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Fix it, then Ship it! LGTM in general. I may not be around for the rest of the day and the weekend, so I mark thas 'Ship it, then fix it'. RELEASE-NOTES.md (line 13) <https://reviews.apache.org/r/53418/#comment224699> This should be elaborated a little bit more. It is confusing as Thermos processes have a `daemon` property. RELEASE-NOTES.md (line 14) <https://reviews.apache.org/r/53418/#comment224700> We should try to make that optional. See below for details. src/main/python/apache/thermos/common/process_util.py (lines 50 - 74) <https://reviews.apache.org/r/53418/#comment224703> I would propose to wrap that entire method in a try-catch block so that this method is effectively no-throw. The advantages: * Thermos will still work on Kernels older than 3.4 (even though those would still be affected by the bug you have reported). * We minimize the risk of crashes due to bugs in this low level code. * We can provide propper logging here, as we have the necessary context to explain what is going on and that it is safe to continue. src/main/python/apache/thermos/core/process.py (lines 288 - 297) <https://reviews.apache.org/r/53418/#comment224702> As mentioned above, I would propose to do the error handling in `setup_child_subreaping` directly. src/test/sh/org/apache/aurora/e2e/test_daemonizing_process.aurora (line 38) <https://reviews.apache.org/r/53418/#comment224705> Please add a small comment here for future readers. For example: "Assert that Thermos does not lose track of double forking processes. On task teardown the daemonized process should receive a signal to shut down cleanly." - Stephan Erb On Nov. 4, 2016, 12:48 a.m., Zameer Manji wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/53418/ > ----------------------------------------------------------- > > (Updated Nov. 4, 2016, 12:48 a.m.) > > > Review request for Aurora, Joshua Cohen and Stephan Erb. > > > Bugs: AURORA-1808 > https://issues.apache.org/jira/browse/AURORA-1808 > > > Repository: aurora > > > Description > ------- > > # Problem > > Processes can deamonize and escape the supervision of a coordinator. Using > the Docker Containerizer or the Mesos Containerizer with pid isolation means > that the processes will be come reparented to the sh process that launches > the executor. For example: > > ``` > root@aurora:/# ps xf > PID TTY STAT TIME COMMAND > 48 ? Ss 0:00 /bin/bash > 86 ? R+ 0:00 _ ps xf > 1 ? Ss 0:00 /bin/sh -c ${MESOS_SANDBOX=.}/thermos_executor.pex > --announcer-ensemble localhost:2181 --announcer-zookeeper-auth-config > /home/vagrant/aurora/examples/va > 5 ? Sl 0:02 python2.7 /mnt/mesos/sandbox/thermos_executor.pex > --announcer-ensemble localhost:2181 --announcer-zookeeper-auth-config > /home/vagrant/aurora/examples/vag > 23 ? S 0:00 _ /usr/local/bin/python2.7 > /mnt/mesos/sandbox/thermos_runner.pex > --task_id=www-data-devel-hello_docker_engine-0-bde5cdc7-8685-46fd-9078-4a86bd5be152 > -- > 29 ? Ss 0:00 _ /usr/local/bin/python2.7 > /mnt/mesos/sandbox/thermos_runner.pex > --task_id=www-data-devel-hello_docker_engine-0-bde5cdc7-8685-46fd-9078-4a86bd5be15 > 32 ? S 0:00 | _ /bin/bash -c while true; do > echo hello world sleep 10 done > 81 ? S 0:00 | _ sleep 10 > 31 ? Ss 0:00 _ /usr/local/bin/python2.7 > /mnt/mesos/sandbox/thermos_runner.pex > --task_id=www-data-devel-hello_docker_engine-0-bde5cdc7-8685-46fd-9078-4a86bd5be15 > 33 ? S 0:00 _ /bin/bash -c while true; do > echo hello world sleep 10 done > 82 ? S 0:00 _ sleep 10 > 47 ? S 0:00 python ./daemon.py > ``` > > # Solution > > Ensure processes that escape the supervision of the coordinator reparent to > the runner who can send signals to them on task tear down. We do this by > using the `PR_SET_CHILD_SUBREAPER` flag of `prctl(2)`. > > After this change the process tree looks like: > ``` > root@aurora:/# ps xf > PID TTY STAT TIME COMMAND > 66 ? Ss 0:00 /bin/bash > 70 ? R+ 0:00 _ ps xf > 1 ? Ss 0:00 /bin/sh -c ${MESOS_SANDBOX=.}/thermos_executor.pex > --announcer-ensemble localhost:2181 --announcer-zookeeper-auth-config > /home/vagrant/aurora/examples/va > 5 ? Sl 0:02 python2.7 /mnt/mesos/sandbox/thermos_executor.pex > --announcer-ensemble localhost:2181 --announcer-zookeeper-auth-config > /home/vagrant/aurora/examples/vag > 23 ? S 0:00 _ /usr/local/bin/python2.7 > /mnt/mesos/sandbox/thermos_runner.pex > --task_id=www-data-devel-hello_docker_engine-0-721406db-00f5-4c0c-915e-1dbc5568b849 > -- > 33 ? Ss 0:00 _ /usr/local/bin/python2.7 > /mnt/mesos/sandbox/thermos_runner.pex > --task_id=www-data-devel-hello_docker_engine-0-721406db-00f5-4c0c-915e-1dbc5568b84 > 40 ? S 0:00 | _ /bin/bash -c while true; do > echo hello world sleep 10 done > 63 ? S 0:00 | _ sleep 10 > 36 ? Ss 0:00 _ /usr/local/bin/python2.7 > /mnt/mesos/sandbox/thermos_runner.pex > --task_id=www-data-devel-hello_docker_engine-0-721406db-00f5-4c0c-915e-1dbc5568b84 > 37 ? S 0:00 | _ /bin/bash -c while true; do > echo hello world sleep 10 done > 62 ? S 0:00 | _ sleep 10 > 55 ? S 0:00 _ python ./daemon.py > > ``` > > Now the runner is aware of the reparented procesess can can tear it down > cleanly with a `SIGTERM`. > > > Diffs > ----- > > RELEASE-NOTES.md d89ef2f641373ac229be693a21a2c0111e1f241a > src/main/python/apache/thermos/common/process_util.py > abd2c0ef35858d13971319b0a7436ce2293824ce > src/main/python/apache/thermos/core/helper.py > 68855e1e54ba1cd4456e18a36fb237ce6a468c34 > src/main/python/apache/thermos/core/process.py > 3ec43e2719ef97026f399c4b2aa23002559b3153 > src/main/python/apache/thermos/core/runner.py > 7b9013d11f6ff4172b6b7bf56e62299b0d11c977 > src/test/sh/org/apache/aurora/e2e/test_daemonizing_process.aurora > PRE-CREATION > src/test/sh/org/apache/aurora/e2e/test_end_to_end.sh > 67702d2c0f2e18ee10dcb798b6d421050bd7d4ca > > Diff: https://reviews.apache.org/r/53418/diff/ > > > Testing > ------- > > src/test/sh/org/apache/aurora/e2e/test_end_to_end.sh > > > Thanks, > > Zameer Manji > >
