Package Building

How to find the installed files?

Luckily, it's not too bad. Since we saved the output from our first make install, we can see the filenames as they're installed. Of course, it's important to make sure the install output is valid. Fortunately for us, amanda didn't require much fiddling by the time we got it built and tested. If it had, we would have had to get more recent output from the installation phase.

It's time for more decisions. We have one list of installed files, and two %files lists. It would be silly to put all the files in both %files lists, so we have to decide which file goes where.

This is where experience with the software really pays off, because the wrong decision made here can result in awkward, ill-featured packages. Here's the %files list we came up with for the client subpackage:

%files client /usr/lib/amanda/amandad /usr/lib/amanda/sendsize /usr/lib/amanda/calcsize /usr/lib/amanda/sendbackup-dump /usr/lib/amanda/selfcheck /usr/lib/amanda/sendbackup-gnutar /usr/lib/amanda/runtar README COPYRIGHT docs/INSTALL docs/SYSTEM.NOTES docs/WHATS.NEW

The files in /usr/lib/amanda are all the client-side amanda programs, so that part was easy. The remaining files are part of the original source archive. Amanda doesn't install them, but they contain information that users should see.

Realizing that RPM can't package these files specified as they are, let's leave the client %files list for a moment, and check out the list for the server subpackage:

%files server /usr/sbin/amadmin /usr/sbin/amcheck /usr/sbin/amcleanup /usr/sbin/amdump /usr/sbin/amflush /usr/sbin/amlabel /usr/sbin/amrestore /usr/sbin/amtape /usr/lib/amanda/taper /usr/lib/amanda/dumper /usr/lib/amanda/driver /usr/lib/amanda/planner /usr/lib/amanda/reporter /usr/lib/amanda/getconf /usr/lib/amanda/chg-generic /usr/man/man8/amanda.8 /usr/man/man8/amadmin.8 /usr/man/man8/amcheck.8 /usr/man/man8/amcleanup.8 /usr/man/man8/amdump.8 /usr/man/man8/amflush.8 /usr/man/man8/amlabel.8 /usr/man/man8/amrestore.8 /usr/man/man8/amtape.8 README COPYRIGHT docs/INSTALL docs/KERBEROS docs/SUNOS4.BUG docs/SYSTEM.NOTES docs/TAPE.CHANGERS docs/WHATS.NEW docs/MULTITAPE example

The files in /usr/sbin are programs that will be run by the amanda administrator in order to perform backups and restores. The files in /usr/lib/amanda are the server-side programs that do the actual work during backups. Following that are a number of man pages: one for each program to be run by the amanda administrator, and one with an overview of amanda.

Bringing up the rear are a number of files that are not installed, but would be handy for the amanda administrator to have available. There is some overlap with the files that will be part of the client subpackage, but the additional files here discuss features that would interest only amanda administrators. Included here is the example subdirectory, which contains a few example configuration files for the amanda server.

As in the client %files list, these last files can't be packaged by RPM as we've listed them. We need to use a few more of RPM's tricks to get them packaged.

Applying Directives

Since we'd like the client subpackage to include those files that are not normally installed, and since the files are documentation, let's use the %doc directive on them. That will accomplish two things:

1. When the client subpackage is installed, it will direct RPM to place them in a package-specific directory in /usr/doc

2. It will tag the files as being documentation, making it possible for users to easily track down the documentation with a simple rpm -qd command

In the course of looking over the %files lists, it becomes apparent that the directory /usr/lib/amanda will contain only files from the two amanda subpackages. If the subpackages are erased, the directory will remain, which won't hurt anything, but it isn't as neat as it could be. But if we add the directory to the list, RPM will automatically package every file in the directory. Since the files in that directory are part of both the client and the server subpackages, we'll need to use the %dir directive to instruct RPM to package only the directory.

After these changes, here's what the client %files list looks like now:

%files client %dir /usr/lib/amanda/ /usr/lib/amanda/amandad /usr/lib/amanda/sendsize /usr/lib/amanda/calcsize /usr/lib/amanda/sendbackup-dump /usr/lib/amanda/selfcheck /usr/lib/amanda/sendbackup-gnutar /usr/lib/amanda/runtar %doc README %doc COPYRIGHT %doc docs/INSTALL %doc docs/SYSTEM.NOTES %doc docs/WHATS.NEW

We've also applied the same directives to the server %files list:

%files server /usr/sbin/amadmin /usr/sbin/amcheck /usr/sbin/amcleanup /usr/sbin/amdump /usr/sbin/amflush /usr/sbin/amlabel /usr/sbin/amrestore /usr/sbin/amtape %dir /usr/lib/amanda/ /usr/lib/amanda/taper /usr/lib/amanda/dumper /usr/lib/amanda/driver /usr/lib/amanda/planner /usr/lib/amanda/reporter /usr/lib/amanda/getconf /usr/lib/amanda/chg-generic /usr/man/man8/amanda.8 /usr/man/man8/amadmin.8 /usr/man/man8/amcheck.8 /usr/man/man8/amcleanup.8 /usr/man/man8/amdump.8 /usr/man/man8/amflush.8 /usr/man/man8/amlabel.8 /usr/man/man8/amrestore.8 /usr/man/man8/amtape.8 %doc README %doc COPYRIGHT %doc docs/INSTALL %doc docs/KERBEROS %doc docs/SUNOS4.BUG %doc docs/SYSTEM.NOTES %doc docs/TAPE.CHANGERS %doc docs/WHATS.NEW %doc docs/MULTITAPE %doc example

You'll note that we neglected to use the %doc directive on the man page files. The reason is that RPM automatically tags any file destined for /usr/man as documentation. Now our spec file has a complete set of tags, the two subpackages are defined, it has build-time scripts that work, and now, %files lists for each subpackage. Why don't we try that build again?

# rpm -ba amanda-2.3.0.spec * Package: amanda * Package: amanda-client * Package: amanda-server … echo Executing: %build Executing: %build + cd /usr/src/redhat/BUILD + cd amanda-2.3.0 + make Making all in common-src … + echo Executing: %install Executing: %install + cd /usr/src/redhat/BUILD + cd amanda-2.3.0 + make install Making install in common-src … + echo Executing: special doc Executing: special doc … Binary Packaging: amanda-client-2.3.0-6 Finding dependencies... Requires (3): libc.so.5 libdb.so.2 dump usr/doc/amanda-client-2.3.0-6 usr/doc/amanda-client-2.3.0-6/COPYRIGHT usr/doc/amanda-client-2.3.0-6/INSTALL … usr/lib/amanda/sendbackup-gnutar usr/lib/amanda/sendsize 1453 blocks Generating signature: 0 Wrote: /usr/src/redhat/RPMS/i386/amanda-client-2.3.0-6.i386.rpm Binary Packaging: amanda-server-2.3.0-6 Finding dependencies... Requires (2): libc.so.5 libdb.so.2 usr/doc/amanda-server-2.3.0-6 usr/doc/amanda-server-2.3.0-6/COPYRIGHT usr/doc/amanda-server-2.3.0-6/INSTALL … usr/sbin/amrestore usr/sbin/amtape 3404 blocks Generating signature: 0 Wrote: /usr/src/redhat/RPMS/i386/amanda-server-2.3.0-6.i386.rpm … Source Packaging: amanda-2.3.0-6 amanda-2.3.0.spec amanda-2.3.0-linux.patch amanda-rpm-instructions.tar.gz amanda-2.3.0.tar.gz 393 blocks Generating signature: 0 Wrote: /usr/src/redhat/SRPMS/amanda-2.3.0-6.src.rpm #

If we take a quick look at the client and server subpackages, we find that, sure enough, this time they contain files:

# cd /usr/src/redhat/RPMS/i386/ # ls -l amanda-* -rw-r--r-- 1 root root 211409 Nov 21 15:56 amanda-client-2.3.0-1.i386.rpm -rw-r--r-- 1 root root 512814 Nov 21 15:57 amanda-server-2.3.0-1.i386.rpm # rpm -qilp amanda-* Name : amanda-client Distribution: (none) Version : 2.3.0 Vendor: (none) Release : 1 Build Date: Thu Nov 21 15:55:59 1996 Install date: (none) Build Host: moocow.rpm.org Group : System/Backup Source RPM: amanda-2.3.0-1.src.rpm Size : 737101 Summary : Client-side Amanda package Description : The Amanda Network Backup system contains software necessary to automatically perform backups across a network. Amanda consists of two packages -- a client (this package), and a server: The client package enable a network-capable system to have its filesystems backed up by a system running the Amanda server. NOTE: In order for a system to perform backups of itself, install both the client and server packages! /usr/doc/amanda-client-2.3.0-1 /usr/doc/amanda-client-2.3.0-1/COPYRIGHT /usr/doc/amanda-client-2.3.0-1/INSTALL … /usr/lib/amanda/sendbackup-gnutar /usr/lib/amanda/sendsize Name : amanda-server Distribution: (none) Version : 2.3.0 Vendor: (none) Release : 1 Build Date: Thu Nov 21 15:55:59 1996 Install date: (none) Build Host: moocow.rpm.org Group : System/Backup Source RPM: amanda-2.3.0-1.src.rpm Size : 1733825 Summary : Server-side Amanda package Description : The Amanda Network Backup system contains software necessary to automatically perform backups across a network. Amanda consists of two package -- a client, and a server (this package): The server package enables a network-capable system to control one or more Amanda client systems performing backups. The server system will direct all backups to a locally attached tape drive. Therefore, the server system requires a tape drive. NOTE: In order for a system to perform backups of itself, install both the client and server packages! /usr/doc/amanda-server-2.3.0-1 /usr/doc/amanda-server-2.3.0-1/COPYRIGHT /usr/doc/amanda-server-2.3.0-1/INSTALL … /usr/sbin/amrestore /usr/sbin/amtape #

We're finally ready to test these packages!

Installing the Package On A Different System

Looks like we're almost through. Let's install the packages on another system that had not previously run amanda, and test it there:

# rpm -ivh amanda-*-1.i386.rpm amanda-client ################################################## amanda-server ################################################## #

The install went smoothly enough. However, testing did not. Why? Nothing was set up! The server configuration files, the inetd.conf entry for the client, everything was missing. If we stop and think about it for a moment that makes sense: we had gone through all those steps on the build system, but none of those steps can be packaged as files.

After following the steps in the installation instructions, everything works. While we could expect users to do most of the grunt work associated with getting amanda configured, RPM does have the ability to run scripts when packages are installed and erased. Why don't we use that feature to make life easier for our users?

Creating Install Scripts

When it comes to needing post-installation configuration, amanda certainly is no slouch! We'll work on the client first. Let's look at a section of the script we wrote, comment on it, and move on:

%post client # See if they've installed amanda before... # If they have, none of this should be necessary... if [ "$1" = 1 ]; then

First, we start the script with a %post statement, and indicate that this script is for the client subpackage. As the comments indicate, we only want to perform the following tasks if this is the first time the client subpackage has been installed. To do this, we use the first and only argument passed to the script. It is a number indicating how many instances of this package will be installed after the current installation is complete.

If the argument is equal to 1, that means that no other instances of the client subpackage are presently installed, and that this one is the first. Let's continue:

# Set disk devices so that bin can read them # (This is actually done on Red Hat Linux; only need to add bin to # group disk) if grep "^disk::.*bin" /etc/group > /dev/null then true else # If there are any members in group disk, add bin after a comma... sed -e 's/\(^disk::[0-9]\{1,\}:.\{1,\}\)/\1,bin/' /etc/group > /etc/group.tmp # If there are no members in group disk, add bin... sed -e 's/\(^disk::[0-9]\{1,\}:$\)/\1bin/' /etc/group.tmp > /etc/group # clean up! rm -f /etc/group.tmp fi

One of amanda's requirements is that the user ID running the dumps on the client needs to be able to read from every disk's device file. The folks at Red Hat have done half the work for us by creating a group disk and giving that group read/write access to every disk device. Since our dumpuser is bin, we only need to add bin to the disk group. Two lines of sed, and we're done!

The next section is related to the last. It also focuses on making sure bin can access everything it needs while doing backups:

# Also set /etc/dumpdates to be writable by group disk chgrp disk /etc/dumpdates chmod g+w /etc/dumpdates

Since amanda uses dump to obtain the backups, and since dump keeps track of the backups in /etc/dumpdates, it's only natural that bin will need read/write access to the file. In a perfect world, /etc/dumpdates would have already been set to allow group disk to read and write, but we had to do it ourselves. It's not a big problem, though.

Next, we need to create the appropriate network-related entries, so that amanda clients can communicate with amanda servers, and vice versa:

# Add amanda line to /etc/services if grep "^amanda" /etc/services >/dev/null then true else echo "amanda 10080/udp # Added by package amanda-client" >> /etc/services fi

By using grep to look for lines that begin with the letters amanda, we can easily see if /etc/services is already configured properly. It it isn't, we simply append a line to the end.

We also added a comment so that sysadmins will know where the entry came from, and either take our word for it or issue an rpm -q --scripts amanda-client command and see for themselves. We did it all on one line because it makes the script simpler.

Let's look at the rest of the network-related part of this script:

# Add amanda line to /etc/inetd.conf if grep "^amanda" /etc/inetd.conf >/dev/null then true else echo "amanda dgram udp wait bin /usr/lib/amanda/amandad amandad # added by package amanda-client" >>/etc/inetd.conf # Kick inetd if [ -f /var/run/inetd.pid ]; then kill -HUP `cat /var/run/inetd.pid` fi fi fi

Here, we've used the same approach to add an entry to /etc/inetd.conf. We then hup inetd so the change will take affect, and we're done!

Oh, and that last fi at the end? That's to close the if [ "$1" = 1 ] at the start of the script. Now let's look at the server's post-install script:

%post server # See if they've installed amanda before... if [ "$1" = 1 ]; then # Add amanda line to /etc/services if grep "^amanda" /etc/services >/dev/null then true else echo "amanda 10080/udp # Added by package amanda-server" >>/etc/services fi fi

That was short! And this huge difference brings up a good point about writing install scripts: It's important to understand what you as the package builder should do for the user, and what they should do for themselves.

In the case of the client package, every one of the steps performed by the post-install script was something that a fairly knowledgeable user could have done. But each of these steps have one thing in common. No matter how the user configures amanda, these steps will never change. And given the nature of client/server applications, there's a good chance that many more amanda client packages will be installed than amanda servers. Would you like to be tasked with installing this package on twenty systems, and performing each of the steps we've automated, twenty times? We thought not.

There is one step that we did not automate for the client package. The step we left out is the creation of a .rhosts file. Since this file must contain the name of the amanda server, we have no way of knowing what the file should look like. Therefore, that's one step we can't automate.

The server's post-install script is so short because there's little else that can be automated. The other steps required to set up an amanda server include:

1. Choosing a configuration name, which requires user input

2. Creating a directory to hold the server configuration files, named according to the configuration name, which depends on the first step

3. Modifying example configuration files to suit the site, which requires user input

4. Adding crontab entries to run amanda nightly, which requires user input

Since every step depends on the user making decisions, the best way to handle them is to not handle them at all. Let the user do it!

Creating Uninstall Scripts

Where there are install scripts, there are uninstall scripts. While there is no ironclad rule to that effect, it is a good practice. Following this practice, we have an uninstall script for the client package, and one for the server. Let's take the client first:

%postun client # First, see if we're the last amanda-client package on the system... # If not, then we don't need to do this stuff... if [ "$1" = 0 ]; then

As before, we start out with a declaration of the type of script this is, and which subpackage it is for. Following that we have an if statement similar to the one we used in the install scripts, save one difference. Here, we're comparing the argument against zero. The reason is that we are trying to see if there will be zero instances of this package after the uninstall is complete. If this is the case, the remainder of the script needs to be run, since there are no other amanda client packages left.

Next, we remove bin from the disk group:

# First, get rid of bin from the disk group... if grep "^disk::.*bin" /etc/group > /dev/null then # Nuke bin at the end of the line... sed -e 's/\(^disk::[0-9]\{1,\}:.\{1,\}\),bin$/\1/' /etc/group > /etc/group.tmp # Nuke bin on the line by itself... sed -e 's/\(^disk::[0-9]\{1,\}:\)bin$/\1/' /etc/group.tmp > /etc/group1.tmp # Nuke bin in the middle of the line... sed -e 's/\(^disk::[0-9]\{1,\}:.\{1,\}\),bin,\(.\{1,\}\)/\1,\2/' /etc/group1.tmp > /etc/group2.tmp # Nuke bin at the start of the line... sed -e 's/\(^disk::[0-9]\{1,\}:\)bin,\(.\{1,\}\)/\1\2/' /etc/group2.tmp > /etc/group # Clean up after ourselves... rm -f /etc/group.tmp /etc/group1.tmp /etc/group2.tmp fi

No surprises there. Continuing our uninstall, we start on the network-related tasks:

# Next, lose the amanda line in /etc/services... # We only want to do this if the server package isn't installed # Look for /usr/sbin/amdump, and leave it if there... if [ ! -f /usr/sbin/amdump ]; then if grep "^amanda" /etc/services > /dev/null then grep -v "^amanda" /etc/services > /etc/services.tmp mv -f /etc/services.tmp /etc/services fi fi

That's odd. Why are we looking for a file from the server package? If you look back at the install scripts for the client and server packages, you'll find that the one thing they have in common is that both the client and the server require the same entry in /etc/services.

If an amanda server is going to back itself up, it also needs the amanda client software. Therefore, both subpackages need to add an entry to /etc/services. But what if one of the packages is removed? Perhaps the server is being demoted to a client, or maybe the server is no longer going to be backed up using amanda. In these cases, the entry in /etc/services must stay. So, in the case of the client, we look for a file from the server subpackage, and if it's there, we leave the entry alone.

Granted, this is a somewhat unsightly way to see if a certain package is installed. Some of you are probably even saying, "Why can't RPM be used? Just do an rpm -q amanda-server, and decide what to do based on that." And that would be the best way to do it, except for one small point:

Only one invocation of RPM can run at any given time.

Since RPM is running to perform the uninstall, if the uninstall-script were to attempt to run RPM again, it would fail. The reason it would fail is because only one copy of RPM can access the database at a time. So we are stuck with our unsightly friend.

Continuing the network-related uninstall tasks:

# Finally, the amanda entry in /etc/inetd.conf if grep "^amanda" /etc/inetd.conf > /dev/null then grep -v "^amanda" /etc/inetd.conf > /etc/inetd.conf.tmp mv -f /etc/inetd.conf.tmp /etc/inetd.conf # Kick inetd if [ -f /var/run/inetd.pid ]; then kill -HUP `cat /var/run/inetd.pid` fi fi fi

Here, we're using grep's ability to return lines that don't match the search string, in order to remove every trace of amanda from /etc/inetd.conf. After issuing a hup on inetd, we're done.

On to the server. If you've been noticing a pattern between the various scripts, you won't be disappointed here:

%postun server # See if we're the last server package on the system... # If not, we don't need to do any of this stuff... if [ "$1" = 0 ]; then # Lose the amanda line in /etc/services... # We only want to do this if the client package isn't installed # Look for /usr/lib/amandad, and leave it if there... if [ ! -f /usr/lib/amanda/amandad ]; then if grep "^amanda" /etc/services > /dev/null then grep -v "^amanda" /etc/services > /etc/services.tmp mv -f /etc/services.tmp /etc/services fi fi fi

By now the opening if statement is an old friend. As you might have expected, we are verifying whether the client package is installed, by looking for a file from that package. If the client package isn't there, the entry is removed from /etc/services. And that, is that.

Obviously, these scripts must be carefully tested. In the case of amanda, since the two subpackages have some measure of interdependency, it's necessary to try different sequences of installing and erasing the two packages to make sure the /etc/services logic works properly in all cases.

After a bit of testing, our install and uninstall scripts pass with flying colors. From a technological standpoint, the client and server subpackages are ready to go.

Bits and Pieces

However, just because a package has been properly built, and installs and can be erased without problems, doesn't mean that the package builder's job is done. It's necessary to look at each newly-built package from the user's perspective. Does the package contain everything the user needs in order to deploy it effectively? Or will the user need to fiddle with it, guessing as they go?

In the case of our amanda packages, it was obvious that some additional documentation was required so that the user would know what needed to be done in order to finalize the installation. Simply directing the user to the standard amanda documentation wasn't the right solution, either. Many of the steps outlined in the INSTALL document had already been done by the post-install scripts. No, an interim documente was required. Two, actually: one for the client, and one for the server.

So two files were created, one to be added to each subpackage. The question was, how to do it? Essentially, there were two options:

1. Put the files in the amanda directory tree that had been used to perform the initial builds and generate a new patch file

2. Create a tar file containing the two files, and modify the spec file to unpack the documentation into the amanda directory tree.

3. Drop the files directly into the amanda directory tree without using tar.

Since the second approach was more interesting, that's the approach we chose. It required an additional source tag in the spec file:

Source1: amanda-rpm-instructions.tar.gz

Also required was an additional %setup macro in the %prep script:

%setup -T -D -a 1

While the %setup macro might look intimidating, it wasn't that hard to construct. Here's what each options means:

• -T — Do not perform the default archive unpacking.

• -D — Do not delete the directory before unpacking.

• -a1 — Unpack the archive specified by the source1 tag after changing directory.

Finally, two additions to the %files lists were required. One for the client:

%doc amanda-client.README

And one for the server:

%doc amanda-server.README

At this point, the packages were complete. Certainly there is software out there that doesn't require this level of effort to package. Just as certainly there is software that is much more of a challenge. Hopefully this chapter has given you some idea about how to approach package building for more complex applications.