detect remote host is up or not

[Gary Yu]

Hi,

I'm writing a /sbin/init.d script to start our Apps at system boot time. We are using a Client/Server architecture and I have to use "remsh" to start some process on other hosts(client) from this server. the /sbin/init.d script only run on one host which is the root host.

In a scenario that all client/server hosts are reboot at same time, the client hosts may come up later than the server host, so in the script I have to detect whether the remote hosts are up or not before issue the remsh commands, I'm just wondering what's the best way to do that -- ping the host or just run a "remsh ls" or some better way ...

looking forward to your suggestions,

thanks and have a nice day.

Gary

[Steve Steel · Accepted solution]

Hi

ping will answer you before the machine is completely up.

I would do something like

remsh topaz who -r|grep "run-level 3"

To check when the machine is at the correct run level.


Alternatively let the machiens all run 1 script in startup and shutdown that makes and
removes a file called machineon or similar.

Chekc for that and machine is not there if not found so maintenance and emergencies are all solved by removing the file


Steve steel

[Dirk Wiedemann]

Hello Garry,

a simple workaround:
write a sleep-statement before the remsh-command.
For example: sleep 600 make the script waiting for 10 minutes and meanwhile all servers should be up.

Dirk

[A. Clay Stephenson]

Pinging is probably not good enough because the network services may be up but your required service may not. Whenever, I need to setup complicated related processes across servers, I prefer to use a pair of Perl client/server socket scripts to coordinate these activities. The clients have built-in timeout routines.


I explained this pretty well and attached the Perl pieces along with shell script snippets calling these Perl scripts in this thread:
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x312e8f960573d611abdb0090277a778c,00.html

[Sajid_1]

hello,

the simple way will be to use the 'ping' command. If you want take a look at this man page too:

# man ruptime

[Gary Yu]

thank you guys for all the suggestions, I think I will go with 'who -r | grep "run-level 3" ', it's easy to implement.