Project directories

DebOps uses a concept of "project directories" to store the data required to manage an IT infrastructure. Project directories are kept on the Ansible Controller hosts from where Ansible commands are executed. They are designed to be tracked using git version control and have support for encrypted secret storage using EncFS or git-crypt projects.

There are currently two versions of project directories supported by DebOps - "legacy" and "modern".

The "legacy" directory layout

This was the first directory layout designed for DebOps. This directory layout is focused on a single Ansible inventory. To create it, you can run the command:

debops project init --type legacy ~/src/projects/project1

The above command will create a base set of subdirectories in specified directory and generate an initial Ansible inventory hosts file:

~/src/projects/project1/
├── ansible/
│   ├── collections/
│   │   ├── ansible_collections/
│   │   └── requirements.yml
│   ├── inventory/
│   │   ├── group_vars/
│   │   │   └── all/
│   │   │       └── keyring.yml
│   │   ├── hosts
│   │   └── host_vars/
│   ├── keyring/
│   ├── overrides/
│   │   ├── files/
│   │   ├── tasks/
│   │   └── templates/
│   ├── playbooks/
│   │   └── roles/
│   ├── resources/
│   └── secret/
├── ansible.cfg
├── .debops.cfg
└── .gitignore

This is an example of a project directory after it was used to configure a few hosts using DebOps roles and playbooks (some of the directory contents are trimmed to make the result easier to read):

~/src/projects/project1/
├── ansible/
│   ├── collections/
│   │   ├── ansible_collections/
│   │   └── requirements.yml
│   ├── inventory/
│   │   ├── group_vars/
│   │   │   ├── all/
│   │   │   │   ├── apt.yml
│   │   │   │   ├── keyring.yml
│   │   │   │   └── users.yml
│   │   │   ├── appservers/
│   │   │   │   ├── php.yml
│   │   │   │   └── ruby.yml
│   │   │   └── webservers/
│   │   │       └── nginx.yml
│   │   ├── host_vars/
│   │   │   ├── host1/
│   │   │   │   └── sshd.yml
│   │   │   └── host2/
│   │   │       └── nginx.yml
│   │   └── hosts
│   ├── keyring/
│   ├── overrides/
│   │   ├── files/
│   │   ├── tasks/
│   │   └── templates/
│   ├── playbooks/
│   │   ├── deployment.yml
│   │   └── roles/
│   │       ├── service1/
│   │       └── service2/
│   ├── resources/
│   │   ├── res-dir1/
│   │   │   └── res-file1.zip
│   │   └── res-dir2/
│   │       └── res-file2.jpg
│   │── secret/
│   │   ├── credentials/
│   │   │   ├── host1/
│   │   │   └── host2/
│   │   ├── dhparam/
│   │   │   └── params/
│   │   │       ├── dh2048.pem
│   │   │       └── dh3072.pem
│   │   └── pki/
│   │       ├── authorities/
│   │       ├── ca-certificates/
│   │       ├── lib/
│   │       ├── realms/
│   │       └── requests/
│   └── global-vars.yml
├── .git/
├── ansible.cfg
├── .debops.cfg
└── .gitignore

You can compare this directory structure with Ansible Best Practices directory organization documentation to see where the solutions proposed by Ansible and those implemented in DebOps overlap.

Usually the debops or ansible commands are executed from the root of the project directory. At the moment there are no safeguards against running multiple debops commands at the same time; it's advisable not to do it due to possible deadlocks and issues with concurrent execution of Ansible commands on the same resources located on the remote hosts.

As you can see, the project directory can be managed using git to keep the history of the changes over time and share a given environment among team members. It's also possible to create a "public" project directory and share it on hosting platforms like GitHub - the DebOps for WordPress project is essentially this.

The "modern" directory layout

This directory layout was created after a few years of experience with the "legacy" layout. The design is based around a concept of "infrastructure views", which translates to multiple Ansible inventories with separate secrets and custom resources.

To create a project directory with this layout, you can issue the command:

debops project init --type modern ~/src/projects/project2

This command will create a directory structure with a set of default configuration files used by git and ansible, which looks something like this:

~/src/projects/project2/
├── ansible/
│   ├── collections/
│   │   ├── ansible_collections/
│   │   └── requirements.yml
│   ├── keyring/
│   ├── overrides/
│   │   ├── files/
│   │   ├── tasks/
│   │   └── templates/
│   └── views/
│       └── system/
│           ├── ansible.cfg
│           ├── inventory/
│           │   ├── group_vars/
│           │   │   └── all/
│           │   │       └── keyring.yml
│           │   ├── hosts
│           │   └── host_vars/
│           ├── playbooks/
│           │   └── roles/
│           ├── resources/
│           ├── secret/
│           ├── .gitattributes
│           └── .gitignore
├── .debops/
│   ├── conf.d/
│   │   ├── project.yml
│   │   └── view-system.yml
│   └── environment
└── .gitignore

You can compare this with the "legacy" directory structure above. The important changes with the previous layout are:

• DebOps configuration is now a .debops/conf.d/ directory within the project directory instead of a single file. It can contain files in JSON, TOML and YAML formats that are merged into a unified configuration structure.

• Parts of the project directory (Ansible inventory, custom resources, secrets) are moved into ansible/views/system/ subdirectory. The "system" view is meant to be used as the default privileged view for the infrastructure, with either root or other UNIX account with full sudo access to the host.

Detailed description of each directory and file in the project directory can be found further below.

How to use "infrastructure views"

The core concept of "infrastructure views" in a DebOps project directory is meant to permit use of multiple Ansible inventories against a single infrastructure. There are different ways to implement this in practice.

One example is to have a single Ansible inventory for privileged access to hosts (the "system" view in the default configuration). This view is used by system administrators to provision hosts, install system-wide software and configure different layers of access control in parts of the system (access to databases, filesystem ACLs and permissions, authentication services, and so on). Other views can then be configured to use unprivileged access to parts of the infrastructure, without going through sudo which with Ansible always requires full privileged access. For example, a deployment UNIX account can have proper ACLs in the PostgreSQL service to create its own databases, which still can be managed via Ansible tasks without issues.

Another way to utilize infrastructure views is to have a "production" view, a "development" view and a "shared" view, which is included as an additional inventory in both "production" and "development" inventories. In "production" and "development" Ansible inventories users define hosts and access to them, and in the "shared" Ansible inventory they define service groups and other configuration. With this setup, Ansible configuration can be applied on the "development" infrastructure, and when everything works OK, new configuration can be deployed on "production" hosts without requiring any changes in inventories. There might be more layers of inventories if needed, or a blue-green deployment scheme if desired.

Infrastructure views can be defined in a hierarchical directory structure. For example, you can have system view as default, and then deploy/app1 and deploy/app2 views for different applications. Nesting a view inside of another view is disallowed to avoid security issues and unpredictable Ansible behaviour. To see what views are defined in a project, you can use the command:

debops config get -k views

The debops script tries to automatically detect which "infrastructure view" should be used - if the user has changed the current directory to one under ansible/views/<view>/, that particular view will be used in various DebOps commands. Otherwise, the default view for a given project will be used automatically. Users can override which view should be used by specifying the -V <view> or --view <view> option in most of the script commands. This also works outside of the project directory, when used with the --project-dir <path> option. See the manual pages of different DebOps commands to learn more.

The default view used by DebOps in a given project is defined in the <project_dir>/.debops/conf.d/project.yml configuration file, in the project.default_view configuration key. It can be set to an empty string; in such case there will be no default view and it will have to be selected using the -V <view> or --view <view> option on the command line. Alternatively, users can cd into a view subdirectory before executing a debops command to use it.

In the <project_dir>/.debops/conf.d/view-*.yml configuration file created for each "infrastructure view", users can select which Ansible Collections will be searched for playbooks if one is specified without a <namespace>.<collection>/` prefix. This can be used to change the default collection for a given "infrastructure view" to one which contains unprivileged playbooks and roles, or add more Ansible Collections which should be searched for playbooks.

Per-view playbook sets

Users can define "playbook sets" at the view level, using the views.<name>.playbook_sets configuration option. This option is a YAML dictionary with lists of playbooks to execute when a particular "playbook set" is specified on the command line. An example configuration:

---
views:
  system:
    playbook_sets:
      'webservice':
        - 'layer/common'
        - 'service/nginx'
        - 'custom-app'

With the above configuration, users can execute a set of playbooks using the command:

debops run webservice -l webserver

which will be internally expanded to:

debops run layer/common service/nginx custom-app -l webserver

After that, the usual playbook expansion will take place. The first two playbooks will be found in the DebOps collection, and the custom-app playbook will be presumably in the ansible/views/system/playbooks/ subdirectory of the project directory. If a potential playbook set is not found, the argument will be expanded into a playbook if possible, or passed to the ansible-playbook command as-is.

This mechanism can be used to redefine existing playbooks into playbook sets. For example, if users want to include additional playbooks in the "site" playbook, they can:

---
views:
  system:
    playbook_sets:
      'site':
        - 'site'
        - '<namespace>.<collection>.custom_playbook'

Now calling the "site" playbook will execute the DebOps own site.yml playbook, and an additional playbook from a specific Ansible Collection.

Please remember that this feature does not modify the actual playbooks, just the way they are called from the command line. This means that including the site.yml playbook in another playbook will run just that one playbook, not all the playbooks defined in a playbook set.

DebOps and git integration

Project directories are designed to be stored in git repositories. The repository will be initialized by default when a new project is created; to avoid this users can use the --no-git parameter during project creation.

When git repositories are configured with encrypted secrets, using either EncFS or git-crypt, the debops script will by default commit current contents of the project repository when certain actions are performed. Currently, this happens when project secrets are unlocked or locked - this is required by git-crypt to work correctly (the git repository needs to be clean), but DebOps will do this for EncFS as well, for consistency.

If the project secrets were unlocked manually, using the debops project unlock command, any changes done afterwards will be committed when the secrets are locked again. This allows users to perform multiple changes in the project directory and commit them by hand as they see fit.

Any commits done by DebOps automatically can be updated, for example to provide a more extensive commit message. Users can use git rebase -i command to edit older commits; latest commit can be modified using the git commit --amend command.

Contents of the project directory

Main Ansible configuration file

legacy

ansible.cfg

modern

ansible/views/<view>/ansible.cfg

This is a configuration file read by the ansible and ansible-playbook commands. This file is generated when the project is initialized, but it's not stored in the git version control to avoid conflicts with paths on different Ansible Controllers.

The contents of this file are configured using the DebOps configuration system. You can use the debops project refresh command to update this file or recreate it after the project directory is cloned from a git repository. Any changes in this file made directly will be lost, so it's best to save them in DebOps configuration files after testing them.

Ansible Collection requirements

both

ansible/collections/requirements.yml

This file contains a list of Ansible Collections which are required by DebOps or other parts of a given project. It can be edited and committed to version control.

If you installed Ansible using just the ansible-core Python package, without any collections included, you might need to install the listed collections manually if they are not already available on your user account or system-wide. To install these collections within the project directory, you can run the command:

debops env ansible-galaxy collection install -r ansible/collections/requirements.yml

to download the listed collections and their dependencies. They will be unpacked inside of the ansible/collections/ansible_collections/ subdirectory and ignored by version control.

To see a list of installed collections, you can run the command:

debops env ansible-galaxy collection list

The Ansible inventory

legacy

ansible/inventory/

modern

ansible/views/<view>/inventory/

This is the directory where Ansible will look for its inventory. In the example above, it's a static inventory based on an INI file format, however if you wish you can switch it to a dynamic inventory generated from a database; just replace the ansible/inventory/hosts file with a script.

The inventory variables can be put either in a single file, or multiple files, which might be more convenient if you want to share the same variables across project directories using symlinks. Just remember that you cannot mix directories and files on the same level of the inventory directory structure.

Better way to share variables across inventories might be to create a "shared" inventory and specify the path to that inventory in the ansible.cfg configuration file.

Playbook and role directory

legacy

ansible/playbooks/roles/

modern

ansible/views/<view>/playbooks/roles/

This is a set of directories that can hold Ansible playbooks and roles in the project directory which are not part of an Ansible Collection. Each "infrastructure view" has its own set of playbook and role directories, since they are tied to that particular view's Ansible inventory and resulting access control.

Data for debops.resources role

legacy

ansible/resources/

modern

ansible/views/<view>/resources/

This directory can be used to store various files which can be accessed by the debops.resources Ansible role to copy them over to the remote hosts.

Data store for debops.secret role

legacy

ansible/secret/

modern

ansible/views/<view>/secret/

This directory is maintained by the debops.secret Ansible role. You can find there plaintext passwords, randomly generated by different roles, as well as PKI configuration and some other data - the directory is sometimes used to distribute public keys or other information between hosts via Ansible Controller.

Global variables passed to Ansible

legacy

ansible/global-vars.yml

modern

ansible/views/<view>/global-vars.yml

This is an optional YAML file, not created by default. If the debops script detects this file, it will be provided to the ansible-playbook command using the --extra-vars parameter. For Ansible to work correctly, this file has to contain at least one valid variable, otherwise Ansible will return with an error.

The ansible/global-vars.yml file can contain global variables which will override any other variables in the inventory, playbooks or roles. In DebOps, this file can be used to define variables which affect how playbooks are processed by Ansible during initialization. For example, global variables can be used to change the role used by the import_role Ansible module without modifying the role/playbook code, which is only possible via the --extra-vars parameter since Ansible inventory variables are not available at that stage.

Warning

Variables defined in the ansible/global-vars.yml file should be treated as "global" for the entire environment managed by DebOps and shouldn't be scoped to a particular host or host group, otherwise unexpected things can happen.

If you don't use the debops command to run DebOps playbooks, you need to specify this file manually on the command line, for example:

ansible-playbook --extra-vars '@ansible/global-vars.yml' playbook.yml

DebOps configuration files

legacy

.debops.cfg

modern

.debops/conf.d/

The debops command is looking for this file for current directory to see if it's a project directory; if it's not found the execution is aborted to not cause issues in the filesystem.

This file contains configuration for some of the custom DebOps lookup plugins, as well as configuration which should be added to the automatically generated ansible.cfg configuration file.

Persistent environment variables

both

.env

modern

.debops/environment

These files can contain environment variables which will be included in the runtime environment in various debops subcommands.

Overriding the site playbook

The debops/ansible/playbooks/site.yml playbook located in the DebOps monorepo connects all debops roles.

By creating a playbook named ansible/playbooks/site.yml inside your project folder, you can override the debops version of site.yml and hook your role to the debops command instead:

in ansible/playbooks/site.yml:

---
- import_playbook: '{{ lookup("ENV", "HOME") + "/.local/share/debops/debops/ansible/playbooks/site.yml" }}'
- import_playbook: your_role.yml

in ansible/playbooks/your_role.yml:

---
- name: Manage the your specific setup
  hosts: [ 'debops_all_hosts' ]
  roles:
    - role: ansible.your_role
      tags: [ 'role::your_role' ]

Note

Note that the path to debops/ansible/playbooks/site.yml can vary per OS and installation method. You can either provide the path to the playbook, or create a symlink to the correct destination in your project folder.

You can override any of the other DebOps playbooks in a similar fashion.