet timeservers listed
> in /etc/ntp.conf. The machine boots up (this is FC2) , but because no
> Internet connection is available the ntpd times out, goes out to lunch, gives
> up trying to contact the timeservers, whatever. Post boot up, and running
> ntpq> pe, sometimes there is 1 of the 6 timeservers showing, and sometimes 4
> of the 6.
>
> If I now stop and start ntpd all 6 of the timeservers are listed when running
> ntpq> pe.
>
> So, and this is a problem with ntpd on FC2. On FC6 ncpd seems to handle an
> ititial "no Internet connection available" ok, and when I make the connection
> to the Internet all the timeservers are listed on ntpq> pe. Back to the FC2
> problem.
>
> Smoothwall is running, but dialup connection is down. Boot up the machine on
> the LAN that has the Internet timeservers in /etc/ntp.conf. Ntpd is started
> on bootup, but can't find the timeservers, as there is no Internet
> connection, so ntpd decides to go out to lunch.
>
> The sort of script that I'm looking for is one that will be either run
> from /etc/rc.d/rc.local, but without delaying, hanging, stalling the bootup
> sequence, or being run post bootup as root. A cron job won't do this, as it
> runs at a specific time. This script needs to be run either during, or post
> bootup.
>
> So this is the script I need. Either started with /etc/init.d/rc.local. or
> post boot up
>
> Ping an Internet address every minute. When a response is received showing an
> active Internet connection, then run /usr/local/bin/ntp-restart.
>
> Perhaps I'm asking too much.
>
> Nigel.

Why the obsession with ntp? The on board clock should be able maintain
accurate time for at least a day or two.