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This is definitely the direction we want to head towards (Job objects, without leaking handles). But, due to the partial duplication of logic in: https://reviews.apache.org/r/56366/ I think we should move much of this logic into libprocess. Here's the gist of what should be done: * We'll want a new, Windows-only actor that is created in `process::initialize`. This will look very similar to the `GarbageCollector` process in `include/process/gc.hpp`. Something like: ``` class JobObjectManager : public Process<JobObjectManager> { public: JobObjectManager() : ProcessBase("__job_object_manager__") {} virtual ~JobObjectManager() {} // NOTE: Maybe you'll want the actor to create the JobObject itself. // You could even move the CREATE_JOB parent hook into this file. void manage(const pid_t pid, const std::string& name, const SharedHandle& handle) { objects[pid] = {name, handle}; process::reap(pid) .onAny(lambda::bind(&Self::cleanup, lambda::_1, pid)); } protected: virtual void cleanup(Future<Option<int>> exit_code, const pid_t pid) { CHECK(!exit_code.isPending()); CHECK(!exit_code.isDiscarded()); Try<Nothing> killJobResult = os::kill_job(objects[pid].handle.get()); CHECK(!killJobResult.isError()) << "Failed to kill job object: " + killJobResult.error(); objects.erase(pid); } private: struct JobData { std::string name; SharedHandle handle; } std::map<pid, JobData> objects; }; ``` * You can either expose the actor's methods via `process.hpp` or via moving the ParentHook into the new actor. * The WindowsLauncher would become a thin wrapper around the new actor. * https://reviews.apache.org/r/56366/ should become much simpler. src/slave/containerizer/mesos/windows_launcher.cpp (lines 50 - 62) <https://reviews.apache.org/r/56362/#comment238647> Erm... saving the set of PIDs in a prior loop guarantees that the `pids.contains(pid)` condition will be met. - Joseph Wu On Feb. 10, 2017, 6:04 p.m., Andrew Schwartzmeyer wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/56362/ > ----------------------------------------------------------- > > (Updated Feb. 10, 2017, 6:04 p.m.) > > > Review request for mesos, Alex Clemmer and Joseph Wu. > > > Bugs: MESOS-6892 > https://issues.apache.org/jira/browse/MESOS-6892 > > > Repository: mesos > > > Description > ------- > > Instead of deriving `WindowsLauncher` from `PosixLauncher`, > this commit implements a separate `WindowsLauncher` derived > from `Launcher` parallel to the `PosixLauncher`. > > This launcher is then refactored to use Windows' "Job Objects," which > are similar to Linux's cgroups, and enable us to reason about a group > of processes associated with a task/container as a "Job Object" > instead of a root PID and the tree containing its children. The latter > is not a reasonable approach on Windows, and has been the source of > subtle bugs. > > The Job Object approach creates a named job with a one-to-one mapping > to the containerizer, and assigns the first process started for the > task to the job object. After being assigned, the Windows kernel > ensures all spawned child processes > (specifically those made with the `CreateProcess` system call) are > also assigned to the named job object. Thus this job object can then > be used to query the process group's resource usage, kill the process > group, and set limits on the process group. > > So instead of seeing a process group as a tree and referring to it by > the root process's PID, the `WindowsLauncher` sees a process group as > a named Job Object, the same way the Windows kernel sees it. However, > the containerizer code which interacts with the launcher still refers > to a task group by the singular PID, and so we have a sort of shim > which maps the initial PID to the name of the job object. This is a an > unfortunate consequence of the shared containerizer code being > originally written for POSIX-like systems. > > This abstraction sets us up for implementing resource usage limits on > the process group as a whole. > > > Diffs > ----- > > src/CMakeLists.txt 3a4ace9c8011ac8eec5067cd085fa7fe4166b9ee > src/slave/containerizer/mesos/containerizer.cpp > d2b4f75a55dbe4746bc2dfc180335fa831a554ef > src/slave/containerizer/mesos/launcher.hpp > 79f6eea0ee8e564e90b36208672df150dbc5d540 > src/slave/containerizer/mesos/launcher.cpp > 5114c130efbfb252dde1e85c081f5174e66f57af > src/slave/containerizer/mesos/windows_launcher.hpp PRE-CREATION > src/slave/containerizer/mesos/windows_launcher.cpp PRE-CREATION > > Diff: https://reviews.apache.org/r/56362/diff/ > > > Testing > ------- > > > Thanks, > > Andrew Schwartzmeyer > >
