Package Management and Chef - ChefConf 2015
•
0 likes•1,004 views
This talk aims to cover a breadth of topics about package management and Chef, starting with some fundamentals and continuing on to more advanced techniques and tips. This talk will begin by explaining why packages and package management are fundamental tenants to managing infrastructure. We'll examine why the common practice of simply running "make install" in a Chef recipe is a bad idea and what users can do when they see recipes like this in the wild. An extremely common problem with package management is misconfiguration of package repositories and client software. Most of the existing documentation available does not cover all of the configuration required to correctly setup and access package repositories securely and lots of configurations are simply copy-and-pasted from unreliable sources. In order to combat some of this, the talk will continue by examining some common Chef resources for controlling package repositories with care to carefully go over commonly misunderstood and misused options. We'll examine how to generate secure package repositories, what options must be set in Chef recipes to access repositories securely, and what bugs you may bump into in your infrastructure that may prevent you from securely accessing package repositories. Finally, this talk will wrap up with some concluding tips, tricks, and thoughts about packaging and how to use it to carefully manage infrastructure. https://youtu.be/-HJ7EZ85THU
Report
Share
Package Management and Chef - ChefConf 2015
- 3. hi, I’m joe! • i think these things are cool: • computer programs • reproducible builds / infrastructure • automation • configuration management • tahdig* * an rice food
- 4. 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. • it’s a perfect companion to Chef Delivery
- 6. “packagecloud:enterprise has solved the problem of distributing public and private package repositories. We’re extremely satisfied with the support and we trust it with all the GitLab Omnibus package downloads of more than 1TB per week." Sytse Sijbrandij, CEO & Founder
- 9. Why? • Central to maintaining, building, and testing infrastructure. • Packages are a primitive in Chef. • 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!
- 10. 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 Chef
- 11. What is a package? Beck Gusler, https://flic.kr/p/4A15jm
- 12. 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)
- 14. 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
- 15. man 8 rpm
- 17. 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
- 18. 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!
- 19. man 1 dpkg
- 20. Common package types • There are lots more! (ruby gems, npm, java, python, …) • Some packaging systems also have source packages.
- 21. 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.
- 22. Install packages with chef Use the ‘package’ resource to install packages: package "zlib1g" do action :install end
- 23. Install packages with chef Specify the version you want by setting ‘version’: package "zlib1g" do version "1:1.2.8-1" action :install end
- 24. 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.
- 26. Dependencies • Installing 1 package is as easy as: • dpkg -i filename.deb • rpm -ivh filename.rpm • Of course, you should use chef instead :D • But what if your program needs other programs? • For example: nginx depends on libssl, zlib, …
- 28. So, what’s a package manager?
- 29. 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.
- 31. • yum (Yellowdog Updater, Modified) • Common on RHEL, CentOS, Fedora, … • Used for installing, removing, configuring, and querying RPM packages and dependencies. Common package managers
- 33. Common package managers • APT (Advanced Package Tool) • Common on Debian, Ubuntu, KNOPPIX, … • Used for installing, removing, configuring, and querying Debian packages and dependencies.
- 34. Install packages with chef • When you install packages with chef, chef will automatically detect which package manager to use. • You won’t need to worry about which command to run, or what options to pass; chef will take care of that for you!
- 35. Summary • package managers help you install software and associated dependencies • easily remove, upgrade, and query packages • Chef will automatically detect the system’s package manager when you install a package.
- 37. 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?
- 38. Common (not great) solution • A common solution to this sort of problem is building redis (or ruby, or …) from source in your chef cookbook • Like this….
- 39. execute ‘compile redis' do cwd ‘/tmp/redis’ command ‘make clean && make’ end ! execute ‘install redis' do cwd ‘/tmp/redis’ command ‘make install’ end Common (not great) solution
- 40. Why? • It’s easy! • ./configure && make && make install • It works! • I’m using chef so it’s reproducible!
- 41. 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?
- 42. 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
- 43. 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 chef • Makes writing tests for cookbooks painful
- 44. 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 chef cookbooks about config management • Your build steps are “factored out” into the package
- 45. Your new chef recipe package "redis" do action :install end
- 46. Your package • Your build steps get encapsulated in the package itself • Makes iterating on the build more straight forward • Don’t need to run (potentially) a huge number of cookbooks every time you do a build
- 48. “How do I make a package?”
- 50. Use tools! • debbuild • rpmbuild • git-buildpackage • fpm • omnibus • mock and pbuilder (more advanced)
- 51. Tradeoffs • Takes time to learn new tools • Takes time to understand packaging • No one ever has enough time
- 52. BUT…
- 53. 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 kitchen.ci
- 55. “How do I store and organize my packages?”
- 56. 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
- 58. 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!
- 60. 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
- 61. 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.
- 62. 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.
- 63. Wouldn’t it be cool to do all that with Chef instead? Good news: you can!
- 64. createrepo via chef Chef can create YUM repositories for you! $ knife cookbook site install yumrepo_server
- 65. yumrepo_server 'creates my yum repo' do action :create dir 'relative/yum/repo/path' remote_source "http://upstream.com/path" packages %w(pkg1.rpm pkg2.rpm pkg3.rpm) end createrepo via chef
- 66. You still need to GPG sign the repository yourself :( execute ‘gpg sign yum metadata' do cwd ‘relative/yum/repo/path/repodata’ command ‘gpg --detach-sign —armor repomd.xml’ end
- 67. Once the repository is created, it must be added to the client machines.
- 68. Add YUM repos with chef most people never turn on repo_gpgcheck or sslverify, or set the ssl certificate path, but you should!! yum_repository ‘my_repo' do description “packagecloud.io is better than this” baseurl “https://myurl.com/repo“ gpgkey ‘http://myurl.com/gpg.pub.key' gpgcheck true repo_gpgcheck true sslverify true sslcacert “/etc/pki/tls/certs/ca-bundle.crt” action :create end
- 69. 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!!
- 70. Make sure to install pygpgme package "pygpgme" do action :install end
- 71. reprepro APT
- 72. reprepro • mkdir /var/www/myrepo • mkdir /var/www/myrepo/conf • Create a file named “distributions” in the conf directory
- 73. reprepro Codename: precise Components: main Architectures: i386 amd64 SignWith: 7ABDB001 /var/www/myrepo/conf/distributions:
- 74. 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 !!!
- 75. reprepro import your Ubuntu 12.04 packages: reprepro -b /var/www/myrepo/ includedeb precise filename.deb
- 76. Wouldn’t it be cool to do all that with Chef instead? Good news: you can!
- 77. reprepro via chef Chef can create APT repositories for you! $ knife cookbook site install reprepro
- 78. reprepro via chef { "id": "main", "fqdn": "apt.example.com", "repo_dir": "/srv/apt", "incoming": "/srv/apt_incoming", "description": "APT Repository for our packages.", "codenames": [ "lucid", "hardy", "sid", "squeeze", "lenny" ], "allow": [ "unstable>sid", "stable>squeeze" ], "pgp": { "email": "packages@example.com", "fingerprint": "PGP Fingerprint for the key", "public": "-----BEGIN PGP PUBLIC KEY BLOCK-----n-----END PGP PUBLIC KEY BLOCK-----n", "private": "-----BEGIN PGP PRIVATE KEY BLOCK-----n-----END PGP PRIVATE KEY BLOCK-----n" }, "pulls": { "name": "sid", "from": "sid", "component": "main" }, "architectures": [ "amd64","i386","all","source" ] }
- 79. Once the repository is created, it must be added to the client machines.
- 80. Add APT repos with chef apt_repository 'repo' do uri ‘http://repo.com/ubuntu/' arch 'amd64' distribution 'precise' components ['main'] key ‘http://repo.com/ubuntu/archive.key' end $ knife cookbook site install apt
- 81. 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.
- 82. Make sure to install apt-transport-https package “apt-transport-https“ do action :install end
- 84. Success • You can now use kitchen.ci to test your infrastructure. • Determine if the packages you need are actually installed after your cookbooks have run. • Determine if the repositories you added are actually added after your cookbooks have run. • Don’t need to wait forever for Ruby, redis, et al to build during a test run.
- 85. BEST OF ALL !!!! • You can now run Chef on your development VM using the same cookbooks you use in production • The cookbooks 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
- 86. 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.
- 87. Use chef to automate your infrastructure. Use packagecloud.io to deliver software.