I'm sponsoring this fast-track request for Jack Meng. The timer is
set to 10/24/2008.
Background
By default, dhcpagent "canonizes" interfaces under its control on
receipt of SIGTERM. This means that it will reset the IP address
back to 0.0.0.0 during shutdown. This happens regardless of whether
dhcpagent is configured to release or drop leases.
Problem
When DHCP canonizes as a normal part of system shut-down, iSCSI may
lose contact with the server. If the system is diskless, and the
root file system is mounted via iSCSI, this causes at least a
lock-up and may cause data loss.
Solution
Release binding for this change is Patch/Micro.
A new Consolidation Private ioctl (ISCSI_IS_ACTIVE) will be added to
"/devices/iscsi:devctl". dhcpagent will invoke this ioctl to
determine whether it can canonize interfaces on exit.
Related Projects and Future Work
When the root file system is mounted via NFS, a completely different
mechanism is used. In this case, /sbin/netstrategy indicates a
"dhcp" boot, and we start dhcpagent with the somewhat obscure "-a"
(adopt) flag. In addition to pulling DHCPACK information from OBP,
this causes dhcpagent to avoid canonizing on shutdown (per CR
4291141).
This entire area is one that requires future study, in particular
for the relationship between booting, interface configuration,
system shutdown sequencing, and SMF. However, that is not this
project.
References
6751246 dhcp release the lease before sync is committed on iSCSI disk
PSARC 2008/427 iSCSI Boot
4291141 Reboot after install w/DHCP hangs due to dhcpagent
canonizing interface
6701045 iSCSI boot on x86
--
James Carlson, Solaris Networking <james.d.carlson at sun.com>
Sun Microsystems / 35 Network Drive 71.232W Vox +1 781 442 2084
MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677
