BIND 10 #1049: bind10 should not resort to SIGKILL

[BIND 10 Development]

#1049: bind10 should not resort to SIGKILL
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                   Reporter:  jreed  |                 Owner:
                       Type:         |                Status:  new
  defect                             |             Milestone:  Year 3 Task
                   Priority:  major  |  Backlog
                  Component:  Boss   |            Resolution:
  of BIND                            |             Sensitive:  0
                   Keywords:         |           Sub-Project:  DNS
            Defect Severity:  N/A    |  Estimated Difficulty:  0.0
Feature Depending on Ticket:         |           Total Hours:  0
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Changes (by shane):

 * milestone:  New Tasks => Year 3 Task Backlog


Comment:

 There are two issues here.

 First, I agree that a process not exiting with the shutdown message - or
 at least SIGTERM - is a bug. I also agree that using SIGKILL masks this.
 So we do need a way for developers to disable this.

 The second issue is that in real operation the system needs to promptly
 shut down, even if there are developer errors. So I argue that for default
 operation we need to keep the system "as is".

 As for the timing... waiting a few seconds seems insane to me. All of our
 tasks need to be able to handle being shut down at any time anyway (we may
 get accidental "kill -9" from administrator mistyping process ID, the
 Linux out-of-memory handler can shut things down, power cables can be
 tripped over, and so on). Having the system take more than a second to
 shutdown seems like a defect to me, and there doesn't seem to be any real
 need for it.

 So I think this ticket has a few work items, both minor:

   1. Add a flag to disable SIGKILL on shutdown (or perhaps one to set the
 interval before falling back to SIGKILL?)
   1. Fix any processes that currently block or catch SIGTERM (besides the
 boss)
   1. Insure all processes properly handle shutdown requests

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Ticket URL: <http://bind10.isc.org/ticket/1049#comment:1>
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