Posts in this category
- Automating Deployments: A New Year and a Plan
- Automating Deployments: Why bother?
- Automating Deployments: Simplistic Deployment with Git and Bash
- Automating Deployments: Building Debian Packages
- Automating Deployments: Debian Packaging for an Example Project
- Automating Deployments: Distributing Debian Packages with Aptly
- Automating Deployments: Installing Packages
- Automating Deployments: 3+ Environments
- Architecture of a Deployment System
- Introducing Go Continuous Delivery
- Technology for automating deployments: the agony of choice
- Automating Deployments: New Website, Community
- Continuous Delivery for Libraries?
- Managing State in a Continuous Delivery Pipeline
- Automating Deployments: Building in the Pipeline
- Automating Deployments: Version Recycling Considered Harmful
- Automating Deployments: Stage 2: Uploading
- Automating Deployments: Installation in the Pipeline
- Automating Deployments: Pipeline Templates in GoCD
- Automatically Deploying Specific Versions
- Story Time: Rollbacks Saved the Day
- Automated Deployments: Unit Testing
- Automating Deployments: Smoke Testing and Rolling Upgrades
- Automating Deployments and Configuration Management
- Ansible: A Primer
- Continuous Delivery and Security
- Continuous Delivery on your Laptop
Wed, 13 Jan 2016
Automating Deployments: Distributing Debian Packages with Aptly
Once a Debian package is built, it must be distributed to the servers it is to be installed on.
Debian, as well as all other operating systems I know of, use a pull model for that. That is, the package and its meta data are stored on a server that the client can contact, and request the meta data and the package.
The sum of meta data and packages is called a repository. In order to distribution packages to the servers that need them, we must set up and maintain such a repository.
In Debian land, packages are also signed cryptographically, to ensure packages aren't tampered with on the server or during transmission.
So the first step is to create a key pair that is used to sign this particular repository. (If you already have a PGP key for signing packages, you can skip this step).
The following assumes that you are working with a pristine system user that
does not have a gnupg keyring yet, and which will be used to maintain the
debian repository. It also assumes you have the
$ gpg --gen-key
This asks a bunch of questions, like your name and email address, key type and bit width, and finally a pass phrase. I left the pass phrase empty to make it easier to automate updating the repository, but that's not a requirement.
$ gpg --gen-key gpg (GnuPG) 1.4.18; Copyright (C) 2014 Free Software Foundation, Inc. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. gpg: directory `/home/aptly/.gnupg' created gpg: new configuration file `/home/aptly/.gnupg/gpg.conf' created gpg: WARNING: options in `/home/aptly/.gnupg/gpg.conf' are not yet active during this run gpg: keyring `/home/aptly/.gnupg/secring.gpg' created gpg: keyring `/home/aptly/.gnupg/pubring.gpg' created Please select what kind of key you want: (1) RSA and RSA (default) (2) DSA and Elgamal (3) DSA (sign only) (4) RSA (sign only) Your selection? 1 RSA keys may be between 1024 and 4096 bits long. What keysize do you want? (2048) Requested keysize is 2048 bits Please specify how long the key should be valid. 0 = key does not expire <n> = key expires in n days <n>w = key expires in n weeks <n>m = key expires in n months <n>y = key expires in n years Key is valid for? (0) Key does not expire at all Is this correct? (y/N) y You need a user ID to identify your key; the software constructs the user ID from the Real Name, Comment and Email Address in this form: "Heinrich Heine (Der Dichter) <firstname.lastname@example.org>" Real name: Aptly Signing Key Email address: email@example.com You selected this USER-ID: "Moritz Lenz <firstname.lastname@example.org>" Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O You need a Passphrase to protect your secret key. You don't want a passphrase - this is probably a *bad* idea! I will do it anyway. You can change your passphrase at any time, using this program with the option "--edit-key". We need to generate a lot of random bytes. It is a good idea to perform some other action (type on the keyboard, move the mouse, utilize the disks) during the prime generation; this gives the random number generator a better chance to gain enough entropy. ..........+++++ .......+++++ Not enough random bytes available. Please do some other work to give the OS a chance to collect more entropy! (Need 99 more bytes) ..+++++ gpg: /home/aptly/.gnupg/trustdb.gpg: trustdb created gpg: key 071B4856 marked as ultimately trusted public and secret key created and signed. gpg: checking the trustdb gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model gpg: depth: 0 valid: 1 signed: 0 trust: 0-, 0q, 0n, 0m, 0f, 1u pub 2048R/071B4856 2016-01-10 Key fingerprint = E80A D275 BAE1 DEDE C191 196D 078E 8ED8 071B 4856 uid Moritz Lenz <email@example.com> sub 2048R/FFF787F6 2016-01-10
Near the bottom the line starting with
pub contains the key
pub 2048R/071B4856 2016-01-10
We'll need the public key later, so it's best to export it:
$ gpg --export --armor 071B4856 > pubkey.asc
Preparing the Repository
There are several options for managing Debian repositories. My experience with debarchiver is mixed: Once set up, it works, but it does not give immediate feedback on upload; rather it communicates the success or failure by email, which isn't very well-suited for automation.
Instead I use aptly, which works fine from the command line, and additionally supports several versions of the package in one repository.
To initialize a repo, we first have to come up with a name. Here I call it
$ aptly repo create -distribution=jessie -architectures=amd64,i386,all -component=main internal Local repo [internal] successfully added. You can run 'aptly repo add internal ...' to add packages to repository. $ aptly publish repo -architectures=amd64,i386,all internal Warning: publishing from empty source, architectures list should be complete, it can't be changed after publishing (use -architectures flag) Loading packages... Generating metadata files and linking package files... Finalizing metadata files... Signing file 'Release' with gpg, please enter your passphrase when prompted: Clearsigning file 'Release' with gpg, please enter your passphrase when prompted: Local repo internal has been successfully published. Please setup your webserver to serve directory '/home/aptly/.aptly/public' with autoindexing. Now you can add following line to apt sources: deb http://your-server/ jessie main Don't forget to add your GPG key to apt with apt-key. You can also use `aptly serve` to publish your repositories over HTTP quickly.
As the message says, there needs to be a HTTP server that makes these files available. For example an Apache virtual host config for serving these files could look like this:
<VirtualHost *:80> ServerName apt.example.com ServerAdmin firstname.lastname@example.org DocumentRoot /home/aptly/.aptly/public/ <Directory /home/aptly/.aptly/public/> Options +Indexes +FollowSymLinks Require all granted </Directory> # Possible values include: debug, info, notice, warn, error, crit, # alert, emerg. LogLevel notice CustomLog /var/log/apache2/apt/access.log combined ErrorLog /var/log/apache2/apt/error.log ServerSignature On </VirtualHost>
After creating the logging directory (
/var/log/apache2/apt/), enabling the the virtual host
a2ensite apt.conf) and restarting Apache, the Debian repository
Adding Packages to the Repository
Now that the repository is set up, you can add a package by running
$ aptly repo add internal package-info_0.1-1_all.deb $ aptly publish update internal
Configuring a Host to use the Repository
Copy the PGP public key with which the repository is signed
pubkey.asc) to the host which shall use the repository, and
$ apt-key add pubkey.asc
Then add the actual package source:
$ echo "deb http://apt.example.com/ jessie main" > /etc/apt/source.list.d/internal
apt-get update, the contents of the repository are
available, and an
apt-cache policy package-info shows the
repository as a possible source for this package:
$ apt-cache policy package-info package-info: Installed: (none) Candidate: 0.1-1 Version table: *** 0.1-1 0 990 http://apt.example.com/ jessie/main amd64 Packages 100 /var/lib/dpkg/status
This concludes the whirlwind tour through debian repository management and thus package distribution. Next up will be the actual package installation.
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