Fix NToSelect in state storage config auto generation in distconf 25-1-2 (#20390)

Author: Evgenik2

ydb/core/blobstorage/nodewarden/distconf_generate.cpp

@@ -206,7 +206,7 @@ namespace NKikimr::NStorage {
                         pdiskInfo.Usable = false;
                         pdiskInfo.WhyUnusable += 'S';
                     }
-                    const bool usableInTermsOfDecommission = 
+                    const bool usableInTermsOfDecommission =
                         pdisk.GetDecommitStatus() == NKikimrBlobStorage::EDecommitStatus::DECOMMIT_NONE ||
                         pdisk.GetDecommitStatus() == NKikimrBlobStorage::EDecommitStatus::DECOMMIT_REJECTED && !isSelfHealReasonDecommit;
                     if (!usableInTermsOfDecommission) {
@@ -568,15 +568,29 @@ namespace NKikimr::NStorage {
 
         const size_t maxNodesPerDataCenter = nodesByDataCenter.size() == 1 ? 8 : 3;
         for (auto& [_, v] : nodesByDataCenter) {
-            auto r = pickNodes(v, Min<size_t>(v.size(), maxNodesPerDataCenter));
+            size_t countToSelect = Min<size_t>(v.size(), maxNodesPerDataCenter);
+            if (v.size() < maxNodesPerDataCenter && nodesByDataCenter.size() > 1) {
+                countToSelect = 1;
+            }
+            auto r = pickNodes(v, countToSelect);
             nodes.insert(nodes.end(), r.begin(), r.end());
         }
 
         for (ui32 nodeId : nodes) {
             ring->AddNode(nodeId);
         }
-
-        ring->SetNToSelect(nodes.size() / 2 + 1);
+        ui32 nodesCnt = nodes.size();
+        ui32 nToSelect = 1;
+        if (nodesCnt <= 2) {
+            nToSelect = 1;
+        } else if (nodesCnt < 8) {
+            nToSelect = 3;
+        } else if (nodesCnt == 8) {
+            nToSelect = 5;
+        } else if (nodesCnt > 8) {
+            nToSelect = 9;
+        }
+        ring->SetNToSelect(nToSelect);
     }
 
     bool TDistributedConfigKeeper::UpdateConfig(NKikimrBlobStorage::TStorageConfig *config) {

ydb/core/blobstorage/nodewarden/distconf_ut.cpp

@@ -0,0 +1,89 @@
+#include <ydb/core/testlib/tablet_helpers.h>
+
+#include <ydb/core/base/tablet_resolver.h>
+#include <ydb/core/base/statestorage_impl.h>
+#include <ydb/core/blobstorage/nodewarden/node_warden.h>
+#include <ydb/core/blobstorage/nodewarden/node_warden_impl.h>
+#include <ydb/core/blobstorage/base/blobstorage_events.h>
+#include <ydb/core/blobstorage/pdisk/blobstorage_pdisk_tools.h>
+#include <ydb/core/blobstorage/pdisk/blobstorage_pdisk_ut_http_request.h>
+#include <ydb/core/mind/bscontroller/bsc.h>
+#include <ydb/core/util/actorsys_test/testactorsys.h>
+
+#include <ydb/library/pdisk_io/sector_map.h>
+#include <ydb/core/util/random.h>
+
+#include <google/protobuf/text_format.h>
+#include <library/cpp/testing/unittest/registar.h>
+
+#include <ydb/core/blobstorage/nodewarden/distconf.h>
+
+namespace NKikimr {
+namespace NBlobStorageNodeWardenTest{
+
+Y_UNIT_TEST_SUITE(TDistconfGenerateConfigTest) {
+
+    NKikimrConfig::TDomainsConfig::TStateStorage GenerateSimpleStateStorage(ui32 nodes) {
+        NKikimrConfig::TDomainsConfig::TStateStorage ss;
+        NKikimrBlobStorage::TStorageConfig config;
+        for (ui32 i : xrange(nodes)) {
+            auto *node = config.AddAllNodes();
+            node->SetNodeId(i + 1);
+        }
+        NKikimr::NStorage::TDistributedConfigKeeper keeper(nullptr, config, true);
+        keeper.GenerateStateStorageConfig(&ss, config);
+        return ss;
+    }
+
+    NKikimrConfig::TDomainsConfig::TStateStorage GenerateDCStateStorage(ui32 dcCnt, ui32 racksCnt,  ui32 nodesInRack) {
+        NKikimrBlobStorage::TStorageConfig config;
+        ui32 nodeId = 1;
+        for (ui32 dc : xrange(dcCnt)) {
+            for (ui32 rack : xrange(racksCnt)) {
+                for (auto _ : xrange(nodesInRack)) {
+                    auto *node = config.AddAllNodes();
+                    node->SetNodeId(nodeId++);
+                    node->MutableLocation()->SetDataCenter("dc-" + std::to_string(dc));
+                    node->MutableLocation()->SetRack(std::to_string(rack));
+                }
+            }
+        }
+        NKikimrConfig::TDomainsConfig::TStateStorage ss;
+        NKikimr::NStorage::TDistributedConfigKeeper keeper(nullptr, config, true);
+        keeper.GenerateStateStorageConfig(&ss, config);
+        return ss;
+    }
+
+    void CheckStateStorage(const NKikimrConfig::TDomainsConfig::TStateStorage& ss, ui32 nToSelect, const std::unordered_set<ui32>& nodes) {
+        auto &rg = ss.GetRing();
+        Cerr << "Actual: " << ss << " Expected: NToSelect: " << nToSelect << Endl;
+        UNIT_ASSERT_EQUAL(rg.GetNToSelect(), nToSelect);
+        UNIT_ASSERT_EQUAL(rg.NodeSize(), nodes.size());
+        std::unordered_set<ui32> usedNodes;
+        for (ui32 i : xrange(nodes.size())) {
+            auto n = rg.GetNode(i);
+            UNIT_ASSERT(nodes.contains(n));
+            UNIT_ASSERT(usedNodes.insert(n).second);
+        }
+    }
+
+    Y_UNIT_TEST(GenerateConfigSimpleCases) {
+        CheckStateStorage(GenerateSimpleStateStorage(1), 1, {1});
+        CheckStateStorage(GenerateSimpleStateStorage(2), 1, {1, 2});
+        CheckStateStorage(GenerateSimpleStateStorage(3), 3, {1, 2, 3});
+        CheckStateStorage(GenerateSimpleStateStorage(8), 5, {1, 2, 3, 4, 5, 6, 7, 8});
+        CheckStateStorage(GenerateSimpleStateStorage(9), 5, {1, 2, 3, 4, 5, 6, 7, 8});
+        CheckStateStorage(GenerateDCStateStorage(1, 1, 20), 5, {1, 2, 3, 4, 5, 6, 7, 8});
+        CheckStateStorage(GenerateDCStateStorage(1, 10, 5), 5, {1, 6, 11, 16, 21, 26, 31, 36});
+    }
+
+    Y_UNIT_TEST(GenerateConfig3DCCases) {
+        CheckStateStorage(GenerateDCStateStorage(3, 1, 1), 3, {1, 2, 3});
+        CheckStateStorage(GenerateDCStateStorage(3, 1, 2), 3, {1, 3, 5});
+        CheckStateStorage(GenerateDCStateStorage(3, 1, 3), 9, {1, 2, 3, 4, 5, 6, 7, 8, 9});
+        CheckStateStorage(GenerateDCStateStorage(3, 1, 18), 9, {1, 2, 3, 19, 20, 21, 37, 38, 39});
+        CheckStateStorage(GenerateDCStateStorage(3, 3, 3), 9, {1, 4, 7, 10, 13, 16, 19, 22, 25});
+    }
+}
+}
+}

ydb/core/blobstorage/nodewarden/ut/ya.make

@@ -16,6 +16,7 @@ PEERDIR(
 SRCS(
     blobstorage_node_warden_ut.cpp
     bind_queue_ut.cpp
+    distconf_ut.cpp
 )
 
 YQL_LAST_ABI_VERSION()