Red Hat Linux Networking , System Administration (P22) potx

32_599496 ch25.qxd 8/30/05 7:32 PM Page 594 PART Four System Administration Chapter 26: Keeping Your System Updated with up2date and the Red Hat Network Chapter 27: Upgrading and Customizing the Kernel Chapter 28: Configuring the System at the Command Line Chapter 29: Administering Users and Groups Chapter 30: Installing and Upgrading Software Packages Chapter 31: Backing Up and Restoring the File System Chapter 32: Performance Monitoring 33_599496 pt04.qxd 8/30/05 7:21 PM Page 595 33_599496 pt04.qxd 8/30/05 7:21 PM Page 596 597 Keeping Your System Updated with up2date and the Red Hat Network IN THIS CHAPTER ■■ Using the RedHat up2date Agent ■■ Registering Your System with the Red Hat Network ■■ Accessing the Red Hat Network with a Web browser The Red Hat Network up2date agent is a program that is installed by default when you install Fedora Core or Red Hat Enterprise Linux. The Red Hat Net- work up2date software will give you visual notification of the update right on your desktop. If you purchased Enterprise Linux, you are entitled to subscribe to the Red Hat Network, which gives you access to many additional services, such as registering your system, receiving email notifications and scheduling automatic system updates. As a registered Red Hat Network user, you can use a Web browser to access your account. This might not sound like much at first, but think about the many steps involved in keeping your system up to date with the latest versions of the hun- dreds of packages that are installed on your system. The Red Hat Network practically eliminates the need for you to search for these packages because you can receive this information by email. As a registered Red Hat Network user, or a Fedora Core user you can also search for updates by using the up2date agent. With the Red Hat Network, you can now easily keep your sys- tem running reliably and securely. A few steps are involved in setting up the Red Hat Network, but they are well worth the effort. In this chapter, you can read how to configure the up2date agent, and then connect to look for updated files. If you are running Enterprise Linux you learn how to register your sys- tem with Red Hat. CHAPTER 26 34_599496 ch26.qxd 8/30/05 7:19 PM Page 597 Using the Red Hat up2date Agent The up2date agent is a valuable tool for you because it helps you keep your system running the most current versions of the packages installed on your system. During the system installation, an Alert icon is placed on the right side of the top desktop panel that provides visual notification when your system needs to be updated. Figure 26-1 shows the location of the Alert icon on the panel. The Alert icon is colored-coded, representing a different state of the update. The icons and their meaning are discussed in the following list: ■■ Blue check mark — The system is up to date. ■■ Green double arrows — The system is checking for updates. ■■ Red exclamation point — The system needs to be updated. ■■ Gray question mark — An error has occurred. Figure 26-1 The Red Hat Network Alert icon. 598 Chapter 26 34_599496 ch26.qxd 8/30/05 7:19 PM Page 598 Configuring the up2date Agent Before you can use the Red Hat up2date agent, you need to configure it. The first time you start the up2date agent you will be prompted to install the GPG public key from Red Hat, which is used to verify the packages are signed and are from Red Hat. Be sure to install the key. You can start the up2date Agent Configuration tool by doing any of the following: ■■ Open a terminal window, and from the command line, type up2date-config. ■■ Right-click the alert icon, and choose Configuration from the pop-up menu. Choose Application ➪ System Settings ➪ Red Hat Network Configuration. The Red Hat Network Configuration dialog box, shown in Figure 26-2, opens. This dialog box has three tabs — General, Retrieval/Installation, and Pack- age Exceptions: ■■ General — The General tab is the tab shown by default when the dia- log box opens. A server is already selected for you to use, and you should not need to change it. If you need to use a proxy server to con- nect to the Web, you can enter this information here by first selecting the Enable HTTP Proxy check box and then entering the name of your server in the field next to the check box. If you need to use authentica- tion, you can enable it by selecting the Use Authentication check box and filling in the Username and the Password fields. Figure 26-2 The Red Hat Network Configuration dialog box. Keeping Your System Updated with up2date and the Red Hat Network 599 34_599496 ch26.qxd 8/30/05 7:19 PM Page 599 ■■ Retrieval/Installation — From this tab (see Figure 26-3), you can choose options that affect how the packages are retrieved and subsequently installed. The Package Retrieval Options are: ■■ Do Not Install Packages After Retrieval — By default, packages are automatically installed after they are retrieved. If you enable this option, packages are retrieved to the specified directory but not installed. ■■ Do Not Upgrade Packages When Local Configuration File Has Been Modified — If you have manually modified configuration files for packages on your system, these packages are not displayed by default. If you disable this option, the packages are displayed. ■■ Retrieve Source RPM Along with Binary Package — By default, the source Red Hat Package Manager (RPM) is not downloaded with the binary version of the package. By enabling this option, you also retrieve the source of the RPM. The Package Verification Options has but one choice: ■■ Use GPG to Verify Package Integrity — By default, for security purposes, the packages are verified to ensure they contain the Red Hat GPG signature. If you disable this option, the security check is not performed. Figure 26-3 The Retrieval/Installation tab. 600 Chapter 26 34_599496 ch26.qxd 8/30/05 7:19 PM Page 600 NOTE GPG stands for GNU Privacy Guard, which is the open-source replacement for PGP. PGP (Pretty Good Privacy) was developed in the mid- 1990s by Phil Zimmerman to provide data encryption. GPG was developed to replace PGP because PGP contained a patented algorithm and its use was restricted. GPG can be freely used without concern for patented information. The Package Installation Options are: ■■ After Installation, Keep Binary Packages on Disk — By default, the packages are removed from the local disk after they are installed. Enabling this option leaves a copy of the package in the specified directory. ■■ Enable RPM rollbacks — Choosing this option lets you restore your system to its condition before the RPM was installed. The last two items on this tab are: ■■ Override Version Stored in System Profile — By filling in this field, you can override the version stored in your System Profile with the ver- sion in the field. ■■ Package Storage Directory — Here you can specify the storage location of the packages on your system. ■■ Package Exceptions — From this tab (see Figure 26-4), you can choose to exclude packages by the name of the package or by the name of the file. ■■ To exclude a package by package name — Type the name of the package in the Add New field in the Package Names to Skip section, and then click the top Add button. ■■ To exclude a package by filename — Type the name of the file in the Add New field in the File Names to Skip section, and then click the bottom Add button. After you make any changes to the three tabs, click OK. Your configuration changes are saved, and you can now use the up2date agent. Keeping Your System Updated with up2date and the Red Hat Network 601 34_599496 ch26.qxd 8/30/05 7:19 PM Page 601 Figure 26-4 The Package Exceptions tab. Updating Your System Whenever your system needs to be updated, the Alert icon will appear as a red circle containing an exclamation point. You can roll the mouse over the Alert icon to view a small pop-up window that gives additional information. If your system needs to be updated the pop-up window will show the number of updates available. There are multiple ways to start the up2date agent, here is one way. To start the up2date agent to update your system, do the following: 1. Right-click the Alert icon and select Launch Up2date from the contextual menu. You see the Red Hat Update Agent Welcome screen. NOTE If you are not logged in as root, you will be prompted for the root password. 2. Click Forward to continue to the Channels dialog box, as shown in Figure 26-5. 3. The channels dialog box lists the channels that will be searched from which the updated packages will be obtained. You can think of the channels as file repositories on various servers in many locations. Click Forward to continue. 602 Chapter 26 34_599496 ch26.qxd 8/30/05 7:19 PM Page 602 The program connects to the selected channel to search for package updates. Next you see the Skipped Packages dialog box, as shown in Figure 26-6. By default the kernel packages are not automatically updated and will be listed as packages to be skipped. Figure 26-5 The Channels dialog box. Figure 26-6 The Skipped Packages dialog box. Keeping Your System Updated with up2date and the Red Hat Network 603 34_599496 ch26.qxd 8/30/05 7:19 PM Page 603 [...]... program (the Red Hat Update agent ), you could download and install those RPMs, reboot, and you’re done Alternatively, if you’re not a Red Hat Network subscriber or haven’t purchased RHEL, you could download the source RPM from Red Hat s FTP server or one of their mirror sites and build it yourself In this particular case, you would need the file kernel-2.6.9-5.EL.src.rpm, which is stored on ftp.redhat.com... Your System N OT E If you installed Fedora Core on your system, you can skip this section because you do not need to register this version If you installed any version of Enterprise Linux, you should register your system Before you can begin using the Red Hat Network, you must first register your system with Red Hat by using the Red Hat Network registration client N OT E You can also register for the Red. .. on ftp.redhat.com in /pub/redhat /linux/ enterprise/4/en/os/i386/SRPMS The Red Hat Update agent handles all of this for you automatically if you subscribe to the Red Hat Network or have purchased one of the RHEL products, so there’s not much more to say about it in this chapter For more information about using the Red Hat Network and the Red Hat Update Agent, see Chapter 2 6, which discusses these topics... Fedora Core or Enterprise Linux system updated You learned how to use the up2date program to find out about new updates for your system and to download and install them You learned how to register your Enterprise Linux system with the Red Hat Network Finally, you learned that you can access the Red Hat Network using a Web browser, and you looked at the Web interface pages to learn what you can do with them... remarked earlier, you might need to rebuild any LKMs provided by third parties against the new kernel 619 620 Chapter 27 Of course, you don’t have to rely on the Red Hat Update agent To see if an updated kernel RPM is available for your version of RHEL, go to https:// www.redhat.com/security/updates, select the version of RHEL you are using (such as Red Hat Enterprise Linux AS, version 4 ), and see if... Activate dialog box, as shown in Figure 26-11 On this page, you can enter your subscription number, if you have one, and set your system name By default, your system hardware information and installed packages are sent to the Red Hat Network, but you can choose not to send them by deselecting the appropriate check box 5 Click Forward to continue Your system profile is sent to the Red Hat network 6 Next... system (or systems, depending on how many you have configured) Along the left side of the page are links to information about your account and settings that you can change ■ ■ Systems — The Systems link opens a page that provides a general overview of your systems, as shown in Figure 26-13 You can click the link for your system that is shown in the body of the page to get information specific to that... and Red Hat (for RHEL) release a steady stream of patches to address kernel security issues, and these errata should be applied as quickly as possible, especially on systems exposed to the Internet We personally consider a kernel customized for your specific hardware, usage profile, and personal preferences superior to the stock Red Hat kernel, although you will not go wrong using the standard Red Hat. .. update In this case, the kernel does not need to be rebuilt, but you will need a configured kernel source tree matching the newly installed kernel so that the LKMs can be rebuilt against that kernel Okay, that takes care of the practical reasons for and against upgrading to a new kernel A significant portion of the Linux community, particularly home users, hobbyists, and developers, constantly upgrade... that support once it becomes available or to improve existing support ■ ■ You’re dying to use the latest and greatest bleeding-edge kernel version Why should you not build a custom kernel? The compelling reason for RHEL users is that when you diverge from the Red Hat blessed kernel or kernel sources, you lose official Red Hat support; if Red Hat support is important to you, stick with official Red Hat . Using the RedHat up2date Agent ■■ Registering Your System with the Red Hat Network ■■ Accessing the Red Hat Network with a Web browser The Red Hat Network up2date agent is a program that is installed. system. Before you can begin using the Red Hat Network, you must first register your system with Red Hat by using the Red Hat Network registration client. NOTE You can also register for the Red. the Red Hat Network, which gives you access to many additional services, such as registering your system, receiving email notifications and scheduling automatic system updates. As a registered Red