Configuring Load Balancing. Oracle Applications Release 10.7 NCA Windows NT Edition. Gary Burch. April 15, 1998

Transcription

1 Configuring Load Balancing Oracle Applications Release 10.7 NCA Windows NT Edition Gary Burch April 15,

2 Table of Contents Table of Contents.. Introduction. Installation Manuals.. Software Requirements.. Shared Applications File System Model. Configuration Steps Configure the Web Cartridge for Load Balancing.. Configure your Load Balancing Web cartridge on the Metrics Server.. Install your Metrics Server NT Service. Modify your cartridge base HTML file. (sample-d.htm). Install your Metrics Client NT Service Drive Mapping to the Server APPL_TOP. Set up the environment on each Metric Client. Run adadmin on Each Metric Client Start your Metrics Server NT Service Start your Oracle Web Server on the Metrics Server Start your Metrics Clients NT Service Start the Forms Listener and Web listener on the Metric Server Start the Forms Listener and Web listener on each Metrics Client system.. Establishing Connections. Independent Applications File System Model Configuration Steps Configure the Web Cartridge for Load Balancing.. Configure your Load Balancing Web cartridge on the Metrics Server.. Install your Metrics Server NT Service. Modify your cartridge base HTML file. (sample-d.htm). Install your Metrics Client NT Service Set up the environment on each Metric Client. Unload the APPL_TOP on the Metrics Client. Unload Help Files. Run adadmin on Each Metric Client Start your Metrics Server NT Service Start your Oracle Web Server on the Metrics Server Start your Metrics Clients NT Service Start the Forms Listener and Web listener on the Metric Server Start the Forms Listener and Web listener on each Metrics Client system.. Establishing Connections. Patching Issues Troubleshooting.. 2

3 Introduction This paper addresses two implementation methods for using the Developer/2000 load Balancing feature. One method allows the sharing of one central Applications directory structure for ease of administration. The other method allows multiple applications directories to exist on each Metrics Client for increased performance across the network. This paper assumes that the steps have been successfully followed to connect dynamically to a NCA 10.7 database instance. Installation Manuals This paper takes excerpts from the following manuals or notes: Developer/2000 Release 1.6 Deploying Applications on the Web Oracle Applications Release 10.7 NCA Installation Manual Windows NT Server Edition Oracle Applications Release 10.7 NCA Release Notes Windows NT Server Edition. Software Requirements Following are the requirements for using the Forms Server load balancing feature: Metrics Server: Oracle Developer/ X Oracle Web Server or Oracle Web Application Server ( is preferred.) SQL*Net version 2.3 SQL*Plus 3.3 Metrics Server NT Service Metrics Clients: Oracle Developer/ X Oracle Web Server or Oracle Web Application Server ( is preferred.) SQL*Net version 2.3 SQL*Plus 3.3 Metrics Client NT Service If you are unsure of what software components are certified, contact Oracle World Wide Support. Shared Applications File System Model The following sections will walk you through configuring load balancing using a single APPL_TOP. This Oracle Application top directory will contain a single location for all form files for the middle tier. Attention: Every Metrics Client ORACLE_HOME must mirror the ORACLE_HOME location by drive letter and path of every other Metrics Client and the Metrics Server. 3

4 Note: If your network is not capable of supporting this type of configuration we recommend you use the Independent Applications File System Model described later in this paper. Sharing a single application file system with web technology is extremely network intensive. Configuration Steps The following is the sequence of steps to take to set up and use your load balancing environment: Configure your load balancing Web cartridge on the Metrics Server Install your Metrics Server NT Service Modify your cartridge base HTML file. (sample-d.htm) Install your Metrics Client NT Service Map a drive to your Metric Server APPL_TOP Set up the environment on each Metric Client. Run ADADMIN on Each Metric Client Start your Metrics Server NT Service Start your Oracle Web Server on the Metrics Server Start your Metrics Clients NT Service Start the Forms Listener and Web listener on the Metric Server Start the Forms Listener and Web listener on each Metrics Client system Configure Web Cartridge for Load Balancing on the Metrics Server Access the Oracle Web Application Server Administration page by navigating to the appropriate URL. For example: Enter your administrative username and password. Navigate to: Web Applications Server Manager Oracle Web Application Server Cartridge Administration Select your Forms Web cartridge Click Cartridge specific Parameters. Add the following parameters to your cartridge for load balancing: Note: Cartridge parameters and parameter values are case sensitive 4

5 Parameter MetricsServerHost MetricsServerPort MetricsServerErrorURL Parameter Values Enter the name of the host (system) where the Metrics Server is running. This parameter is required if load balancing is used. For example: system1.company.com Enter the port number on which the Metrics Server will be listening for requests from the cartridge for the least-loaded system. This parameter is required if load balancing is used and its value must be different from the Forms Listener value. For example: Enter the URL to which the Web Client will be directed if the Metrics Server does not respond with the name of the least-loaded system within the MetricsTimeout period. This parameter is required if load balancing is used. 1.The URL can Point to a Forms Web cartridge on another host, which will then automatically service the request. For example: serverport MetricsTimeout 2. Point to a static HTML page on any Web server. This page can be used for giving help and instructions to users when the Metrics Server goes down, or point to the sample-s.htm on another server. For example: This is the Port the Forms servers will be listening on. The default value is (Optional) Enter the timeout value, in seconds, for the Forms cartridge to use while making requests to the Metrics Server for the name of the least-loaded system. If the cartridge does not receive a response in that time interval, it replaces the %LEASTLOADEDHOST% entry in the HTML file with the MetricsServerErrorURL value. The MetricsTimeout parameter is optional. If not specified, the default value is 30 seconds. For example: 35 Click Modify Cartridge Configuration. In order to activate your changes, stop and start the following web listeners in this order. owsctl stop www owsctl stop admin owsctl stop wrb 5

6 owsctl start wrb owsctl start admin owsctl start www Creating a batch file for bouncing the web listeners is recommended. You can accomplish this by creating a text file containing the above commands. Rename the text file with a *.bat extension, and execute it from either the Windows Explorer or the command line. Note: It is not necessary to bounce all of the above listeners. However, from experience, bouncing the listeners in this order ensures the best success rate. Install your Metrics Server NT Service On Windows NT, run the following command to install the Metrics Server as an NT Service: d2ls1032 -install To deactivate the Metrics Server service: d2ls1032 -remove Modify your cartridge base HTML file on the Metrics Server. (sample-d.htm) Open the sample-d.htm file and edit the section that looks like this: <!-- If you are implementing load balancing, remove the comment tags in the next two lines (the! symbol) and replace the ^ delimiters with percent symbols. --> <!PARAM name="serverhost" value="^leastloadedhost^"> <!PARAM name="serverport" value="^serverport^"> It should look like this when you are done: <!-- If you are implementing load balancing, remove the comment tags in the next two lines (the! symbol) and replace the ^ delimiters with percent symbols. --> <PARAM name="serverhost" value="%leastloadedhost%"> <PARAM name="serverport" value="%serverport%"> 6

7 Install your Metrics Client NT Service On Windows NT, run the following command on each system to install each Metrics Client as an NT Service: d2lc1032 -install To deactivate the Metrics Client service: d2lc1032 -remove Drive Mapping to the Server APPL_TOP Map a drive to your Metric Server APPL_TOP. (For a distributed install.) From the Metrics Clients map a drive that matches exactly to the Metric Server APPL_TOP. For example: Metrics Server APPL_TOP=H:\appsnca Right click Network Neighborhood and select Map Network Drive and fill in the required information. Select the drive letter that matches the Metrics Server drive letter. (H: for example). Enter the path to the network drive. (\\APPS-SERVER\H$ matches the previous example) This will allow the Metrics Clients to create a logical drive that matches the drive letter of the Metrics Server s APPL_TOP. The $ in the path allows an administrative connection to a hidden share, this allows you to skip sharing out the drive from the metrics server. Attention: If this is not mapped correctly the desktop client will not be able to download the initial sign-on form FNDSCSGN. 7

8 Setting up the Environment Variables on Each Metrics Client. The following environment variables must be set on each Metrics Client: APPL_TOP This will match the value of the Metrics Server APPL_TOP since it was mapped in a previous step. ORACLE_HOME This is the location that exists on the Local Metrics Client where the Forms and Web Server are installed. LOCAL This is set to the Tnsnames Alias for your SQL*Net connection to the database server. Run the ADADMIN Utility on Each Metrics Client At the command prompt, change to the bin subdirectory in the AD directory on your mapped network drive. Run the adadmin utility: C:\> cd %APPL_TOP%\ad\10.7\bin C:\> adadmin Note: You must run the adadmin utility on each of the Metrics Clients. This utility will be run from the mapped drive on the Metrics Server. Answer the initial questions asked by adadmin, which include your APPL_TOP and database settings. Select the Maintain Applications Files option from the Main Menu. From this screen, choose the Create Applications environment file option. The following is a list of questions asked by adadmin: Registry subkey for this installation. Directory in which you want Applications temporary files stored. This will likely be your C:\temp directory on the local Metrics Client. Machine name and domain on which web server is installed for accessing Applications forms. This is the local Metrics Client that you are running adadmin from. HTTP port for Applications forms web server. This is the local Metrics Client that you are running adadmin from. Machine name and domain on which web server is installed for accessing Applications online help files. This is the local Metrics Client that you are running adadmin from. HTTP port for Applications online help web server. This is the port for the local Metrics Client that you are running adadmin from. Directory to which all Applications HTML files should be copied. This location is the local ORACLE_HOME on the Metrics Client you are running adadmin from. Directory to which all Applications Java files should be copied. This location is the local ORACLE_HOME on the Metrics Client you are running adadmin from. 8

9 The AD Administration utility provides further information about these options. Make note of the values you entered for the location of Java, HTML, and temporary files. You will need these directories when configuring your web server. Select the Maintain Applications Files menu option from the Main Menu and choose the option Copy Java and HTML files. This copies the Java and HTML files to the locations you selected. Attention: To move the Java and HTML files later, rerun the previous two steps in the AD Administration utility. Do not copy the files. Copying the files will cause future upgrades and patches to those files to break. Create Virtual Mappings for the Web Server on the Metrics Client Access the Oracle Web Application Server Administrative page by navigating to the appropriate URL. For example: Enter your administrative username and password. Navigate to: Web Applications Server Manager Oracle Web Listener Select the configure button for your listener and navigate to the directory section of the listener. Enter the following directories and virtual directories: File-System Directory Flag Virtual Directory Local directory for temp files: NR /oa-tmp/ C:\temp\ location of Oracle Home\forms45\java: NR /oa-java/ D:\orant\forms45\java\ Location of your online help files. This can be either local or mapped to the exact drive specification on the server. H:\appsdoc\ NR /oa-doc/ Note: Always include the trailing slashes. Start your Metrics Server NT Service Starting the Metrics Server on Windows NT Click Start Settings Control Panel Double-click Services Choose D2LS Server Service Place your cursor in the bottom window that is titled Startup Parameters Enter values for the following startup parameters: MetricsClientToServerPort# MetricsServerToCartridgePort# [max_no_metricsclients] 9

10 Where: MetricsClientToServerPort# is the port on the Metrics Server where the Metrics Clients will connect and will send their load information. Example: Port MetricsServerToCartridgePort# is the port on the Metrics Server which the cartridges will use to query the Metrics Server for information. This value corresponds to the MetricsServerPort property, as entered in the cartridge configuration. The example was max_no_metricsclients is the maximum number of Metrics Clients that will be running and sending load information to the Metrics Server. This parameter is optional. The default value is Example: Enter in the Parameter Startup window. Click Start to start the service. Note: Examples for both the Metrics Server and Metrics Clients NT Services are working examples. Passing the above parameters will allow both the Metrics Server and Client to Communicate. Start your Metrics Clients NT Service Do these steps for each system where a Metrics Client will run. Starting the Metrics Clients on Windows NT Click Start Settings Control Panel. Double-click Services. Choose D2LC Client Service. Enter values for the following startup parameters: MetricsServerHostName MetricsClientToServerPort# MetricsClientLocalPort# [ScaleFactor] Where: MetricsServerHostName is the name of the system where the Metrics Server is running. MetricsClientToServerPort# is the port on the Metrics Server where the Metrics Clients will connect. MetricsClientLocalPort# is the port on the Metrics Client which the Client will use to query the Metrics Server for information. ScaleFactor is an optional parameter that allows you to reduce the imbalances resulting from varying capacities of Metrics Clients. Since Forms Server load balancing is based only on total number of processes running on each Metrics Client, a system that appears to be the least-loaded system may not necessarily be the best place to run a new process. You should assign a higher value for ScaleFactor for your lower capacity systems. The default value for ScaleFactor is 1 for UNIX and 4 for Windows NT. Example: Enter yourserver.yourcompany.com in the Parameter Startup window. Click Start to start the service. 10

11 Note: Examples for both the Metrics Server and Metrics Clients NT Services are working examples. Passing the above parameters will allow both the Metrics Server and Client to communicate. Start the Forms Listener and Web listener on the Metrics Server If you have not already started the web server, start it with the following commands: owsctl start wrb owsctl start admin owsctl start www Start the Form Listener by Navigating to Start Programs Developer 2000 for NT Forms Server Listener Start the Forms Listener and Web listener on each Metrics Client system. If you have not already started the web server, start it with the following commands: owsctl start wrb owsctl start admin owsctl start www Start the Form Listener by Navigating to Start Programs Developer 2000 for NT Forms Server Listener Establishing Connections From the desktop client appletviewer connect to the forms cartridge URL. Example: appletviewer -J-Djava.compiler=symcjit The /APPS portion of the URL points to the forms cartridge located on the metrics server. The cartridge dynamically inserts the value of the %LEASTLOADEDHOST% in the sample-d.htm file that is downloaded to the client making the connection request. Note: From the small appletviewer window you can determine which Metrics Client a desktop client has connected to. Select Applet Tag from the pull down menu. This shows all parameters that have been passed to the user s appletviewer. The parameter server host value shows the Metrics Client the connection is established with. 11

12 Attention: If you have already implemented the Shared Applications File System Model you may stop here. Only one section needs to be followed. 12

13 Independent Applications File System Model The following section will walk you through configuring load balancing using independent APPL_TOP directories located on each individual Metrics Client. This section assumes you have either successfully connected to the Metrics Server with a dynamic connection to your 10.7 NCA Database, or you will follow the manuals to create the dynamic cartridge. Attention: Every Metrics Client ORACLE_HOME must mirror the ORACLE_HOME location by drive letter and path of every other Metrics Client and the Metrics Server. Every Metrics Client must mirror the APPL_TOP location by drive letter and path to every other Metrics Client and the Metrics Server. The Metrics Server does not need to have a local APPL_TOP directory in this model. However, the cartridge information must be filled out as if the APPL_TOP and ORACLE_HOME were on the Metrics Server Machine. Since these values must match across every machine, it is not difficult to implement. You should create the cartridge as if there was a matching APPL_TOP on the Metrics Server. Note: Since the dynamic HTML page is sent down to the desktop client with the location of the Metrics Client APPL_TOP it is not necessary to have an APPL_TOP on the Metrics Server. Configuration Steps Configure the Web Cartridge for Load Balancing Configure your Load Balancing Web cartridge on the Metrics Server Install your Metrics Server NT Service Modify your cartridge base HTML file. (sample-d.htm) Install your Metrics Client NT Service Set up the environment on each Metrics Client Run adadmin on Each Metrics Client Start your Metrics Server NT Service Start your Oracle Web Server on the Metrics Server Start your Metrics Client NT Service Start the Forms Listener and Web listener on the Metrics Server Start the Forms Listener and Web listener on each Metrics Client system Establishing Connections 13

14 Configure Web Cartridge for Load Balancing on the Metrics Server Attention: If you do not plan to have an APPL_TOP on the Metrics Server you must still set up the cartridge and Web Server virtual paths according to chapter 3 of the Oracle Applications Release 10.7 NCA Installation Manual Windows NT Server Edition. All parameters should be set up as if the APPL_TOP was local to the Metrics Server. Since the APPL_TOP and ORACLE_HOME locations should match with all other Metrics systems this will not be difficult to implement. Access the Oracle Web Application Server Administration page by navigating to the appropriate URL. For example: Enter your administrative username and password. Navigate to: Web Applications Server Manager Oracle Web Application Server Cartridge Administration Select your Forms Web cartridge Click Cartridge specific Parameters. Add the following parameters to your cartridge for load balancing: Note: Cartridge parameters and parameter values are case sensitive 14

15 Parameter MetricsServerHost MetricsServerPort MetricsServerErrorURL Parameter Values Enter the name of the host (system) where the Metrics Server is running. This parameter is required if load balancing is used. For example: system1.company.com Enter the port number on which the Metrics Server will be listening for requests from the cartridge for the least-loaded system. This parameter is required if load balancing is used and its value must be different from the Forms Listener value. For example: Enter the URL to which the Web Client will be directed if the Metrics Server does not respond with the name of the least-loaded system within the MetricsTimeout period. This parameter is required if load balancing is used. 1.The URL can Point to a Forms Web cartridge on another host, which will then automatically service the request. For example: serverport MetricsTimeout 2. Point to a static HTML page on any Web server. This page can be used for giving help and instructions to users when the Metrics Server goes down, or point to the sample-s.htm on another server. For example: This is the Port the Forms servers will be listening on. The default value is (Optional) Enter the timeout value, in seconds, for the Forms cartridge to use while making requests to the Metrics Server for the name of the least-loaded system. If the cartridge does not receive a response in that time interval, it replaces the %LEASTLOADEDHOST% entry in the HTML file with the MetricsServerErrorURL value. The MetricsTimeout parameter is optional. If not specified, the default value is 30 seconds. For example: 35 Click Modify Cartridge Configuration. In order to activate your changes, stop and start the following web listeners in this order. owsctl stop www 15

16 owsctl stop admin owsctl stop wrb owsctl start wrb owsctl start admin owsctl start www Creating a batch file for bouncing the web listeners is recommended. You can accomplish this by creating a text file containing the above commands. Rename the text file with a *.bat extension, and execute it from either the Windows Explorer or the command line. Note: It is not necessary to bounce all of the above listeners. However, from experience, bouncing the listeners in this order ensures the best success rate. Install your Metrics Server NT Service On Windows NT, run the following command to install the Metrics Server as an NT Service: d2ls1032 -install To deactivate the Metrics Server service: d2ls1032 -remove Modify your cartridge base HTML file on the Metrics Server. (sample-d.htm) Open the sample-d.htm file and edit the section that looks like this: <!-- If you are implementing load balancing, remove the comment tags in the next two lines (the! symbol) and replace the ^ delimiters with percent symbols. --> <!PARAM name="serverhost" value="^leastloadedhost^"> <!PARAM name="serverport" value="^serverport^"> It should look like this when you are done: <!-- If you are implementing load balancing, remove the comment tags in the next two lines (the! symbol) and replace the ^ delimiters with percent symbols. --> <PARAM name="serverhost" value="%leastloadedhost%"> <PARAM name="serverport" value="%serverport%"> 16

17 Install your Metrics Client NT Service On Windows NT, run the following command on each system to install each Metrics Client as an NT Service: d2lc1032 -install To deactivate the Metrics Client service: d2lc1032 -remove Setting up the Environment Variables on Each Metrics Client. The following environment variables must be set on each Metrics Client: APPL_TOP This will match the value of the Metrics Server APPL_TOP since it was mapped in a previous step. ORACLE_HOME This is the location that exists on the Local Metrics Client where the Forms and Web Server are installed. LOCAL This is set to the Tnsnames Alias for your SQL*Net connection to the database server. Note: You should use SQL*Plus to check Database connectivity from each Metrics Client Unload the APPL_TOP on the Metrics Client Insert the Oracle Applications Release 10.7 NCA CD into your local CD-ROM drive, or into a CD-ROM drive on the network. Open the CD in Windows Explorer and double-click on the file labeled PRDNCA10.EXE. Follow the instructions to extract the Oracle Applications Release 10.7 NCA product files from the archive into the APPL_TOP directory you chose previously. Install Help Files Unload the help files you want to use for this installation. Follow chapter 3 of the Oracle Applications Release 10.7 NCA Installation Manual Windows NT Server Edition to accomplish this. Run the ADADMIN Utility on Each Metrics Client At the command prompt, change to the bin subdirectory in the AD directory on your local machine. Run the adadmin utility: C:\> cd %APPL_TOP%\ad\10.7\bin C:\> adadmin 17

18 Answer the initial questions asked by adadmin, which include your APPL_TOP and database settings. Select the Maintain Applications Files option from the Main Menu. From this screen, choose the Create Applications environment file option. Registry subkey for this installation. Directory in which you want Applications temporary files stored. This will likely be your C:\temp directory on the local Metrics Client. Machine name and domain on which web server is installed for accessing Applications forms. This is the local Metrics Client that you are running adadmin from. HTTP port for Applications forms web server. This is the local Metrics Client that you are running adadmin from. Machine name and domain on which web server is installed for accessing Applications online help files. This is the local Metrics Client that you are running adadmin from. HTTP port for Applications online help web server. This is the port for the local Metrics Client that you are running adadmin from. Directory to which all Applications HTML files should be copied. This location is the local ORACLE_HOME on the Metrics Client you are running adadmin from. Directory to which all Applications Java files should be copied. This location is the local ORACLE_HOME on the Metrics Client you are running adadmin from. The AD Administration utility provides further information about these options. Make note of the values you entered for the location of Java, HTML, and temporary files. You will need these directories when configuring your web server. Select the Maintain Applications Files menu option from the Main Menu. Choose the following options: Copy Java and HTML files This copies the Java and HTML files to the locations you selected. Generate Message Files Generate form libraries, form menus, and form files (Optional) Attention: To move the Java and HTML files later, rerun the previous two steps in the AD Administration utility. Do not copy the files. Copying the files will cause future upgrades and patches to those files to break. Create Virtual Mappings for the Web Server on the Metrics Client Access the Oracle Web Application Server Administrative page by navigating to the appropriate URL. For example: Enter your administrative username and password. Navigate to: Web Applications Server Manager Oracle Web Listener Select the configure button for your listener and navigate to the directory section of the listener. 18

19 Enter the following directories and virtual directories: File-System Directory Flag Virtual Directory Local directory for temp files: C:\temp\ NR /oa-tmp location of Oracle Home\forms45\java: D:\orant\forms45\java\ NR /oa-java/ Location of your online help files. This is the physical location where the help files have been unloaded. D:\appsdoc\ NR /oa-doc/ Start your Metrics Server NT Service Starting the Metrics Server on Windows NT Click Start Settings Control Panel Double-click Services Choose D2LS Server Service Place your cursor in the bottom window that is titled Startup Parameters Enter values for the following startup parameters: MetricsClientToServerPort# MetricsServerToCartridgePort# [max_no_metricsclients] Where: MetricsClientToServerPort# is the port on the Metrics Server where the Metrics Clients will connect and will send their load information. Example: Port MetricsServerToCartridgePort# is the port on the Metrics Server which the cartridges will use to query the Metrics Server for information. This value corresponds to the MetricsServerPort property, as entered in the cartridge configuration. The example was max_no_metricsclients is the maximum number of Metrics Clients that will be running and sending load information to the Metrics Server. This parameter is optional. The default value is Example: Enter in the Parameter Startup window. Click Start to start the service. Note: Examples for both the Metrics Server and Metrics Clients NT Services are working examples. Passing the above parameters will allow both the Metrics Server and Client to Communicate. Start your Metrics Clients NT Service Do these steps for each system where a Metrics Client will run. Starting the Metrics Clients on Windows NT Click Start Settings Control Panel. Double-click Services. 19

20 Choose D2LC Client Service. Enter values for the following startup parameters: MetricsServerHostName MetricsClientToServerPort# MetricsClientLocalPort# [ScaleFactor] Where: MetricsServerHostName is the name of the system where the Metrics Server is running. MetricsClientToServerPort# is the port on the Metrics Server where the Metrics Clients will connect. MetricsClientLocalPort# is the port on the Metrics Client which the Client will use to query the Metrics Server for information. ScaleFactor is an optional parameter that allows you to reduce the imbalances resulting from varying capacities of Metrics Clients. Since Forms Server load balancing is based only on total number of processes running on each Metrics Client, a system that appears to be the least-loaded system may not necessarily be the best place to run a new process. You should assign a higher value for ScaleFactor for your lower capacity systems. The default value for ScaleFactor is 1 for UNIX and 4 for Windows NT. Example: Enter yourserver.yourcompany.com in the Parameter Startup window. Click Start to start the service. Note: Examples for both the Metrics Server and Metrics Clients NT Services are working examples. Passing the above parameters will allow both the Metrics Server and Client to communicate. Start the Forms Listener and Web listener on the Metrics Server If you have not already started the web server, start it with the following commands: owsctl start wrb owsctl start admin owsctl start www Start the Form Listener by Navigating to Start Programs Developer 2000 for NT Forms Server Listener Start the Forms Listener and Web listener on each Metrics Client If you have not already started the web server, start it with the following commands: owsctl start wrb owsctl start admin owsctl start www 20