Administering Web Applications

6 Administering Web Applications

This chapter explains how to administer web applications in the GlassFish Server Open Source Edition 5.0 environment.

The following topics are addressed here:

Invoking a Servlet by Alternate Means
Changing Log Output for a Servlet
Defining Global Features for Web Applications
Redirecting a URL
Administering mod_jk
Administering mod_proxy_ajp

Instructions for accomplishing some of these tasks by using the Administration Console are contained in the Administration Console online help.

Invoking a Servlet by Alternate Means

You can call a servlet deployed to GlassFish Server by using a URL in a browser or embedded as a link in an HTML or JSP file. The format of a servlet invocation URL is as follows:

http://server:port/context-root/servlet-mapping?name=value

The following table describes each URL section.

Table 6-1 URL Fields for Servlets Within an Application

URL element Description

URL element	Description
server`:`port	The IP address (or host name) and optional port number. To access the default web module for a virtual server, specify only this URL section. You do not need to specify the context-root or servlet-name unless you also wish to specify name-value parameters.
context-root	For an application, the context root is defined in the `context-root` element of the `application.xml`, `sun-application.xml`, or `sun-web.xml` file. For an individually deployed web module, the context root is specified during deployment. For both applications and individually deployed web modules, the default context root is the name of the WAR file minus the `.war` suffix.
servlet-mapping	The `servlet-mapping` as configured in the `web.xml` file.
?`name=`value`…`	Optional request parameters.

server`:`port

The IP address (or host name) and optional port number.

To access the default web module for a virtual server, specify only this URL section. You do not need to specify the context-root or servlet-name unless you also wish to specify name-value parameters.

context-root

For an application, the context root is defined in the context-root element of the application.xml, sun-application.xml, or sun-web.xml file. For an individually deployed web module, the context root is specified during deployment.

For both applications and individually deployed web modules, the default context root is the name of the WAR file minus the .war suffix.

servlet-mapping

The servlet-mapping as configured in the web.xml file.

?`name=value…`

Optional request parameters.

Example 6-1 Invoking a Servlet With a URL

In this example, localhost is the host name, MortPages is the context root, and calcMortgage is the servlet mapping.

http://localhost:8080/MortPages/calcMortgage?rate=8.0&per=360&bal=180000

Example 6-2 Invoking a Servlet From Within a JSP File

To invoke a servlet from within a JSP file, you can use a relative path. For example:

<jsp:forward page="TestServlet"/><jsp:include page="TestServlet"/>

Changing Log Output for a Servlet

ServletContext.log messages are sent to the server log. By default, the System.out and System.err output of servlets are sent to the server log. During startup, server log messages are echoed to the System.err output. Also by default, there is no Windows-only console for the System.err output.

You can change these defaults using the Administration Console Write to System Log box. If this box is checked, System.out output is sent to the server log. If it is unchecked, System.out output is sent to the system default location only.

Defining Global Features for Web Applications

You can use the default-web.xml file to define features such as filters and security constraints that apply to all web applications.

For example, directory listings are disabled by default for added security. To enable directory listings in your domain’s default-web.xml file, search for the definition of the servlet whose servlet-name is equal to default, and set the value of the init-param named listings to true. Then restart the server.

<init-param>
   <param-name>listings</param-name>
   <param-value>true</param-value>
</init-param>

If listings is set to true, you can also determine how directory listings are sorted. Set the value of the init-param named sortedBy to NAME, SIZE, or LAST_MODIFIED. Then restart the server.

<init-param>
   <param-name>sortedBy</param-name>
   <param-value>LAST_MODIFIED</param-value>
</init-param>

The mime-mapping elements in default-web.xml are global and inherited by all web applications. You can override these mappings or define your own using mime-mapping elements in your web application’s web.xml file. For more information about mime-mapping elements, see the Servlet specification.

You can use the Administration Console to edit the default-web.xml file, or edit the file directly using the following steps.

To Use the `default-web.xml` File

Place the JAR file for the filter, security constraint, or other feature in the domain-dir`/lib` directory.
Edit the domain-dir`/config/default-web.xml` file to refer to the JAR file.
To apply your changes, restart GlassFish Server.
See To Restart a Domain.

Redirecting a URL

You can specify that a request for an old URL be treated as a request for a new URL. This is called redirecting a URL.

To specify a redirected URL for a virtual server, use the redirect_n property, where n is a positive integer that allows specification of more than one. Each of these redirect_n properties is inherited by all web applications deployed on the virtual server.

The value of each redirect_n property has two components which can be specified in any order:

The first component, from, specifies the prefix of the requested URI to match.
The second component, url-prefix, specifies the new URL prefix to return to the client. The from prefix is replaced by this URL prefix.

Example 6-3 Redirecting a URL

This example redirects from dummy to etude:

<property name="redirect_1" value="from=/dummy url-prefix=http://etude"/>

Administering `mod_jk`

The Apache Tomcat Connector mod_jk can be used to connect the web container with web servers such as Apache HTTP Server. By using mod_jk, which comes with GlassFish Server, you can front GlassFish Server with Apache HTTP Server.

You can also use mod_jk directly at the JSP/servlet engine for load balancing. For more information about configuring mod_jk and Apache HTTP Server for load balancing with GlassFish Server 5.0 refer to "Configuring HTTP Load Balancing" in GlassFish Server Open Source Edition High Availability Administration Guide.

The following topics are addressed here:

To Enable mod_jk
To Load Balance Using mod_jk and GlassFish Server
To Enable SSL Between the mod_jk Load Balancer and the Browser
To Enable SSL Between the mod_jk Load Balancer and GlassFish Server

To Enable `mod_jk`

You can front GlassFish Server with Apache HTTP Server by enabling the mod_jk protocol for one of GlassFish Server’s network listeners, as described in this procedure. A typical use for mod_jk would be to have Apache HTTP Server handle requests for static resources, while having requests for dynamic resources, such as servlets and JavaServer Pages (JSPs), forwarded to, and handled by the GlassFish Server back-end instance.

When you use the jk-enabled attribute of the network listener, you do not need to copy any additional JAR files into the /lib directory. You can also create JK connectors under different virtual servers by using the network listener attribute jk-enabled.

Install Apache HTTP Server and mod_jk.
- For information on installing Apache HTTP Server, see http://httpd.apache.org/docs/2.2/install.html.
- For information on installing mod_jk, see http://tomcat.apache.org/connectors-doc/webserver_howto/apache.html.
Configure the following files:
- apache2/conf/httpd.conf, the main Apache configuration file
- apache2/conf/workers.properties
  Example 6-4 and Example 6-5 provide examples of configuring these two files.
Start Apache HTTP Server (httpd).
Start GlassFish Server with at least one web application deployed.
In order for the mod_jk-enabled network listener to start listening for requests, the web container must be started. Normally, this is achieved by deploying a web application.
Create a jk-enabled network listener by using the create-network-listener subcommand.

asadmin> create-network-listener --protocol http-listener-1 \
--listenerport 8009 --jkenabled true jk-connector

If you are using the glassfish-jk.properties file to use non-default values of attributes described at http://tomcat.apache.org/tomcat-5.5-doc/config/ajp.html), set the jk-configuration-file property of the network listener to the fully-qualified file name of the glassfish-jk.properties file.

asadmin> set server-config.network-config.network-listeners.network-listener.\
jk-connector.jk-configuration-file=domain-dir/config/glassfish-jk.properties

If you expect to need more than five threads for the listener, increase the maximum threads in the http-thread-pool pool:

asadmin> set configs.config.server-config.thread-pools.thread-pool.\
http-thread-pool.max-thread-pool-size=value

To apply your changes, restart GlassFish Server.
See To Restart a Domain.

Example 6-4 httpd.conf File for mod_jk

This example shows an httpd.conf file that is set for mod_jk. In this example, mod_jk used as a simple pass-through.

LoadModule jk_module /usr/lib/httpd/modules/mod_jk.so
JkWorkersFile /etc/httpd/conf/worker.properties
# Where to put jk logs
JkLogFile /var/log/httpd/mod_jk.log
# Set the jk log level [debug/error/info]
JkLogLevel debug
# Select the log format
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
# JkOptions indicate to send SSL KEY SIZE,
JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories
# JkRequestLogFormat set the request format
JkRequestLogFormat "%w %V %T"
# Send all jsp requests to GlassFish
JkMount /*.jsp worker1
# Send all glassfish-test requests to GlassFish
JkMount /glassfish-test/* worker1

Example 6-5 workers.properties File for mod_jk

This example shows a workers.properties that is set for mod_jk. This workers.properties file is referenced in the second line of Example 6-4.

# Define 1 real worker using ajp13
worker.list=worker1
# Set properties for worker1 (ajp13)
worker.worker1.type=ajp13
worker.worker1.host=localhost
worker.worker1.port=8009

To Load Balance Using `mod_jk` and GlassFish Server

Load balancing is the process of dividing the amount of work that a computer has to do between two or more computers so that more work gets done in the same amount of time. Load balancing can be configured with or without security.

In order to support stickiness, the Apache mod_jk load balancer relies on a jvmRoute system property that is included in any JSESSIONID received by the load balancer. This means that every GlassFish Server instance that is front-ended by the Apache load balancer must be configured with a unique jvmRoute system property.

On each of the instances, perform the steps in To Enable mod_jk.
If your instances run on the same machine, you must choose different JK ports. The ports must match worker.worker*.port in your workers.properties file. See the properties file in Example 6-5.
On each of the instances, create the jvmRoute system property of GlassFish Server by using the create-jvm-options subcommand.
Use the following format:

asadmin> create-jvm-options "-DjvmRoute=/instance-worker-name"/

where instance-worker-name is the name of the worker that you defined to represent the instance in the workers.properties file. 3. To apply your changes, restart Apache HTTP Server and GlassFish Server.

Example 6-6 httpd.conf File for Load Balancing

This example shows an httpd.conf file that is set for load balancing.

LoadModule jk_module /usr/lib/httpd/modules/mod_jk.so
JkWorkersFile /etc/httpd/conf/worker.properties
# Where to put jk logs
JkLogFile /var/log/httpd/mod_jk.log
# Set the jk log level [debug/error/info]
JkLogLevel debug
# Select the log format
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
# JkOptions indicate to send SSL KEY SIZE,
JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories
# JkRequestLogFormat set the request format
JkRequestLogFormat "%w %V %T"
# Send all jsp requests to GlassFish
JkMount /*.jsp worker1
# Send all glassfish-test requests to GlassFish
JkMount /glassfish-test/* loadbalancer

Example 6-7 workers.properties File for Load Balancing

This example shows a workers.properties or glassfish-jk.properties file that is set for load balancing. The worker.worker*.port should match with JK ports you created.

worker.list=worker1,worker2,loadbalancer
worker.worker1.type=ajp13
worker.worker1.host=localhost
worker.worker1.port=8009
worker.worker1.lbfactor=1
worker.worker1.socket_keepalive=1
worker.worker1.socket_timeout=300
worker.worker2.type=ajp13
worker.worker2.host=localhost
worker.worker2.port=8010
worker.worker2.lbfactor=1
worker.worker2.socket_keepalive=1
worker.worker2.socket_timeout=300
worker.loadbalancer.type=lb
worker.loadbalancer.balance_workers=worker1,worker2

To Enable SSL Between the `mod_jk` Load Balancer and the Browser

To activate security for mod_jk on GlassFish Server, you must first generate a Secure Socket Layer (SSL) self-signed certificate on the Apache HTTP Server with the mod_ssl module. The tasks include generating a private key, a Certificate Signing Request (CSR), a self-signed certificate, and configuring SSL-enabled virtual hosts.

Before You Begin

The mod_jk connector must be enabled.

Generate the private key as follows:

openssl genrsa -des3 -rand file1:file2:file3:file4:file5 -out server.key 1024

where file1:file2: and so on represents the random compressed files. 2. Remove the pass-phrase from the key as follows:

openssl rsa -in server.key -out server.pem

Generate the CSR is as follows:

openssl req -new -key server.pem -out server.csr

Enter the information you are prompted for. 4. Generate a temporary certificate as follows:

openssl x509 -req -days 60 -in server.csr -signkey server.pem -out server.crt

This temporary certificate is good for 60 days. 5. Create the http-ssl.conf file under the /etc/apache2/conf.d directory. 6. In the http-ssl.conf file, add one of the following redirects: * Redirect a web application, for example, JkMount /hello/* worker1. * Redirect all requests, for example, JkMount /* worker1.

# Send all jsp requests to GlassFish
JkMount /*.jsp worker1
# Send all glassfish-test requests to GlassFish
JkMount /glassfish-test/* loadbalancer

Example 6-8 http-ssl.conf File for mod_jk Security

A basic SSL-enabled virtual host will appear in the http-ssl.conf file. In this example, all requests are redirected.

Listen 443
<VirtualHost _default_:443>
SSLEngine on
SSLCipherSuite ALL:!ADH:!EXP56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP:+eNULL
SSLCertificateFile "/etc/apache2/2.2/server.crt"
SSLCertificateKeyFile "/etc/apache2/2.2/server.pem"
JkMount /* worker1
</VirtualHost>

To Enable SSL Between the `mod_jk` Load Balancer and GlassFish Server

This procedure does not enable SSL transfer between mod_jk and GlassFish Server. It enables mod_jk to forward SSL-encrypted information from the browser to GlassFish Server.

Before You Begin

The self-signed certificate must be configured.

Perform the steps in To Enable mod_jk.
Start another GlassFish Server with at least one web application deployed.
In order for the mod_jk-enabled network listener to start listening for requests, the web container must be started. Normally, this is achieved by deploying a web application.
Follow instructions from To Configure an HTTP Listener for SSL on the mod_jk connector.
Use the following format:

asadmin> create-ssl --type http-listener --certname sampleCert new-listener

Add the following directives in the httpd.conf file under the /etc/apache2/conf.d directory:

# Should mod_jk send SSL information (default is On)
JkExtractSSL On
# What is the indicator for SSL (default is HTTPS)
JkHTTPSIndicator HTTPS
# What is the indicator for SSL session (default is SSL_SESSION_ID)
JkSESSIONIndicator SSL_SESSION_ID
# What is the indicator for client SSL cipher suit (default is SSL_CIPHER )
JkCIPHERIndicator SSL_CIPHER
# What is the indicator for the client SSL certificated? (default is SSL_CLIENT_CERT )
JkCERTSIndicator SSL_CLIENT_CERT

To apply your changes, restart Apache HTTP Server and GlassFish Server.

Administering `mod_proxy_ajp`

The Apache Connector mod_proxy_ajp can be used to connect the web container with Apache HTTP Server. By using mod_proxy_ajp, you can front GlassFish Server with Apache HTTP Server.

To Enable `mod_proxy_ajp`

You can front GlassFish Server with Apache HTTP Server and its mod_proxy_ajp connector by enabling the AJP protocol for one of GlassFish Server’s network listeners, as described in this procedure. A typical use for mod_proxy_ajp would be to have Apache HTTP Server handle requests for static resources, while having requests for dynamic resources, such as servlets and JavaServer Pages (JSPs), forwarded to, and handled by the GlassFish Server back-end instance.

Install Apache HTTP Server.
For information on installing Apache HTTP Server, see http://httpd.apache.org/docs/2.2/install.html.
Configure apache2/conf/httpd.conf, the main Apache configuration file.
For example:

LoadModule proxy_module /usr/lib/httpd/modules/mod_proxy.so
LoadModule proxy_ajp_module /usr/lib/httpd/modules/mod_proxy_ajp.so

Listen 1979
NameVirtualHost *:1979
<VirtualHost *:1979>
   ServerName localhost
   ErrorLog /var/log/apache2/ajp.error.log
   CustomLog /var/log/apache2/ajp.log combined

   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>

   ProxyPass / ajp://localhost:8009/
   ProxyPassReverse / ajp://localhost:8009/
</VirtualHost>

Start Apache HTTP Server (httpd).
Create a jk-enabled network listener by using the create-network-listener subcommand.

asadmin> create-network-listener --protocol http-listener-1 \
--listenerport 8009 --jkenabled true jk-connector

If you expect to need more than five threads for the listener, increase the maximum threads in the http-thread-pool pool:

asadmin> set configs.config.server-config.thread-pools.thread-pool.\
http-thread-pool.max-thread-pool-size=value

To apply your changes, restart GlassFish Server.
See To Restart a Domain.

To Load Balance Using `mod_proxy_ajp` and GlassFish Server

Load balancing is the process of dividing the amount of work that a computer has to do between two or more computers so that more work gets done in the same amount of time. In the GlassFish Server context, load balancing is most frequently used to distribute work among the instances in a GlassFish Server cluster.

To configure load balancing using mod_proxy_ajp, you must use the mod_proxy_balancer Apache module in addition to mod_proxy_ajp.

In order to support stickiness, the mod_proxy_balancer load balancer relies on a jvmRoute system property that is included in any JSESSIONID received by the load balancer. Consequently, every GlassFish Server instance that is front-ended by the Apache load balancer must be configured with a unique jvmRoute system property.

Install Apache HTTP Server.
For information on installing Apache HTTP Server, see http://httpd.apache.org/docs/2.2/install.html.
Configure apache2/conf/httpd.conf, the main Apache configuration file.
For example:

LoadModule proxy_module /usr/lib/httpd/modules/mod_proxy.so
LoadModule proxy_ajp_module /usr/lib/httpd/modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module /usr/lib/httpd/modules/mod_proxy_balancer.so

# Forward proxy needs to be turned off
ProxyRequests Off
# Keep the original Host Header
ProxyPreserveHost On

   <Proxy *>
      Order deny,allow
      Deny from all
      Allow from localhost
   </Proxy>

# Each BalancerMember corresponds to an instance in the GlassFish Server
# cluster. The port specified for each instance must match the ajp port
# specified for that instance.
<Proxy balancer://localhost>
    BalancerMember ajp://localhost:8009
    BalancerMember ajp://localhost:8010
    BalancerMember ajp://localhost:8011
</Proxy>

Start Apache HTTP Server (httpd).
In GlassFish Server, use the create-network-listener subcommand to create a jk-enabled network listener targeted to the cluster.
For example:

asadmin> create-network-listener --jkenabled true --target cluster1 \
--protocol http-listener-1 --listenerport ${AJP_PORT} jk-listener

In this example, cluster1 is the name of the cluster and jk-listener is the name of the new listener. 5. If you expect to need more than five threads for the listener, increase the maximum threads in the http-thread-pool pool:

asadmin> set configs.config.cluster1-config.thread-pools.thread-pool.\
http-thread-pool.max-thread-pool-size=value

Use the create-jvm-options subcommand to create the jvmRoute property targeted to the cluster.
For example:

asadmin> create-jvm-options --target cluster1 \
"-DjvmRoute=\${AJP_INSTANCE_NAME}"

Use the create-system-properties subcommand to define the AJP_PORT and AJP_INSTANCE_NAME properties for each of the instances in the cluster, making sure to match the port values you used in Step 2 when specifying the load balancer members.
For example:

asadmin> create-system-properties --target instance1 AJP_PORT=8009
asadmin> create-system-properties --target instance1 \
AJP_INSTANCE_NAME=instance1
asadmin> create-system-properties --target instance2 AJP_PORT=8010
asadmin> create-system-properties --target instance2 \
AJP_INSTANCE_NAME=instance2
asadmin> create-system-properties --target instance3 AJP_PORT=8011
asadmin> create-system-properties --target instance3 \
AJP_INSTANCE_NAME=instance3

In this example, instance1, instance2 and instance3 are the names of the GlassFish Server instances in the cluster. 8. To apply your changes, restart GlassFish Server.
See To Restart a Domain.

6 Administering Web Applications

Invoking a Servlet by Alternate Means

Changing Log Output for a Servlet

Defining Global Features for Web Applications

To Use the default-web.xml File

Redirecting a URL

Administering mod_jk

To Enable mod_jk

To Load Balance Using mod_jk and GlassFish Server

To Enable SSL Between the mod_jk Load Balancer and the Browser

To Enable SSL Between the mod_jk Load Balancer and GlassFish Server

Administering mod_proxy_ajp

To Enable mod_proxy_ajp

To Load Balance Using mod_proxy_ajp and GlassFish Server