[j-nsp] EX4200 9.4R2.9 process crash on previously valid config

[Jeff S Wheeler]

Upon upgrading an EX4200 stack from 9.2R2.15 to 9.4R2.9, I found that
some damned process, chassism or something, was crashing repeatedly and
preventing any interfaces from coming up.  I wish I had taken the time
to note which process it was, but the following will reproduce it.

configure any interface as follows
interfaces {
  ge-0/0/0 {
    ether-options {
      speed {
        1g;
      }
    802.3ad ae0;
  }
}

JUNOS 9.4 won't let you configure that, but the upgrade validator does
not catch it (and numerous other problems) when you already have it
configured on an older version.  So if you have the above in your config
in 9.4R2.9, no interfaces will come up, whatever process (forgot) will
crash repeatedly, and you will have to hunt down the problem and correct
it before any ports on your stack can come up again.

Dearest Juniper, please pay more attention to validating configs in
newer JUNOS vs configs that are allowed on older EX-series software.
It's stupid that things like virtual-chassis { pre-provisioned } still
pass muster and then your whole stack is broken post-upgrade until you
run a "commit check" and find out what's wrong.  The software for EX4200
has come a long way in recent months, but you obviously don't have your
shit together with the upgrade process.  A working software rollback
process would be a nice addition, too.  Much love -- Jeff ;)

-- 
Jeff S Wheeler <jsw at inconcepts.biz> +1-212-981-0607
Sr Network Operator  /  Innovative Network Concepts