Linux Package Management (Distribute Your App)

Revision as of 09:56, 13 February 2016

Background:

Is there background reading material?

• http://www.howtogeek.com/191245/beginner-geek-how-to-install-software-on-linux/ - Read about the various software installation methods on Linux
• http://www.control-escape.com/linux/lx-swinstall.html
• https://help.ubuntu.com/community/SoftwarePackagingFormats
• http://www.rpm.org/wiki/Docs
• https://en.m.wikipedia.org/wiki/DNF_(software)

Are there other related activities?

• Linux_Beginner_Activity - Students can follow this to get command-line basics.
  • Note that the requirements above ask for slightly more in-depth command-line experience via sudo and code compilation.
• Installing_a_Virtual_Machine - If Students need virtual linux machines for command-line access, they can use this activity.
• Introduction_to_building_open_source_software and Building_a_GnomeMusic_Clone both give linux compilation and build experience.

What is the rationale for this activity?

• Students may wonder how they can distribute linux-based code that they develop out to other everyday users. Not many users enjoy compiling code, so the RPM package structure allows easy installation of binary pre-compiled code packages. Basically, a student could have coded a small sample command-line application and now they can send it to others easily. The other side of it is that students, as users of Linux, will be interfacing with RPM packages not of their making and it will be good to have an understanding of the backends of how this works. Students will interface with the dnf and yum commands even if simply using linux for fun. Now, they can have knowledge into how it works and how they can employ it for their careers and personal uses.

Directions:

Keep a working log

Log your shell commands, answers to questions, and commentary in a text file, wiki, or blog. You will be constructing and troubleshooting numerous linux shell command's and their outputs. Your assignment is to document these commands and the process you went through in an organized fashion. You might use bullet points or a new set of commands on each line. Make sure it is easily consumable by a human (your instructor), as well as yourself 10 years from now.

The data that is the output of the commands is not as interesting as a summary or comment of their output or on what the command has done - ex: failed, succeeded, why, what it did, what it changed, etc. Write these in complete sentences. Commentary is especially important if you run into problems. When this occurs, state the problem and how you intend to solve it. At the end, you should have a text document with all of the commands, right and wrong, that you went through to get this activity completed. It should read as a timeline of what you did and what your thoughts were, to get the assignment complete. After this is complete, you will summarize the most useful commands into a sort of cheatsheet - this can come in useful for years to come.

You might consider upping your terminal windows buffer for the number of lines it holds, to somewhere in the tens of thousands - just in case you decide you want to come back to something you learned a while back, or in case a command spits out thousands of lines of results - which can happen. Some terminal applications can record commands and output to text files. Either way, make your written log human readable, make it a story if you wish. When you come back to this years from now, needing to remind yourself how to package some newly minted code, you want a summary/cheatsheet and you want to be able to understand the context and follow your thoughts of why you tried certain things. You don't want to be parsing through lines and lines of shell input and output.

The activity will follow these general steps

1. Use dnf/yum and rpm files.
2. Learn about creating rpm's and the rpmbuild command.
3. Package the htop project into an RPM.

Step 1: dnf / yum and .rpm's

• First, lets do some learning before we jump into shell commands. Answer the following in your log:
  • What is the difference between dnf and yum? Why was the change made?
  • What are .rpm files? Where might you find them and how are they used?
• Use the dnf command to view what packages have been recently installed on your machine.
  • Hint: There is a specific command for this. man dnf is your friend
  • Attempting to list all packages will often be quite a long listing.
• Use the dnf command to install a .rpm package not currently installed on your machine.
  • Pick something simple, as you will need to operate it in the next steps.
  • Hint: If you dont find your own (more credit given for this), you can install screen
• Use dnf to show that the new package is now installed.
• Run or operate this newly installed utility. Where did dnf place the executable file?
  • For hints, read this http://www.cyberciti.biz/faq/linux-unix-command-not-found-error-and-how-to-get-rid-of-it/

Step 2: RPM's and rpmbuild

Required reading / watching:

1. RPM Build Example Video - Watch, at least, the first 8 mins of this video from a recording of a local Linux User Group meeting
2. RPM process Diagram from video - Find the diagram that the video references on the page labeled 12-17
   • Document authored by Guru Labs, L.C. released under the CC-BY-NC-ND 2.0 license
3. Packaging the `wget` command - Read this example in its entirety
   • This will take some time to read through.
   • If you were to try to follow along in the shell, there may be some hickups with wget.
   • Instead, save it for Part 3; You will use this readings structure to RPM'ize the htop project.

Questions:

• What is the rpmbuild command?
• Quickly summarize the directory structure when making your own RPM - you will stick this into your cheat sheet later, so make it short.

Step 3: Create your own 'htop' RPM

• Compile it to test that the code can be turned into binary form in your environment
  • This is not outright a piece of turning code into an RPM, but code must compile before it can be turned into an RPM
  • Anyway, there is always some odd ./configure setting or dependency that needs installing (other rpm package that this project uses)
• Create RPM dir structure
• Run rpmbuild command
• FIXME

Deliverables:

Students will hand in:

• The working log
  • See the above lengthy note about the working log.
• Cheat sheet / Summary
  • A quick-reference guide, truly meant for your future use.
  • List key commands and what they do
  • Succinctly explain the RPM directory structure

Assessment:

Comments:

What should the instructor know before using this activity?

Students should know how to compile Linux software code before doing this activity.

• There exists an activity which covers this: Introduction_to_building_open_source_software
• Particularly, students should have experience using the configure, make, and make install commands
• If students have not compiled in the past, it is common to not have all of the required libraries and modules already installed for the compilation process to succeed. This is a major part of creating RPM's. This setup takes time to troubleshoot and setup, and it could be different on each system if students are not using identical operating systems.

If you wanted to do this activity in Ubuntu, Debian, etc:

• Students could optionally do this activity on Ubuntu or other Linux OS's which use a different Package Management toolset.
• Ubuntu is debian-based and uses the ``dpkg`` command. For more info on equivalent commands, see:
  • http://wiki.openvz.org/Package_managers
  • http://askubuntu.com/questions/85839/deb-equivalents-to-rpm-commands/85849

What are some likely difficulties that an instructor may encounter using this activity?

Additional Information:

Suggestions for Open Source Community:

Suggestions for an open source community member who is working in conjunction with the instructor:

• Why did your community decide to standardize on the autotools-based config/make building? Or, why not?
• Explain to students why packaging skills can be used on many open source linux-based projects, across their careers.
• Help students through the often-confusing build process
• Help students to find alternate examples to step through - aka, finding project code other than the ones listed above and making it into an RPM.

This work is licensed under a Creative Commons Attribution 4.0 International License

Appendix

Consider breaking these additional steps into a new activity

1. Have students host the package on a web source (ftp? Some free internet service that makes the .rpm accessible by URL)
   • Package Repo location
     • http://copr.fedorainfracloud.org - Use this for students to make their own packages and repositories
     • https://fedorahosted.org/copr/ - The actual community / project page where user manuals and developer resources exist
2. Have each student in the class pair up and try to install the other person's RPM and run the new command

Ideas on what to create into an RPM:

• screen
• htop
• from http://www.tecmint.com/command-line-tools-to-monitor-linux-performance/

Other readings:

• https://wiki.archlinux.org/index.php/Arch_User_Repository
• https://wiki.archlinux.org/index.php/Arch_packaging_standards
• https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#Writing_a_package_from_scratch