Files
scylladb/db/hints/resource_manager.cc
Dawid Medrek 58784cd8db db/hints: Handle arbitrary directories in resource manager
Before these changes, resource manager only handled
the case when directories it browsed represented
valid host IDs. However, since before migrating
hinted handoff to using host IDs we still name
directories after IP addresses, that would lead
to exceptins that shouldn't happen.

We make resource manager handle directories
of arbitrary names correctly.
2024-04-27 22:31:07 +02:00

288 lines
12 KiB
C++

/*
* Copyright (C) 2018-present ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#include "resource_manager.hh"
#include "gms/inet_address.hh"
#include "locator/token_metadata.hh"
#include "manager.hh"
#include "log.hh"
#include <boost/range/algorithm/for_each.hpp>
#include <boost/range/adaptor/map.hpp>
#include "utils/disk-error-handler.hh"
#include "seastarx.hh"
#include <seastar/core/sleep.hh>
#include <seastar/core/seastar.hh>
#include "utils/div_ceil.hh"
#include "utils/lister.hh"
namespace db {
namespace hints {
static logging::logger resource_manager_logger("hints_resource_manager");
future<dev_t> get_device_id(const fs::path& path) {
return file_stat(path.native()).then([] (struct stat_data sd) {
return sd.device_id;
});
}
future<bool> is_mountpoint(const fs::path& path) {
// Special case for '/', which is always a mount point
if (path == path.parent_path()) {
return make_ready_future<bool>(true);
}
return when_all(get_device_id(path), get_device_id(path.parent_path())).then([](std::tuple<future<dev_t>, future<dev_t>> ids) {
return std::get<0>(ids).get() != std::get<1>(ids).get();
});
}
future<semaphore_units<named_semaphore::exception_factory>> resource_manager::get_send_units_for(size_t buf_size) {
// In order to impose a limit on the number of hints being sent concurrently,
// require each hint to reserve at least 1/(max concurrency) of the shard budget
const size_t per_node_concurrency_limit = _max_hints_send_queue_length();
const size_t per_shard_concurrency_limit = (per_node_concurrency_limit > 0)
? div_ceil(per_node_concurrency_limit, smp::count)
: default_per_shard_concurrency_limit;
const size_t min_send_hint_budget = _max_send_in_flight_memory / per_shard_concurrency_limit;
// Let's approximate the memory size the mutation is going to consume by the size of its serialized form
size_t hint_memory_budget = std::max(min_send_hint_budget, buf_size);
// Allow a very big mutation to be sent out by consuming the whole shard budget
hint_memory_budget = std::min(hint_memory_budget, _max_send_in_flight_memory);
resource_manager_logger.trace("memory budget: need {} have {}", hint_memory_budget, _send_limiter.available_units());
return get_units(_send_limiter, hint_memory_budget);
}
size_t resource_manager::sending_queue_length() const {
return _send_limiter.waiters();
}
const std::chrono::seconds space_watchdog::_watchdog_period = std::chrono::seconds(1);
space_watchdog::space_watchdog(shard_managers_set& managers, per_device_limits_map& per_device_limits_map)
: _shard_managers(managers)
, _per_device_limits_map(per_device_limits_map)
, _update_lock(1, named_semaphore_exception_factory{"update lock"})
{}
void space_watchdog::start() {
_started = seastar::async([this] {
while (!_as.abort_requested()) {
try {
const auto units = get_units(_update_lock, 1).get();
on_timer();
} catch (...) {
resource_manager_logger.trace("space_watchdog: unexpected exception - stop all hints generators");
// Stop all hint generators if space_watchdog callback failed
for (manager& shard_manager : _shard_managers) {
shard_manager.forbid_hints();
}
}
seastar::sleep_abortable(_watchdog_period, _as).get();
}
}).handle_exception_type([] (const seastar::sleep_aborted& ignored) { });
}
future<> space_watchdog::stop() noexcept {
_as.request_abort();
return std::move(_started);
}
// Called under the end_point_hints_manager::file_update_mutex() of the corresponding end_point_hints_manager instance.
future<> space_watchdog::scan_one_ep_dir(fs::path path, manager& shard_manager,
std::optional<std::variant<locator::host_id, gms::inet_address>> maybe_ep_key) {
// It may happen that we get here and the directory has already been deleted in the context of manager::drain_for().
// In this case simply bail out.
if (!co_await file_exists(path.native())) {
co_return;
}
co_await lister::scan_dir(path, lister::dir_entry_types::of<directory_entry_type::regular>(),
coroutine::lambda([this, maybe_ep_key, &shard_manager] (fs::path dir, directory_entry de) -> future<> {
// Put the current end point ID to state.eps_with_pending_hints when we see the second hints file in its directory
if (maybe_ep_key && _files_count == 1) {
shard_manager.add_ep_with_pending_hints(*maybe_ep_key);
}
++_files_count;
const auto filename = (std::move(dir) / std::move(de.name)).native();
_total_size += co_await io_check(file_size, filename);
}));
}
// Called from the context of a seastar::thread.
void space_watchdog::on_timer() {
// The hints directories are organized as follows:
// <hints root>
// |- <shard1 ID>
// | |- <EP1 address>
// | |- <hints file1>
// | |- <hints file2>
// | |- ...
// | |- <EP2 address>
// | |- ...
// | |-...
// |- <shard2 ID>
// | |- ...
// ...
// |- <shardN ID>
// | |- ...
//
for (auto& per_device_limits : _per_device_limits_map | boost::adaptors::map_values) {
_total_size = 0;
for (manager& shard_manager : per_device_limits.managers) {
shard_manager.clear_eps_with_pending_hints();
lister::scan_dir(shard_manager.hints_dir(), lister::dir_entry_types::of<directory_entry_type::directory>(), [this, &shard_manager] (fs::path dir, directory_entry de) {
_files_count = 0;
// Let's scan per-end-point directories and enumerate hints files...
//
// Let's check if there is a corresponding end point manager (may not exist if the corresponding DC is
// not hintable).
// If exists - let's take a file update lock so that files are not changed under our feet. Otherwise, simply
// continue to enumeration - there is no one to change them.
auto maybe_variant = std::invoke([&] () -> std::optional<std::variant<locator::host_id, gms::inet_address>> {
try {
const auto hid_or_ep = locator::host_id_or_endpoint{de.name};
if (hid_or_ep.has_host_id()) {
return std::variant<locator::host_id, gms::inet_address>(hid_or_ep.id());
} else {
return std::variant<locator::host_id, gms::inet_address>(hid_or_ep.endpoint());
}
} catch (...) {
return std::nullopt;
}
});
// Case 1: The directory is managed by an endpoint manager.
if (maybe_variant && shard_manager.have_ep_manager(*maybe_variant)) {
const auto variant = *maybe_variant;
return shard_manager.with_file_update_mutex_for(variant, [this, variant, &shard_manager, dir = std::move(dir), ep_name = std::move(de.name)] () mutable {
return scan_one_ep_dir(dir / ep_name, shard_manager, variant);
});
}
// Case 2: The directory isn't managed by an endpoint manager, but it represents either an IP address,
// or a host ID.
else if (maybe_variant) {
return scan_one_ep_dir(dir / de.name, shard_manager, *maybe_variant);
}
// Case 3: The directory isn't managed by an endpoint manager, and it represents neither an IP address,
// nor a host ID.
else {
return scan_one_ep_dir(dir / de.name, shard_manager, {});
}
}).get();
}
// Adjust the quota to take into account the space we guarantee to every end point manager
size_t adjusted_quota = 0;
size_t delta = boost::accumulate(per_device_limits.managers, 0, [] (size_t sum, manager& shard_manager) {
return sum + shard_manager.ep_managers_size() * resource_manager::hint_segment_size_in_mb * 1024 * 1024;
});
if (per_device_limits.max_shard_disk_space_size > delta) {
adjusted_quota = per_device_limits.max_shard_disk_space_size - delta;
}
resource_manager_logger.trace("space_watchdog: consuming {}/{} bytes", _total_size, adjusted_quota);
for (manager& shard_manager : per_device_limits.managers) {
shard_manager.update_backlog(_total_size, adjusted_quota);
}
}
}
future<> resource_manager::start(shared_ptr<gms::gossiper> gossiper_ptr) {
_gossiper_ptr = std::move(gossiper_ptr);
return with_semaphore(_operation_lock, 1, [this] () {
return parallel_for_each(_shard_managers, [this](manager& m) {
return m.start(_gossiper_ptr);
}).then([this]() {
return do_for_each(_shard_managers, [this](manager& m) {
return prepare_per_device_limits(m);
});
}).then([this]() {
return _space_watchdog.start();
}).then([this]() {
set_running();
});
});
}
void resource_manager::allow_replaying() noexcept {
set_replay_allowed();
boost::for_each(_shard_managers, [] (manager& m) { m.allow_replaying(); });
}
future<> resource_manager::stop() noexcept {
return with_semaphore(_operation_lock, 1, [this] () {
return parallel_for_each(_shard_managers, [](manager& m) {
return m.stop();
}).finally([this]() {
return _space_watchdog.stop();
}).then([this]() {
unset_running();
});
});
}
future<> resource_manager::register_manager(manager& m) {
return with_semaphore(_operation_lock, 1, [this, &m] () {
return with_semaphore(_space_watchdog.update_lock(), 1, [this, &m] {
const auto [it, inserted] = _shard_managers.insert(m);
if (!inserted) {
// Already registered
return make_ready_future<>();
}
if (!running()) {
// The hints manager will be started later by resource_manager::start()
return make_ready_future<>();
}
// If the resource_manager was started, start the hints manager, too.
return m.start(_gossiper_ptr).then([this, &m] {
// Calculate device limits for this manager so that it is accounted for
// by the space_watchdog
return prepare_per_device_limits(m).then([this, &m] {
if (this->replay_allowed()) {
m.allow_replaying();
}
});
}).handle_exception([this, &m] (auto ep) {
_shard_managers.erase(m);
return make_exception_future<>(ep);
});
});
});
}
future<> resource_manager::prepare_per_device_limits(manager& shard_manager) {
dev_t device_id = shard_manager.hints_dir_device_id();
auto it = _per_device_limits_map.find(device_id);
if (it == _per_device_limits_map.end()) {
return is_mountpoint(shard_manager.hints_dir().parent_path()).then([this, device_id, &shard_manager](bool is_mountpoint) {
auto [it, inserted] = _per_device_limits_map.emplace(device_id, space_watchdog::per_device_limits{});
// Since we possibly deferred, we need to recheck the _per_device_limits_map.
if (inserted) {
// By default, give each group of managers 10% of the available disk space. Give each shard an equal share of the available space.
it->second.max_shard_disk_space_size = std::filesystem::space(shard_manager.hints_dir().c_str()).capacity / (10 * smp::count);
// If hints directory is a mountpoint, we assume it's on dedicated (i.e. not shared with data/commitlog/etc) storage.
// Then, reserve 90% of all space instead of 10% above.
if (is_mountpoint) {
it->second.max_shard_disk_space_size *= 9;
}
}
it->second.managers.emplace_back(std::ref(shard_manager));
});
} else {
it->second.managers.emplace_back(std::ref(shard_manager));
return make_ready_future<>();
}
}
}
}