应用程序服务通过 VNET 失去与 SQL Server 的连接

Question

我有一个 Linux 应用服务和一个 SQL Server。应用服务需要连接到 SQL 数据库。这两种资源都集成在具有两个子网的 VNET 中：

• 默认（服务端点：Microsoft.Web、Microsoft.Sql；委派：无）-> SQL Server
• webApp（服务端点：Microsoft.Web、Microsoft.Sql；委派：serverFarms）-> 应用服务

我的 SQL Server 网络设置是：

• 公共访问：已禁用
• 私有访问：私有终结点（VNET -> 默认）

一切都按预期进行，但只是在随机的时间内（分钟 - 天）。此后，我的应用服务将无法再连接到 SQL Server。例外情况如下：

未处理的异常。 Microsoft.Data.SqlClient.SqlException (0x80131904): 发生网络相关或实例特定的错误 同时建立与 SQL Server 的连接。服务器没有 已找到或无法访问。验证实例名称是否正确 并且 SQL Server 配置为允许远程连接。 （提供者：TCP 提供者，错误：35 - 捕获内部异常）

2024-09-12T11:05:35.8086896Z Unhandled exception. Microsoft.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 35 - An internal exception was caught)
2024-09-12T11:05:35.8087667Z  ---> System.Net.Sockets.SocketException (00000005, 0xFFFDFFFF): Name or service not known
2024-09-12T11:05:35.8087732Z    at System.Net.Dns.GetHostEntryOrAddressesCore(String hostName, Boolean justAddresses, AddressFamily addressFamily, Nullable`1 startingTimestamp)
2024-09-12T11:05:35.8087778Z    at System.Net.Dns.GetHostAddresses(String hostNameOrAddress, AddressFamily family)
2024-09-12T11:05:35.8087840Z    at Microsoft.Data.SqlClient.SNI.SNICommon.GetDnsIpAddresses(String serverName)
2024-09-12T11:05:35.8087960Z    at Microsoft.Data.SqlClient.SNI.SNITCPHandle.Connect(String serverName, Int32 port, TimeSpan timeout, Boolean isInfiniteTimeout, SqlConnectionIPAddressPreference ipPreference, String cachedFQDN, SQLDNSInfo& pendingDNSInfo)
2024-09-12T11:05:35.8088009Z    at Microsoft.Data.SqlClient.SNI.SNITCPHandle..ctor(String serverName, Int32 port, Int64 timerExpire, Boolean parallel, SqlConnectionIPAddressPreference ipPreference, String cachedFQDN, SQLDNSInfo& pendingDNSInfo, Boolean tlsFirst, String hostNameInCertificate, String serverCertificateFilename)
2024-09-12T11:05:35.8088048Z    at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
2024-09-12T11:05:35.8088096Z    at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
2024-09-12T11:05:35.8088140Z    at Microsoft.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnectionString connectionOptions, Boolean withFailover)
2024-09-12T11:05:35.8088210Z    at Microsoft.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover)
2024-09-12T11:05:35.8088258Z    at Microsoft.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
2024-09-12T11:05:35.8088304Z    at Microsoft.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
2024-09-12T11:05:35.8088362Z    at Microsoft.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling, String accessToken, DbConnectionPool pool)
2024-09-12T11:05:35.8088410Z    at Microsoft.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
2024-09-12T11:05:35.8088476Z    at Microsoft.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
2024-09-12T11:05:35.8088524Z    at Microsoft.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternaloldConnection)
2024-09-12T11:05:35.8088568Z    at Microsoft.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
2024-09-12T11:05:35.8088624Z    at Microsoft.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
2024-09-12T11:05:35.8088659Z    at Microsoft.Data.ProviderBase.DbConnectionPool.WaitForPendingOpen()
2024-09-12T11:05:35.8088906Z --- End of stack trace from previous location ---
2024-09-12T11:05:35.8088981Z    at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenInternalAsync(Boolean errorsExpected, CancellationToken cancellationToken)
2024-09-12T11:05:35.8089031Z    at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenInternalAsync(Boolean errorsExpected, CancellationToken cancellationToken)
2024-09-12T11:05:35.8089080Z    at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenAsync(CancellationToken cancellationToken, Boolean errorsExpected)
2024-09-12T11:05:35.8089131Z    at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerDatabaseCreator.<>c__DisplayClass20_0.<<ExistsAsync>b__0>d.MoveNext()
2024-09-12T11:05:35.8089177Z --- End of stack trace from previous location ---
2024-09-12T11:05:35.8089226Z    at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerDatabaseCreator.<>c__DisplayClass20_0.<<ExistsAsync>b__0>d.MoveNext()
2024-09-12T11:05:35.8089300Z --- End of stack trace from previous location ---
2024-09-12T11:05:35.8089352Z    at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerDatabaseCreator.<>c__DisplayClass20_0.<<ExistsAsync>b__0>d.MoveNext()
2024-09-12T11:05:35.8089400Z --- End of stack trace from previous location ---
2024-09-12T11:05:35.8089454Z    at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func`4 operation, Func`4 verifySucceeded, CancellationToken cancellationToken)
2024-09-12T11:05:35.8089507Z    at Microsoft.EntityFrameworkCore.Storage.RelationalDatabaseCreator.EnsureCreatedAsync(CancellationToken cancellationToken)
2024-09-12T11:05:35.8089555Z    at Microsoft.EntityFrameworkCore.Storage.RelationalDatabaseCreator.EnsureCreatedAsync(CancellationToken cancellationToken)
2024-09-12T11:05:35.8089607Z    at [...].Data.DbInitializer.InitializeAsync(IServiceProvider serviceProvider) in C:\[...].cs:line 17
2024-09-12T11:05:35.8089669Z    at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_1(Object state)
2024-09-12T11:05:35.8089713Z    at System.Threading.ThreadPoolWorkQueue.Dispatch()
2024-09-12T11:05:35.8089757Z    at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()

应用服务计划升级后也会发生这种情况。

可能是什么原因？

Answer 1

应用服务通过 VNET 失去与 SQL Server 的连接

一般来说，您提到的错误是由于专用端点配置不完整或可能是由于引用不正确的专用端点引起的。

正如 VenkatV 提到的，我们需要重新创建一个私有端点，并使用正确的端点再次引用它。

删除并读取专用端点将触发与端点关联的 DNS 记录的更新，这将确保是否删除任何过期的 DNS 条目并更新为新条目，并且此方法还将重置连接。

参考：

https://learn.microsoft.com/en-us/azure/private-link/private-endpoint-overview

https://learn.microsoft.com/en-us/azure/private-link/troubleshoot-private-endpoint-connectivity