Unmounted any mount points in gc paths. In various corner cases, agent may not get chance to properly unmount persistent volumes mounted inside an executor's sandbox. When GC later gets to these sandbox directories, permanent data loss can happen (see MESOS-8830).
Currently, the only mounts in the host mount namespace under the sandbox directories are persistent volumes, so this diff added protection to unmount any dangling mount points before calling `rmdir` on the directory. NOTE: this means agent will not garbage collect any path if it cannot read its own `mountinfo` table. Review: https://reviews.apache.org/r/67264 Project: http://git-wip-us.apache.org/repos/asf/mesos/repo Commit: http://git-wip-us.apache.org/repos/asf/mesos/commit/0d76cc09 Tree: http://git-wip-us.apache.org/repos/asf/mesos/tree/0d76cc09 Diff: http://git-wip-us.apache.org/repos/asf/mesos/diff/0d76cc09 Branch: refs/heads/1.5.x Commit: 0d76cc090d18c86a04caac797322f3473b025cef Parents: c25ff64 Author: Zhitao Li <zhitaoli...@gmail.com> Authored: Tue May 22 10:55:50 2018 -0700 Committer: Chun-Hung Hsiao <chhs...@mesosphere.io> Committed: Mon Jul 2 13:56:46 2018 -0700 ---------------------------------------------------------------------- src/local/local.cpp | 2 +- src/slave/gc.cpp | 74 +++++++++++++++++++++++++++++++++++++++---- src/slave/gc.hpp | 2 +- src/slave/gc_process.hpp | 7 ++-- src/slave/main.cpp | 2 +- src/tests/cluster.cpp | 2 +- src/tests/gc_tests.cpp | 6 ++-- 7 files changed, 79 insertions(+), 16 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/local/local.cpp ---------------------------------------------------------------------- diff --git a/src/local/local.cpp b/src/local/local.cpp index ba1bcf2..9eb477b 100644 --- a/src/local/local.cpp +++ b/src/local/local.cpp @@ -423,7 +423,7 @@ PID<Master> launch(const Flags& flags, Allocator* _allocator) << slaveFlags.runtime_dir << "': " << mkdir.error(); } - garbageCollectors->push_back(new GarbageCollector()); + garbageCollectors->push_back(new GarbageCollector(slaveFlags.work_dir)); taskStatusUpdateManagers->push_back( new TaskStatusUpdateManager(slaveFlags)); fetchers->push_back(new Fetcher(slaveFlags)); http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/slave/gc.cpp ---------------------------------------------------------------------- diff --git a/src/slave/gc.cpp b/src/slave/gc.cpp index 390b35e..8770d88 100644 --- a/src/slave/gc.cpp +++ b/src/slave/gc.cpp @@ -25,6 +25,7 @@ #include <process/metrics/metrics.hpp> +#include <stout/adaptor.hpp> #include <stout/foreach.hpp> #include <stout/lambda.hpp> @@ -32,6 +33,10 @@ #include "logging/logging.hpp" +#ifdef __linux__ +#include "linux/fs.hpp" +#endif + #include "slave/gc_process.hpp" using namespace process; @@ -193,12 +198,69 @@ void GarbageCollectorProcess::remove(const Timeout& removalTime) Counter _succeeded = metrics.path_removals_succeeded; Counter _failed = metrics.path_removals_failed; + const string _workDir = workDir; - auto rmdirs = [_succeeded, _failed, infos]() { + auto rmdirs = + [_succeeded, _failed, _workDir, infos]() mutable -> Future<Nothing> { // Make mutable copies of the counters to work around MESOS-7907. Counter succeeded = _succeeded; Counter failed = _failed; +#ifdef __linux__ + // Clear any possible persistent volume mount points in `infos`. See + // MESOS-8830. + Try<fs::MountInfoTable> mountTable = fs::MountInfoTable::read(); + if (mountTable.isError()) { + LOG(ERROR) << "Skipping any path deletion because of failure on read " + "MountInfoTable for agent process: " + << mountTable.error(); + + foreach (const Owned<PathInfo>& info, infos) { + info->promise.fail(mountTable.error()); + ++failed; + } + + return Failure(mountTable.error()); + } + + foreach (const fs::MountInfoTable::Entry& entry, + adaptor::reverse(mountTable->entries)) { + // Ignore mounts whose targets are not under `workDir`. + if (!strings::startsWith( + path::join(entry.target, ""), + path::join(_workDir, ""))) { + continue; + } + + for (auto it = infos.begin(); it != infos.end(); ) { + const Owned<PathInfo>& info = *it; + // TODO(zhitao): Validate that both `info->path` and `workDir` are + // real paths. + if (strings::startsWith( + path::join(entry.target, ""), path::join(info->path, ""))) { + LOG(WARNING) + << "Unmounting dangling mount point '" << entry.target + << "' of persistent volume '" << entry.root + << "' inside garbage collected path '" << info->path << "'"; + + Try<Nothing> unmount = fs::unmount(entry.target); + if (unmount.isError()) { + LOG(WARNING) << "Skipping deletion of '" + << info->path << "' because unmount failed on '" + << entry.target << "': " << unmount.error(); + + info->promise.fail(unmount.error()); + ++failed; + it = infos.erase(it); + continue; + } + } + + it++; + } + } +#endif // __linux__ + foreach (const Owned<PathInfo>& info, infos) { // Run the removal operation with 'continueOnError = true'. // It's possible for tasks and isolators to lay down files @@ -241,11 +303,9 @@ void GarbageCollectorProcess::remove(const Timeout& removalTime) } -void GarbageCollectorProcess::_remove(const Future<Nothing>& result, - const list<Owned<PathInfo>> infos) +void GarbageCollectorProcess::_remove(const Future<Nothing>& result, + const list<Owned<PathInfo>> infos) { - CHECK_READY(result); - // Remove path records from `paths` and `timeouts` data structures. foreach (const Owned<PathInfo>& info, infos) { CHECK(paths.remove(timeouts[info->path], info)); @@ -268,9 +328,9 @@ void GarbageCollectorProcess::prune(const Duration& d) } -GarbageCollector::GarbageCollector() +GarbageCollector::GarbageCollector(const string& workDir) { - process = new GarbageCollectorProcess(); + process = new GarbageCollectorProcess(workDir); spawn(process); } http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/slave/gc.hpp ---------------------------------------------------------------------- diff --git a/src/slave/gc.hpp b/src/slave/gc.hpp index df40165..0275c73 100644 --- a/src/slave/gc.hpp +++ b/src/slave/gc.hpp @@ -42,7 +42,7 @@ class GarbageCollectorProcess; class GarbageCollector { public: - GarbageCollector(); + explicit GarbageCollector(const std::string& workDir); virtual ~GarbageCollector(); // Schedules the specified path for removal after the specified http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/slave/gc_process.hpp ---------------------------------------------------------------------- diff --git a/src/slave/gc_process.hpp b/src/slave/gc_process.hpp index 433b0e0..920c6ba 100644 --- a/src/slave/gc_process.hpp +++ b/src/slave/gc_process.hpp @@ -45,9 +45,10 @@ class GarbageCollectorProcess : public process::Process<GarbageCollectorProcess> { public: - GarbageCollectorProcess() + explicit GarbageCollectorProcess(const std::string& _workDir) : ProcessBase(process::ID::generate("agent-garbage-collector")), - metrics(this) {} + metrics(this), + workDir(_workDir) {} virtual ~GarbageCollectorProcess(); @@ -97,6 +98,8 @@ private: process::metrics::Gauge path_removals_pending; } metrics; + const std::string workDir; + // Store all the timeouts and corresponding paths to delete. // NOTE: We are using Multimap here instead of Multihashmap, because // we need the keys of the map (deletion time) to be sorted. http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/slave/main.cpp ---------------------------------------------------------------------- diff --git a/src/slave/main.cpp b/src/slave/main.cpp index 43292ea..abbb84f 100644 --- a/src/slave/main.cpp +++ b/src/slave/main.cpp @@ -546,7 +546,7 @@ int main(int argc, char** argv) } Files* files = new Files(READONLY_HTTP_AUTHENTICATION_REALM, authorizer_); - GarbageCollector* gc = new GarbageCollector(); + GarbageCollector* gc = new GarbageCollector(flags.work_dir); TaskStatusUpdateManager* taskStatusUpdateManager = new TaskStatusUpdateManager(flags); http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/tests/cluster.cpp ---------------------------------------------------------------------- diff --git a/src/tests/cluster.cpp b/src/tests/cluster.cpp index de4ddf4..17642cf 100644 --- a/src/tests/cluster.cpp +++ b/src/tests/cluster.cpp @@ -486,7 +486,7 @@ Try<process::Owned<Slave>> Slave::create( // If the garbage collector is not provided, create a default one. if (gc.isNone()) { - slave->gc.reset(new slave::GarbageCollector()); + slave->gc.reset(new slave::GarbageCollector(flags.work_dir)); } // If the resource estimator is not provided, create a default one. http://git-wip-us.apache.org/repos/asf/mesos/blob/0d76cc09/src/tests/gc_tests.cpp ---------------------------------------------------------------------- diff --git a/src/tests/gc_tests.cpp b/src/tests/gc_tests.cpp index 0e34c01..fde4d69 100644 --- a/src/tests/gc_tests.cpp +++ b/src/tests/gc_tests.cpp @@ -95,7 +95,7 @@ class GarbageCollectorTest : public TemporaryDirectoryTest {}; TEST_F(GarbageCollectorTest, Schedule) { - GarbageCollector gc; + GarbageCollector gc("work_dir"); // Make some temporary files to gc. const string& file1 = "file1"; @@ -179,7 +179,7 @@ TEST_F(GarbageCollectorTest, Schedule) TEST_F(GarbageCollectorTest, Unschedule) { - GarbageCollector gc; + GarbageCollector gc("work_dir"); // Attempt to unschedule a file that is not scheduled. AWAIT_ASSERT_FALSE(gc.unschedule("bogus")); @@ -228,7 +228,7 @@ TEST_F(GarbageCollectorTest, Unschedule) TEST_F(GarbageCollectorTest, Prune) { - GarbageCollector gc; + GarbageCollector gc("work_dir"); // Make some temporary files to prune. const string& file1 = "file1";
