Making an empty RPM

I am definitely not an RPM expert, in fact, I’m afraid of it, but with recent tools such as COPR, and my glorious Makefile, some aspects of it have become palatable. This post will be about a recent journey I had building the most useless RPM ever.

A video of my journey building this RPM.

Because of reasons, I wanted to satisfy an RPM dependency for a package that I wanted to install without rebuilding that RPM. As a result, I wanted to build as small an RPM as possible. This took me down a much longer path than I thought it would.

Step 1: The empty spec file

I thought this would be easy. It turns out it was not. Here’s what happened…

james@computer:/tmp/rpmbuild$ cat vagrant-libvirt.spec
%global project_version 0.0.24

Name:       vagrant-libvirt
Version:    0.0.24
Release:    noop
Summary:    A fake vagrant-libvirt RPM
License:    AGPLv3+
BuildArch:  noarch

Requires:   vagrant >= 1.6.5

%description
A fake vagrant-libvirt RPM

%prep
%setup -c -q -T -D -a 0

%build

%install

%files

%changelog
james@computer:/tmp/rpmbuild$ rpmbuild -bs vagrant-libvirt.spec 
error: No "Source:" tag in the spec file

Amazingly, rpmbuild fails to build without specifying a Source0 directive. Gah… As an aside, yes the License field was also required, or it won’t build either! So let’s create a dummy RPM to use as the source!

Step 2: The empty tarball

james@computer:/tmp/rpmbuild$ tar -cjf vagrant-libvirt-noop.tar.bz2
tar: Cowardly refusing to create an empty archive
Try 'tar --help' or 'tar --usage' for more information.

Apparently tar doesn’t want to cooperate either! Maybe these utilities have some sort of ingrained existential fear of nothingness? I can work around this though.

Step 3: The empty file

james@computer:/tmp/rpmbuild$ echo hello > README
james@computer:/tmp/rpmbuild$ tar -cjf vagrant-libvirt-noop.tar.bz2 README
james@computer:/tmp/rpmbuild$ echo $?
0
james@computer:/tmp/rpmbuild$ cat vagrant-libvirt.spec
%global project_version 0.0.24

Name:       vagrant-libvirt
Version:    0.0.24
Release:    noop
Summary:    A fake vagrant-libvirt RPM
License:    AGPLv3+
Source0:    vagrant-libvirt-noop.tar.bz2
BuildArch:  noarch

Requires:   vagrant >= 1.6.5

%description
A fake vagrant-libvirt RPM

%prep
%setup -c -q -T -D -a 0

%build

%install

%files

%changelog

Okay great! Now to build the RPM…

Step 4: The empty RPM

james@computer:/tmp/rpmbuild$ mkdir SOURCES
james@computer:/tmp/rpmbuild$ mv vagrant-libvirt-noop.tar.bz2 SOURCES/
james@computer:/tmp/rpmbuild$ rpmbuild --define "_topdir $(pwd)/" -bs vagrant-libvirt.spec
Wrote: /tmp/rpmbuild/SRPMS/vagrant-libvirt-0.0.24-noop.src.rpm
james@computer:/tmp/rpmbuild$ rpmbuild --define "_topdir $(pwd)/" -bb vagrant-libvirt.spec
Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.dUivHv
+ umask 022
+ cd /tmp/rpmbuild//BUILD
+ cd /tmp/rpmbuild/BUILD
+ /usr/bin/mkdir -p vagrant-libvirt-0.0.24
+ cd vagrant-libvirt-0.0.24
+ /usr/bin/bzip2 -dc /tmp/rpmbuild/SOURCES/vagrant-libvirt-noop.tar.bz2
+ /usr/bin/tar -xf -
+ STATUS=0
+ '[' 0 -ne 0 ']'
+ /usr/bin/chmod -Rf a+rX,u+w,g-w,o-w .
+ exit 0
Executing(%build): /bin/sh -e /var/tmp/rpm-tmp.kLSHn2
+ umask 022
+ cd /tmp/rpmbuild//BUILD
+ cd vagrant-libvirt-0.0.24
+ exit 0
Executing(%install): /bin/sh -e /var/tmp/rpm-tmp.xTiM4y
+ umask 022
+ cd /tmp/rpmbuild//BUILD
+ '[' /tmp/rpmbuild/BUILDROOT/vagrant-libvirt-0.0.24-noop.x86_64 '!=' / ']'
+ rm -rf /tmp/rpmbuild/BUILDROOT/vagrant-libvirt-0.0.24-noop.x86_64
++ dirname /tmp/rpmbuild/BUILDROOT/vagrant-libvirt-0.0.24-noop.x86_64
+ mkdir -p /tmp/rpmbuild/BUILDROOT
+ mkdir /tmp/rpmbuild/BUILDROOT/vagrant-libvirt-0.0.24-noop.x86_64
+ cd vagrant-libvirt-0.0.24
+ /usr/lib/rpm/find-debuginfo.sh --strict-build-id -m --run-dwz --dwz-low-mem-die-limit 10000000 --dwz-max-die-limit 110000000 /tmp/rpmbuild//BUILD/vagrant-libvirt-0.0.24
/usr/lib/rpm/sepdebugcrcfix: Updated 0 CRC32s, 0 CRC32s did match.
+ /usr/lib/rpm/check-rpaths /usr/lib/rpm/check-buildroot
+ /usr/lib/rpm/brp-compress
+ /usr/lib/rpm/brp-strip-static-archive /usr/bin/strip
+ /usr/lib/rpm/brp-python-bytecompile /usr/bin/python 1
+ /usr/lib/rpm/brp-python-hardlink
+ /usr/lib/rpm/redhat/brp-java-repack-jars
Processing files: vagrant-libvirt-0.0.24-noop.noarch
Checking for unpackaged file(s): /usr/lib/rpm/check-files /tmp/rpmbuild/BUILDROOT/vagrant-libvirt-0.0.24-noop.x86_64
Wrote: /tmp/rpmbuild/RPMS/noarch/vagrant-libvirt-0.0.24-noop.noarch.rpm
Executing(%clean): /bin/sh -e /var/tmp/rpm-tmp.0lR0a6
+ umask 022
+ cd /tmp/rpmbuild//BUILD
+ cd vagrant-libvirt-0.0.24
+ /usr/bin/rm -rf /tmp/rpmbuild/BUILDROOT/vagrant-libvirt-0.0.24-noop.x86_64
+ exit 0
james@computer:/tmp/rpmbuild$

This worked too! It has some interesting output though…

james@computer:/tmp/rpmbuild$ rpm -qlp RPMS/noarch/vagrant-libvirt-0.0.24-noop.noarch.rpm
(contains no files)
james@computer:/tmp/rpmbuild$ ls -lAh RPMS/noarch/vagrant-libvirt-0.0.24-noop.noarch.rpm
-rw-rw-r--. 1 james 5.5K Aug 11 11:53 RPMS/noarch/vagrant-libvirt-0.0.24-noop.noarch.rpm
james@computer:/tmp/rpmbuild$

As you can see this has created an empty RPM, but which is about 5k in size. While this worked, builds submitted in COPR don’t generate any output. I suppose this is a bug in COPR, but in the meantime, I still wanted something working. I added some nonsense to the spec file to continue.

Step 5: The final product

james@computer:/tmp/rpmbuild$ cat vagrant-libvirt.spec 
%global project_version 0.0.24

Name:       vagrant-libvirt
Version:    0.0.24
Release:    noop
Summary:    A fake vagrant-libvirt RPM
License:    AGPLv3+
Source0:    vagrant-libvirt-noop.tar.bz2
BuildArch:  noarch

Requires:   vagrant >= 1.6.5

%description
A fake vagrant-libvirt RPM

%prep
%setup -c -q -T -D -a 0

%build

%install
rm -rf %{buildroot}
# _datadir is typically /usr/share/
install -d -m 0755 %{buildroot}/%{_datadir}/vagrant-libvirt/
echo "This is a phony vagrant-libvirt package." > %{buildroot}/%{_datadir}/vagrant-libvirt/README

%files
%{_datadir}/vagrant-libvirt/README

%changelog

After running the usual build commands, and sticking an SRPM up in COPR, this builds and installs as expected! Phew! There might a manual way to do this with cpio, but I wanted to use the official tools, and avoid hacking the spec.

Perhaps there is a simpler way to workaround all of this, but until I find it, I hope you’ve enjoyed my story,

Happy Hacking!

James

UPDATE: Reader Jan pointed out, that you could use fpm to accomplish the same thing with a one-liner. The modified one-liner is:

fpm -s empty -t rpm -d 'vagrant >= 1.6.5' -n vagrant-libvirt -v 0.0.24 --iteration noop

This is a much shorter and more elegant solution, with the one exception that fpm doesn’t currently produce SRPMS, which are needed so that a trusted build service like COPR distributes them to the users.

Here’s the full output and comparison and anyways:

james@computer:/tmp/ftest$ fpm -s empty -t rpm -d 'vagrant >= 1.6.5' -n vagrant-libvirt -v 0.0.24 --iteration noop
no value for epoch is set, defaulting to nil {:level=>:warn}
no value for epoch is set, defaulting to nil {:level=>:warn}
Created package {:path=>"vagrant-libvirt-0.0.24-noop.x86_64.rpm"}
james@computer:/tmp/ftest$ sha1sum vagrant-libvirt-0.0.24-noop.x86_64.rpm 61b1c200d2efa87d790a2243ccbc4c4ebb7ef64d  vagrant-libvirt-0.0.24-noop.x86_64.rpm
james@computer:/tmp/ftest$ sha1sum ~/code/oh-my-vagrant/extras/.rpmbuild/RPMS/noarch/vagrant-libvirt-0.0.24-noop.noarch.rpm 
5f2abb15264de6c1c7f09039945cd7bbd3a96404  /home/james/code/oh-my-vagrant/extras/.rpmbuild/RPMS/noarch/vagrant-libvirt-0.0.24-noop.noarch.rpm

While the two sha1sums aren’t identical (probably due to timestamps or some other variant) the two RPM’s should be functionally identical.

Git archive with submodules and tar magic

Git submodules are actually a very beautiful thing. You might prefer the word powerful or elegant, but that’s not the point. The downside is that they are sometimes misused, so as always, use with care. I’ve used them in projects like puppet-gluster, oh-my-vagrant, and others. If you’re not familiar with them, do a bit of reading and come back later, I’ll wait.

I recently did some work packaging Oh-My-Vagrant as RPM’s. My primary goal was to make sure the entire process was automatic, as I have no patience for manually building RPM’s. Any good packager knows that the pre-requisite for building a SRPM is a source tarball, and I wanted to build those automatically too.

Simply running a tar -cf on my source directory wouldn’t work, because I only want to include files that are stored in git. Thankfully, git comes with a tool called git archive, which does exactly that! No scary tar commands required:

Nobody likes tar

Here’s how you might run it:

$ git archive --prefix=some-project/ -o output.tar.bz2 HEAD

Let’s decompose:

The --prefix argument prepends a string prefix onto every file in the archive. Therefore, if you’d like the root directory to be named some-project, then you prepend that string with a trailing slash, and you’ll have everything nested inside a directory!

The -o flag predictably picks the output file and format. Using .tar.bz2 is quite common.

Lastly, the HEAD portion at the end specifies which git tree to pull the files from. I usually specify a git tag here, but you can specify a commit id if you prefer.

Obligatory, “make this article more interesting” meme image.

This is all well and good, but unfortunately, when I open my newly created archive, it is notably missing my git submodules! It would probably make sense for there to be an upstream option so that a --recursive flag would do this magic for you, but unfortunately it doesn’t exist yet.

There are a few scripts floating around that can do this, but I wanted something small, and without any real dependencies, that I can embed in my project Makefile, so that it’s all self-contained.

Here’s what that looks like:

sometarget:
    @echo Running git archive...
    # use HEAD if tag doesn't exist yet, so that development is easier...
    git archive --prefix=oh-my-vagrant-$(VERSION)/ -o $(SOURCE) $(VERSION) 2> /dev/null || (echo 'Warning: $(VERSION) does not exist.' && git archive --prefix=oh-my-vagrant-$(VERSION)/ -o $(SOURCE) HEAD)
    # TODO: if git archive had a --submodules flag this would easier!
    @echo Running git archive submodules...
    # i thought i would need --ignore-zeros, but it doesn't seem necessary!
    p=`pwd` && (echo .; git submodule foreach) | while read entering path; do \
        temp="$${path%\'}"; \
        temp="$${temp#\'}"; \
        path=$$temp; \
        [ "$$path" = "" ] && continue; \
        (cd $$path && git archive --prefix=oh-my-vagrant-$(VERSION)/$$path/ HEAD > $$p/rpmbuild/tmp.tar && tar --concatenate --file=$$p/$(SOURCE) $$p/rpmbuild/tmp.tar && rm $$p/rpmbuild/tmp.tar); \
    done

This is a bit tricky to read, so I’ll try to break it down. Remember, double dollar signs are used in Make syntax for embedded bash code since a single dollar sign is a special Make identifier. The $(VERSION) variable corresponds to the version of the project I’m building, which matches a git tag that I’ve previously created. $(SOURCE) corresponds to an output file name, ending in the .tar.bz2 suffix.

    p=`pwd` && (echo .; git submodule foreach) | while read entering path; do \

In this first line, we store the current working directory for use later, and then loop through the output of the git submodule foreach command. That output normally looks something like this:

james@computer:~/code/oh-my-vagrant$ git submodule foreach 
Entering 'vagrant/gems/xdg'
Entering 'vagrant/kubernetes/templates/default'
Entering 'vagrant/p4h'
Entering 'vagrant/puppet/modules/module-data'
Entering 'vagrant/puppet/modules/puppet'
Entering 'vagrant/puppet/modules/stdlib'
Entering 'vagrant/puppet/modules/yum'

As you can see, this shows that the above read command, eats up the Entering string, and pulls the quoted path into the second path variable. The next part of the code:

        temp="$${path%\'}"; \
        temp="$${temp#\'}"; \
        path=$$temp; \
        [ "$$path" = "" ] && continue; \

uses bash idioms to remove the two single quotes that wrap our string, and then skip over any empty versions of the path variable in our loop. Lastly, for each submodule found, we first switch into that directory:

        (cd $$path &&

Run a normal git archive command and create a plain uncompressed tar archive in a temporary directory:

git archive --prefix=oh-my-vagrant-$(VERSION)/$$path/ HEAD > $$p/rpmbuild/tmp.tar &&

Then use the magic of tar to overlay this new tar file, on top of the source file that we’re now building up with each iteration of this loop, and then remove the temporary file.

tar --concatenate --file=$$p/$(SOURCE) $$p/rpmbuild/tmp.tar && rm $$p/rpmbuild/tmp.tar); \

Finally, we end the loop:

    done

Boom, magic! Short, concise, and without any dependencies but bash and git.

Nobody should have to figure that out by themselves, and I wish it was built in to git, but until then, here’s how it’s done! Many thanks to #git on IRC for pointing me in the right direction.

This is the commit where I landed this patch for oh-my-vagrant, if you’re curious to see this in the wild. Now that this is done, I can definitely say that it was worth the time:

Is it worth the time? In this case, it was.

With this feature merged, along with my automatic COPR builds, a simple ‘make rpm‘, causes all of this automation to happen, and delivers a fresh build from git in a few minutes.

I hope you enjoyed this technique, and I hope you have some coding skills to get this feature upstream in git.

Happy Hacking,

James

Oh-My-Vagrant “Mainstream” mode and COPR RPM’s

Making Oh-My-Vagrant (OMV) more developer accessible and easy to install (from a distribution package like RPM) has always been a goal, but was previously never a priority. This is all sorted out now. In this article, I’ll explain how “mainstream” mode works, and how the RPM work was done. (I promise this will be somewhat interesting!)

Prerequisites:

If you haven’t read any of the previous articles about Oh-My-Vagrant, I’d recommend you start there. Many of the articles include screencasts, and combined with the examples/ folder, this is probably the best way to learn OMV, because the documentation could use some love.

Installation:

OMV is now easily installable on Fedora 22 via COPR. It probably works on other distros and versions, but I haven’t tested all of those combinations. This is a colossal improvement from when I first posted about this publicly in 2013. There is still one annoying bug that I occasionally hit. Let me know if you can reproduce.

Install from COPR:

james@computer:~$ sudo dnf copr enable purpleidea/oh-my-vagrant

You are about to enable a Copr repository. Please note that this
repository is not part of the main Fedora distribution, and quality
may vary.

The Fedora Project does not exercise any power over the contents of
this repository beyond the rules outlined in the Copr FAQ at
, and
packages are not held to any quality or security level.

Please do not file bug reports about these packages in Fedora
Bugzilla. In case of problems, contact the owner of this repository.

Do you want to continue? [y/N]: y
Repository successfully enabled.
james@computer:~$ sudo dnf install oh-my-vagrant
Last metadata expiration check performed 0:05:08 ago on Tue Jul  7 22:58:45 2015.
Dependencies resolved.
================================================================================
 Package           Arch     Version            Repository                  Size
================================================================================
Installing:
 oh-my-vagrant     noarch   0.0.7-1            purpleidea-oh-my-vagrant   270 k
 vagrant           noarch   1.7.2-7.fc22       updates                    428 k
 vagrant-libvirt   noarch   0.0.26-2.fc22      fedora                      57 k

Transaction Summary
================================================================================
Install  3 Packages

Total download size: 755 k
Installed size: 2.5 M
Is this ok [y/N]: n
Operation aborted.
james@computer:~$ sudo dnf install -y oh-my-vagrant
Last metadata expiration check performed 0:05:19 ago on Tue Jul  7 22:58:45 2015.
Dependencies resolved.
================================================================================
 Package           Arch     Version            Repository                  Size
================================================================================
Installing:
 oh-my-vagrant     noarch   0.0.7-1            purpleidea-oh-my-vagrant   270 k
 vagrant           noarch   1.7.2-7.fc22       updates                    428 k
 vagrant-libvirt   noarch   0.0.26-2.fc22      fedora                      57 k

Transaction Summary
================================================================================
Install  3 Packages

Total download size: 755 k
Installed size: 2.5 M
Downloading Packages:
(1/3): vagrant-1.7.2-7.fc22.noarch.rpm          626 kB/s | 428 kB     00:00    
(2/3): vagrant-libvirt-0.0.26-2.fc22.noarch.rpm  70 kB/s |  57 kB     00:00    
(3/3): oh-my-vagrant-0.0.7-1.noarch.rpm         243 kB/s | 270 kB     00:01    
--------------------------------------------------------------------------------
Total                                           246 kB/s | 755 kB     00:03     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Installing  : vagrant-1.7.2-7.fc22.noarch                                 1/3 
  Installing  : vagrant-libvirt-0.0.26-2.fc22.noarch                        2/3 
  Installing  : oh-my-vagrant-0.0.7-1.noarch                                3/3 
  Verifying   : oh-my-vagrant-0.0.7-1.noarch                                1/3 
  Verifying   : vagrant-libvirt-0.0.26-2.fc22.noarch                        2/3 
  Verifying   : vagrant-1.7.2-7.fc22.noarch                                 3/3 

Installed:
  oh-my-vagrant.noarch 0.0.7-1                vagrant.noarch 1.7.2-7.fc22       
  vagrant-libvirt.noarch 0.0.26-2.fc22       

Complete!
james@computer:~$

If you’d like to avoid typing passwords over and over again when using vagrant, you can add yourself into the vagrant group. 99% of people do this. The downside is that it could allow your user account to get root privileges. Since most developers have a single user environment, it’s not a big issue. This is necessary because vagrant uses the qemu:///system connection instead of qemu:///session. If you can help fix this, please hack on it.

james@computer:~$ groups
james wheel docker
james@computer:~$ sudo usermod -aG vagrant james
# you'll need to logout/login for this change to take effect...

Lastly, there is a user session plugin addition that is required. Installation is automatic the first time you create a new OMV project. Let’s do that and see how it works!

james@computer:~$ mkdir /tmp/omvtest
james@computer:~$ cd !$
cd /tmp/omvtest
james@computer:/tmp/omvtest$ which omv
/usr/bin/omv
james@computer:/tmp/omvtest$ omv init
Oh-My-Vagrant needs to install a modified vagrant-hostmanager plugin.
Is this ok [y/N]: y
Cloning into 'vagrant-hostmanager'...
remote: Counting objects: 801, done.
remote: Total 801 (delta 0), reused 0 (delta 0), pack-reused 801
Receiving objects: 100% (801/801), 132.22 KiB | 0 bytes/s, done.
Resolving deltas: 100% (467/467), done.
Checking connectivity... done.
Branch feat/oh-my-vagrant set up to track remote branch feat/oh-my-vagrant from origin.
Switched to a new branch 'feat/oh-my-vagrant'
sending incremental file list
./
vagrant-hostmanager.rb
vagrant-hostmanager/
vagrant-hostmanager/action.rb
vagrant-hostmanager/command.rb
vagrant-hostmanager/config.rb
vagrant-hostmanager/errors.rb
vagrant-hostmanager/plugin.rb
vagrant-hostmanager/provisioner.rb
vagrant-hostmanager/util.rb
vagrant-hostmanager/version.rb
vagrant-hostmanager/action/
vagrant-hostmanager/action/update_all.rb
vagrant-hostmanager/action/update_guest.rb
vagrant-hostmanager/action/update_host.rb
vagrant-hostmanager/hosts_file/
vagrant-hostmanager/hosts_file/updater.rb

sent 20,560 bytes  received 286 bytes  41,692.00 bytes/sec
total size is 19,533  speedup is 0.94
Patched successfully!
Current machine states:

omv1                      not created (libvirt)

The Libvirt domain is not created. Run `vagrant up` to create it.
james@computer:/tmp/omvtest$ ls
ansible/  docker/  kubernetes/  omv.yaml  puppet/  shell/
james@computer:/tmp/omvtest$

You can see that the plugin installation worked perfectly, and that OMV created a few files and folders.

More usage:

You can hide that generated mess in a subfolder if you prefer:

james@computer:/tmp/omvtest$ mkdir /tmp/omvtest2
james@computer:/tmp/omvtest$ cd !$
cd /tmp/omvtest2
james@computer:/tmp/omvtest2$ omv init mess
Current machine states:

omv1                      not created (libvirt)

The Libvirt domain is not created. Run `vagrant up` to create it.
james@computer:/tmp/omvtest2$ ls
mess/  omv.yaml@
james@computer:/tmp/omvtest2$ ls -lAh
total 0
drwxrwxr-x. 7 james 160 Jul  7 23:26 mess/
lrwxrwxrwx. 1 james  13 Jul  7 23:26 omv.yaml -> mess/omv.yaml
drwxrwxr-x. 3 james  60 Jul  7 23:26 .vagrant/
james@computer:/tmp/omvtest2$ tree
.
├── mess
│   ├── ansible
│   │   └── modules
│   ├── docker
│   ├── kubernetes
│   │   ├── applications
│   │   └── templates
│   ├── omv.yaml
│   ├── puppet
│   │   └── modules
│   └── shell
└── omv.yaml -> mess/omv.yaml

10 directories, 2 files
james@computer:/tmp/omvtest2$

As you can see all the mess is wrapped up in a single folder. This could even be named .omv if you prefer, and should all be committed inside of your project. Now that we’re installed, let’s get hacking!

Mainstream mode:

Mainstream mode further hides the ruby/Vagrantfile aspect of a Vagrant project and extends OMV so that you can define your entire project via the omv.yaml file, without the rest of the OMV project cluttering up your development tree. This makes it possible to have your project use OMV by only committing that one yaml file into the project repo.

The main difference is that you now control everything with the new omv command line tool. It’s essentially a smart wrapper around the vagrant command, so any command you used to use vagrant for, you can now substitute in omv. It also saves typing four extra characters!

As it turns out (and by no accident) the omv tool works exactly like the vagrant tool. For example:

james@computer:/tmp/omvtest2$ omv status
Current machine states:

omv1                      not created (libvirt)

The Libvirt domain is not created. Run `vagrant up` to create it.
james@computer:/tmp/omvtest2$ omv up
Bringing machine 'omv1' up with 'libvirt' provider...
==> omv1: Box 'centos-7.1' could not be found. Attempting to find and install...
    omv1: Box Provider: libvirt
    omv1: Box Version: >= 0
==> omv1: Adding box 'centos-7.1' (v0) for provider: libvirt
    omv1: Downloading: https://dl.fedoraproject.org/pub/alt/purpleidea/vagrant/centos-7.1/centos-7.1.box
[snip]
james@computer:/tmp/omvtest2$ omv destroy
Unlocking shell provisioning for: omv1...
==> omv1: Domain is not created. Please run `vagrant up` first.
james@computer:/tmp/omvtest2$

BUT THAT’S NOT ALL…

The existing tools you know and love, like vlog, vsftp, vscreen, vcssh, vfwd, vansible, have all been modified to work with OMV mainstream mode as well. The same goes for common aliases such as vs, vp, vup, vdestroy, vrsync, and the useful (but occasionally dangerous) vrm-rf. Have a look at the above links on my blog and the source to see what these do. If it’s not clear enough, let me know!

All of these are now packaged up in the oh-my-vagrant COPR and are installed automatically into /etc/profile.d/oh-my-vagrant.sh for your convenience. Since they’re part of the OMV project, you’ll get updates when new functions or bug fixes are made.

The plumbing:

Mainstream mode is possible because of an idea rbarlow had. He gets full credit for the idea, in particular for teaching me about VAGRANT_CWD which is what makes it all work. I rejected his 6 line prototype, but loved the idea, and since he was busy making juice, I got bored one day and hacked on a full implementation.

james@computer:~/code/oh-my-vagrant$ git diff --stat 853073431d227cbb0ba56aaf4fedd721904de9a8 aa764ae79d69475b87f293c43af4f20fd7d1d000
 DOCUMENTATION.md    | 18 +++++++++++++++
 bin/omv.sh          | 50 +++++++++++++++++++++++++++++++++++++++++
 vagrant/Vagrantfile | 65 ++++++++++++++++++++++++++++++++++-------------------
 3 files changed, 110 insertions(+), 23 deletions(-)
james@computer:~/code/oh-my-vagrant$

It turned out it was a little longer, but I artificially inflated this by including some quick doc patches. What does it actually do differently? It sets VAGRANT_CWD and VAGRANT_DOTFILE_PATH so that the vagrant command looks in a different directory for the Vagrantfile and .vagrant/ directories. That way, all the plumbing is hidden and part of the RPM.

Making the RPM:

The RPM’s happened because stefw made me feel bad about not having them. He was right to do so. In an case, RPM packaging still scares me. I think repetitive work scares me even more. That’s why I automate as much as I can. So after a lot of brain loss, I finally made you an RPM so that you could easily install it. Here’s how it went:

I started by adding the magic so that my Makefile could build an RPM.

This made it so I can easily run make srpm to get a new RPM or SRPM.

Then I added COPR integration, so a make copr automatically kicks off a new COPR build. This was the interesting part. You’ll need a Fedora account for this to work. Once you’re logged in, if you go to https://copr.fedoraproject.org/api you’ll be able to download a snippet to put in your ~/.config/copr file. Lastly, the work happens in copr-build.py where the python copr library does the heavy lifting.

#!/usr/bin/python

# README:
# for initial setup, browse to: https://copr.fedoraproject.org/api/
# and it will have a ~/.config/copr config that you can download.
# happy hacking!

import os
import sys
import copr

COPR = 'oh-my-vagrant'
if len(sys.argv) != 2:
    print("Usage: %s <srpm url>" % sys.argv[0])
    sys.exit(1)

url = sys.argv[1]

client = copr.CoprClient.create_from_file_config(os.path.expanduser("~/.config/copr"))

result = client.create_new_build(COPR, [url])
if result.output != "ok":
    print(result.error)
    sys.exit(1)
print(result.message)

A build looks like this:

james@computer:~/code/oh-my-vagrant$ git tag 0.0.8 # set a new tag
james@computer:~/code/oh-my-vagrant$ make copr 
Running templater...
Running git archive...
Running git archive submodules...
Running rpmbuild -bs...
Wrote: /home/james/code/oh-my-vagrant/rpmbuild/SRPMS/oh-my-vagrant-0.0.8-1.src.rpm
Running SRPMS sha256sum...
/home/james/code/oh-my-vagrant
Running SRPMS gpg...

You need a passphrase to unlock the secret key for
user: "James Shubin (Third PGP key.) <james@shubin.ca>"
4096-bit RSA key, ID 24090D66, created 2012-05-09

gpg: WARNING: The GNOME keyring manager hijacked the GnuPG agent.
gpg: WARNING: GnuPG will not work properly - please configure that tool to not interfere with the GnuPG system!
Running SRPMS upload...
sending incremental file list
SHA256SUMS
SHA256SUMS.asc
oh-my-vagrant-0.0.8-1.src.rpm

sent 8,583 bytes  received 2,184 bytes  4,306.80 bytes/sec
total size is 1,456,741  speedup is 135.30
Build was added to oh-my-vagrant.
james@computer:~/code/oh-my-vagrant$

A few minutes later, the COPR build page should look like this:

A screenshot of the Oh-My-Vagrant COPR build page for people who like to look at pretty pictures instead of just terminal output.

There was a bunch of additional fixing and polishing required to get this as seamless as possible for you. Have a look at the git commits and you’ll get an idea of all the work that was done, and you’ll probably even learn about some new, features I haven’t blogged about yet. It was exhausting!

As a result of all this, you can download fresh builds easily. Visit the COPR page to see how things are cooking:

https://copr.fedoraproject.org/coprs/purpleidea/oh-my-vagrant/

I’ll try to keep this pumping out releases regularly. If I lag behind, please holler at me. In any case, please let me know if you appreciate this work. Comment, tweeter, or contact me!

Happy Hacking,

James

Building base images for Vagrant with a Makefile

I needed a base image “box” for my Puppet-Gluster+Vagrant work. It would have been great if good boxes already existed, and even better if it were easy to build my own. As it turns out, I wasn’t able to satisfy either of these conditions, so I’ve had to build one myself! I’ve published all of my code, so that you can use these techniques and tools too!

Status quo:

Having an NIH problem is bad for your vision, and it’s best to benefit from existing tools before creating your own. I first tried using vagrant-cachier, and then veewee, and packer. Vagrant-cachier is a great tool, but it turned out not being very useful because there weren’t any base images available for download that met my needs. Veewee and packer can build those images, but they both failed in doing so for different reasons. Hopefully this situation will improve in the future.

Writing a script:

I started by hacking together a short shell script of commands for building base images. There wasn’t much programming involved as the process was fairly linear, but it was useful to figure out what needed getting done.

I decided to use the excellent virt-builder command to put together the base image. This is exactly what it’s good at doing! To install it on Fedora 20, you can run:

$ sudo yum install libguestfs-tools

It wasn’t available in Fedora 19, but after a lot of pain, I managed to build (mostly correct?) packages. I have posted them online if you are brave (or crazy?) enough to want them.

Using the right tool:

After building a few images, I realized that a shell script was the wrong tool, and that it was time for an upgrade. What was the right tool? GNU Make! After working on this for more hours than I’m ready to admit, I present to you, a lovingly crafted virtual machine base image (“box”) builder:

Makefile

The Makefile itself is quite compact. It uses a few shell scripts to do some of the customization, and builds a clean image in about ten minutes. To use it, just run make.

Customization:

At the moment, it builds x86_64, CentOS 6.5+ machines for vagrant-libvirt, but you can edit the Makefile to build a custom image of your choosing. I’ve gone out of my way to add an $(OUTPUT) variable to the Makefile so that your generated files get saved in /tmp/ or somewhere outside of your source tree.

Download the image:

If you’d like to download the image that I generated, it is being generously hosted by the Gluster community here. If you’re using the Vagrantfile from my Puppet-Gluster+Vagrant setup, then you don’t have to download it manually, this will happen automatically.

Open issues:

The biggest issue with the images is that SELinux gets disabled! You might be okay with this, but it’s actually quite unfortunate. It is disabled to avoid the SELinux relabelling that happens on first boot, as this overhead defeats the usefulness of a fast vagrant deployment. If you know of a way to fix this problem, please let me know!

Example output:

If you’d like to see this in action, but don’t want to run it yourself, here’s an example run:

$ date && time make && date
Mon Jan 20 10:57:35 EST 2014
Running templater...
Running virt-builder...
[   1.0] Downloading: http://libguestfs.org/download/builder/centos-6.xz
[   4.0] Planning how to build this image
[   4.0] Uncompressing
[  19.0] Resizing (using virt-resize) to expand the disk to 40.0G
[ 173.0] Opening the new disk
[ 181.0] Setting a random seed
[ 181.0] Setting root password
[ 181.0] Installing packages: screen vim-enhanced git wget file man tree nmap tcpdump htop lsof telnet mlocate bind-utils koan iftop yum-utils nc rsync nfs-utils sudo openssh-server openssh-clients
[ 212.0] Uploading: files/epel-release-6-8.noarch.rpm to /root/epel-release-6-8.noarch.rpm
[ 212.0] Uploading: files/puppetlabs-release-el-6.noarch.rpm to /root/puppetlabs-release-el-6.noarch.rpm
[ 212.0] Uploading: files/selinux to /etc/selinux/config
[ 212.0] Deleting: /.autorelabel
[ 212.0] Running: yum install -y /root/epel-release-6-8.noarch.rpm && rm -f /root/epel-release-6-8.noarch.rpm
[ 214.0] Running: yum install -y bash-completion moreutils
[ 235.0] Running: yum install -y /root/puppetlabs-release-el-6.noarch.rpm && rm -f /root/puppetlabs-release-el-6.noarch.rpm
[ 239.0] Running: yum install -y puppet
[ 254.0] Running: yum update -y
[ 375.0] Running: files/user.sh
[ 376.0] Running: files/ssh.sh
[ 376.0] Running: files/network.sh
[ 376.0] Running: files/cleanup.sh
[ 377.0] Finishing off
Output: /home/james/tmp/builder/gluster/builder.img
Output size: 40.0G
Output format: qcow2
Total usable space: 38.2G
Free space: 37.3G (97%)
Running convert...
Running tar...
./Vagrantfile
./metadata.json
./box.img

real	9m10.523s
user	2m23.282s
sys	0m37.109s
Mon Jan 20 11:06:46 EST 2014
$

If you have any other questions, please let me know!

Happy hacking,

James

PS: Be careful when writing Makefile‘s. They can be dangerous if used improperly, and in fact I once took out part of my lib/ directory by running one. Woops!

UPDATE: This technique now exists in it’s own repo here: https://github.com/purpleidea/vagrant-builder

scary cool bash scripting inside a Makefile

Makefiles are both scary and wonderful. When both these adjectives are involved, it often makes for interesting hacking. This is likely the reason I use bash.

In any case, I digress, back to real work. I use Makefiles as a general purpose tool to launch any of a number of shell scripts which I use to maintain my code, and instead of actually having external shell scripts, I just build any necessary bash right into the Makefile.

One benefit of all this is that when you type “Make <target>”, the <target> can actually autocomplete which makes your shell experience that much more friendly.

In any case, let me show you the code in question. Please note the double $$ for shell execution and for variable referencing. The calls to rsync and sort make me pleased.

rsync -avz --include=*$(EXT) --exclude='*' --delete dist/ $(WWW)
# empty the file
echo -n '' > $(METADATA)
cd $(WWW);
for i in *$(EXT); do
b=$$(basename $$i $(EXT));
V=$$(echo -n $$(basename "`echo -n "$$b" | rev`"
"`echo -n "$(NAME)-" | rev`") | rev);
echo $(NAME) $$V $$i >> $(METADATA);
done;
sort -V -k 2 -o $(METADATA) $(METADATA) # sort by version key


The full Makefile can be found inside of the bash-tutor tarball.

why linux is powerful or: how to erase half your system and then fix it

after a brief bout of stupidity i quickly realized that my makefile had gone awry and was quickly eating through my filesystem.

after ^C killing it, it seems i only took out most of /lib/* and /usr/sbin/* — who needs those anyways… apparently almost everyone.

what happened next. well it turns out i was lucky and had a few shells and a webbrowser open– attempts to launch new programs will fail, but existing programs are already loaded in memory so i was able to work.

since almost everything was broken, i first had to get dpkg and apt/apt-utils going again. after much anguish, i manually installed the missing library files and binaries from http://packages.ubuntu.com/ and i was on my way with apt.

if you’re manually installing files from .deb’s use:
dpkg -x <package_file.deb> outputfolder/

which will let you get in and use mv and cp to put back the missing .so files.
once some basic tools were working, you can try and fix up your tool chain doing things like:
sudo apt-get --reinstall install <package_name>

it’s good to do this to apt-utils, dpkg, and whatever other utilities are throwing library errors. the packages themselves need various utilities installed, and as you get a missing abc.so file, find out what package it needs with:
dpkg -S <filename>

my apt seems to be back, but many utilities still aren’t. finding out what should go in /lib was a little harder but i was able to get a list of packages like this:

(find out what *should* be installed)
dpkg --get-selections > installed-software

(list which files come from these packages, sort and uniq it)
dpkg -L `cat installed-software` | sort | uniq > uniq-software

(find what we deleted)
cat uniq-software | grep ^/lib/ > missing-software

(which packages does this come from, sort and uniq it. (might get too long argument list))
dpkg -S `cat missing-software` > package-list

(find the package name by itself, get rid of the colons, sort, uniq)
cat package-list | awk '{print $1}' | sed -e 's/://' | sed -e 's/,//' | sort | uniq > reinstall-me

(do the reinstall)
sudo apt-get --reinstall install `cat reinstall-me`

at the moment this is running, and i luckily had a cd lying around to help speed up the process. use:
apt-cdrom add

(with the cd in the drive) to add it to your /etc/apt/sources.list

turns out this eventually failed with some obscure errors… it ultimately might be a more concise list if you know what got killed, but i think the sheer number of packages i messed up and that needed to get updated somehow confused apt with some cyclical cycles, and i had to go about it slightly more manually and generally.

first of all, when every i had an annoying library error, i ran this script:
#!/bin/bash
in=`echo $1 | sed -e 's/://'`
fix=`dpkg -S $in | awk '{print $1}' | sed -e 's/://'`
sudo apt-get -y --reinstall install $fix

which would reinstall the missing library. since i ended up doing this rather repetitively, it helped a lot.

secondly, i was forced to run something like this:
for i in `cat get-selections`; do
sudo apt-get -y --reinstall install $i;
done


which reinstalls each package. slowly after pruning the list for problem packages, and deleting the successful ones, my system came back. at one point you won’t have to run them individually, and you can run:
sudo apt-get --reinstall install `cat get-selections`

and be done! i finished with a:
do-release-upgrade

and now things are looking great. luckily no important user files were squished, and hopefully this is a good reference for you. i hopefully won’t have to reference it again for all the dpkg commands i’ll forget.