pool/pool.go

@@ -96,7 +96,7 @@ type clientStatus interface {
 	address() string
 	// currentErrorRate returns current errors rate.
 	// After specific threshold connection is considered as unhealthy.
-	// Pool.startRebalance routine can make this connection healthy again.
+	// Pool.rebalance routine can make this connection healthy again.
 	currentErrorRate() uint32
 	// overallErrorRate returns the number of all happened errors.
 	overallErrorRate() uint64
@@ -293,7 +293,7 @@ func (x *wrapperPrm) setStreamTimeout(timeout time.Duration) {
 }
 
 // setErrorThreshold sets threshold after reaching which connection is considered unhealthy
-// until Pool.startRebalance routing updates its status.
+// until Pool.rebalance routing updates its status.
 func (x *wrapperPrm) setErrorThreshold(threshold uint32) {
 	x.errorThreshold = threshold
 }
@@ -1814,9 +1814,232 @@ type resCreateSession struct {
 //
 // See pool package overview to get some examples.
 type Pool struct {
+	pool atomic.Pointer[pool]
+}
+
+// NewPool creates connection pool using parameters.
+func NewPool(options InitParameters) (*Pool, error) {
+	pool, err := newPool(options)
+	if err != nil {
+		return nil, err
+	}
+
+	var p Pool
+	p.pool.Store(pool)
+	return &p, nil
+}
+
+// Balance requests current balance of the FrostFS account.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) Balance(ctx context.Context, prm PrmBalanceGet) (accounting.Decimal, error) {
+	return p.pool.Load().Balance(ctx, prm)
+}
+
+// Close closes the Pool and releases all the associated resources.
+func (p *Pool) Close() {
+	p.pool.Load().Close()
+}
+
+// DeleteContainer sends request to remove the FrostFS container and waits for the operation to complete.
+//
+// Waiting parameters can be specified using SetWaitParams. If not called, defaults are used:
+//
+//	polling interval: 5s
+//	waiting timeout: 120s
+//
+// Success can be verified by reading by identifier (see GetContainer).
+func (p *Pool) DeleteContainer(ctx context.Context, prm PrmContainerDelete) error {
+	return p.pool.Load().DeleteContainer(ctx, prm)
+}
+
+// DeleteObject marks an object for deletion from the container using FrostFS API protocol.
+// As a marker, a special unit called a tombstone is placed in the container.
+// It confirms the user's intent to delete the object, and is itself a container object.
+// Explicit deletion is done asynchronously, and is generally not guaranteed.
+func (p *Pool) DeleteObject(ctx context.Context, prm PrmObjectDelete) error {
+	return p.pool.Load().DeleteObject(ctx, prm)
+}
+
+// Dial establishes a connection to the servers from the FrostFS network.
+// It also starts a routine that checks the health of the nodes and
+// updates the weights of the nodes for balancing.
+// Returns an error describing failure reason.
+//
+// If failed, the Pool SHOULD NOT be used.
+//
+// See also InitParameters.SetClientRebalanceInterval.
+func (p *Pool) Dial(ctx context.Context) error {
+	pool := p.pool.Load()
+	if err := pool.Dial(ctx); err != nil {
+		return err
+	}
+
+	pool.cancelLock.Lock()
+	if pool.cancel != nil {
+		pool.cancel()
+	}
+	pool.cancelLock.Unlock()
+
+	pool.startRebalance(ctx)
+
+	return nil
+}
+
+// FindSiblingByParentID implements relations.Relations.
+func (p *Pool) FindSiblingByParentID(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) ([]oid.ID, error) {
+	return p.pool.Load().FindSiblingByParentID(ctx, cnrID, objID, tokens)
+}
+
+// FindSiblingBySplitID implements relations.Relations.
+func (p *Pool) FindSiblingBySplitID(ctx context.Context, cnrID cid.ID, splitID *object.SplitID, tokens relations.Tokens) ([]oid.ID, error) {
+	return p.pool.Load().FindSiblingBySplitID(ctx, cnrID, splitID, tokens)
+}
+
+// GetContainer reads FrostFS container by ID.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) GetContainer(ctx context.Context, prm PrmContainerGet) (container.Container, error) {
+	return p.pool.Load().GetContainer(ctx, prm)
+}
+
+// GetEACL reads eACL table of the FrostFS container.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) GetEACL(ctx context.Context, prm PrmContainerEACL) (eacl.Table, error) {
+	return p.pool.Load().GetEACL(ctx, prm)
+}
+
+// GetLeftSibling implements relations.Relations.
+func (p *Pool) GetLeftSibling(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) (oid.ID, error) {
+	return p.pool.Load().GetLeftSibling(ctx, cnrID, objID, tokens)
+}
+
+// GetObject reads object header and initiates reading an object payload through a remote server using FrostFS API protocol.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) GetObject(ctx context.Context, prm PrmObjectGet) (ResGetObject, error) {
+	return p.pool.Load().GetObject(ctx, prm)
+}
+
+// GetSplitInfo implements relations.Relations.
+func (p *Pool) GetSplitInfo(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) (*object.SplitInfo, error) {
+	return p.pool.Load().GetSplitInfo(ctx, cnrID, objID, tokens)
+}
+
+// HeadObject reads object header through a remote server using FrostFS API protocol.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) HeadObject(ctx context.Context, prm PrmObjectHead) (object.Object, error) {
+	return p.pool.Load().HeadObject(ctx, prm)
+}
+
+// ListChildrenByLinker implements relations.Relations.
+func (p *Pool) ListChildrenByLinker(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) ([]oid.ID, error) {
+	return p.pool.Load().ListChildrenByLinker(ctx, cnrID, objID, tokens)
+}
+
+// ListContainers requests identifiers of the account-owned containers.
+func (p *Pool) ListContainers(ctx context.Context, prm PrmContainerList) ([]cid.ID, error) {
+	return p.pool.Load().ListContainers(ctx, prm)
+}
+
+// NetMapSnapshot requests information about the FrostFS network map.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) NetMapSnapshot(ctx context.Context) (netmap.NetMap, error) {
+	return p.pool.Load().NetMapSnapshot(ctx)
+}
+
+// NetworkInfo requests information about the FrostFS network of which the remote server is a part.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) NetworkInfo(ctx context.Context) (netmap.NetworkInfo, error) {
+	return p.pool.Load().NetworkInfo(ctx)
+}
+
+// ObjectRange initiates reading an object's payload range through a remote
+// server using FrostFS API protocol.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) ObjectRange(ctx context.Context, prm PrmObjectRange) (ResObjectRange, error) {
+	return p.pool.Load().ObjectRange(ctx, prm)
+}
+
+// PutContainer sends request to save container in FrostFS and waits for the operation to complete.
+//
+// Waiting parameters can be specified using SetWaitParams. If not called, defaults are used:
+//
+//	polling interval: 5s
+//	waiting timeout: 120s
+//
+// Success can be verified by reading by identifier (see GetContainer).
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) PutContainer(ctx context.Context, prm PrmContainerPut) (cid.ID, error) {
+	return p.pool.Load().PutContainer(ctx, prm)
+}
+
+// PutObject writes an object through a remote server using FrostFS API protocol.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) PutObject(ctx context.Context, prm PrmObjectPut) (oid.ID, error) {
+	return p.pool.Load().PutObject(ctx, prm)
+}
+
+// SearchObjects initiates object selection through a remote server using FrostFS API protocol.
+//
+// The call only opens the transmission channel, explicit fetching of matched objects
+// is done using the ResObjectSearch. Resulting reader must be finally closed.
+//
+// Main return value MUST NOT be processed on an erroneous return.
+func (p *Pool) SearchObjects(ctx context.Context, prm PrmObjectSearch) (ResObjectSearch, error) {
+	return p.pool.Load().SearchObjects(ctx, prm)
+}
+
+// SetEACL sends request to update eACL table of the FrostFS container and waits for the operation to complete.
+//
+// Waiting parameters can be specified using SetWaitParams. If not called, defaults are used:
+//
+//	polling interval: 5s
+//	waiting timeout: 120s
+//
+// Success can be verified by reading by identifier (see GetEACL).
+func (p *Pool) SetEACL(ctx context.Context, prm PrmContainerSetEACL) error {
+	return p.pool.Load().SetEACL(ctx, prm)
+}
+
+// Statistic returns connection statistics.
+func (p *Pool) Statistic() Statistic {
+	return p.pool.Load().Statistic()
+}
+
+// Update is a method that lets you refresh the list of nodes without recreating the pool.
+// Use a long-lived context to avoid early rebalance stop.
+// Can interrupt an operation being performed on a node that was removed.
+// Ensures that:
+// 1) Preserved connections would not be closed.
+// 2) In the event of an error, the pool remains operational.
+func (p *Pool) Update(ctx context.Context, prm []NodeParam) error {
+	pool := p.pool.Load()
+
+	newPool, equal, err := pool.update(ctx, prm)
+	if equal || err != nil {
+		return err
+	}
+
+	newPool.startRebalance(ctx)
+	oldPool := p.pool.Swap(newPool)
+	oldPool.stopRebalance()
+
+	return nil
+}
+
+type pool struct {
 	innerPools      []*innerPool
 	key             *ecdsa.PrivateKey
 	cancel          context.CancelFunc
+	cancelLock      *sync.Mutex
 	closedCh        chan struct{}
 	cache           *sessionCache
 	stokenDuration  uint64
@@ -1845,8 +2068,7 @@ const (
 	defaultBufferMaxSizeForPut = 3 * 1024 * 1024 // 3 MB
 )
 
-// NewPool creates connection pool using parameters.
-func NewPool(options InitParameters) (*Pool, error) {
+func newPool(options InitParameters) (*pool, error) {
 	if options.key == nil {
 		return nil, fmt.Errorf("missed required parameter 'Key'")
 	}
@@ -1863,7 +2085,7 @@ func NewPool(options InitParameters) (*Pool, error) {
 
 	fillDefaultInitParams(&options, cache)
 
-	pool := &Pool{
+	pool := &pool{
 		key:            options.key,
 		cache:          cache,
 		logger:         options.logger,
@@ -1875,26 +2097,44 @@ func NewPool(options InitParameters) (*Pool, error) {
 			sessionExpirationDuration: options.sessionExpirationDuration,
 		},
 		clientBuilder: options.clientBuilder,
+		cancelLock:    &sync.Mutex{},
 	}
 
 	return pool, nil
 }
 
-// Dial establishes a connection to the servers from the FrostFS network.
-// It also starts a routine that checks the health of the nodes and
-// updates the weights of the nodes for balancing.
-// Returns an error describing failure reason.
-//
-// If failed, the Pool SHOULD NOT be used.
-//
-// See also InitParameters.SetClientRebalanceInterval.
-func (p *Pool) Dial(ctx context.Context) error {
+func (p *pool) Dial(ctx context.Context) error {
+	err := p.dial(ctx, nil)
+	if err != nil {
+		return err
+	}
+
+	ni, err := p.NetworkInfo(ctx)
+	if err != nil {
+		return fmt.Errorf("get network info for max object size: %w", err)
+	}
+	p.maxObjectSize = ni.MaxObjectSize()
+
+	return nil
+}
+
+// dial initializes clients in accordance with p.rebalanceParams.nodesParams.
+// existingClients is optional. After dial is executed, existingClients will contain only unused clients.
+func (p *pool) dial(ctx context.Context, existingClients map[string]client) error {
 	inner := make([]*innerPool, len(p.rebalanceParams.nodesParams))
 	var atLeastOneHealthy bool
 
 	for i, params := range p.rebalanceParams.nodesParams {
 		clients := make([]client, len(params.weights))
 		for j, addr := range params.addresses {
+			if client, ok := existingClients[addr]; ok {
+				clients[j] = client
+				atLeastOneHealthy = true
+
+				delete(existingClients, addr)
+				continue
+			}
+
 			clients[j] = p.clientBuilder(addr)
 			if err := clients[j].dial(ctx); err != nil {
 				p.log(zap.WarnLevel, "failed to build client", zap.String("address", addr), zap.Error(err))
@@ -1926,22 +2166,70 @@ func (p *Pool) Dial(ctx context.Context) error {
 		return fmt.Errorf("at least one node must be healthy")
 	}
 
-	ctx, cancel := context.WithCancel(ctx)
-	p.cancel = cancel
-	p.closedCh = make(chan struct{})
 	p.innerPools = inner
 
-	ni, err := p.NetworkInfo(ctx)
-	if err != nil {
-		return fmt.Errorf("get network info for max object size: %w", err)
-	}
-	p.maxObjectSize = ni.MaxObjectSize()
-
-	go p.startRebalance(ctx)
 	return nil
 }
 
-func (p *Pool) log(level zapcore.Level, msg string, fields ...zap.Field) {
+func nodesParamEqual(a, b []*nodesParam) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for i, v := range a {
+		if v.priority != b[i].priority || len(v.addresses) != len(b[i].addresses) {
+			return false
+		}
+
+		for j, address := range v.addresses {
+			if address != b[i].addresses[j] {
+				return false
+			}
+		}
+	}
+
+	return true
+}
+
+// Update requires that no other parallel operations are executed concurrently on the pool instance.
+func (p *pool) update(ctx context.Context, prm []NodeParam) (*pool, bool, error) {
+	newPool := *p
+
+	existingClients := make(map[string]client)
+	for i, pool := range newPool.rebalanceParams.nodesParams {
+		for j := range pool.weights {
+			existingClients[pool.addresses[j]] = newPool.innerPools[i].clients[j]
+		}
+	}
+
+	nodesParams, err := adjustNodeParams(prm)
+	if err != nil {
+		return nil, false, err
+	}
+
+	if nodesParamEqual(newPool.rebalanceParams.nodesParams, nodesParams) {
+		return nil, true, err
+	}
+
+	newPool.rebalanceParams.nodesParams = nodesParams
+
+	err = newPool.dial(ctx, existingClients)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// After newPool.dial(ctx, existingClients), existingClients will contain only outdated clients.
+	// Removing outdated clients
+	for _, client := range existingClients {
+		if clientErr := client.close(); clientErr != nil {
+			err = errors.Join(err, clientErr)
+		}
+	}
+
+	return &newPool, false, err
+}
+
+func (p *pool) log(level zapcore.Level, msg string, fields ...zap.Field) {
 	if p.logger == nil {
 		return
 	}
@@ -1994,6 +2282,11 @@ func fillDefaultInitParams(params *InitParameters, cache *sessionCache) {
 	}
 }
 
+type addressWeightPair struct {
+	address string
+	weight  float64
+}
+
 func adjustNodeParams(nodeParams []NodeParam) ([]*nodesParam, error) {
 	if len(nodeParams) == 0 {
 		return nil, errors.New("no FrostFS peers configured")
@@ -2020,11 +2313,39 @@ func adjustNodeParams(nodeParams []NodeParam) ([]*nodesParam, error) {
 		return nodesParams[i].priority < nodesParams[j].priority
 	})
 
+	for _, nodes := range nodesParams {
+		addressWeightPairs := make([]addressWeightPair, len(nodes.addresses))
+		for i := range nodes.addresses {
+			addressWeightPairs[i] = addressWeightPair{address: nodes.addresses[i], weight: nodes.weights[i]}
+		}
+
+		sort.Slice(addressWeightPairs, func(i, j int) bool {
+			return addressWeightPairs[i].address < addressWeightPairs[j].address
+		})
+
+		for i, pair := range addressWeightPairs {
+			nodes.addresses[i] = pair.address
+			nodes.weights[i] = pair.weight
+		}
+	}
+
 	return nodesParams, nil
 }
 
-// startRebalance runs loop to monitor connection healthy status.
-func (p *Pool) startRebalance(ctx context.Context) {
+func (p *pool) startRebalance(ctx context.Context) {
+	p.cancelLock.Lock()
+	defer p.cancelLock.Unlock()
+
+	rebalanceCtx, cancel := context.WithCancel(ctx)
+
+	p.closedCh = make(chan struct{})
+	p.cancel = cancel
+
+	go p.rebalance(rebalanceCtx)
+}
+
+// rebalance runs loop to monitor connection healthy status.
+func (p *pool) rebalance(ctx context.Context) {
 	ticker := time.NewTimer(p.rebalanceParams.clientRebalanceInterval)
 	buffers := make([][]float64, len(p.rebalanceParams.nodesParams))
 	for i, params := range p.rebalanceParams.nodesParams {
@@ -2043,7 +2364,15 @@ func (p *Pool) startRebalance(ctx context.Context) {
 	}
 }
 
-func (p *Pool) updateNodesHealth(ctx context.Context, buffers [][]float64) {
+func (p *pool) stopRebalance() {
+	p.cancelLock.Lock()
+	defer p.cancelLock.Unlock()
+
+	p.cancel()
+	<-p.closedCh
+}
+
+func (p *pool) updateNodesHealth(ctx context.Context, buffers [][]float64) {
 	wg := sync.WaitGroup{}
 	for i, inner := range p.innerPools {
 		wg.Add(1)
@@ -2057,12 +2386,11 @@ func (p *Pool) updateNodesHealth(ctx context.Context, buffers [][]float64) {
 	wg.Wait()
 }
 
-func (p *Pool) updateInnerNodesHealth(ctx context.Context, i int, bufferWeights []float64) {
+func (p *pool) updateInnerNodesHealth(ctx context.Context, i int, bufferWeights []float64) {
 	if i > len(p.innerPools)-1 {
 		return
 	}
 	pool := p.innerPools[i]
-	options := p.rebalanceParams
 
 	healthyChanged := new(atomic.Bool)
 	wg := sync.WaitGroup{}
@@ -2072,12 +2400,12 @@ func (p *Pool) updateInnerNodesHealth(ctx context.Context, i int, bufferWeights
 		go func(j int, cli client) {
 			defer wg.Done()
 
-			tctx, c := context.WithTimeout(ctx, options.nodeRequestTimeout)
+			tctx, c := context.WithTimeout(ctx, p.rebalanceParams.nodeRequestTimeout)
 			defer c()
 
 			healthy, changed := cli.restartIfUnhealthy(tctx)
 			if healthy {
-				bufferWeights[j] = options.nodesParams[i].weights[j]
+				bufferWeights[j] = p.rebalanceParams.nodesParams[i].weights[j]
 			} else {
 				bufferWeights[j] = 0
 				p.cache.DeleteByPrefix(cli.address())
@@ -2116,7 +2444,7 @@ func adjustWeights(weights []float64) []float64 {
 	return adjusted
 }
 
-func (p *Pool) connection() (client, error) {
+func (p *pool) connection() (client, error) {
 	for _, inner := range p.innerPools {
 		cp, err := inner.connection()
 		if err == nil {
@@ -2159,7 +2487,7 @@ func formCacheKey(address string, key *ecdsa.PrivateKey, clientCut bool) string
 	return address + stype + k.String()
 }
 
-func (p *Pool) checkSessionTokenErr(err error, address string) bool {
+func (p *pool) checkSessionTokenErr(err error, address string) bool {
 	if err == nil {
 		return false
 	}
@@ -2238,7 +2566,7 @@ type callContext struct {
 	sessionClientCut bool
 }
 
-func (p *Pool) initCallContext(ctx *callContext, cfg prmCommon, prmCtx prmContext) error {
+func (p *pool) initCallContext(ctx *callContext, cfg prmCommon, prmCtx prmContext) error {
 	cp, err := p.connection()
 	if err != nil {
 		return err
@@ -2271,7 +2599,7 @@ func (p *Pool) initCallContext(ctx *callContext, cfg prmCommon, prmCtx prmContex
 
 // opens new session or uses cached one.
 // Must be called only on initialized callContext with set sessionTarget.
-func (p *Pool) openDefaultSession(ctx context.Context, cc *callContext) error {
+func (p *pool) openDefaultSession(ctx context.Context, cc *callContext) error {
 	cacheKey := formCacheKey(cc.endpoint, cc.key, cc.sessionClientCut)
 
 	tok, ok := p.cache.Get(cacheKey)
@@ -2305,7 +2633,7 @@ func (p *Pool) openDefaultSession(ctx context.Context, cc *callContext) error {
 
 // opens default session (if sessionDefault is set), and calls f. If f returns
 // session-related error then cached token is removed.
-func (p *Pool) call(ctx context.Context, cc *callContext, f func() error) error {
+func (p *pool) call(ctx context.Context, cc *callContext, f func() error) error {
 	var err error
 
 	if cc.sessionDefault {
@@ -2322,16 +2650,13 @@ func (p *Pool) call(ctx context.Context, cc *callContext, f func() error) error
 }
 
 // fillAppropriateKey use pool key if caller didn't specify its own.
-func (p *Pool) fillAppropriateKey(prm *prmCommon) {
+func (p *pool) fillAppropriateKey(prm *prmCommon) {
 	if prm.key == nil {
 		prm.key = p.key
 	}
 }
 
-// PutObject writes an object through a remote server using FrostFS API protocol.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) PutObject(ctx context.Context, prm PrmObjectPut) (oid.ID, error) {
+func (p *pool) PutObject(ctx context.Context, prm PrmObjectPut) (oid.ID, error) {
 	cnr, _ := prm.hdr.ContainerID()
 
 	var prmCtx prmContext
@@ -2371,11 +2696,7 @@ func (p *Pool) PutObject(ctx context.Context, prm PrmObjectPut) (oid.ID, error)
 	return id, nil
 }
 
-// DeleteObject marks an object for deletion from the container using FrostFS API protocol.
-// As a marker, a special unit called a tombstone is placed in the container.
-// It confirms the user's intent to delete the object, and is itself a container object.
-// Explicit deletion is done asynchronously, and is generally not guaranteed.
-func (p *Pool) DeleteObject(ctx context.Context, prm PrmObjectDelete) error {
+func (p *pool) DeleteObject(ctx context.Context, prm PrmObjectDelete) error {
 	var prmCtx prmContext
 	prmCtx.useDefaultSession()
 	prmCtx.useVerb(session.VerbObjectDelete)
@@ -2441,10 +2762,7 @@ type ResGetObject struct {
 	Payload io.ReadCloser
 }
 
-// GetObject reads object header and initiates reading an object payload through a remote server using FrostFS API protocol.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) GetObject(ctx context.Context, prm PrmObjectGet) (ResGetObject, error) {
+func (p *pool) GetObject(ctx context.Context, prm PrmObjectGet) (ResGetObject, error) {
 	p.fillAppropriateKey(&prm.prmCommon)
 
 	var cc callContext
@@ -2466,10 +2784,7 @@ func (p *Pool) GetObject(ctx context.Context, prm PrmObjectGet) (ResGetObject, e
 	})
 }
 
-// HeadObject reads object header through a remote server using FrostFS API protocol.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) HeadObject(ctx context.Context, prm PrmObjectHead) (object.Object, error) {
+func (p *pool) HeadObject(ctx context.Context, prm PrmObjectHead) (object.Object, error) {
 	p.fillAppropriateKey(&prm.prmCommon)
 
 	var cc callContext
@@ -2516,11 +2831,7 @@ func (x *ResObjectRange) Close() error {
 	return err
 }
 
-// ObjectRange initiates reading an object's payload range through a remote
-// server using FrostFS API protocol.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) ObjectRange(ctx context.Context, prm PrmObjectRange) (ResObjectRange, error) {
+func (p *pool) ObjectRange(ctx context.Context, prm PrmObjectRange) (ResObjectRange, error) {
 	p.fillAppropriateKey(&prm.prmCommon)
 
 	var cc callContext
@@ -2578,13 +2889,7 @@ func (x *ResObjectSearch) Close() {
 	_, _ = x.r.Close()
 }
 
-// SearchObjects initiates object selection through a remote server using FrostFS API protocol.
-//
-// The call only opens the transmission channel, explicit fetching of matched objects
-// is done using the ResObjectSearch. Resulting reader must be finally closed.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) SearchObjects(ctx context.Context, prm PrmObjectSearch) (ResObjectSearch, error) {
+func (p *pool) SearchObjects(ctx context.Context, prm PrmObjectSearch) (ResObjectSearch, error) {
 	p.fillAppropriateKey(&prm.prmCommon)
 
 	var cc callContext
@@ -2606,17 +2911,7 @@ func (p *Pool) SearchObjects(ctx context.Context, prm PrmObjectSearch) (ResObjec
 	})
 }
 
-// PutContainer sends request to save container in FrostFS and waits for the operation to complete.
-//
-// Waiting parameters can be specified using SetWaitParams. If not called, defaults are used:
-//
-//	polling interval: 5s
-//	waiting timeout: 120s
-//
-// Success can be verified by reading by identifier (see GetContainer).
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) PutContainer(ctx context.Context, prm PrmContainerPut) (cid.ID, error) {
+func (p *pool) PutContainer(ctx context.Context, prm PrmContainerPut) (cid.ID, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return cid.ID{}, err
@@ -2630,10 +2925,7 @@ func (p *Pool) PutContainer(ctx context.Context, prm PrmContainerPut) (cid.ID, e
 	return cnrID, nil
 }
 
-// GetContainer reads FrostFS container by ID.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) GetContainer(ctx context.Context, prm PrmContainerGet) (container.Container, error) {
+func (p *pool) GetContainer(ctx context.Context, prm PrmContainerGet) (container.Container, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return container.Container{}, err
@@ -2647,8 +2939,7 @@ func (p *Pool) GetContainer(ctx context.Context, prm PrmContainerGet) (container
 	return cnrs, nil
 }
 
-// ListContainers requests identifiers of the account-owned containers.
-func (p *Pool) ListContainers(ctx context.Context, prm PrmContainerList) ([]cid.ID, error) {
+func (p *pool) ListContainers(ctx context.Context, prm PrmContainerList) ([]cid.ID, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return nil, err
@@ -2662,15 +2953,7 @@ func (p *Pool) ListContainers(ctx context.Context, prm PrmContainerList) ([]cid.
 	return cnrIDs, nil
 }
 
-// DeleteContainer sends request to remove the FrostFS container and waits for the operation to complete.
-//
-// Waiting parameters can be specified using SetWaitParams. If not called, defaults are used:
-//
-//	polling interval: 5s
-//	waiting timeout: 120s
-//
-// Success can be verified by reading by identifier (see GetContainer).
-func (p *Pool) DeleteContainer(ctx context.Context, prm PrmContainerDelete) error {
+func (p *pool) DeleteContainer(ctx context.Context, prm PrmContainerDelete) error {
 	cp, err := p.connection()
 	if err != nil {
 		return err
@@ -2684,10 +2967,7 @@ func (p *Pool) DeleteContainer(ctx context.Context, prm PrmContainerDelete) erro
 	return nil
 }
 
-// GetEACL reads eACL table of the FrostFS container.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) GetEACL(ctx context.Context, prm PrmContainerEACL) (eacl.Table, error) {
+func (p *pool) GetEACL(ctx context.Context, prm PrmContainerEACL) (eacl.Table, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return eacl.Table{}, err
@@ -2701,15 +2981,7 @@ func (p *Pool) GetEACL(ctx context.Context, prm PrmContainerEACL) (eacl.Table, e
 	return eaclResult, nil
 }
 
-// SetEACL sends request to update eACL table of the FrostFS container and waits for the operation to complete.
-//
-// Waiting parameters can be specified using SetWaitParams. If not called, defaults are used:
-//
-//	polling interval: 5s
-//	waiting timeout: 120s
-//
-// Success can be verified by reading by identifier (see GetEACL).
-func (p *Pool) SetEACL(ctx context.Context, prm PrmContainerSetEACL) error {
+func (p *pool) SetEACL(ctx context.Context, prm PrmContainerSetEACL) error {
 	cp, err := p.connection()
 	if err != nil {
 		return err
@@ -2723,10 +2995,7 @@ func (p *Pool) SetEACL(ctx context.Context, prm PrmContainerSetEACL) error {
 	return nil
 }
 
-// Balance requests current balance of the FrostFS account.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) Balance(ctx context.Context, prm PrmBalanceGet) (accounting.Decimal, error) {
+func (p *pool) Balance(ctx context.Context, prm PrmBalanceGet) (accounting.Decimal, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return accounting.Decimal{}, err
@@ -2740,8 +3009,7 @@ func (p *Pool) Balance(ctx context.Context, prm PrmBalanceGet) (accounting.Decim
 	return balance, nil
 }
 
-// Statistic returns connection statistics.
-func (p Pool) Statistic() Statistic {
+func (p *pool) Statistic() Statistic {
 	stat := Statistic{}
 	for _, inner := range p.innerPools {
 		nodes := make([]string, 0, len(inner.clients))
@@ -2818,10 +3086,7 @@ func waitFor(ctx context.Context, params *WaitParams, condition func(context.Con
 	}
 }
 
-// NetworkInfo requests information about the FrostFS network of which the remote server is a part.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) NetworkInfo(ctx context.Context) (netmap.NetworkInfo, error) {
+func (p *pool) NetworkInfo(ctx context.Context) (netmap.NetworkInfo, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return netmap.NetworkInfo{}, err
@@ -2835,10 +3100,7 @@ func (p *Pool) NetworkInfo(ctx context.Context) (netmap.NetworkInfo, error) {
 	return netInfo, nil
 }
 
-// NetMapSnapshot requests information about the FrostFS network map.
-//
-// Main return value MUST NOT be processed on an erroneous return.
-func (p *Pool) NetMapSnapshot(ctx context.Context) (netmap.NetMap, error) {
+func (p *pool) NetMapSnapshot(ctx context.Context) (netmap.NetMap, error) {
 	cp, err := p.connection()
 	if err != nil {
 		return netmap.NetMap{}, err
@@ -2852,12 +3114,8 @@ func (p *Pool) NetMapSnapshot(ctx context.Context) (netmap.NetMap, error) {
 	return netMap, nil
 }
 
-// Close closes the Pool and releases all the associated resources.
-func (p *Pool) Close() {
-	p.cancel()
-	<-p.closedCh
-
-	// close all clients
+func (p *pool) Close() {
+	p.stopRebalance()
 	for _, pools := range p.innerPools {
 		for _, cli := range pools.clients {
 			if cli.isDialed() {
@@ -2875,7 +3133,7 @@ func (p *Pool) Close() {
 //
 // Returns any error that does not allow reading configuration
 // from the network.
-func SyncContainerWithNetwork(ctx context.Context, cnr *container.Container, p *Pool) error {
+func SyncContainerWithNetwork(ctx context.Context, cnr *container.Container, p *pool) error {
 	ni, err := p.NetworkInfo(ctx)
 	if err != nil {
 		return fmt.Errorf("network info: %w", err)
@@ -2886,8 +3144,7 @@ func SyncContainerWithNetwork(ctx context.Context, cnr *container.Container, p *
 	return nil
 }
 
-// GetSplitInfo implements relations.Relations.
-func (p *Pool) GetSplitInfo(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) (*object.SplitInfo, error) {
+func (p *pool) GetSplitInfo(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) (*object.SplitInfo, error) {
 	var addr oid.Address
 	addr.SetContainer(cnrID)
 	addr.SetObject(objID)
@@ -2916,8 +3173,7 @@ func (p *Pool) GetSplitInfo(ctx context.Context, cnrID cid.ID, objID oid.ID, tok
 	}
 }
 
-// ListChildrenByLinker implements relations.Relations.
-func (p *Pool) ListChildrenByLinker(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) ([]oid.ID, error) {
+func (p *pool) ListChildrenByLinker(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) ([]oid.ID, error) {
 	var addr oid.Address
 	addr.SetContainer(cnrID)
 	addr.SetObject(objID)
@@ -2939,8 +3195,7 @@ func (p *Pool) ListChildrenByLinker(ctx context.Context, cnrID cid.ID, objID oid
 	return res.Children(), nil
 }
 
-// GetLeftSibling implements relations.Relations.
-func (p *Pool) GetLeftSibling(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) (oid.ID, error) {
+func (p *pool) GetLeftSibling(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) (oid.ID, error) {
 	var addr oid.Address
 	addr.SetContainer(cnrID)
 	addr.SetObject(objID)
@@ -2966,8 +3221,7 @@ func (p *Pool) GetLeftSibling(ctx context.Context, cnrID cid.ID, objID oid.ID, t
 	return idMember, nil
 }
 
-// FindSiblingBySplitID implements relations.Relations.
-func (p *Pool) FindSiblingBySplitID(ctx context.Context, cnrID cid.ID, splitID *object.SplitID, tokens relations.Tokens) ([]oid.ID, error) {
+func (p *pool) FindSiblingBySplitID(ctx context.Context, cnrID cid.ID, splitID *object.SplitID, tokens relations.Tokens) ([]oid.ID, error) {
 	var query object.SearchFilters
 	query.AddSplitIDFilter(object.MatchStringEqual, splitID)
 
@@ -2998,8 +3252,7 @@ func (p *Pool) FindSiblingBySplitID(ctx context.Context, cnrID cid.ID, splitID *
 	return members, nil
 }
 
-// FindSiblingByParentID implements relations.Relations.
-func (p *Pool) FindSiblingByParentID(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) ([]oid.ID, error) {
+func (p *pool) FindSiblingByParentID(ctx context.Context, cnrID cid.ID, objID oid.ID, tokens relations.Tokens) ([]oid.ID, error) {
 	var query object.SearchFilters
 	query.AddParentIDFilter(object.MatchStringEqual, objID)
 

pool/pool_test.go

@@ -4,7 +4,9 @@ import (
 	"context"
 	"crypto/ecdsa"
 	"errors"
+	"reflect"
 	"strconv"
+	"sync"
 	"testing"
 	"time"
 
@@ -101,11 +103,11 @@ func TestBuildPoolOneNodeFailed(t *testing.T) {
 
 	expectedAuthKey := frostfsecdsa.PublicKey(clientKeys[1].PublicKey)
 	condition := func() bool {
-		cp, err := clientPool.connection()
+		cp, err := clientPool.pool.Load().connection()
 		if err != nil {
 			return false
 		}
-		st, _ := clientPool.cache.Get(formCacheKey(cp.address(), clientPool.key, false))
+		st, _ := clientPool.pool.Load().cache.Get(formCacheKey(cp.address(), clientPool.pool.Load().key, false))
 		return st.AssertAuthKey(&expectedAuthKey)
 	}
 	require.Never(t, condition, 900*time.Millisecond, 100*time.Millisecond)
@@ -138,9 +140,9 @@ func TestOneNode(t *testing.T) {
 	require.NoError(t, err)
 	t.Cleanup(pool.Close)
 
-	cp, err := pool.connection()
+	cp, err := pool.pool.Load().connection()
 	require.NoError(t, err)
-	st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 	expectedAuthKey := frostfsecdsa.PublicKey(key1.PublicKey)
 	require.True(t, st.AssertAuthKey(&expectedAuthKey))
 }
@@ -168,12 +170,156 @@ func TestTwoNodes(t *testing.T) {
 	require.NoError(t, err)
 	t.Cleanup(pool.Close)
 
-	cp, err := pool.connection()
+	cp, err := pool.pool.Load().connection()
 	require.NoError(t, err)
-	st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 	require.True(t, assertAuthKeyForAny(st, clientKeys))
 }
 
+func TestTwoNodesUpdate(t *testing.T) {
+	var clientKeys []*ecdsa.PrivateKey
+	mockClientBuilder := func(addr string) client {
+		key := newPrivateKey(t)
+		clientKeys = append(clientKeys, key)
+		return newMockClient(addr, *key)
+	}
+
+	opts := InitParameters{
+		key: newPrivateKey(t),
+		nodeParams: []NodeParam{
+			{2, "peer0", 1},
+			{2, "peer1", 1},
+		},
+	}
+	opts.setClientBuilder(mockClientBuilder)
+
+	pool, err := NewPool(opts)
+	require.NoError(t, err)
+	err = pool.Dial(context.Background())
+	require.NoError(t, err)
+	t.Cleanup(pool.Close)
+
+	cp, err := pool.pool.Load().connection()
+	require.NoError(t, err)
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
+	require.True(t, assertAuthKeyForAny(st, clientKeys))
+
+	pool.Update(context.Background(), []NodeParam{
+		{1, "peer-1", 1},
+		{2, "peer0", 1},
+		{2, "peer1", 1},
+	})
+
+	st1, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
+	require.Equal(t, &st1, &st)
+
+	cp2, err := pool.pool.Load().connection()
+	require.NoError(t, err)
+	require.Equal(t, cp2.address(), "peer-1")
+}
+
+func TestUpdateNodeMultithread(t *testing.T) {
+	key1 := newPrivateKey(t)
+	mockClientBuilder := func(addr string) client {
+		return newMockClient(addr, *key1)
+	}
+
+	opts := InitParameters{
+		key:        newPrivateKey(t),
+		nodeParams: []NodeParam{{1, "peer0", 1}},
+	}
+	opts.setClientBuilder(mockClientBuilder)
+
+	pool, err := NewPool(opts)
+	require.NoError(t, err)
+	err = pool.Dial(context.Background())
+	require.NoError(t, err)
+	t.Cleanup(pool.Close)
+
+	wg := sync.WaitGroup{}
+
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+			err := pool.Update(context.Background(), []NodeParam{{1, "peer" + strconv.Itoa(i+1), 1}})
+			require.NoError(t, err)
+		}(i)
+	}
+
+	wg.Wait()
+}
+
+func TestUpdateNodeEqualConfig(t *testing.T) {
+	key1 := newPrivateKey(t)
+	mockClientBuilder := func(addr string) client {
+		return newMockClient(addr, *key1)
+	}
+
+	opts := InitParameters{
+		key:        newPrivateKey(t),
+		nodeParams: []NodeParam{{1, "peer0", 1}},
+	}
+	opts.setClientBuilder(mockClientBuilder)
+
+	pool, err := NewPool(opts)
+
+	require.NoError(t, err)
+	err = pool.Dial(context.Background())
+	require.NoError(t, err)
+	t.Cleanup(pool.Close)
+
+	cp, err := pool.pool.Load().connection()
+	require.NoError(t, err)
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
+	expectedAuthKey := frostfsecdsa.PublicKey(key1.PublicKey)
+	require.True(t, st.AssertAuthKey(&expectedAuthKey))
+
+	_, flag, err := pool.pool.Load().update(context.Background(), []NodeParam{{1, "peer0", 1}})
+	require.NoError(t, err)
+	require.True(t, flag)
+}
+
+func TestUpdateNode(t *testing.T) {
+	key1 := newPrivateKey(t)
+	mockClientBuilder := func(addr string) client {
+		return newMockClient(addr, *key1)
+	}
+
+	opts := InitParameters{
+		key:        newPrivateKey(t),
+		nodeParams: []NodeParam{{1, "peer0", 1}},
+	}
+	opts.setClientBuilder(mockClientBuilder)
+
+	pool, err := NewPool(opts)
+	require.NoError(t, err)
+	err = pool.Dial(context.Background())
+	require.NoError(t, err)
+	t.Cleanup(pool.Close)
+
+	cp, err := pool.pool.Load().connection()
+	require.NoError(t, err)
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
+	expectedAuthKey := frostfsecdsa.PublicKey(key1.PublicKey)
+	require.True(t, st.AssertAuthKey(&expectedAuthKey))
+
+	pool.Update(context.Background(), []NodeParam{{1, "peer0", 1}})
+	cp1, err := pool.pool.Load().connection()
+	st1, _ := pool.pool.Load().cache.Get(formCacheKey(cp1.address(), pool.pool.Load().key, false))
+	require.NoError(t, err)
+	require.Equal(t, &st, &st1)
+	require.Equal(t, &cp, &cp1)
+
+	pool.Update(context.Background(), []NodeParam{{1, "peer1", 1}})
+	cp2, err := pool.pool.Load().connection()
+	require.NoError(t, err)
+
+	st2, _ := pool.pool.Load().cache.Get(formCacheKey(cp2.address(), pool.pool.Load().key, false))
+	require.NotEqual(t, cp.address(), cp2.address())
+	require.NotEqual(t, &st, &st2)
+}
+
 func assertAuthKeyForAny(st session.Object, clientKeys []*ecdsa.PrivateKey) bool {
 	for _, key := range clientKeys {
 		expectedAuthKey := frostfsecdsa.PublicKey(key.PublicKey)
@@ -223,9 +369,9 @@ func TestOneOfTwoFailed(t *testing.T) {
 	time.Sleep(2 * time.Second)
 
 	for i := 0; i < 5; i++ {
-		cp, err := pool.connection()
+		cp, err := pool.pool.Load().connection()
 		require.NoError(t, err)
-		st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+		st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 		require.True(t, assertAuthKeyForAny(st, clientKeys))
 	}
 }
@@ -259,7 +405,7 @@ func TestTwoFailed(t *testing.T) {
 
 	time.Sleep(2 * time.Second)
 
-	_, err = pool.connection()
+	_, err = pool.pool.Load().connection()
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "no healthy")
 }
@@ -293,9 +439,9 @@ func TestSessionCache(t *testing.T) {
 	t.Cleanup(pool.Close)
 
 	// cache must contain session token
-	cp, err := pool.connection()
+	cp, err := pool.pool.Load().connection()
 	require.NoError(t, err)
-	st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 	require.True(t, st.AssertAuthKey(&expectedAuthKey))
 
 	var prm PrmObjectGet
@@ -306,9 +452,9 @@ func TestSessionCache(t *testing.T) {
 	require.Error(t, err)
 
 	// cache must not contain session token
-	cp, err = pool.connection()
+	cp, err = pool.pool.Load().connection()
 	require.NoError(t, err)
-	_, ok := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+	_, ok := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 	require.False(t, ok)
 
 	var prm2 PrmObjectPut
@@ -318,9 +464,9 @@ func TestSessionCache(t *testing.T) {
 	require.NoError(t, err)
 
 	// cache must contain session token
-	cp, err = pool.connection()
+	cp, err = pool.pool.Load().connection()
 	require.NoError(t, err)
-	st, _ = pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+	st, _ = pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 	require.True(t, st.AssertAuthKey(&expectedAuthKey))
 }
 
@@ -362,17 +508,17 @@ func TestPriority(t *testing.T) {
 
 	expectedAuthKey1 := frostfsecdsa.PublicKey(clientKeys[0].PublicKey)
 	firstNode := func() bool {
-		cp, err := pool.connection()
+		cp, err := pool.pool.Load().connection()
 		require.NoError(t, err)
-		st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+		st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 		return st.AssertAuthKey(&expectedAuthKey1)
 	}
 
 	expectedAuthKey2 := frostfsecdsa.PublicKey(clientKeys[1].PublicKey)
 	secondNode := func() bool {
-		cp, err := pool.connection()
+		cp, err := pool.pool.Load().connection()
 		require.NoError(t, err)
-		st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+		st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 		return st.AssertAuthKey(&expectedAuthKey2)
 	}
 	require.Never(t, secondNode, time.Second, 200*time.Millisecond)
@@ -407,9 +553,9 @@ func TestSessionCacheWithKey(t *testing.T) {
 	require.NoError(t, err)
 
 	// cache must contain session token
-	cp, err := pool.connection()
+	cp, err := pool.pool.Load().connection()
 	require.NoError(t, err)
-	st, _ := pool.cache.Get(formCacheKey(cp.address(), pool.key, false))
+	st, _ := pool.pool.Load().cache.Get(formCacheKey(cp.address(), pool.pool.Load().key, false))
 	require.True(t, st.AssertAuthKey(&expectedAuthKey))
 
 	var prm PrmObjectDelete
@@ -419,7 +565,7 @@ func TestSessionCacheWithKey(t *testing.T) {
 
 	err = pool.DeleteObject(ctx, prm)
 	require.NoError(t, err)
-	st, _ = pool.cache.Get(formCacheKey(cp.address(), anonKey, false))
+	st, _ = pool.pool.Load().cache.Get(formCacheKey(cp.address(), anonKey, false))
 	require.True(t, st.AssertAuthKey(&expectedAuthKey))
 }
 
@@ -460,10 +606,10 @@ func TestSessionTokenOwner(t *testing.T) {
 	cc.sessionTarget = func(tok session.Object) {
 		tkn = tok
 	}
-	err = p.initCallContext(&cc, prm, prmCtx)
+	err = p.pool.Load().initCallContext(&cc, prm, prmCtx)
 	require.NoError(t, err)
 
-	err = p.openDefaultSession(ctx, &cc)
+	err = p.pool.Load().openDefaultSession(ctx, &cc)
 	require.NoError(t, err)
 	require.True(t, tkn.VerifySignature())
 	require.True(t, tkn.Issuer().Equals(anonOwner))
@@ -668,6 +814,25 @@ func TestHandleError(t *testing.T) {
 	}
 }
 
+func TestAdjustNodeParams(t *testing.T) {
+	nodes1 := []NodeParam{
+		{1, "peer0", 1},
+		{1, "peer1", 2},
+		{1, "peer2", 3},
+		{2, "peer21", 2},
+	}
+	nodes2 := []NodeParam{
+		{1, "peer0", 1},
+		{1, "peer2", 3},
+		{1, "peer1", 2},
+		{2, "peer21", 2},
+	}
+
+	nodesParam1, _ := adjustNodeParams(nodes1)
+	nodesParam2, _ := adjustNodeParams(nodes2)
+	require.True(t, reflect.DeepEqual(nodesParam1, nodesParam2))
+}
+
 func TestSwitchAfterErrorThreshold(t *testing.T) {
 	nodes := []NodeParam{
 		{1, "peer0", 1},
@@ -708,14 +873,14 @@ func TestSwitchAfterErrorThreshold(t *testing.T) {
 	t.Cleanup(pool.Close)
 
 	for i := 0; i < errorThreshold; i++ {
-		conn, err := pool.connection()
+		conn, err := pool.pool.Load().connection()
 		require.NoError(t, err)
 		require.Equal(t, nodes[0].address, conn.address())
 		_, err = conn.objectGet(ctx, PrmObjectGet{})
 		require.Error(t, err)
 	}
 
-	conn, err := pool.connection()
+	conn, err := pool.pool.Load().connection()
 	require.NoError(t, err)
 	require.Equal(t, nodes[1].address, conn.address())
 	_, err = conn.objectGet(ctx, PrmObjectGet{})

pool/sampler_test.go

@@ -59,7 +59,7 @@ func TestHealthyReweight(t *testing.T) {
 		sampler: newSampler(weights, rand.NewSource(0)),
 		clients: []client{client1, client2},
 	}
-	p := &Pool{
+	p := &pool{
 		innerPools:      []*innerPool{inner},
 		cache:           cache,
 		key:             newPrivateKey(t),
@@ -108,7 +108,7 @@ func TestHealthyNoReweight(t *testing.T) {
 			newMockClient(names[1], *newPrivateKey(t)),
 		},
 	}
-	p := &Pool{
+	p := &pool{
 		innerPools:      []*innerPool{inner},
 		rebalanceParams: rebalanceParameters{nodesParams: []*nodesParam{{weights: weights}}},
 	}