Chef: Load Attributes from encrypted databag in json role

chefjson

I'm want to use the postfix cookbook for chef. The sasl password is expected to be in an attribute. So usually you would do this:

"default_attributes": {
  "postfix": {
    "sasl": {
      "smtp_sasl_passwd": "somepassword"
    }
  }
}

The thing is: I don't want to have the password in the repository in plain text. So I put it in an encrypted data bag. Now I want to access it. This can be done with this:

Chef::EncryptedDataBagItem.load("passwords", "postfix")['password']

The problem: This only works in a .rb file, but my role is in json; all my roles are in json! I don't want to change that just for this purpose. Does anybody have an idea what to do here? Help is very appreciated.

Best Answer

Converting your roles to the Ruby DSL would not help here - they are converted to JSON before being uploaded to the Chef server, and it is the JSON version that is loaded by chef-client. The same is true of environments.

In other words, there's no way to load a databag (encrypted or otherwise) from a role or environment. You'll need to put that kind of logic into a cookbook recipe.

Related Solutions

Chef best Practices/Questions

Edit This question and answer are years old. The definitive best practices are taught via the Learn Chef Rally self-paced training modules produced by Chef Software, Inc. The bulk of the original answer is below.

In this answer, "Chef" or "chef-client" usually refers to Chef Infra, the product. Opscode renamed to Chef Software, Inc in 2013. In April, 2019, Chef opened the source code for all its products, along with creating consistent brand naming.

Not clear if it's better to setup roles in ruby DSL, JSON, or from the management console? Why are there multiple ways to do the same thing?

2019 Update: Policyfiles are the best workflow to use. Roles are considered an inferior practice, and Chef Software, Inc. recommends migrating to Policyfiles.

There are multiple ways to do the same thing because people have different workflows. You pick the workflow that is best for your environment. Let me explain what the differences are so you can make an informed decision.

The Ruby DSL for Roles exists to make it easier to write roles without knowing the syntax of JSON. It is a simple way to get started with Roles. Once you have made changes, you upload them to the Chef Server with knife.

knife role from file myrole.rb

This converts the role to JSON and stores it on the server. If you have an environment that enforces the Chef Repository where your roles live as the source of truth, this works quite well.

JSON is what the Chef Server stores, so you also edit JSON directly in the management console. It does require more fields than the Ruby DSL in order for Knife to recognize it properly to upload. Those details are hidden to some degree via the web UI.

The disadvantage of using the webui/management console for editing roles is they aren't in your local version control system unless you download them from the server. You can do this with knife:

knife role show myrole -Fj

The -Fj tells knife to "display in JSON format." You can redirect the output to a .json file if you like.

Years ago update: There are additional knife commands for working with the files in the local chef repository. Currently these commands support only JSON format files. A community RFC is open which will address adding support for the Ruby DSL for these plugins. Here's a brief summary of the workflow.

Check content differences between the server and the local file.

knife diff roles/myrole.json

Upload a JSON formatted role file. The roles/ path is required. This gets mapped to the same API endpoint on the server.

knife upload roles/myrole.json

Download the content from the server overwriting the content of the file in the repository.

knife download roles/myrole.json

These commands come from knife-essentials, which is built into the chef client package.

Can you organize cookbooks into subdirectories? eg- we have custom software that I'd like to write a cookbook for and stick that into: chef-repo/cookbooks/ourcompanystuff/customsoftwarecookbook would this be a good practice?

No. Knife has an expectation of where cookbooks should live because it uses an API to upload cookbooks to the Server. This is set in the knife.rb with cookbook_path. In older versions of Chef Infra, you could specify an array of paths for cookbooks, but this is being deprecated because it required more maintenance and was confusing to users.

By convention we name customer specific or site specific cookbooks with the name prefixed in the cookbook diretory. For your example, it would be:

chef-repo/cookbooks/ourcompany_customsoftware

There might be multiple different cookbooks for "ourcompany" depending on what you're doing.

Further reference:

Do I create a cookbook for each type of role that specifies what it does? Do I have these cookbooks include other cookbooks (i.e.- the cookbook for my webserver role includes the apache cookbook). I'm not sure how cookbook inter-dependencies and inheritance are handled.

There is no direct relationship or dependency between roles and cookbooks.

Roles have a run list, which specifies the recipes and other roles that should be applied to any node that has that role. Nodes have a run list that can contain roles or recipes. When Chef runs on the node, it will expand the run list for all the roles and recipes it includes, and then download the cookbooks required. In a node run list:

recipe[apache2]

Chef will download the apache2 cookbook for the node so it can apply this recipe.

You might have a cookbook specific for a role in your infrastructure. More commonly you'll have cookbooks that are for setting up certain types of services like apache2, mysql, redis, haproxy, etc. Then you would put those into appropriate roles. If you have custom application specific things that need to happen to fulfill a role, then you could write this into a custom cookbook (like I referenced above).

Further reference:

Is there anything like puppets external node classifier so nodes automatically determine their roles?

"Yes." The Chef Infra Server does node data storage (in JSON) automatically, and the server also automatically indexes all the node data for search.

Further reference:

It seems like you can configure things with knife or within the management console, or editing JSON files? This is super confusing to me why there are so many ways to do things, it's paralyzing! Is there a reason to use one or the other?

The Chef Infra Server has a RESTful API that sends and receives JSON responses. Knife and the management console are user interfaces for interacting with the API from an administration point of view.

You can use the tool you like better, though the management console doesn't have as many features as Knife. Most people that use Chef Infra prefer the command-line interface for the power and flexibility it provides, even folks who are using Chef Infra on Windows. Further, knife is a plugin based tool that you can create new plugins to interact with the Chef Infra Server, or with other parts of your infrastruture.

Chef Infra is a set of libraries, primitives, and an API. It gives you the flexibility to build the configuration management system that works best for your infrastructure.

Overriding attributes with Chef Solo

Hmm. There should be chef output that indicates what's wrong.

Looking at the cookbook, I see that it's trying to download maven 3 as: http://www.apache.org/dist/maven/binaries/apache-maven-3.0.3-bin.tar.gz (as specified in maven/attributes/default.rb, as the maven.3.url attribute).

If you try to wget that URL, you'll get a 404. So, the cookbook is broken in an obvious way because of that. This should have shown up in the chef run log, though.

You can try modifying the cookbook, as it's out of date. You can also try setting the maven.3.url attribute for the node to something more up to date, so you don't touch the cookbook in that case, e.g.:

"maven": {
    "version": "3",
    "3": {
      "url": "http://www.apache.org/dist/maven/binaries/apache-maven-3.0.4-bin.tar.gz"
    }
},

or, if you want to continue using 3.0.3:

"maven": {
    "version": "3",
    "3": {
      "url": "http://archive.apache.org/dist/maven/binaries/apache-maven-3.0.3-bin.tar.gz"
    }
},

Best Answer

Related Solutions

Chef best Practices/Questions

Overriding attributes with Chef Solo

Related Topic