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Package Managers and Puppet
Joe Damato packagecloud.io
slides available at:
blog.packagecloud.io
hi, I’m joe!• i think these things are cool:
• computer programs
• reproducible builds / infrastructure
• automation
• configuration management
• tahdig** an rice food
packagecloud.io
• I work on packagecloud.io
• packagecloud makes it easy to upload, download, store, and delete software packages
• you should use it, it’s cool.
Why?• Central to maintaining, building, and testing
infrastructure.
• Packages are a primitive in Puppet.
• Understanding where packages come from, and how to store them properly is a requirement for infrastructure of any size.
• Packages and packaging are much trickier than they seem!
Overview
• what is a package?
• what is a package manager?
• ./configure && make && make install pattern
• open source tools for package repositories
• HOWTO manage repos in your infra with puppet
What is a package?
• A package generally consists of:
• metadata (version, architecture, deps, etc)
• files to be written to the filesystem (/usr/sbin/nginx, etc)
Common package types
Common package types• RPM packages
• Used on CentOS, RHEL, Scientific Linux, Fedora, …
• files typically have the “.rpm” file extension
• can be inspected, installed, and removed with rpm
• are actually a:
• header structure (binary data)
• CPIO archive
man 8 rpm
Common package types
Common package types• Deb packages:
• Used on Ubuntu, Debian, Knoppix, …
• files typically have the “.deb” file extension
• can be inspected, installed, and removed with dpkg
Common package types• Deb packages:
• are actually an AR archive with:
• version file: the debian format version
• data.tar.gz: the actual files to write to the filesystem
• control.tar.gz: the package metadata
• Can be GPG signed, but signatures are never checked!
man 1 dpkg
Common package types
• There are lots more! (ruby gems, npm, java, python, …)
• Some packaging systems also have source packages.
What is a source package?• A source package consists of:
• metadata (version, architecture(s), build deps, etc).
• source files (C source, C++ source, py scripts, etc).
• Allows you to rebuild a binary package easily.
Install packages with puppet
Use the resource type ‘package’ to install packages:
package { 'pygpgme': ensure => latest, }
Install packages with puppet
package { 'pygpgme': ensure => ‘0.3-11’, }
Specify the version you want by setting ensure:
Summary• Packages are a collection of files with metadata.
• The metadata usually has info like:
• architecture
• version
• dependency info
• and more.
• Installation is easy if you don’t have dependencies.
Dependencies• Installing 1 package is as easy as:
• dpkg -i filename.deb
• rpm -ivh filename.rpm
• Of course, you should use puppet instead :D
• But what if your program needs other programs?
• For example: nginx depends on libssl, zlib, …
So, what’s a package manager?
Package manager
• A package manager is a collection of software that allows you to:
• install, upgrade, remove packages
• query package info from local system or repos
• Some tools include more advanced features like mirroring or more advanced caching features.
Common package managers
http://en.wikipedia.org/wiki/Yellowdog_Updater,_Modified#mediaviewer/File:Yum.png
• yum (Yellowdog Updater, Modified)
• Common on RHEL, CentOS, Fedora, …
• Used for installing, removing, configuring, and querying RPM packages and dependencies.
Common package managers
Common package managers
APT
Common package managers
• APT (Advanced Package Tool)
• Common on Debian, Ubuntu, KNOPPIX, …
• Used for installing, removing, configuring, and querying Debian packages and dependencies.
Install packages with puppet
• When you install packages with puppet, puppet will automatically detect which package manager to use.
• You won’t need to worry about which command to run, or what options to pass; puppet will take care of that for you!
Summary• package managers help you install software and
associated dependencies
• easily remove, upgrade, and query packages
• Puppet will automatically detect the system’s package manager when you install a package.
A problem
• You run Ubuntu 10.04 LTS
• You want to install redis
• Ubuntu 10.04 comes with redis-server 1.2.0-1
• That’s too old! You need 2.8.19!
• So, now what?
Common (not great) solution
• A common solution to this sort of problem is building redis (or ruby, or …) from source in your puppet manifest
• Like this….
exec { 'install-redis': command => "make && make install PREFIX=${redis_bin_dir}", cwd => $redis_src_dir, path => '/bin:/usr/bin', unless => "test $(${redis_bin_dir}/bin/redis-server --version | cut -d ' ' -f 1) = ‘Redis'", require => [ Exec['unpack-redis'], Class['gcc'] ], }
Common (not great) solution
Why?• It’s easy!
• ./configure && make && make install
• It works!
• I’m using puppet so it’s reproducible!
But…• What happens if you need to:
• completely remove Redis?
• install a security update?
• install a new version?
• install the same exact Redis on 200 machines?
The not-so great side• Not all Makefiles have uninstall targets, so you
have to remove files manually
• Leaving artifacts on the filesystem can cause really, really hard to debug problems later
• If the build process changes version to version, it can be painful to rollback
The not-so great side• Rebuilding the same source does not necessarily
get you the same byte-for-byte binary
• If the binaries aren’t identical, you can end up with bugs in some of the compiled binaries but not others
• Painful to recreate source builds inside of puppet
• Makes writing tests for manifests painful
Make a package• Install the same binary on every machine
• When the package is removed, all installed files are removed
• Versioning of build process built in (with most tools)
• Keep your puppet manifests about config management
• Your build steps are “factored out” into the package
Your new puppet manifest
package { 'redis': ensure => latest, }
Your package• Your build steps get encapsulated in the package
itself
• Makes iterating on the build more straight forward
• Don’t need to apply (potentially) a bunch of manifests to a machine every time you do a build
“How do I make a package?”
Use tools!• debbuild
• rpmbuild
• fpm
• mock and pbuilder (more advanced)
Tradeoffs
• Takes time to learn new tools
• Takes time to understand packaging
• No one ever has enough time
BUT…
Tradeoffs
• Once you learn how to make packages you can build reproducible infrastructure much more easily
• You can use your prod environment in dev and test
• You can more easily build tests for your infrastructure with beaker/kitchen.ci
“How do I store and organize my packages?”
Package repositories
• Major linux distributions keep repositories of packages for users:
• EPEL
• Ubuntu / Debian official repositories
• You can store a package and its dependencies to make it easy to install them all on your infrastructure
Package repositories• createrepo: creates yum repositories
• reprepro: creates apt repositories
• Many other free tools available!
• Read the documentation carefully. Lots of tricky options.
• I’ll show some examples to get you started!
createrepo
http://en.wikipedia.org/wiki/Yellowdog_Updater,_Modified#mediaviewer/File:Yum.png
createrepo• mkdir /var/www/myrepo
• cp /path/to/rpms/*.rpm /var/www/myrepo
• createrepo /var/www/myrepo
• gpg --detach-sign --armor /var/www/my/repo/repomd.xml
GPG is important• Using GPG to sign the generated repository
guarantees that you generated the repository.
• This is important.
• This means that no one else modified, removed, or inserted a package other than you.
• GPG signing the repository is not a very well known security measure, but it is incredibly important!
• This is NOT the same as using rpmsign/rpm --sign.
Secure YUM repos
• Sign repository metadata with GPG
• Sign packages with GPG (use rpmsign)
• Serve repositories over SSL
• Enable all the right options for SSL verification, repository GPG checking, AND package GPG checking.
Wouldn’t it be cool to do all that with Puppet instead?
Good news: you can!
createrepo via puppet
Puppet can create YUM repositories for you!
$ puppet module install palli-createrepo
createrepo { 'yumrepo': repository_dir => '/var/yumrepos/yumrepo', repo_cache_dir => '/var/cache/yumrepos/yumrepo' }
createrepo via puppet
You still need to GPG sign the repository yourself :(
exec { “gpg_sign_yumrepo”: command => “gpg --detach-sign --armor /var/yumrepos/yumrepo/repodata/repomd.xml“, }
Once the repository is created, it must be added to the client machines.
Add YUM repos with puppetyumrepo { 'my_repo': baseurl => "http://myurl.com/repo", gpgcheck => 1, repo_gpgcheck => 1, gpgkey => “http://myurl.com/gpg.pub.key”, sslverify => 1, sslcacert => “/etc/pki/tls/certs/ca-bundle.crt”, enabled => 1, }
most people never turn on repo_gpgcheck or sslverify, or set the ssl certificate path, but you should!!
But that’s not all!• You MUST have the ‘pygpgme’ package
installed on the system that will verify the signatures.
• Without pygpgme, yum will not be able to verify signatures!
• Some versions of CentOS / RHEL do not automatically install pygpgme with yum!!
Make sure to install pygpgme
package { 'pygpgme': ensure => latest, }
reprepro
APT
reprepro
• mkdir /var/www/myrepo
• mkdir /var/www/myrepo/conf
• Create a file named “distributions” in the conf directory
reprepro
Codename: precise Components: main Architectures: i386 amd64 SignWith: 7ABDB001
/var/www/myrepo/conf/distributions:
reprepro• You can add more sections if you need more code
names (lucid, trusty, etc).
• SignWith specifies which GPG key to use for signing repository metadata
• You can get your gpg key ID by looking at the output of gpg —list-keys
• This is not the same as using debsigs/debsign !!!
reprepro
import your Ubuntu 12.04 packages:
reprepro -b /var/www/myrepo/ includedeb precise filename.deb
Wouldn’t it be cool to do all that with Puppet instead?
Good news: you can!
reprepro via puppet
Puppet can create APT repositories for you!
$ puppet module install jtopjian-reprepro
# Base Directory shortcut $basedir = '/var/lib/apt/repo' !# Main reprepro class class { 'reprepro': basedir => $basedir, } !# Set up a repository reprepro::repository { 'localpkgs': ensure => present, basedir => $basedir, options => ['basedir .'], }
reprepro via puppet
# Create a distribution within that repository reprepro::distribution { 'precise': basedir => $basedir, repository => 'localpkgs', origin => 'Foobar', label => 'Foobar', suite => 'precise', architectures => 'amd64 i386', components => 'main contrib non-free', description => ‘My repo', sign_with => 'F4D5DAA8', not_automatic => 'No', }
reprepro via puppet
Once the repository is created, it must be added to the client machines.
Add APT repos with puppet
apt::source { 'myrepo': location => ‘http://myurl.com/repo', release => 'precise', repos => 'main', key => '7ABDB001', key_source => ‘http://myurl.com/gpg.pub.key', include_src => true, }
$ puppet module install puppetlabs-apt
But that’s not all!• You MUST have the ‘apt-transport-https’ package
installed on the system if your repository is served over HTTPS!
• Without apt-transport-https, you can’t install packages over HTTPS.
• You definitely want this.
Make sure to install apt-transport-https
package { ‘apt-transport-https‘: ensure => latest, }
Success• You can now use beaker/kitchen.ci/etc to test your
infrastructure.
• Determine if the packages you need are actually installed after your manifests are applied.
• Determine if the repositories you added are actually added after your manifests are applied.
• Don’t need to wait forever for Ruby, redis, et al to build during a test run.
BEST OF ALL !!!!• You can now run Puppet on your development
VM using the same manifests you use in production
• The manifests are applied and you are running the same exact binaries you run in production
• Won’t catch ALL production bugs, but getting closer to production during development is super useful
Summary• Creating package repositories can be tricky. Make
sure to GPG sign repository metadata.
• 99% of package repositories get this wrong.
• Carefully read the documentation of createrepo and reprepro.
• Make sure to install necessary libraries for verifying signatures and accessing repositories via HTTPS.
• Always serve up your repositories over HTTPS.
Use puppet to automate this.
