Citrix Virtual Classroom. Database server load balancing with NetScaler DataStream technology. Self-paced exercise guide

Transcription

1 Database server load balancing with NetScaler DataStream technology Self-paced exercise guide

2 Table of Contents Table Citrix of Contents Virtual... Classroom 2 Overview... 3 Exercise 1: SQL Rate Limiting... 6 Exercise 2: Database Responder Exercise 3: Token Load Balancing and Audit Log for SQL Exercise 4: SQL Caching Page 2

3 Overview NetScaler Citrix DataStream Virtual Technology Classroom provides native database protocol and SQL intelligence by inspecting real-time traffic and applying protocol aware policies for both Microsoft SQL Server and MySQL databases. By performing native SQL load-balancing, it offers a cost-effective solution to offload database server connections considerably reducing the number of SQL connections to the backend servers, while providing an infrastructure to monitor, optimize, and secure a database deployment. The new NetScaler 10 release extends the power and capabilities of DataStream with token-based load balancing of SQL queries for more flexible scaling strategies, and with advanced caching of SQL responses to improve database server efficiency and increase application responsiveness. NetScaler 10 also adds full AppFlow support for DataStream traffic so that performance monitoring and business intelligence tools now have visibility deep into the application stack for richer monitoring, tracking and troubleshooting of both web and data based traffic. Hands-on Training Module This training module has the following details: Objective This lab provides hands on training on the new DataStream enhancements included in NetScaler 10. Audience Primary: Sales engineers, consultants, and support Lab Environment Details Machine AD.training.lab NS10_node0 Windows 7 Apache_MySQL_1 Apache_MySQL_2 Apache_MySQL_2 Details Domain controller, DHCP, and DNS Virtual instance of a NetScaler appliance Administrative workstation Linux server with Apache, PHP, MySQL Linux server with Apache, PHP, MySQL Linux server with Apache, PHP, MySQL NOTE: If prompted with a dialog to restart on any virtual machine, always select Restart Later. Page 3

4 Required Lab Credentials Below are the login credentials required to connect to the workshop system and complete the lab exercises. Machine IP Address Username Password AD.training.lab TRAINING\Administrator Citrix123 Win7Client TRAINING\Administrator Citrix123 Apache_MySQL_ root Citrix123 (GENTOO_1) Apache_MySQL_ root Citrix123 (GENTOO_2) Apache_MySQL_ root Citrix123 (GENTOO_3) NS10_node0 NSIP: SNIP: nsroot nsroot Page 4

5 How to log into the lab environment The self-paced lab environment is hosted on a cloud-based Citrix XenServer. Connecting to your server from the portal page is as easy as Step-by-step login instructions Step Action 1. Once logged in to the self-paced portal, click the Start lab button to launch a connection to published XenCenter. 2. When XenCenter loads, right-click the XenCenter node and select Add 3. On the Add New Server screen enter the XenServer IP address provided on the portal and in the Password field enter the password provided on the portal. The user name will always be root. Page 5

6 Exercise 1: SQL Rate Limiting Overview NetScaler 10 enforces limits depending on the license platform installed on the system by measuring the rate of requests per second. If the data rate exceeds the pre-configured limit, the NetScaler will send an error message to the connecting client indicating the system limit has been reached. Additionally, the administrator can configure an SNMP trap in order to have visibility when this condition occurs. In this exercise we will attempt to install a web application that populates a database with sample data using a MYSQL virtual server to provide access to the database tier. Since many SQL requests will be sent to the virtual server, the rate limiting mechanism is triggered and the operation will fail. To complete the exercise, we will upgrade the platform license on the NetScaler VPX appliance which lifts the rate limit restriction and attempt the install operation once again. Step-by-step guidance The lab environment required for this exercise is as follows: 1. Linux Server 1 : Apache_MySQL_1 - (GENTOO_1) 2. NetScaler VPX: (NS10_node0) 3. Windows 7 Workstation: (WIN7CLIENT) Estimated time to complete this lab: 45 minutes. Step Action 1. In XenCenter, shutdown the SQLServer, SQLServer2, VDA, XA1, XA2 and XD virtual machines and power on the following VMs: 1. AD.training.lab 2. Apache_MySQL_1 3. Apache_MySQL_2 4. Apache_MySQL_3 5. NS10_node0 6. Win7Client Exercise 1: SQL Rate Limiting Page 6

7 2. From the Win7Client VM, login to the workstation using the Domain Administrator account. Open Putty and SSH into the NetScaler (NS10_node0) Click OK to acknowledge the warning. 3. After login in through Putty, enable the load balancing feature on the NetScaler appliance. 4. We need to verify the license installed on the appliance. Since a 1 Gbps license is installed (VPX_1000), the show license command should display: > enable ns feature LB > show license grep Model Model Number ID: 1000 Model Number ID: From the SSH session, > add ns ip type proceed to add a Subnet IP SNIP (SNIP) 6. Create server objects for all Linux servers using the command provided: Apache_MySQL_1 (GENTOO_1) Apache_MySQL_2 (GENTOO_2) Apache_MySQL_3 (GENTOO_3) > add server GENTOO_ > add server GENTOO_ > add server GENTOO_ Exercise 1: SQL Rate Limiting Page 7

8 7. Create service objects for the MYSQL service running on all three servers (TCP port 3306). > add service GENTOO_1_MYSQL_TCP_3306 GENTOO_1 MYSQL 3306 > add service GENTOO_2_MYSQL_TCP_3306 GENTOO_2 MYSQL 3306 > add service GENTOO_3_MYSQL_TCP_3306 GENTOO_3 MYSQL 3306 > bind service GENTOO_1_MYSQL_TCP_3306 -monitorname TCP > bind service GENTOO_2_MYSQL_TCP_3306 -monitorname TCP > bind service GENTOO_3_MYSQL_TCP_3306 -monitorname TCP 8. Create a MYSQL vserver and bind the MYSQL service for Apache_MySQL_1 (GENTOO_1) 9. Verify that the vserver and services created are in an UP state. Note > add lb vserver MYSQL_vserver MYSQL > bind lb vserver MYSQL_vserver GENTOO_1_MYSQL_TCP_3306 > show lb vserver MYSQL_vserver > stat lb vserver MYSQL_vserver All 3 MYSQL servers in the lab already have a set of sample databases loaded. Next, we will setup the correct configuration and query these databases through the NetScaler. The user netscalersql has been granted all privileges. The password for this user is netscaler. 10. Before we can connect to the database, we define the > add db user netscalersql -password account the NetScaler will use netscaler to connect to the SQL backend. From the NetScaler SSH session, create the NetScaler DB user. 11. Switch to the Apache_MySQL_3 VM and login using the root account and password Citrix123. Exercise 1: SQL Rate Limiting Page 8

9 12. Switch to the Apache_MySQL_3 VM and connect to the MYSQL virtual server using the following credentials: U: netscalersql P: netscaler Note: Use the h, u, and p flags to specify the hostname, username, and prompt for a password. gentoo_3 ~ # mysql -h u netscalersql -p Enter password: netscaler mysql> 13. From Apache_MySQL_3, list the databases to verify you have access to the DB server. 14. Execute a simple query to verify access to one of the databases: mysql> show databases; Database information_schema imdb mysql test rows in set (0.07 sec) mysql> mysql> use imdb; mysql> select * from actors where actors.first_name = "Al" and actors.last_name = "Pacino"; id first_name last_name gender Al Pacino M row in set (0.11 sec) mysql> Note Since we will be installing a web application, create an HTTP virtual server and corresponding services Exercise 1: SQL Rate Limiting Page 9

10 15. Go back to the NetScaler SSH session on the HTTP 80 Win7Client VM. Create HTTP services for all Linux servers. > add service GENTOO_1_HTTP_TCP_80 GENTOO_1 > add service GENTOO_2_HTTP_TCP_80 GENTOO_2 HTTP 80 > add service GENTOO_3_HTTP_TCP_80 GENTOO_3 HTTP 80 > bind lb monitor tcp GENTOO_1_HTTP_TCP_80 > bind lb monitor tcp GENTOO_2_HTTP_TCP_80 > bind lb monitor tcp GENTOO_3_HTTP_TCP_ Continue on the Win7Client VM. From the NetScaler SSH session, create the HTTP vserver and bind the Apache_MySQL_1 service. 17. In this exercise, we will use an open-source web application to illustrate SQL connectivity We will go through the installer for a web based CRM application (SugarCRM). > add lb vserver HTTP_vserver HTTP > bind lb vserver HTTP_vserver GENTOO_1_HTTP_TCP_80 To verify connectivity to the web server, open Internet Explorer on the Win7Client and navigate to the HTTP virtual server previously created: Browse to the sugarcrm directory to begin the install: m/install.php Exercise 1: SQL Rate Limiting Page 10

11 Step Note Action If you receive an error message indicating that the installer is locked, please run the following command on Apache_MySQL_1 server and refresh the install page : gentoo_1 ~ # cp /var/sugarcrm_config/config.php /var/www/localhost/htdocs/sugarcrm/ 19. Go through the initial system check and accept the license agreement. Perform a typical install and accept the defaults by clicking next until you get to the screen on the next step. Exercise 1: SQL Rate Limiting Page 11

12 20. During the database configuration, use sugarcrm as the database name and select the virtual server IP as the hostname. For the database administrator username and password, use the NetScaler DB user configured before: User: netscalersql Password: netscaler Select the option to populate the database with demo data in order to trigger the SQL rate limiting mechanism. 21. Pick a password for the SugarCRM admin user. For consistency you can use netscaler as your password. 22. Accept the warning and select Install. Exercise 1: SQL Rate Limiting Page 12

13 23. The install operation will fail due to a database error. You should see the following error message: Database error. Please check sugarcrm.log for details 24. OPTIONAL: Login to Apache_MySQL_1 as root with password Citrix123. Inspect the installation log file on the Apache_MySQL_1 server webroot to verify the rate limit was hit: gentoo_1 ~ # tail /var/www/localhost/htdocs/sugarcrm/sugarcrm.log Fri Mar 16 19:00: [17401][-none-][FATAL] Query Failed: INSERT into relationships (id,relationship_name,lhs_module,lhs_table,lhs_key,rhs_module,rhs_table,rhs_key,rela tionship_type) values ('5a4ff bf6-59d6-4f638d8f997f','projects_modified_user','Users','users','id','Project','project','mod ified_user_id','one-to-many'): MySQL error 6002: NetScaler DataStream rate limits hit gentoo_1 ~ # 25. Go back to the NetScaler NS10_node0 SSH session on the Win7Client VM. To verify the logging capabilities for DataStream, set up the SNMP alarm for the DataStream rate limit hit using the commands provided. In order for the trap to be sent (and appear in syslog), define a generic and specific trap destination. > set alarm DATASTREAM-RATE-LIMIT-HIT - logging ENABLED -state ENABLED -severity Informational > add snmp trap generic communityname public -srcip > add snmp trap specific communityname "\"public\"" -srcip severity Informational > save ns config Save your configuration. Exercise 1: SQL Rate Limiting Page 13

14 Note Next, we will run the web application installer again. Before you can complete the process, a configuration file file needs to be modified to allow the installer process to multiple times. To avoid making manual changes to the configuration file, an modified copy is stored in: /var/sugarcrm_config/config.php 26. Switch to the Apache_MySQL_1 and copy the configuration file to the Apache webroot SugarCRM directory with the command provided: gentoo_1 ~ # cp /var/sugarcrm_config/config.php /var/www/localhost/htdocs/sugarcrm/ 27. From the Windows 7 workstation, close any browser instances and run the web application installer again. ( Refer to steps NOTE: If you receive any warnings to remove the existing tables and populate the data, click on the accept button. 28. OPTIONAL: Switch to Win7Client VM. On the Putty session to NS10_node0, inspect the NetScaler syslog to verify the trap was sent using the commands provided. Look for the error message highlighted in RED. > shell root@ns10_node0# tail -n 20 /var/log/ns.log Mar 21 19:45:09 <local0.info> /21/2012:19:45:09 GMT NS10_node0 0-PPE-0 : DB Message : "MYSQL_CS_CONN_CLOSED: QUIT_CMD_RECEIVED ConnID:14572" Mar 21 19:45:10 <local0.info> /21/2012:19:45:10 GMT NS10_node0 0-PPE-0 : SNMP TRAP_SENT : DataStreamRateLimitHit (alarmhighthreshold = 200, sysipaddress = ) Mar 21 19:45:24 <local0.info> /21/2012:19:45:24 GMT NS10_node0 0-PPE-0 : UI CMD_EXECUTED : User nsroot - Remote_ip Command "shell" - Status "Success" Exercise 1: SQL Rate Limiting Page 14

15 Step Note Action Since some NetScaler platforms are rate limited, we will proceed to upgrade the license to complete the web-application install. The SQL rate limits per platform are as follows: Up to VPX RPS VPX No limit MPX RPS MPX/SDX and higher No limit 29. In order to avoid the limit imposed to the NetScaler VPX 1000, proceed with the license upgrade. A new VPX_3000 license is located in /var/license_backup. root@ns10_node0 # cp /var/license_backup/vpx_3000.lic /nsconfig/license/ root@ns10_node0 # exit Copy the new license file to the /nsconfig/license directory. 30. Before rebooting, save your configuration and reboot. NOTE: You can safely ignore any warnings regarding the configuration not being changed. 31. When the NetScaler VM (NS10_node0) comes back online, reestablish the SSH session and verify the correct license was applied. > save ns config > reboot -warm > show license grep Model Model Number ID: 3000 > Exercise 1: SQL Rate Limiting Page 15

16 32. From the windows 7 workstation, run the web-app installer again. The installation will now complete successfully. IMPORTANT: Remember to overwrite the config.php for the installer to run again. Please refer to step Note At this point, the webapp and corresponding database were populated correctly after the license was upgraded lifting any restriction in the DataStream configuration. Exercise 1: SQL Rate Limiting Page 16

17 33. OPTIONAL: Skip the registration process and test the web-app. Remember to use the Admin credentials supplied before: U: admin P: netscaler END OF EXERCISE Exercise 1: SQL Rate Limiting Page 17

18 Summary Citrix Key Virtual Classroom Takeaways The key takeaways for this exercise are: Depending on the platform license installed on the system, different SQL rate limits will apply to DataStream connections. The following table summarizes the different limits applied: Up to VPX1000 VPX3000 VPX8000 MPX5500 MPX 9500 MPX/SDX and higher 200 RPS No limit 1000 RPS No limit The system log will include additional information when this error condition occurs. Additionally, SNMP alerts can be configured to notify the administrator when the limit is reached. Exercise 1: SQL Rate Limiting Page 18

19 Exercise 2: Database Responder Overview DataStream is a new feature introduced in NetScaler version 9.3. It allows the NetScaler to operate as a proxy between the application and database servers to provide load balancing and content switching functionality. In this exercise, we will cover the new database responder configuration. The student will learn how to leverage this feature to provide an additional layer of control for SQL server deployments. Using database responder, the NetScaler can act on certain conditions and generate a custom response to the connecting client. These responses can be user defined (OK packet, Error packet) or a connection reset. Step-by-step guidance The lab environment required for this exercise is as follows: 1. Apache_MySQL_1: (GENTOO_1) 2. NetScaler VPX appliance: (NS10_node0) 3. Windows 7 Workstation: (WIN7CLIENT) Estimated time to complete this lab: 15 minutes. Step Action 1. From the Win7Client VM, logon to the NetScaler VM > enable ns feature Responder (NS10_node0) using Putty and enable the Responder feature: 2. Create a responder action and policy to prevent someone from deleting a database using the command provided. > add responder action prevent_drop_database sqlresponse_error "This is a destructive operation. Database was NOT modified" > add responder policy prevent_drop_database_pol "MYSQL.REQ.QUERY.COMMAND.CONTAINS(\"drop\")" prevent_drop_database 3. Bind it to the virtual server. > bind lb vserver MYSQL_vserver -policyname prevent_drop_database_pol -priority Save your configuration > save ns config 5. If an existing connection to MySQL is present, please make sure that you exit. mysql> exit Bye gentoo_3 ~ # Exercise 2: Database Responder Page 19

20 6. From Apache_MySQL_3 (GENTOO_3), connect to the MYSQL virtual server and attempt to drop a database: Reminder: The NetScaler db user credentials are: U: netscalersql P: netscaler gentoo_3 ~ # mysql -h u netscalersql -p Enter password: mysql> show databases; Database information_schema imdb mysql sugarcrm test rows in set (0.00 sec) mysql> drop database test; ERROR 6001 (RESAC): This is a destructive operation. Database was NOT modified 7. Since no direct access to the database server is allowed, dropping a database is not permitted. Attempting to connect to the backend MYSQL server (GENTOO_1) directly will fail as only the SNIP has access. Reminder: The NetScaler db user credentials are: mysql> mysql> exit Bye gentoo_3 ~ # mysql -h u netscalersql -p Enter password: ERROR 1130 (HY000): Host is not allowed to connect to this MySQL server gentoo_3 ~ # U: netscalersql P: netscaler END OF EXERCISE Exercise 2: Database Responder Page 20

21 Summary Citrix Key Virtual Classroom Takeaways NOTES The key takeaways for this exercise are: Database responder can be used to enforce certain database operations OK/Error packets or connection resets are the possible actions that can be configured DB responder policies can also be used in conjunction with SQL auditing or Stream Analytics to collect information about the operations or traffic flows traversing the NetScaler. We will look at SQL auditing and Stream Analytics for SQL in a later exercise. Exercise 2: Database Responder Page 21

22 Exercise 3: Token Load Balancing and Audit Log for SQL Overview In this exercise we will explore the new load balancing options for SQL traffic. With NetScaler 10, it is now possible to load balance SQL requests based on parameters found in SQL traffic. By introducing the Token LB method, the load balancing decisions can be based on SQL attributes, such as database name, connecting user, query type, character set, and other. In this exercise, we will configure a few example rules for token load balancing. We will verify how traffic flows to backend services depending on SQL traffic attributes included in the request. Additionally, we will use the SQL audit log to understand why certain operations fail and take appropriate corrective actions. Step-by-step guidance The lab environment required for this exercise is as follows: 1. Linux Server 1: Apache_MySQL_1 (GENTOO_1) 2. Linux Server 2: Apache_MySQL_2 (GENTOO_1) 3. NetScaler VPX appliance: (NS10_node 0) 4. Windows 7 Workstation: (Win7Client) Estimated time to complete this lab: 20 minutes. Step Action Exercise 3: Token Load Balancing and Audit Log for SQL Page 22

23 1. Switch to the Win7Client VM. Go back to the SSH connection to the NetScaler (NS10_node0). Verify the services bound to the MYSQL virtual server. If you have completed the previous exercises, one service should be bound. > show lb vserver MYSQL_vserver If the status of the virtual server is DOWN, please refer to Exercise 1, step In order to illustrate SQL token load balancing, proceed to bind a second MYSQL service to the virtual server. > bind lb vserver MYSQL_vserver GENTOO_2_MYSQL_TCP_ Set the load balancing method to TOKEN on the MYSQL virtual server. Specify a rule to load balance > set lb vserver MYSQL_vserver -lbmethod TOKEN -rule MYSQL.CLIENT.DATABASE on the database name requested by the client. Note Sample databases (IMDB, Test) have been replicated to Apache_MySQL_1 and Apache_MySQL_2. This is very common in master/slave scale-out deployments where multiple backend servers have the same database set. In the next steps, we will verify access to the databases required for this exercise. 4. Login to Apache_MySQL_1 and connect to the localhost using the MYSQL client. Since only the root account has access locally, use the following credentials: gentoo_1 ~ # mysql -u root -p U: root P: Citrix123 Exercise 3: Token Load Balancing and Audit Log for SQL Page 23

24 5. Display the databases to make sure the IMDB and test databases are present. mysql> show databases; Database information_schema imdb mysql sugarcrm test rows in set (0.00 sec) 6. Switch to the Apache_MySQL_2 VM. Execute the same command to inspect the databases loaded on this server. Use the same credentials: U: root P: Citrix123 mysql> gentoo_2 ~ # mysql -u root -p Enter password: mysql> show databases; Database information_schema imdb mysql test rows in set (0.00 sec) mysql> quit gentoo_2 ~ # Exercise 3: Token Load Balancing and Audit Log for SQL Page 24

25 7. Switch back to Win7Client. Using the SSH session to NS10_node0 verify the number of hits on each service. Use the stat command provided. NOTE: The number of hits shown in your environment might differ from the output displayed in the screenshot. > stat lb vserver MYSQL_vserver 8. From Apache_MySQL_3, connect to the MYSQL virtual server and specify IMDB as the initial database on the connection string (use the D flag). Display the available tables. Reminder: The NetScaler database user credentials are: U: netscalersql P: netscaler gentoo_3 ~ # mysql -h u netscalersql -p -D imdb Enter password: mysql> show tables; Tables_in_imdb actors directors directors_genres movies movies_directors movies_genres roles rows in set (0.00 sec) mysql> Exercise 3: Token Load Balancing and Audit Log for SQL Page 25

26 9. Switch to the SSH session to the NetScaler on the Win7Client and execute the same STAT command as in step 7. Compare the number of hits on each service. > stat lb vserver MYSQL_vserver Which service received the request? 10. From Apache_MySQL_3, exit the current MYSQL session and attempt a new connection. This time, specify a different database: (Use the D flag to select the test database). In order to generate traffic, execute a show tables command. 11. Continue on Apache_MySQL_3. After performing the query, quit the MySQL connection. 12. Go back to the Windows 7 workstation SSH session. Using the stat command, observe if a different service received hits. mysql> quit Bye gentoo_3 ~ # gentoo_3 ~ # mysql -h u netscalersql -p -D test Enter password: mysql> show tables; Empty set (0.00 sec) mysql> mysql> quit Bye gentoo_3 ~ # > stat lb vserver MYSQL_vserver Record the number of hits. Which counters where incremented? Note To further illustrate the concept of TOKEN load balancing, we will change the Load Balancing expression to use the username as the TOKEN. We will use the same stat command to observe which service receives the request. Exercise 3: Token Load Balancing and Audit Log for SQL Page 26

27 13. Continue working on the SSH session to the NetScaler. Change the TOKEN rule to: > set lb vserver MYSQL_vserver -rule "MYSQL.CLIENT.USER" MYSQL.CLIENT.USER 14. Create a new DB user for the root account 15. On Apache_MySQL_1 (GENTOO_2), grant the root user ALL privileges to login from any host. Use the following credentials: U: root P: Citrix123 > add db user root -password Citrix123 gentoo_1 ~ # mysql -p Enter password: mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@' ' IDENTIFIED BY 'Citrix123' WITH GRANT OPTION; Query OK, 0 rows affected (0.00 sec) mysql> quit Bye Use the commands provided. 16. Switch back to Apache_MySQL_2. Login to the VM using the following credentials: U: root P: Citrix123 Assign the same privileges as in the previous step. gentoo_2 ~ # mysql -p Enter password: mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@' ' IDENTIFIED BY 'Citrix123' WITH GRANT OPTION; Query OK, 0 rows affected (0.00 sec) mysql> quit Bye Use the commands provided. 17. Go back to the Windows 7 workstation SSH session. Using the stat command, record the number of hits each service is receiving. > stat lb vserver MYSQL_vserver Exercise 3: Token Load Balancing and Audit Log for SQL Page 27

28 18. From Apache_MySQL_3, connect to the MYSQL virtual server using the root account gentoo_3 ~ # mysql -h u root -p -D imdb Enter password: mysql> show tables; Tables_in_imdb actors directors directors_genres movies movies_directors movies_genres roles rows in set (0.00 sec) 19. Go back to the Windows 7 workstation SSH session. Using the stat command, identify the service received hits in comparison with the numbers previously recorded. Refer to step Switch back Apache_MySQL_3 (GENTOO_3) quit the existing connection. Start a new one using the netscalersql user. U: netscalersql P: netscaler 21. Switch back to the Windows 7 workstation. On the SSH session to the NetScaler, use the stat command, inspect if a different service is receiving requests. mysql> > stat lb vserver MYSQL_vserver mysql> quit gentoo_3 ~ # mysql -h u netscalersql -p > stat lb vserver MYSQL_vserver Exercise 3: Token Load Balancing and Audit Log for SQL Page 28

29 END OF EXERCISE Summary Key Takeaways NOTES The key takeaways for this exercise are: NetScaler 10 offers a new TOKEN load balancing method for MYSQL virtual servers. Multiple rules can be used to distribute the load between bound services depending on certain connection attributes. The audit log can be used to troubleshoot SQL connectivity issues. Leveraging TOKEN load balancing for SQL traffic, the administrator can now tailor the load balancing rules to closely resemble the traffic type carried by the virtual server. Using more specific connection attributes for the SQL connections, the administrator has now more control on the traffic distribution. Exercise 3: Token Load Balancing and Audit Log for SQL Page 29

30 Exercise 4: SQL Caching Overview NetScaler 10 extends the integrated caching feature set to include support for SQL traffic. In conjunction with the new DataStream capabilities included in NetScaler 9.3, the integrated caching engine now has the ability to cache result sets and served from memory instantly. Similar to HTTP caching, SQL caching provides mechanisms to cache or invalidate result sets depending on certain conditions. In this exercise, we will explore the different options for caching common SQL queries. We will measure the before and after effects of caching result sets for these CPU intensive operations and visually observe the improvement of the SQL tier when using web applications that rely on such data. Additionally, we will explore common methods for invalidating existing cached objects if the result set is modified, ensuring data integrity at all times. Step-by-step guidance The lab environment required for this exercise is as follows: 1. Linux Server 1: Apache_MySQL_1 (GENTOO_1) 2. NetScaler VPX appliance: NS10_node0 3. Windows 7 Workstation: (WIN7CLIENT) Estimated time to complete this lab: 20 minutes. Step Action 1. From the Windows 7 workstation, connect via SSH (Putty) to the NetScaler (NS10_node0). > show lb vserver MYSQL_vserver > unbind lb vserver MYSQL_vserver GENTOO_2_MYSQL_TCP_3306 To simplify the configuration, verify that only 1 service is bound to the MYSQL virtual server. If more than 1 service is bound, please proceed to unbind the necessary services so that only the binding is present: GENTOO_1_MYSQL_TCP_3306 Exercise 4: SQL Caching Page 30

31 2. From the Win7Client VM, open another Putty session to Apache_MySQL_3. Use the IP address and credentials provided: IP: U: root P: Citrix From the SSH session to Apache_MySQL_3, connect to the MYSQL virtual server using the following credentials: U: netscalersql P: netscaler Display the tables in the IMDB database to verify connectivity. gentoo_3 ~ # mysql -h u netscalersql -p -D imdb Enter password: mysql> show tables; Tables_in_imdb actors directors directors_genres movies movies_directors movies_genres roles rows in set (0.00 sec) mysql> Exercise 4: SQL Caching Page 31

32 4. From the SSH session to Apache_MySQL_3, execute a CPU intensive query. You can use the following example: The IMDB database contains a SQL dump of the information available in the International Movie database. As an exercise, write a query to find the movies where the director also played an acting role. Use the query provided in the next column. This step will take a long time to execute. Please continue to step While the query executes, logon to Apache_MySQL_1 and inspect the CPU utilization. Note the CPU usage value for the MYSQL daemon. Use the command top to inspect resource usage. 6. From the SSH session to Apache_MySQL_3, inspect the amount of time the query took to execute. NOTE: Since this query takes over min to execute, wait until you receive the output shown in the screenshot. mysql> select distinct a.first_name, a.last_name, m.name FROM actors AS a INNER JOIN roles AS r ON a.id = r.actor_id INNER JOIN movies AS m ON r.movie_id = m.id INNER JOIN movies_directors AS md ON m.id = md.movie_id INNER JOIN directors AS d ON md.director_id = d.id WHERE CONCAT(a.first_name,a.last_name) = CONCAT(d.first_name,d.last_name); Note In our example, SELECT queries are perfect candidates for caching as they only display information contained in the database. We will configure the NetScaler to cache all responses for SELECT queries. Exercise 4: SQL Caching Page 32

33 7. From the SSH session to the NetScaler, enable the Integrated Caching feature. 8. From the same SSH session, then create a MYSQL content group and define the minimum and maximum response size to 500 and 1024 KB respectively. > enable ns feature IC > add cache contentgroup MYSQL -relexpiry 500 -minressize 500 -maxressize type MYSQL 9. Create a cache policy for SELECT statements with a CACHE action. > add cache policy cache_select_queries -rule "MYSQL.REQ.QUERY.COMMAND.CONTAINS(\"select\")" -action CACHE - storeingroup MYSQL Note Since SQL cache policies require a cache hit selector to successfully cache objects, we need to define a cache selector. 10. Create the cache selector. > add cache selector cache_selector1 MYSQL.REQ.QUERY.TEXT 11. Bind to the MYSQL virtual server. > bind lb vserver MYSQL_vserver - policyname cache_select_queries -priority 100 -type REQUEST 12. Select this cache selector in the MYSQL content group hit selector list. > set contentgroup MYSQL -hitselector cache_selector1 13. Then bind the cache policy previously created. 14. Set the memory limit for the cache engine. 15. Verify there are no objects cached in the content group. Nothing should be displayed. 16. On the SSH session to Apache_MySQL_3, run the same query as in step 4. Tip: You can use the up arrow to invoke the last query run. > bind lb vserver MYSQL_vserver - policyname cache_select_queries -priority 100 -type REQUEST > set cache parameter -memlimit 500 > show cacheobjects mysql> select distinct a.first_name, a.last_name, m.name FROM actors AS a INNER JOIN roles AS r ON a.id = r.actor_id INNER JOIN movies AS m ON r.movie_id = m.id INNER JOIN movies_directors AS md ON m.id = md.movie_id INNER JOIN directors AS d ON md.director_id = d.id WHERE CONCAT(a.first_name,a.last_name) = CONCAT(d.first_name,d.last_name); Exercise 4: SQL Caching Page 33

34 17. Note the time it took to execute this query. NOTE: Since this is the first time we execute this query after creating the IC configuration, the amount of time for this query to execute should be similar as before. 18. Go back to the SSH session to NS10_node0. Display the cached objects to verify the result set has been cached. > show cacheobjects 0x bb MYSQL SQL?_1=select distinct a.first_name, a.last_name, m.name FROM actors AS a INNER JOIN roles AS r ON a.id = r.actor_id INNER JOIN movies AS m ON r.movie_id = m.id INNER JOIN movies_directors AS md ON m.id = md.movie_id INNER JOIN directors AS d ON md.director_id = Done 19. Switch back to the SSH session to Apache_MySQL_3. Run the query again. NOTE: The results should start appearing instantly. Note the execution time. Note There is one problem with this configuration. The content group has been defined to cache objects for 500 seconds. If the data is modified, the cached result set is incorrect. 20. OPTIONAL: From the SSH session to the NetScaler, show the properties of the content group. > show contentgroup MYSQL Name: MYSQL Type: MYSQL Relative expiry time: 500 secs Exercise 4: SQL Caching Page 34

35 21. To solve this problem, we will alter one of the tables in the database. First, modify the minimum response size to 0 KB (to cache ALL responses). In practice, avoid setting the content group to 0 as this caches empty result sets. 22. From the SSH session to Apache_MySQL_3, execute a simple select statement for it to be cached. 23. Using the same SSH session, insert some values into the actors table. 24. Execute the same select query. (Refer to step 22) > set contentgroup MYSQL -minressize 0 mysql> select * from actors where actors.last_name = "Stooge"; Empty set (0.00 sec) mysql> mysql> insert into actors values ("999999","Moe","Stooge","M"); Query OK, 1 row affected (0.00 sec) mysql> insert into actors values ("999998","Larry","Stooge","M"); Query OK, 1 row affected (0.04 sec) mysql> select * from actors where actors.last_name = "Stooge"; Empty set (0.00 sec) Since the cached object is empty and mysql> it is still valid, the NetScaler serves the result from cache. Note To alleviate this problem, we can configure an Cache Invalidation policy. Anytime a modification is requested, the NetScaler can invalidate the objects in the content group. 25. Return to the SSH session to NS10_node0 and create a new cache policy to identify any modification operation and use an INVAL action to the objects in the content group. Use the command provided: > add cache policy invalidate_when_modified -rule "MYSQL.REQ.QUERY.COMMAND.CONTAINS(\"insert\") MYSQL.REQ.QUERY.COMMAND.CONTAINS(\"delete\") MYSQL.REQ.QUERY.COMMAND.CONTAINS(\"alter\")" -action INVAL -invalobjects MYSQL Exercise 4: SQL Caching Page 35

36 26. Bind this policy to the MYSQL virtual server. > bind lb vserver MYSQL_vserver -policyname invalidate_when_modified -priority 110 -type REQUEST 27. Proceed to flush the objects in cache > flush contentgroup MYSQL 28. Switch to the SSH session to Apache_MySQL_3. Perform the same select statement as on step 24. mysql> select * from actors where actors.last_name = "Stooge"; The previous two entries should now be listed id first_name last_name gender Moe Stooge M Larry Stooge M rows in set (0.00 sec) 29. From this SSH session, insert a new object into the actors table. 30. Repeat the select query. The cached objects should be flushed and the new result set should be fetched from the backend server, effectively caching the new data for the next request. mysql> mysql> insert into actors values ("999997","Curly","Stooge","M"); Query OK, 1 row affected (0.03 sec) mysql> select * from actors where actors.last_name = "Stooge"; id first_name last_name gender Moe Stooge M Larry Stooge M Curly Stooge M rows in set (0.00 sec) mysql> Exercise 4: SQL Caching Page 36

37 31. IMPORTANT! This is the last exercise for this lab. Please go back to the Self-paced Learning Citrix Lab site Virtual and do the following Classroom before you go: Provide us feedback by selecting the Take web survey link. After completing the survey, click the Logout link towards the bottom right to close out your lab session. Key Takeaways END OF EXERCISE The key takeaways for this exercise are: The Integrated Caching engine is now able to cache SQL responses. Hit selectors and invalidate policies can be used to enforce data integrity. Please complete this survey We value your feedback! Please take a moment to let us know about your self-paced lab experience by completing a brief survey on the web portal before you logout. Exercise 4: SQL Caching Page 37

38 Revision History Citrix Revision Change Virtual Description Classroom Updated By Date 1.0 Original Version WW Technical Readiness October 2012 About Citrix Citrix Systems, Inc. designs, develops and markets technology solutions that enable information technology (IT) services. The Enterprise division and the Online Services division constitute its two segments. Its revenues are derived from sales of Enterprise division products, which include its Desktop Solutions, Datacenter and Cloud Solutions, Cloud-based Data Solutions and related technical services and from its Online Services division's Web collaboration, remote access and support services. It markets and licenses its products directly to enterprise customers, over the Web, and through systems integrators (Sis) in addition to indirectly through value-added resellers (VARs), value-added distributors (VADs) and original equipment manufacturers (OEMs). In July 2012, the Company acquired Bytemobile, provider of data and video optimization solutions for mobile network operators Citrix Systems, Inc. All rights reserved. Page 38