318 Technique 43: Keeping an Eye on Your Servers

Watching Your Web Server Traffic with apachetop

apachetop is a real-time monitor for the Apache Web server. It’s an open-source project, readily available on the Web. Installation is quick, and it’s an easy program to use.

With apachetop, you can see the host machine that your visitors are using, determine whether they came by way of a search engine, and find out what pages they visited while they were there.

You can also use apachetop to see if your visitors are repeatedly asking for documents that don’t exist. You may want to rename your Web pages if the same page name is mistyped over and over.

8.

9.

This command tells apachetop where to find the Apache log file. (The Apache server distributed with Fedora writes log files in an unusual location, so you have to tell apachetop how to find them.)

configure checks out your system, looking for the compilers and libraries it needs to properly build a working program.

Compile the program with the following command:

# make

Then copy the file into a useful place with this command:

# make install

With apachetop installed, you’re ready to run the program and start putting it to use. See the following sections for details.

Installing apachetop

To download and install apachetop, follow these steps:

1. Open a browser window and surf to

clueful.shagged.org/apachetop

2. Click the link to download the latest stable release. As of this writing, it’s

apachetop-0.11.tar.gz

3. When the Download Manager opens, save the download to your home directory.

4. Open a terminal window and give yourself superuser privileges with the su command.

5. Unpack the tarball with this command:

#tar -zxvf apachetop-0.11.tar.gz

6.Move to the apachetop directory:

#cd apachetop-0.11

7.Configure the package with the following command:

#./configure --with-logfile=/etc/ httpd/logs/access_log

Running and exiting apachetop

To run apachetop, move to the /usr/local/sbin directory and enter the following command:

# ./apachetop

apachetop opens, displaying a status window that shows your server activity (see Figure 43-1).

• Figure 43-1: apachetop in action.

When you’re done using apachetop, just type q to quit, and apachetop returns you to the command line.

Watching Your Web Server Traffic with apachetop 319

Navigating apachetop

The top portion of the apachetop display (refer to Figure 43-1) shows the statistics for the server. The lower portion of the display lists information about specific HTTP requests. Here are some navigation tricks that help you find your way around apachetop:

Use the upand down-arrow keys to move the selection asterisk through the list of specific requests.

For more information about a specific request, move the cursor to the request line and press the right-arrow key. The request screen now includes the host and referrer IP addresses for the visitor, as shown in Figure 43-2.

• Figure 43-2: Extended information about who’s visiting your server.

To customize the information displayed about a specific request from a user visiting your Apache server, type t to view the Toggle Subdisplay menu. From here, type

u to exclude URL information

r to exclude or include referrer information

h to exclude or include host information

When you’re finished looking at detailed information about a specific request, use the left-arrow key to return to the request list.

You can sort the information in the request list by typing s to access the Sort By menu. From this menu, you can choose from

r to sort by the number of requests made

R to sort by the number of requests per second

b to sort by the size of the request in bytes

B to sort by the number of bytes per second transferred

Enter #apachetop -h at the command line (or type ? while apachetop is running) to see online help.

Switching among the log files (or watching several at once)

By default, Apache records activity in five different log files, which you can find in the /etc/httpd/logs directory:

access_log

error_log

ssl_access_log

ssl_error_log

ssl_request_log

At configuration time, we told apachetop to watch the access_log. To view entries in one of the other log files, use the following command:

# apachetop -f /etc/httpd/logs/filename

You can watch many log files at the same time by appending multiple -f logfile options to the end of the command line:

#apachetop -f /etc/httpd/logs/access_log

\

-f /etc/httpd/logs/error_log \ -f /etc/httpd/logs/ssl_access_log

\

-f /etc/httpd/logs/ssl_error_log

320 Technique 43: Keeping an Eye on Your Servers

Changing the display time of apachetop statistics

By default, apachetop displays statistics for only the previous 30 seconds. Unless you have a lot of traffic at your server, you may want to extend the display time to hold the information longer.

You can customize the apachetop display to retain statistics about your server for a longer or shorter length of time, depending on your needs. If you have a lot of server traffic, shortening the display time leaves you with easier- to-read reports. If your server traffic is low, a longer display time allows you to gather information over the course of hours for the sake of comparison and easy monitoring.

Use the following command to extend the display time to an hour (3600 seconds):

# apachetop -T 3600

The default refresh rate for the display is 5 seconds. If you have a lot of traffic and want the screen to refresh more often, use the following command:

# apachetop -r 2

Now, the screen refreshes every 2 seconds. Of course, you can combine display options on the command line:

# apachetop -r 2 -T 3600

This command refreshes the statistics every 2 seconds and displays the request activities for the previous hour.

Monitoring MySQL Server with the MySQL Control Center

One cool tool for monitoring and maintaining your MySQL databases in a graphical environment is the MySQL Control Center (MySQLCC). The MySQL Control Center is available from the official MySQL

Web site (www.mysql.com). The Control Center (like MySQL) is dual-licensed — see the MySQL Web site for licensing specifics.

Downloading and installing the

MySQL Control Center

To download and install the MySQL Control Center, follow these steps:

1. Open a browser and surf to

www.mysql.com/downloads/mysqlcc.html

2. Click the Pick a Mirror link for the Linux

(x86, glibc 2.3) download.

It’s the second link in the Linux Downloads portion of the page.

3. When the Select a Mirror page opens, click an

HTTP link from a mirror close to your location.

4. When the Download Manager opens, save the tarball to your home directory.

We’re telling you to download and install MySQLCC in your home directory for the sake of having a consistent point of reference for this technique. You may want to save it elsewhere on your system. To make it easy to run (no matter where you install it), include the directory in your search path so you can run it without issuing the complete pathname every time. See Technique 7 to find out how.

5. Open a terminal window, give yourself superuser privileges with the su command, and unpack the tarball with the following command:

#tar -xzvf \ mysqlcc-0.9.4-linux-glibc23.tar.gz

6.Move into the mysqlcc-0.9.4-linux-glibc23 directory:

#cd mysql-0.9.4-linux-glibc23

That’s it! MySQLCC doesn’t come with any fancy installers; you just load the program onto your computer and run it as we describe in the next section.

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Accessing MySQL Control Center features

After you install the MySQL Control Center, you’re ready to take advantage of its handy tools. Here’s how to get to them:

1. Start the Control Center with the following command:

#./mysqlcc

The MySQLCC window and the Register Server dialog both open (see Figure 43-3).

• Figure 43-3: MySQLCC’s opening view.

2. On the General tab of the Register Server dialog, enter the name of the computer in the Host Name field.

If you have multiple MySQL servers running (scattered around your network), you may want to enter a server name that’s meaningful to you in the Name field to make the different servers easy to distinguish.

3. Click Add to display the session properties

•Figure 43-4: The Console Manager.

4.Double-click a server name in the MySQL Servers frame to expand the tree control and display the controls for Databases, Server Administration, and User Administration.

5.Highlight any entry in the Server tree control (Databases, Server Administration, or User Administration) to display status information about that aspect of the MySQL server.

The following sections have more details on each of these controls.

Viewing, managing, and repairing a database with the Databases controls

The Databases controls enable you to view your database, and you also have tools for managing data and fixing problems as well.

MySQLCC is a complete MySQL client application. You can use MySQLCC to execute SQL commands and queries, but it’s really designed to give you

a quick overview of the state of your database. To view the statistics for databases, follow these steps:

neatly in the Console Manager (see Figure 43-4).

322 Technique 43: Keeping an Eye on Your Servers

1. Follow the steps in the section, “Accessing

MySQL Control Center features,” earlier in this technique, to access the controls.

2. Highlight the Databases entry, as shown in

Figure 43-5.

•Figure 43-5: The Databases statistics.

3.Click the tree control next to the Databases folder to display the databases on the server.

4.Click the tree control next to the Tables entry to view the tables in the database.

5.Highlight a table name to view the fields within that table (see Figure 43-6).

6.Double-click the table name to see the data within that table.

The table data is displayed, as shown in Figure 43-7.

You can adjust the number of rows displayed, but by default, MySQLCC displays the first 1,000 rows. To adjust the default row limit, highlight the server (in the left-most pane), click the Edit button (in the toolbar), then choose MySQL Options and type a row count into the limit field.

• Figure 43-6: A quick view of the fields within a table.

• Figure 43-7: Table data displayed with the Control Center.

The Databases controls include some handy tools to help you manage and repair your MySQL database:

1. Highlight Tables in the tree control and then choose Action Tools to open the drop-down menu (see Figure 43-8).

2. Choose an option from the Tools menu. Here are your choices: