DataStream :47:58 UTC Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement

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1 DataStream :47:58 UTC 2015 Citrix Systems, Inc. All rights reserved. Terms of Use Trademarks Privacy Statement

2 Contents DataStream... 3 Database Switching... 4 How NetScaler DataStream Works... 6 Configuring Database Users... 8 Configuring Load Balancing for DataStream Configuring Content Switching for DataStream Configuring Monitors for DataStream Configuring DataStream for a Master/Slave Database Architecture

3 DataStream The NetScaler DataStream feature provides an intelligent mechanism for request switching at the database layer by distributing requests based on the SQL query being sent. When deployed in front of database servers, a NetScaler ensures optimal distribution of traffic from the application servers and Web servers. Administrators can segment traffic according to information in the SQL query and on the basis of database names, usernames, character sets, and packet size. You can either configure load balancing to switch requests based on load balancing algorithms or elaborate the switching criteria by configuring content switching to make a decision based on an SQL query parameters. You can further configure monitors to track the state of database servers. Note: NetScaler DataStream is supported only for MySQL and MS SQL databases. For information about the supported protocol version, character sets, special queries, and transactions, see the Appendix NetScaler DataStream Reference. 3

4 How NetScaler DataStream Works In DataStream, the NetScaler is placed in-line between the application and/or Web servers and the database servers. On the NetScaler appliance, the database servers are represented by services. A typical DataStream deployment consists of the entities described in the following diagram. Figure 1. DataStream Entity Model As shown in this figure, a DataStream configuration can consist of an optional content switching virtual server (CS), a load balancing setup consisting of load balancing virtual servers (LB1 and LB2) and services (Svc1, Svc2, Svc3, and Svc4), and content switching policies (optional). The clients (application or Web servers) send requests to the IP address of a content switching virtual server (CS) configured on the NetScaler appliance. The NetScaler, then, authenticates the clients using the database user credentials configured on the NetScaler appliance. The content switching virtual server (CS) applies the associated content switching policies to the requests. After evaluating the policies, the content switching virtual server (CS) routes the requests to the appropriate load balancing virtual server (LB1 or LB2), which, then, distributes the requests to the appropriate database servers (represented by services on the NetScaler) based on the load balancing algorithm. The NetScaler uses the same database user credentials to authenticate the connection with the 4

5 Database Switching database server. If a content switching virtual server is not configured on the NetScaler, the clients (application or Web servers) send their requests to the IP address of a load balancing virtual server configured on the NetScaler appliance. The NetScaler authenticates the client by using the database user credentials configured on the NetScaler appliance, and then uses the same credentials to authenticate the connection with the database server. The load balancing virtual server distributes the requests to the database servers according to the load balancing algorithm. The most effective load balancing algorithm for database switching is the least connection method. DataStream uses connection multiplexing to enable multiple client-side requests to be made over the same server-side connection. The following connection properties are considered: User name Database name Packet size Character set 5

6 How NetScaler DataStream Works In DataStream, the NetScaler is placed in-line between the application and/or Web servers and the database servers. On the NetScaler appliance, the database servers are represented by services. A typical DataStream deployment consists of the entities described in the following diagram. Figure 1. DataStream Entity Model As shown in this figure, a DataStream configuration can consist of an optional content switching virtual server (CS), a load balancing setup consisting of load balancing virtual servers (LB1 and LB2) and services (Svc1, Svc2, Svc3, and Svc4), and content switching policies (optional). The clients (application or Web servers) send requests to the IP address of a content switching virtual server (CS) configured on the NetScaler appliance. The NetScaler, then, authenticates the clients using the database user credentials configured on the NetScaler appliance. The content switching virtual server (CS) applies the associated content switching policies to the requests. After evaluating the policies, the content switching virtual server (CS) routes the requests to the appropriate load balancing virtual server (LB1 or LB2), which, then, distributes the requests to the appropriate database servers (represented by services on the NetScaler) based on the load balancing algorithm. The NetScaler uses the same database user credentials to authenticate the connection with the 6

7 How NetScaler DataStream Works database server. If a content switching virtual server is not configured on the NetScaler, the clients (application or Web servers) send their requests to the IP address of a load balancing virtual server configured on the NetScaler appliance. The NetScaler authenticates the client by using the database user credentials configured on the NetScaler appliance, and then uses the same credentials to authenticate the connection with the database server. The load balancing virtual server distributes the requests to the database servers according to the load balancing algorithm. The most effective load balancing algorithm for database switching is the least connection method. DataStream uses connection multiplexing to enable multiple client-side requests to be made over the same server-side connection. The following connection properties are considered: User name Database name Packet size Character set 7

8 Configuring Database Users In databases, a connection is always stateful, which means that as soon as a connection is established, it must be authenticated. You need to configure your database user name and password on the NetScaler. For example, if you have a user John configured on the database, you need to configure the user John on the NetScaler too. When you add the database user names and passwords on the NetScaler, these are added to the nsconfig file. NetScaler uses these user credentials to authenticate the clients, and then authenticate the server connections with the database servers. To add a database user by using the NetScaler command line At the NetScaler command prompt, type add db user <username> -password <password> Example > add db user nsdbuser -password dd260427edf Parameters for creating a database user username The database user name. This is a mandatory argument. The maximum length of the user name is 127 characters. password The password used to log on to the database. The maximum length of the password is 127 characters. 8

9 Configuring Database Users To add a database user by using the configuration utility 1. In the navigation pane, expand System, and then click Database Users. 2. In the details pane, click Add. 3. In the Create Database User dialog box, specify values for the following parameters. User Name Password Confirm Password 4. Click Create, and then click Close. The service you created appears in the Database Users pane. If you have changed the password of the database user on the database server, you must reset the password of the corresponding user configured on the NetScaler. To reset the password of a database user by using the NetScaler command line At the NetScaler command prompt, type set db user <username> -password <password> Example > set db user nsdbuser -password dd260538abs 9

10 Configuring Database Users To reset the password of database users by using the configuration utility 1. In the navigation pane, expand System, and then click Database Users. 2. In the details pane, select the database user for which you want to reset the password, and then click Open. 3. In the Configure Database User dialog box, modify the values for the following parameters. Password Confirm Password 4. Click OK. If a database user no longer exists on the database server, you can remove the user from the NetScaler. However, if the user continues to exist on the database server and you remove the user from the NetScaler, any request from the client with this user name does not get authenticated, and therefore, does not get routed to the database server. To remove a database user by using the NetScaler command line At the NetScaler command prompt, type rm db user <username> Example > rm db user nsdbuser To remove a database user by using the configuration utility 1. In the navigation pane, expand System, and then click Database Users. 2. In the details pane, select the database user that you want to remove, and then click Open. 3. In the Proceed message box, click Yes. 10

11 Configuring Load Balancing for DataStream Before configuring a load balancing setup, you must enable the load balancing feature. Then, begin by creating at least one service for each database server in the load balancing group. With the services configured, you are ready to create a load balancing virtual server and bind the services to the virtual server. For instructions about configuring load balancing, see. Parameter values specific to DataStream Protocol Port Use the MYSQL protocol type for MySQL databases and MS SQL protocol type for MS SQL databases while configuring virtual servers and services. The MySQL and TDS protocols are used by the clients to communicate with the respective database servers by using SQL queries. For information about the MySQL protocol, see For information about the TDS protocol, see Port on which the virtual server listens for client connections. Use port 3306 for MySQL database servers. Method It is recommended that you use the Least Connection method for better load balancing and lower server load. However, other methods, such as Round Robin, Least Response Time, Source IP Hash, Source IP Destination IP Hash, Least Bandwidth, Least Packets, and Source IP Source Port Hash, are also supported. Note: URL Hash method is not supported for DataStream. MS SQL Server Version If you are using Microsoft SQL Server, and you expect some clients to not be running the same version as your Microsoft SQL Server product, set the Server Version parameter for the load balancing virtual server. The version setting provides compatibility between the client-side and server-side connections by ensuring that all communication conforms to the server's version. For more information about setting the Server Version parameter, see Configuring the Microsoft SQL Server Version Setting. 11

12 Configuring Content Switching for DataStream You can segment traffic according to information in the SQL query, on the basis of database names, usernames, character sets, and packet size. You can configure content switching policies with default syntax expressions to switch content based on connection properties, such as user name and database name, command parameters, and the SQL query to select the server. The default syntax expressions evaluate traffic associated with MYSQL and MS SQL database servers. You can use request-based expressions in default syntax policies to make request switching decisions at the content switching virtual server bind point and response-based expressions (expressions that begin with MYSQL.RES)to evaluate server responses to user-configured health monitors. Note: For information about default syntax expressions, see. Parameter values specific to DataStream Protocol Port Use the MYSQL protocol type for MySQL databases and MS SQL protocol type for MS SQL databases while configuring virtual servers and services. The MySQL and TDS protocols are used by the clients to communicate with the respective database servers by using SQL queries. For information about the MySQL protocol, see For information about the TDS protocol, see Port on which the virtual server listens for client connections. Use port 3306 for MySQL database servers. MS SQL Server Version If you are using Microsoft SQL Server, and you expect some clients to not be running the same version as your Microsoft SQL Server product, set the Server Version parameter for the content switching virtual server. The version setting provides compatibility between the client-side and server-side connections by ensuring that all communication conforms to the server's version. For more information about setting the Server Version parameter, see Configuring the Microsoft SQL Server Version Setting. For instructions about configuring content switching, see. 12

13 Configuring Monitors for DataStream To track the state of each load balanced database server in real time, you need to bind a monitor to each service. The monitor is configured to test the service by sending periodic probes to the service. (This is sometimes referred to as performing a health check.) If the monitor receives a timely response to its probes, it marks the service as UP. If it does not receive a timely response to the designated number of probes, it marks the service as DOWN. For DataStream, you need to use the built-in monitors, MYSQL-ECV and MSSQL-ECV. This monitor provides the ability to send an SQL request and parse the response for a string. Before configuring monitors for DataStream, you must add database user credentials to your NetScaler. For information about configuring monitors, see Monitors. When you create a monitor, a TCP connection is established with the database server, and the connection is authenticated by using the user name provided while creating the monitor. You can then run an SQL query to the database server and evaluate the server response to check whether it matches the configured rule. Parameters specific to DataStream type Type of monitor. Use the MYSQL-ECV monitor type for MySQL databases and MSSQL-ECV monitor type for MS SQL databases. sqlquery SQL query for the MYSQL-ECV and MSSQL-ECV monitors. After the connection to the database server is authenticated, you can run this query to the server. evalrule Rule evaluated to determine the state of the monitor. A rule consists of default syntax expressions. database Name of the database that needs to be probed. During authentication, this database name is used to connect to the database. username User name to connect to the database. This is looked up in the database user list to extract the database. Examples In the following example, the value of the error message is evaluated to determine the state of the server. 13

14 Configuring Monitors for DataStream add lb monitor lb_mon1 MYSQL_ECV -sqlquery "select * from table2;" -evalrule "mysql.res.error.message.contains(\"invalid User\")"-database "NS" -username "user1" In the following example, the number of rows in the response is evaluated to determine the state of the server. add lb monitor lb_mon4 MYSQL_ECV -sqlquery "select * from table4;" -evalrule "mysql.res.atleast_rows_count(7)" -database "NS" -username "user2" In the following example, the value of a particular column is evaluated to determine the state of the server. add lb monitor lb_mon3 MYSQL_ECV -sqlquery "select * from ABC;" -evalrule "mysql.res.row(1).double_elem(2) == " -database "NS" -username "user3" 14

15 Configuring DataStream for a Master/Slave Database Architecture A commonly used deployment scenario is the master/slave database architecture where the master database replicates all information to the slave databases. For master/slave database architecture, you may want all WRITE requests to be sent to the master database and all READ requests to the slave databases. The following figure shows the entities and the values of the parameters you need to configure on the appliance. Figure 1. DataStream Entity Model for Master/Slave Database Setup In this example scenario, a service (Svc_mysql_1) is created to represent the master database and is bound to a load balancing virtual server (Lb_vsr_mysql_master). Three more services (Svc_mysql_2, Svc_mysql_3, and Svc_mysql_4) are created to represent the three slave databases, and they are bound to another load balancing virtual server (Lb_vsr_mysql_slave). A content switching virtual server (Cs_vsr_mysql_1) is configured with associated policies to send all WRITE requests to the load balancing virtual server, Lb_vsr_mysql_master, and all READ requests to the load balancing virtual server, Lb_vsr_mysql_slave. 15

16 When a request reaches the content switching virtual server, the virtual server applies the associated content switching policies to that request. After evaluating the policies, the content switching virtual server routes the request to the appropriate load balancing virtual server, which sends it to the appropriate service. The following table lists the names and values of the entities and the policy configured on the NetScaler. Table 1. Entity and Policy Names and Values Entity Type Name IP Address Protocol Port Expression Services Svc_mysql_ MYSQL 3306 NA Load balancing virtual servers Content switching virtual server Content switching policy Configuring DataStream for a Master/Slave Database Architecture Svc_mysql_ MYSQL 3306 NA Svc_mysql_ MYSQL 3306 NA Svc_mysql_ MYSQL 3306 NA Lb_vsr_mysql_master MYSQL 3306 NA Lb_vsr_mysql_slave MYSQL 3306 NA Cs_vsr_mysql_ MYSQL 3306 NA Cs_select NA NA NA "MYSQL.REQ.QUERY.COMMAND.contains(\"selec To configure DataStream for a master/slave database setup by using the NetScaler command line At the NetScaler command prompt, type add service Svc_mysql_ mysql 3306 add service Svc_mysql_ mysql 3306 add service Svc_mysql_ mysql 3306 add service Svc_mysql_ mysql 3306 add lb vserver Lb_vsr_mysql_master mysql add lb vserver Lb_vsr_mysql_slave mysql bind lb vserver Lb_vsr_mysql_master svc_mysql_1 bind lb vserver Lb_vsr_mysql_slave svc_mysql_2 16

17 Configuring DataStream for a Master/Slave Database Architecture bind lb vserver Lb_vsr_mysql_slave svc_mysql_3 bind lb vserver Lb_vsr_mysql_slave svc_mysql_4 add cs vserver Cs_vsr_mysql_1 mysql add cs policy Cs_select rule "MYSQL.REQ.QUERY.COMMAND.contains(\"select\")" bind cs vserver Cs_vsr_mysql_1 Lb_vsr_mysql_master bind cs vserver Cs_vsr_mysql_1 Lb_vsr_mysql_slave policy Cs_select priority 10 To configure DataStream for a master/slave database setup by using the configuration utility Add four services, one to represent the master database server and three to represent the slave database servers. To add a service by using the configuration utility 1. In the navigation pane, expand Load Balancing, and then click Services. 2. In the details pane, click Add. 3. In the Create Service dialog box, specify values for the following parameters as listed in the table "Entity and Policy Names and Values." Service Name IP Address Protocol Port 4. Click Create, and then click Close. The service you created appears in the Services pane. Add two load balancing virtual servers. 17

18 Configuring DataStream for a Master/Slave Database Architecture To create a load balancing virtual server by using the configuration utility 1. In the navigation pane, expand Load Balancing, and then click Virtual Servers. 2. In the details pane, click Add. 3. In the Create Virtual Server (Load Balancing) dialog box, specify values for the following parameters as listed in the table "Entity and Policy Names and Values." Name IP Address Protocol Port 4. Click Create, and then click Close. Bind the service Svc_mysql_1 to the load balancing virtual server Lb_vsr_mysql_master, and bind the three services (Svc_mysql_2, Svc_mysql_3, and Svc_mysql_4) to the load balancing virtual server Lb_vsr_mysql_slave. To bind a service to a load balancing virtual server by using the configuration utility 1. In the navigation pane, expand Load Balancing, and then click Virtual Servers. 2. In the details pane, select the virtual server to which you want to bind the service (for example, Lb_vsr_mysql_master). 3. Click Open. 4. In the Configure Virtual Server (Load Balancing) dialog box, on the Services tab, select the Active check box next to the service that you want to bind to the virtual server (for example, Svc_mysql_1). 5. Click OK. Create a content switching virtual server. 18

19 Configuring DataStream for a Master/Slave Database Architecture To add a content switching virtual server by using the configuration utility 1. In the navigation pane, expand Content Switching, and then click Virtual Servers. 2. In the details pane, click Add. 3. In the Create Virtual Server (Content Switching) dialog box, specify values for the following parameters as listed in the table "Entity and Policy Names and Values." Name IP Address Protocol Port 4. Click Create, and then click Close. Create a content switching policy to evaluate all READ requests. To create a content switching policy by using the configuration utility 1. In the navigation pane, expand Content Switching, and then click Policies. 2. In the details pane, click Add. 3. In the Create Content Switching Policy dialog box, in the Name text box, type the name of the policy (for example, Cs_select). 4. Choose the type of policy that you want to create, and configure the policy. To create a rule-based policy, click Configure, and do the following: In the Create Expression dialog box, choose the expression syntax you want to use and enter your policy expressions as listed in the table "Entity and Policy Names and Values." 5. Click Create, and then click Close. Bind the content switching policy to the content switching virtual server. You should also select a load balancing virtual server as the target for the policy so that, after the content switching virtual server evaluates the policy, it routes requests that match the policy to the load balancing virtual server to forward them to the appropriate database server. 19

20 Configuring DataStream for a Master/Slave Database Architecture To bind the policy to the content switching virtual server and select a load balancing virtual server target by using the configuration utility 1. In the navigation pane, expand Content Switching, and then click Policies. 2. In the details pane, double-click the virtual server to which you want to bind the policy (for example, Cs_vsr_mysql_1). 3. In the Configure Virtual Server (Content Switching) dialog box, on the Policies tab, click Insert Policy, and in the Policy Name column, select the policy that you want to bind to the virtual server (for example, Cs_select). 4. In the Target column next to the policy, select the load balancing virtual server that you want to assign as the target for the policy (for example, Lb_vsr_mysql_slave). 5. Click OK. Set the load balancing virtual server, Lb_vsr_mysql_master, as the default virtual server for the content switching virtual server by binding the content switching virtual server to this load balancing virtual server. This ensures that the content switching virtual server routes requests that do not match the Cs_select policy to the load balancing virtual server to forward them to the appropriate database server. To bind the content switching virtual server to a load balancing virtual server by using the configuration utility 1. In the navigation pane, expand Content Switching, and then click Policies. 2. In the details pane, double-click the virtual server to which you want to bind the policy (for example, Cs_vsr_mysql_1). 3. In the Configure Virtual Server (Content Switching) dialog box, on the Policies tab, click Insert Policy, and in the Policy Name column, select (Default). 4. In the Target column next to the policy, select the load balancing virtual server that you want to assign as the target for the policy (for example, Lb_vsr_mysql_master). 5. Click OK. 20