[gPXE] Setting delay time to boot

[Jonathan Andrews]

> > 
> > #!gpxe
> > clear script_errors
> > dhcp net0
> > : test_download
> > chain http://ip:8080/some_boot_file
> > sleep 10
> > goto test_download
> > 

Sorry for a follow up so soon. I've read bit more of the gpxe docs. This
code does kinda miss the point.

My suggestion for "waitfor" is to test 

1) Is the server running ?
2) Is it ready ?

Its crude because its not a test "is the server for my boot protocol
ready" but simply "is the server ready".

The TCP port you are testing need have no relationship with protocol
your using to boot - or need not even be the machine your booting from !
It would just be a generic way of saying "After server N is ready,
continue". Very flexible and useful logic for clusters etc.

In script terms

dhcp net0
waitfor IP PORT 0
<any other script commands go here in the knowledge that my server is
now available>

Or if your going to get posh "waitfor IP_or_HOSTNAME PORT TIMEOUT"


Take a cluster booting after a power failure: 

waitfor DHCP_SERVER_IP  A_LATE_STARTING_SERVICE 0
dhcp net0
waitfor SAN_SERVER_IP A_LATE_STARTING_SERVICE 0
chain <some cryptic SAN rune>

My only concern would be it would need to have an ASCII spin thingi or
some other indication that its not just locked up :-)

Others might not agree that the logic is friendly or even that the idea
is good ?

Cheers,
Jon