I'm guessing this is waiting for a SRU. Here's the patch for Lucid and
Maverick. Description updated for SRU. Please somebody add some notes to
'REGRESSION POTENTIAL' because I have no idea about that...
** Description changed:
When sshd gets a signal 1 for reload, it forks a new process and ditches
the old. This causes upstart to believe that ssh has crashed, and loses
track of it. A second reload (or any other initctl operation on ssh)
will thus say:
reload: Unknown instance:
There would be 2 ways to fix this:
1. Don't have ssh fork on relod, but keep the same pid
2. Use a different mechanism in upstart to keep track of ssh. Maybe a pid
file? Just tracking children of the exited ssh won't work, or it might
accidentally track a particular session rather than the master, if somebody
just happens to log in close to reload time.
+ openssh-server 1:5.3p1-3ubuntu4
+ upstart 0.6.5-7
- # lsb_release -rd
- Description: Ubuntu 10.04.1 LTS
- Release: 10.04
+ ==== Info for Maverick, Lucid SRU ====
+ IMPACT: if sshd gets a HUP signal, it forks a new process and upstart thinks
the process died and loses track of it, so the user/admin uses the ability to
stop/start/reload the daemon through upstart.
+ The problem is fixed in Natty 5.6p1-2ubuntu3. See attached patches for
Maverick and Lucid.
- # dpkg -l openssh-server | cat
- Desired=Unknown/Install/Remove/Purge/Hold
- | Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend
- |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
- ||/ Name Version
Description
-
+++-===========================================-==========================================================-=================================================================
- ii openssh-server 1:5.3p1-3ubuntu4
secure shell (SSH) server, for secure access from
remote machines
+ TEST CASE:
- # dpkg -l upstart
- Desired=Unknown/Install/Remove/Purge/Hold
- | Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend
- |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
- ||/ Name Version Description
- +++-==============-==============-============================================
- ii upstart 0.6.5-7 event-based init daemon
+ - install openssh-server
+ - send a HUP signal to sshd
+ - the daemon is restarted, but upstart thinks that it crashed
(/var/log/daemon.log):
+
+ Dec 28 20:59:57 utest-lls32 init: ssh main process ended, respawning
+ Dec 28 20:59:57 utest-lls32 init: ssh main process (1451) terminated with
status 255
+ Dec 28 20:59:57 utest-lls32 init: ssh main process ended, respawning
+ Dec 28 20:59:57 utest-lls32 init: ssh main process (1455) terminated with
status 255
+ Dec 28 20:59:57 utest-lls32 init: ssh respawning too fast, stopped
+
+ - after this, upstart won't know about sshd, despite the daemon running
+ just fine:
+
+ r...@utest-lls32:~# reload ssh
+ reload: Unknown instance:
+
+ With the fix applied, the correct behavior is:
+
+ - send a HUP signal to sshd
+ ps ax |grep sshd
+ kill -HUP sshd
+ - the daemon reloads (/var/log/auth.log):
+
+ Dec 28 21:37:01 utest-lls32 sshd[742]: Received SIGHUP; restarting.
+ Dec 28 21:37:01 utest-lls32 sshd[742]: Server listening on 0.0.0.0 port 22.
+ Dec 28 21:37:01 utest-lls32 sshd[742]: Server listening on :: port 22.
+
+ - reloading with upstart gives the same result, and NOT an error
+ message.
+
+ REGRESSION POTENTIAL: TODO
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https://bugs.launchpad.net/bugs/687535
Title:
upstart loses track of ssh daemon after reload ssh
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