Files
scylladb/test/boost/tablets_test.cc
Tomasz Grabiec 551cc0233d tablets, raft topology: Add support for decommission with tablets
Load balancer will recognize decommissioning nodes and will
move tablet replicas away from such nodes with highest priority.

Topology changes have now an extra step called "tablet draining" which
calls the load balancer. The step will execute tablet migration track
as long as there are nodes which require draining. It will not do regular
load balancing.

If load balancer is unable to find new tablet replicas, because RF
cannot be met or availability is at risk due to insufficient node
distribution in racks, it will throw an exception. Currently, topology
change will retry in a loop. We should make this error cause topology
change to be paused so that admin becomes aware of the problem and
issues an abort on the topology change. There is no infrastructure for
aborts yet, so this is not implemented.
2023-09-14 13:05:49 +02:00

1399 lines
52 KiB
C++

/*
* Copyright (C) 2023-present-2020 ScyllaDB
*/
/*
* SPDX-License-Identifier: AGPL-3.0-or-later
*/
#include "test/lib/scylla_test_case.hh"
#include "test/lib/random_utils.hh"
#include <seastar/testing/thread_test_case.hh>
#include "test/lib/cql_test_env.hh"
#include "test/lib/log.hh"
#include "db/config.hh"
#include "schema/schema_builder.hh"
#include "replica/tablets.hh"
#include "replica/tablet_mutation_builder.hh"
#include "locator/tablets.hh"
#include "service/tablet_allocator.hh"
#include "locator/tablet_sharder.hh"
#include "locator/load_sketch.hh"
#include "locator/tablet_replication_strategy.hh"
#include "utils/fb_utilities.hh"
#include "utils/UUID_gen.hh"
#include "utils/error_injection.hh"
using namespace locator;
using namespace replica;
using namespace service;
static api::timestamp_type next_timestamp = api::new_timestamp();
static utils::UUID next_uuid() {
static uint64_t counter = 1;
return utils::UUID_gen::get_time_UUID(std::chrono::system_clock::time_point(
std::chrono::duration_cast<std::chrono::system_clock::duration>(
std::chrono::seconds(counter++))));
}
static
void verify_tablet_metadata_persistence(cql_test_env& env, const tablet_metadata& tm) {
save_tablet_metadata(env.local_db(), tm, next_timestamp++).get();
auto tm2 = read_tablet_metadata(env.local_qp()).get0();
BOOST_REQUIRE_EQUAL(tm, tm2);
}
static
cql_test_config tablet_cql_test_config() {
cql_test_config c;
c.db_config->experimental_features({
db::experimental_features_t::feature::TABLETS,
}, db::config::config_source::CommandLine);
c.db_config->consistent_cluster_management(true);
return c;
}
static
future<table_id> add_table(cql_test_env& e) {
auto id = table_id(utils::UUID_gen::get_time_UUID());
co_await e.create_table([id] (std::string_view ks_name) {
return *schema_builder(ks_name, id.to_sstring(), id)
.with_column("p1", utf8_type, column_kind::partition_key)
.with_column("r1", int32_type)
.build();
});
co_return id;
}
SEASTAR_TEST_CASE(test_tablet_metadata_persistence) {
return do_with_cql_env_thread([] (cql_test_env& e) {
auto h1 = host_id(utils::UUID_gen::get_time_UUID());
auto h2 = host_id(utils::UUID_gen::get_time_UUID());
auto h3 = host_id(utils::UUID_gen::get_time_UUID());
auto table1 = add_table(e).get0();
auto table2 = add_table(e).get0();
{
tablet_metadata tm;
// Empty
verify_tablet_metadata_persistence(e, tm);
// Add table1
{
tablet_map tmap(1);
tmap.set_tablet(tmap.first_tablet(), tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h2, 3},
tablet_replica {h3, 1},
}
});
tm.set_tablet_map(table1, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
// Add table2
{
tablet_map tmap(4);
auto tb = tmap.first_tablet();
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
}
});
tb = *tmap.next_tablet(tb);
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h3, 3},
}
});
tb = *tmap.next_tablet(tb);
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h2, 2},
}
});
tb = *tmap.next_tablet(tb);
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h1, 1},
}
});
tm.set_tablet_map(table2, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
// Increase RF of table2
{
auto&& tmap = tm.get_tablet_map(table2);
auto tb = tmap.first_tablet();
tb = *tmap.next_tablet(tb);
tmap.set_tablet_transition_info(tb, tablet_transition_info{
tablet_transition_stage::allow_write_both_read_old,
tablet_replica_set {
tablet_replica {h3, 3},
tablet_replica {h1, 7},
},
tablet_replica {h1, 7}
});
tb = *tmap.next_tablet(tb);
tmap.set_tablet_transition_info(tb, tablet_transition_info{
tablet_transition_stage::use_new,
tablet_replica_set {
tablet_replica {h1, 4},
tablet_replica {h2, 2},
},
tablet_replica {h1, 4}
});
}
verify_tablet_metadata_persistence(e, tm);
// Reduce tablet count in table2
{
tablet_map tmap(2);
auto tb = tmap.first_tablet();
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
}
});
tb = *tmap.next_tablet(tb);
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h3, 3},
}
});
tm.set_tablet_map(table2, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
// Reduce RF for table1, increasing tablet count
{
tablet_map tmap(2);
auto tb = tmap.first_tablet();
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h3, 7},
}
});
tb = *tmap.next_tablet(tb);
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h1, 3},
}
});
tm.set_tablet_map(table1, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
// Reduce tablet count for table1
{
tablet_map tmap(1);
auto tb = tmap.first_tablet();
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h1, 3},
}
});
tm.set_tablet_map(table1, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
// Change replica of table1
{
tablet_map tmap(1);
auto tb = tmap.first_tablet();
tmap.set_tablet(tb, tablet_info {
tablet_replica_set {
tablet_replica {h3, 7},
}
});
tm.set_tablet_map(table1, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
}
}, tablet_cql_test_config());
}
SEASTAR_TEST_CASE(test_get_shard) {
return do_with_cql_env_thread([] (cql_test_env& e) {
auto h1 = host_id(utils::UUID_gen::get_time_UUID());
auto h2 = host_id(utils::UUID_gen::get_time_UUID());
auto h3 = host_id(utils::UUID_gen::get_time_UUID());
auto table1 = table_id(utils::UUID_gen::get_time_UUID());
tablet_metadata tm;
tablet_id tid(0);
tablet_id tid1(0);
{
tablet_map tmap(2);
tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h3, 5},
}
});
tid1 = *tmap.next_tablet(tid);
tmap.set_tablet(tid1, tablet_info {
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h3, 1},
}
});
tmap.set_tablet_transition_info(tid, tablet_transition_info {
tablet_transition_stage::allow_write_both_read_old,
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h2, 3},
},
tablet_replica {h2, 3}
});
tm.set_tablet_map(table1, std::move(tmap));
}
auto&& tmap = tm.get_tablet_map(table1);
BOOST_REQUIRE_EQUAL(tmap.get_shard(tid1, h1), std::make_optional(shard_id(2)));
BOOST_REQUIRE(!tmap.get_shard(tid1, h2));
BOOST_REQUIRE_EQUAL(tmap.get_shard(tid1, h3), std::make_optional(shard_id(1)));
BOOST_REQUIRE_EQUAL(tmap.get_shard(tid, h1), std::make_optional(shard_id(0)));
BOOST_REQUIRE_EQUAL(tmap.get_shard(tid, h2), std::make_optional(shard_id(3)));
BOOST_REQUIRE_EQUAL(tmap.get_shard(tid, h3), std::make_optional(shard_id(5)));
}, tablet_cql_test_config());
}
SEASTAR_TEST_CASE(test_mutation_builder) {
return do_with_cql_env_thread([] (cql_test_env& e) {
auto h1 = host_id(utils::UUID_gen::get_time_UUID());
auto h2 = host_id(utils::UUID_gen::get_time_UUID());
auto h3 = host_id(utils::UUID_gen::get_time_UUID());
auto table1 = add_table(e).get0();
tablet_metadata tm;
tablet_id tid(0);
tablet_id tid1(0);
{
tablet_map tmap(2);
tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h3, 5},
}
});
tid1 = *tmap.next_tablet(tid);
tmap.set_tablet(tid1, tablet_info {
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h3, 1},
}
});
tm.set_tablet_map(table1, std::move(tmap));
}
save_tablet_metadata(e.local_db(), tm, next_timestamp++).get();
{
tablet_mutation_builder b(next_timestamp++, "ks", table1);
auto last_token = tm.get_tablet_map(table1).get_last_token(tid1);
b.set_new_replicas(last_token, tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h2, 3},
});
b.set_stage(last_token, tablet_transition_stage::write_both_read_new);
e.local_db().apply({freeze(b.build())}, db::no_timeout).get();
}
{
tablet_map expected_tmap(2);
tid = expected_tmap.first_tablet();
expected_tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h3, 5},
}
});
tid1 = *expected_tmap.next_tablet(tid);
expected_tmap.set_tablet(tid1, tablet_info {
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h3, 1},
}
});
expected_tmap.set_tablet_transition_info(tid1, tablet_transition_info {
tablet_transition_stage::write_both_read_new,
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h2, 3},
},
tablet_replica {h2, 3}
});
auto tm_from_disk = read_tablet_metadata(e.local_qp()).get0();
BOOST_REQUIRE_EQUAL(expected_tmap, tm_from_disk.get_tablet_map(table1));
}
{
tablet_mutation_builder b(next_timestamp++, "ks", table1);
auto last_token = tm.get_tablet_map(table1).get_last_token(tid1);
b.set_stage(last_token, tablet_transition_stage::use_new);
e.local_db().apply({freeze(b.build())}, db::no_timeout).get();
}
{
tablet_map expected_tmap(2);
tid = expected_tmap.first_tablet();
expected_tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h3, 5},
}
});
tid1 = *expected_tmap.next_tablet(tid);
expected_tmap.set_tablet(tid1, tablet_info {
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h3, 1},
}
});
expected_tmap.set_tablet_transition_info(tid1, tablet_transition_info {
tablet_transition_stage::use_new,
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h2, 3},
},
tablet_replica {h2, 3}
});
auto tm_from_disk = read_tablet_metadata(e.local_qp()).get0();
BOOST_REQUIRE_EQUAL(expected_tmap, tm_from_disk.get_tablet_map(table1));
}
{
tablet_mutation_builder b(next_timestamp++, "ks", table1);
auto last_token = tm.get_tablet_map(table1).get_last_token(tid1);
b.set_replicas(last_token, tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h2, 3},
});
b.del_transition(last_token);
e.local_db().apply({freeze(b.build())}, db::no_timeout).get();
}
{
tablet_map expected_tmap(2);
tid = expected_tmap.first_tablet();
expected_tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 0},
tablet_replica {h3, 5},
}
});
tid1 = *expected_tmap.next_tablet(tid);
expected_tmap.set_tablet(tid1, tablet_info {
tablet_replica_set {
tablet_replica {h1, 2},
tablet_replica {h2, 3},
}
});
auto tm_from_disk = read_tablet_metadata(e.local_qp()).get0();
BOOST_REQUIRE_EQUAL(expected_tmap, tm_from_disk.get_tablet_map(table1));
}
}, tablet_cql_test_config());
}
SEASTAR_TEST_CASE(test_sharder) {
return do_with_cql_env_thread([] (cql_test_env& e) {
auto h1 = host_id(utils::UUID_gen::get_time_UUID());
auto h2 = host_id(utils::UUID_gen::get_time_UUID());
auto h3 = host_id(utils::UUID_gen::get_time_UUID());
auto table1 = table_id(utils::UUID_gen::get_time_UUID());
token_metadata tokm(token_metadata::config{ .topo_cfg{ .this_host_id = h1 } });
tokm.get_topology().add_or_update_endpoint(utils::fb_utilities::get_broadcast_address(), h1);
std::vector<tablet_id> tablet_ids;
{
tablet_map tmap(4);
auto tid = tmap.first_tablet();
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h1, 3},
tablet_replica {h3, 5},
}
});
tid = *tmap.next_tablet(tid);
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h2, 3},
tablet_replica {h3, 1},
}
});
tid = *tmap.next_tablet(tid);
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h3, 2},
tablet_replica {h1, 1},
}
});
tmap.set_tablet_transition_info(tid, tablet_transition_info {
tablet_transition_stage::use_new,
tablet_replica_set {
tablet_replica {h1, 1},
tablet_replica {h2, 3},
},
tablet_replica {h2, 3}
});
tid = *tmap.next_tablet(tid);
tablet_ids.push_back(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {h3, 7},
tablet_replica {h2, 3},
}
});
tablet_metadata tm;
tm.set_tablet_map(table1, std::move(tmap));
tokm.set_tablets(std::move(tm));
}
auto& tm = tokm.tablets().get_tablet_map(table1);
tablet_sharder sharder(tokm, table1);
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[0])), 3);
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[1])), 0); // missing
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[2])), 1);
BOOST_REQUIRE_EQUAL(sharder.shard_of(tm.get_last_token(tablet_ids[3])), 0); // missing
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_last_token(tablet_ids[1]), 0), tm.get_first_token(tablet_ids[3]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_last_token(tablet_ids[1]), 1), tm.get_first_token(tablet_ids[2]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_last_token(tablet_ids[1]), 3), dht::maximum_token());
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_first_token(tablet_ids[1]), 0), tm.get_first_token(tablet_ids[3]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_first_token(tablet_ids[1]), 1), tm.get_first_token(tablet_ids[2]));
BOOST_REQUIRE_EQUAL(sharder.token_for_next_shard(tm.get_first_token(tablet_ids[1]), 3), dht::maximum_token());
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[0]));
BOOST_REQUIRE(shard_opt);
BOOST_REQUIRE_EQUAL(shard_opt->shard, 0);
BOOST_REQUIRE_EQUAL(shard_opt->token, tm.get_first_token(tablet_ids[1]));
}
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[1]));
BOOST_REQUIRE(shard_opt);
BOOST_REQUIRE_EQUAL(shard_opt->shard, 1);
BOOST_REQUIRE_EQUAL(shard_opt->token, tm.get_first_token(tablet_ids[2]));
}
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[2]));
BOOST_REQUIRE(shard_opt);
BOOST_REQUIRE_EQUAL(shard_opt->shard, 0);
BOOST_REQUIRE_EQUAL(shard_opt->token, tm.get_first_token(tablet_ids[3]));
}
{
auto shard_opt = sharder.next_shard(tm.get_last_token(tablet_ids[3]));
BOOST_REQUIRE(!shard_opt);
}
}, tablet_cql_test_config());
}
SEASTAR_TEST_CASE(test_large_tablet_metadata) {
return do_with_cql_env_thread([] (cql_test_env& e) {
tablet_metadata tm;
auto h1 = host_id(utils::UUID_gen::get_time_UUID());
auto h2 = host_id(utils::UUID_gen::get_time_UUID());
auto h3 = host_id(utils::UUID_gen::get_time_UUID());
const int nr_tables = 1'00;
const int tablets_per_table = 1024;
for (int i = 0; i < nr_tables; ++i) {
tablet_map tmap(tablets_per_table);
for (tablet_id j : tmap.tablet_ids()) {
tmap.set_tablet(j, tablet_info {
tablet_replica_set {{h1, 0}, {h2, 1}, {h3, 2},}
});
}
auto id = add_table(e).get0();
tm.set_tablet_map(id, std::move(tmap));
}
verify_tablet_metadata_persistence(e, tm);
}, tablet_cql_test_config());
}
SEASTAR_THREAD_TEST_CASE(test_token_ownership_splitting) {
const auto real_min_token = dht::token(dht::token_kind::key, std::numeric_limits<int64_t>::min() + 1);
const auto real_max_token = dht::token(dht::token_kind::key, std::numeric_limits<int64_t>::max());
for (auto&& tmap : {
tablet_map(1),
tablet_map(2),
tablet_map(4),
tablet_map(16),
tablet_map(1024),
}) {
testlog.debug("tmap: {}", tmap);
BOOST_REQUIRE_EQUAL(real_min_token, tmap.get_first_token(tmap.first_tablet()));
BOOST_REQUIRE_EQUAL(real_max_token, tmap.get_last_token(tmap.last_tablet()));
std::optional<tablet_id> prev_tb;
for (tablet_id tb : tmap.tablet_ids()) {
testlog.debug("first: {}, last: {}", tmap.get_first_token(tb), tmap.get_last_token(tb));
BOOST_REQUIRE_EQUAL(tb, tmap.get_tablet_id(tmap.get_first_token(tb)));
BOOST_REQUIRE_EQUAL(tb, tmap.get_tablet_id(tmap.get_last_token(tb)));
if (prev_tb) {
BOOST_REQUIRE_EQUAL(dht::next_token(tmap.get_last_token(*prev_tb)), tmap.get_first_token(tb));
}
prev_tb = tb;
}
}
}
// Reflects the plan in a given token metadata as if the migrations were fully executed.
static
void apply_plan(token_metadata& tm, const migration_plan& plan) {
for (auto&& mig : plan.migrations()) {
tablet_map& tmap = tm.tablets().get_tablet_map(mig.tablet.table);
auto tinfo = tmap.get_tablet_info(mig.tablet.tablet);
tinfo.replicas = replace_replica(tinfo.replicas, mig.src, mig.dst);
tmap.set_tablet(mig.tablet.tablet, tinfo);
}
}
static
tablet_transition_info migration_to_transition_info(const tablet_migration_info& mig, const tablet_info& ti) {
return tablet_transition_info {
tablet_transition_stage::allow_write_both_read_old,
replace_replica(ti.replicas, mig.src, mig.dst),
mig.dst
};
}
// Reflects the plan in a given token metadata as if the migrations were started but not yet executed.
static
void apply_plan_as_in_progress(token_metadata& tm, const migration_plan& plan) {
for (auto&& mig : plan.migrations()) {
tablet_map& tmap = tm.tablets().get_tablet_map(mig.tablet.table);
auto tinfo = tmap.get_tablet_info(mig.tablet.tablet);
tmap.set_tablet_transition_info(mig.tablet.tablet, migration_to_transition_info(mig, tinfo));
}
}
static
void rebalance_tablets(tablet_allocator& talloc, shared_token_metadata& stm) {
while (true) {
auto plan = talloc.balance_tablets(stm.get()).get0();
if (plan.empty()) {
break;
}
stm.mutate_token_metadata([&] (token_metadata& tm) {
apply_plan(tm, plan);
return make_ready_future<>();
}).get();
}
}
static
void rebalance_tablets_as_in_progress(tablet_allocator& talloc, shared_token_metadata& stm) {
while (true) {
auto plan = talloc.balance_tablets(stm.get()).get0();
if (plan.empty()) {
break;
}
stm.mutate_token_metadata([&] (token_metadata& tm) {
apply_plan_as_in_progress(tm, plan);
return make_ready_future<>();
}).get();
}
}
// Completes any in progress tablet migrations.
static
void execute_transitions(shared_token_metadata& stm) {
stm.mutate_token_metadata([&] (token_metadata& tm) {
for (auto&& [tablet, tmap_] : tm.tablets().all_tables()) {
auto& tmap = tmap_;
for (auto&& [tablet, trinfo]: tmap.transitions()) {
auto ti = tmap.get_tablet_info(tablet);
ti.replicas = trinfo.next;
tmap.set_tablet(tablet, ti);
}
tmap.clear_transitions();
}
return make_ready_future<>();
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_load_balancing_with_empty_node) {
do_with_cql_env_thread([] (auto& e) {
// Tests the scenario of bootstrapping a single node
// Verifies that load balancer sees it and moves tablets to that node.
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto table1 = table_id(next_uuid());
unsigned shard_count = 2;
semaphore sem(1);
shared_token_metadata stm([&sem] () noexcept { return get_units(sem, 1); }, locator::token_metadata::config{
locator::topology::config{
.this_endpoint = ip1,
.local_dc_rack = locator::endpoint_dc_rack::default_location
}
});
stm.mutate_token_metadata([&] (auto& tm) {
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_topology(ip1, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip2, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tablet_map tmap(4);
auto tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 1},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 1},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 1},
tablet_replica {host2, 0},
}
});
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
// Sanity check
{
load_sketch load(stm.get());
load.populate().get();
BOOST_REQUIRE_EQUAL(load.get_load(host1), 4);
BOOST_REQUIRE_EQUAL(load.get_avg_shard_load(host1), 2);
BOOST_REQUIRE_EQUAL(load.get_load(host2), 4);
BOOST_REQUIRE_EQUAL(load.get_avg_shard_load(host2), 2);
BOOST_REQUIRE_EQUAL(load.get_load(host3), 0);
BOOST_REQUIRE_EQUAL(load.get_avg_shard_load(host3), 0);
}
rebalance_tablets(e.get_tablet_allocator().local(), stm);
{
load_sketch load(stm.get());
load.populate().get();
for (auto h : {host1, host2, host3}) {
testlog.debug("Checking host {}", h);
BOOST_REQUIRE(load.get_load(h) <= 3);
BOOST_REQUIRE(load.get_load(h) > 1);
BOOST_REQUIRE(load.get_avg_shard_load(h) <= 2);
BOOST_REQUIRE(load.get_avg_shard_load(h) > 0);
}
}
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_decommission_rf_met) {
// Verifies that load balancer moves tablets out of the decommissioned node.
// The scenario is such that replication factor of tablets can be satisfied after decommission.
do_with_cql_env_thread([](auto& e) {
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto table1 = table_id(next_uuid());
semaphore sem(1);
shared_token_metadata stm([&sem]() noexcept { return get_units(sem, 1); }, locator::token_metadata::config {
locator::topology::config {
.this_endpoint = ip1,
.local_dc_rack = locator::endpoint_dc_rack::default_location
}
});
stm.mutate_token_metadata([&](auto& tm) {
const unsigned shard_count = 2;
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_topology(ip1, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip2, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, node::state::being_decommissioned,
shard_count);
tablet_map tmap(4);
auto tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 1},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 1},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host3, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host2, 1},
tablet_replica {host3, 1},
}
});
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
rebalance_tablets(e.get_tablet_allocator().local(), stm);
{
load_sketch load(stm.get());
load.populate().get();
BOOST_REQUIRE(load.get_avg_shard_load(host1) == 2);
BOOST_REQUIRE(load.get_avg_shard_load(host2) == 2);
BOOST_REQUIRE(load.get_avg_shard_load(host3) == 0);
}
stm.mutate_token_metadata([&](auto& tm) {
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, node::state::left);
return make_ready_future<>();
}).get();
rebalance_tablets(e.get_tablet_allocator().local(), stm);
{
load_sketch load(stm.get());
load.populate().get();
BOOST_REQUIRE(load.get_avg_shard_load(host1) == 2);
BOOST_REQUIRE(load.get_avg_shard_load(host2) == 2);
BOOST_REQUIRE(load.get_avg_shard_load(host3) == 0);
}
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_decommission_two_racks) {
// Verifies that load balancer moves tablets out of the decommissioned node.
// The scenario is such that replication constraints of tablets can be satisfied after decommission.
do_with_cql_env_thread([](auto& e) {
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
inet_address ip4("192.168.0.4");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto host4 = host_id(next_uuid());
std::vector<endpoint_dc_rack> racks = {
endpoint_dc_rack{ "dc1", "rack-1" },
endpoint_dc_rack{ "dc1", "rack-2" }
};
auto table1 = table_id(next_uuid());
semaphore sem(1);
shared_token_metadata stm([&sem]() noexcept { return get_units(sem, 1); }, locator::token_metadata::config {
locator::topology::config {
.this_endpoint = ip1,
.local_dc_rack = racks[0]
}
});
stm.mutate_token_metadata([&](auto& tm) {
const unsigned shard_count = 1;
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_host_id(host4, ip4);
tm.update_topology(ip1, racks[0], std::nullopt, shard_count);
tm.update_topology(ip2, racks[1], std::nullopt, shard_count);
tm.update_topology(ip3, racks[0], std::nullopt, shard_count);
tm.update_topology(ip4, racks[1], node::state::being_decommissioned,
shard_count);
tablet_map tmap(4);
auto tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host2, 0},
tablet_replica {host3, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host3, 0},
tablet_replica {host4, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 0},
}
});
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
rebalance_tablets(e.get_tablet_allocator().local(), stm);
{
load_sketch load(stm.get());
load.populate().get();
BOOST_REQUIRE(load.get_avg_shard_load(host1) >= 2);
BOOST_REQUIRE(load.get_avg_shard_load(host2) >= 2);
BOOST_REQUIRE(load.get_avg_shard_load(host3) >= 2);
BOOST_REQUIRE(load.get_avg_shard_load(host4) == 0);
}
// Verify replicas are not collocated on racks
{
auto tm = stm.get();
auto& tmap = tm->tablets().get_tablet_map(table1);
tmap.for_each_tablet([&](auto tid, auto& tinfo) {
auto rack1 = tm->get_topology().get_rack(tinfo.replicas[0].host);
auto rack2 = tm->get_topology().get_rack(tinfo.replicas[1].host);
BOOST_REQUIRE(rack1 != rack2);
}).get();
}
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_decommission_rack_load_failure) {
// Verifies that load balancer moves tablets out of the decommissioned node.
// The scenario is such that it is impossible to distribute replicas without violating rack uniqueness.
do_with_cql_env_thread([](auto& e) {
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
inet_address ip4("192.168.0.4");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto host4 = host_id(next_uuid());
std::vector<endpoint_dc_rack> racks = {
endpoint_dc_rack{ "dc1", "rack-1" },
endpoint_dc_rack{ "dc1", "rack-2" }
};
auto table1 = table_id(next_uuid());
semaphore sem(1);
shared_token_metadata stm([&sem]() noexcept { return get_units(sem, 1); }, locator::token_metadata::config {
locator::topology::config {
.this_endpoint = ip1,
.local_dc_rack = racks[0]
}
});
stm.mutate_token_metadata([&](auto& tm) {
const unsigned shard_count = 1;
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_host_id(host4, ip4);
tm.update_topology(ip1, racks[0], std::nullopt, shard_count);
tm.update_topology(ip2, racks[0], std::nullopt, shard_count);
tm.update_topology(ip3, racks[0], std::nullopt, shard_count);
tm.update_topology(ip4, racks[1], node::state::being_decommissioned,
shard_count);
tablet_map tmap(4);
auto tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host4, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host2, 0},
tablet_replica {host4, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host3, 0},
tablet_replica {host4, 0},
}
});
tid = *tmap.next_tablet(tid);
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host4, 0},
}
});
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
BOOST_REQUIRE_THROW(rebalance_tablets(e.get_tablet_allocator().local(), stm), std::runtime_error);
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_decommission_rf_not_met) {
// Verifies that load balancer moves tablets out of the decommissioned node.
// The scenario is such that replication factor of tablets can be satisfied after decommission.
do_with_cql_env_thread([](auto& e) {
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto table1 = table_id(next_uuid());
semaphore sem(1);
shared_token_metadata stm([&sem]() noexcept { return get_units(sem, 1); }, locator::token_metadata::config {
locator::topology::config {
.this_endpoint = ip1,
.local_dc_rack = locator::endpoint_dc_rack::default_location
}
});
stm.mutate_token_metadata([&](auto& tm) {
const unsigned shard_count = 2;
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_topology(ip1, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip2, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, node::state::being_decommissioned,
shard_count);
tablet_map tmap(1);
auto tid = tmap.first_tablet();
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 0},
tablet_replica {host3, 0},
}
});
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
BOOST_REQUIRE_THROW(rebalance_tablets(e.get_tablet_allocator().local(), stm), std::runtime_error);
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_load_balancing_works_with_in_progress_transitions) {
do_with_cql_env_thread([] (auto& e) {
// Tests the scenario of bootstrapping a single node.
// Verifies that the load balancer balances tablets on that node
// even though there is already an active migration.
// The test verifies that the load balancer creates a plan
// which when executed will achieve perfect balance,
// which is a proof that it doesn't stop due to active migrations.
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto table1 = table_id(next_uuid());
semaphore sem(1);
shared_token_metadata stm([&sem] () noexcept { return get_units(sem, 1); }, locator::token_metadata::config{
locator::topology::config{
.this_endpoint = ip1,
.local_dc_rack = locator::endpoint_dc_rack::default_location
}
});
stm.mutate_token_metadata([&] (auto& tm) {
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_topology(ip1, locator::endpoint_dc_rack::default_location, std::nullopt, 1);
tm.update_topology(ip2, locator::endpoint_dc_rack::default_location, std::nullopt, 1);
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, std::nullopt, 2);
tablet_map tmap(4);
std::optional<tablet_id> tid = tmap.first_tablet();
for (int i = 0; i < 4; ++i) {
tmap.set_tablet(*tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 0},
}
});
tid = tmap.next_tablet(*tid);
}
tmap.set_tablet_transition_info(tmap.first_tablet(), tablet_transition_info {
tablet_transition_stage::allow_write_both_read_old,
tablet_replica_set {
tablet_replica {host3, 0},
tablet_replica {host2, 0},
},
tablet_replica {host3, 0}
});
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
rebalance_tablets_as_in_progress(e.get_tablet_allocator().local(), stm);
execute_transitions(stm);
{
load_sketch load(stm.get());
load.populate().get();
for (auto h : {host1, host2, host3}) {
testlog.debug("Checking host {}", h);
BOOST_REQUIRE(load.get_avg_shard_load(h) == 2);
}
}
}).get();
}
#ifdef SCYLLA_ENABLE_ERROR_INJECTION
SEASTAR_THREAD_TEST_CASE(test_load_balancer_shuffle_mode) {
do_with_cql_env_thread([] (auto& e) {
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto table1 = table_id(next_uuid());
semaphore sem(1);
shared_token_metadata stm([&sem] () noexcept { return get_units(sem, 1); }, locator::token_metadata::config{
locator::topology::config{
.this_endpoint = ip1,
.local_dc_rack = locator::endpoint_dc_rack::default_location
}
});
stm.mutate_token_metadata([&] (auto& tm) {
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_topology(ip1, locator::endpoint_dc_rack::default_location, std::nullopt, 1);
tm.update_topology(ip2, locator::endpoint_dc_rack::default_location, std::nullopt, 1);
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, std::nullopt, 2);
tablet_map tmap(4);
std::optional<tablet_id> tid = tmap.first_tablet();
for (int i = 0; i < 4; ++i) {
tmap.set_tablet(*tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, 0},
tablet_replica {host2, 0},
}
});
tid = tmap.next_tablet(*tid);
}
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
rebalance_tablets(e.get_tablet_allocator().local(), stm);
BOOST_REQUIRE(e.get_tablet_allocator().local().balance_tablets(stm.get()).get0().empty());
utils::get_local_injector().enable("tablet_allocator_shuffle");
auto disable_injection = seastar::defer([&] {
utils::get_local_injector().disable("tablet_allocator_shuffle");
});
BOOST_REQUIRE(!e.get_tablet_allocator().local().balance_tablets(stm.get()).get0().empty());
}).get();
}
#endif
SEASTAR_THREAD_TEST_CASE(test_load_balancing_with_two_empty_nodes) {
do_with_cql_env_thread([] (auto& e) {
inet_address ip1("192.168.0.1");
inet_address ip2("192.168.0.2");
inet_address ip3("192.168.0.3");
inet_address ip4("192.168.0.4");
auto host1 = host_id(next_uuid());
auto host2 = host_id(next_uuid());
auto host3 = host_id(next_uuid());
auto host4 = host_id(next_uuid());
auto table1 = table_id(next_uuid());
unsigned shard_count = 2;
semaphore sem(1);
shared_token_metadata stm([&sem] () noexcept { return get_units(sem, 1); }, locator::token_metadata::config{
locator::topology::config{
.this_endpoint = ip1,
.local_dc_rack = locator::endpoint_dc_rack::default_location
}
});
stm.mutate_token_metadata([&] (auto& tm) {
tm.update_host_id(host1, ip1);
tm.update_host_id(host2, ip2);
tm.update_host_id(host3, ip3);
tm.update_host_id(host4, ip4);
tm.update_topology(ip1, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip2, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip3, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tm.update_topology(ip4, locator::endpoint_dc_rack::default_location, std::nullopt, shard_count);
tablet_map tmap(16);
for (auto tid : tmap.tablet_ids()) {
tmap.set_tablet(tid, tablet_info {
tablet_replica_set {
tablet_replica {host1, tests::random::get_int<shard_id>(0, shard_count - 1)},
tablet_replica {host2, tests::random::get_int<shard_id>(0, shard_count - 1)},
}
});
}
tablet_metadata tmeta;
tmeta.set_tablet_map(table1, std::move(tmap));
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
rebalance_tablets(e.get_tablet_allocator().local(), stm);
{
load_sketch load(stm.get());
load.populate().get();
for (auto h : {host1, host2, host3, host4}) {
testlog.debug("Checking host {}", h);
BOOST_REQUIRE(load.get_avg_shard_load(h) == 4);
}
}
}).get();
}
SEASTAR_THREAD_TEST_CASE(test_load_balancing_with_random_load) {
do_with_cql_env_thread([] (auto& e) {
const int n_hosts = 6;
std::vector<host_id> hosts;
for (int i = 0; i < n_hosts; ++i) {
hosts.push_back(host_id(next_uuid()));
}
std::vector<endpoint_dc_rack> racks = {
endpoint_dc_rack{ "dc1", "rack-1" },
endpoint_dc_rack{ "dc1", "rack-2" }
};
for (int i = 0; i < 13; ++i) {
std::unordered_map<sstring, std::vector<host_id>> hosts_by_rack;
semaphore sem(1);
shared_token_metadata stm([&sem]() noexcept { return get_units(sem, 1); }, locator::token_metadata::config {
locator::topology::config {
.this_endpoint = inet_address("192.168.0.1"),
.local_dc_rack = racks[1]
}
});
size_t total_tablet_count = 0;
stm.mutate_token_metadata([&](auto& tm) {
tablet_metadata tmeta;
int i = 0;
for (auto h : hosts) {
auto ip = inet_address(format("192.168.0.{}", ++i));
auto shard_count = 2;
tm.update_host_id(h, ip);
auto rack = racks[i % racks.size()];
tm.update_topology(ip, rack, std::nullopt, shard_count);
if (h != hosts[0]) {
// Leave the first host empty by making it invisible to allocation algorithm.
hosts_by_rack[rack.rack].push_back(h);
}
}
size_t tablet_count_bits = 8;
int rf = tests::random::get_int<shard_id>(2, 4);
for (int log2_tablets = 0; log2_tablets < tablet_count_bits; ++log2_tablets) {
if (tests::random::get_bool()) {
continue;
}
auto table = table_id(next_uuid());
tablet_map tmap(1 << log2_tablets);
for (auto tid : tmap.tablet_ids()) {
// Choose replicas randomly while loading racks evenly.
std::vector<host_id> replica_hosts;
for (int i = 0; i < rf; ++i) {
auto rack = racks[i % racks.size()];
auto& rack_hosts = hosts_by_rack[rack.rack];
while (true) {
auto candidate_host = rack_hosts[tests::random::get_int<shard_id>(0, rack_hosts.size() - 1)];
if (std::find(replica_hosts.begin(), replica_hosts.end(), candidate_host) == replica_hosts.end()) {
replica_hosts.push_back(candidate_host);
break;
}
}
}
tablet_replica_set replicas;
for (auto h : replica_hosts) {
auto shard_count = tm.get_topology().find_node(h)->get_shard_count();
auto shard = tests::random::get_int<shard_id>(0, shard_count - 1);
replicas.push_back(tablet_replica {h, shard});
}
tmap.set_tablet(tid, tablet_info {std::move(replicas)});
}
total_tablet_count += tmap.tablet_count();
tmeta.set_tablet_map(table, std::move(tmap));
}
tm.set_tablets(std::move(tmeta));
return make_ready_future<>();
}).get();
testlog.debug("tablet metadata: {}", stm.get()->tablets());
testlog.info("Total tablet count: {}, hosts: {}", total_tablet_count, hosts.size());
rebalance_tablets(e.get_tablet_allocator().local(), stm);
{
load_sketch load(stm.get());
load.populate().get();
min_max_tracker<unsigned> min_max_load;
for (auto h: hosts) {
auto l = load.get_avg_shard_load(h);
testlog.info("Load on host {}: {}", h, l);
min_max_load.update(l);
}
testlog.debug("tablet metadata: {}", stm.get()->tablets());
testlog.debug("Min load: {}, max load: {}", min_max_load.min(), min_max_load.max());
// FIXME: The algorithm cannot achieve balance in all cases yet, so we only check that it stops.
// For example, if we have an overloaded node in one rack and target underloaded node in a different rack,
// we won't be able to reduce the load gap by moving tablets between the two. We have to balance the overloaded
// rack first, which is unconstrained.
// Uncomment the following line when the algorithm is improved.
// BOOST_REQUIRE(min_max_load.max() - min_max_load.min() <= 1);
}
}
}).get();
}