Join Brian Eiler for an in-depth discussion in this video Chef introduction, part of Amazon Web Services: Implementing and Troubleshooting PaaS Products.
- [Narrator] Let me give you a quick introduction to what Chef does for you. Chef is really an automation engine that's going to provide you a set of tools that helps you handle the workflow, whether it's an automation of the continuous deployments or it's more of automating your testing for compliance and security. But it's going to give you visibility down to the nodes, what their status is, as well as the user interface. So, Chef Automate is also able to help us with things like the different configuration elements, how the application itself is configured, and whether or not we have the right packages installed.
There's a lot more to this, but from a high level point of view, this just gets us started. Let's take a look at some of these concepts. Chef uses what we call cookbooks in order to automate certain tasks. The cookbooks are then composed of recipes that are basically code templates. The idea is to create what we would otherwise refer to as scripts that define how the configuration state of an instance should look, what it's going to do, and it could be much more involved, getting into the steps as to how to reach that state.
Things like, for example, here's one that says, "We need to install and enable Apache." So, the process first needs to involve bringing the Apache instance down and installing it and then going through the process of first enabling it and then starting that particular service. Chef is a client-server architecture. The idea is that there's a server that serves as the central repository for the different cookbooks, which also would then contain the policies that we apply to each of those nodes and then metadata describing the different nodes.
Now from a high level point of view, looking at how the quick setup process would work, we'll start off with setup the Chef server. This is going to include the different cookbooks that you might pull down, either from your own creation or community, and then assign also those recipe rules. And the recipe rules are based, think about them more like what the workload is going to do, web server, app server, database server. The next step is to install the Chef client on your instances.
Now these could be on-premises servers or instances within AWS. Once we do this, we need to register the instances as a Chef node with the Chef server. So this gives us the ability to manage it. Step number four is where we assign that node with a role. So when the node is registered, we can look at it and say, "Hmm, that is a web server and so therefore, "it's going to get this set of policies "and we want it configured in a certain way." Now, we could also decide that instead of a web server, maybe it's an app server, or database server, whatever it happens to be.
Step five is where the Chef client on that node it's going to pull down the recipe based on the role that it was assigned. So, at this point, the Chef client is essentially bringing down the configuration files from the central server that it was designed to run. The next step is, the Chef client goes through that recipe and applies the different configuration values on the node, by running that Chef recipe. Everything's working well and then, oh no.
Somebody goes in, they change the configuration and we have what we now call configuration drift. What do we do? No worries. Chef client automatically, every 30 minutes checks, pulls down the recipe, looks at the configuration, and step number eight, the Chef client says, "Yeah. We're changing that back "to the way it's supposed to be." So it is a method to not only just push the configuration process down but it's also to maintain the state to avoid that configuration drift issue.
- Creating an IAM user, group, and role
- Using the IAM policy simulator
- IAM best practices
- Components of CloudFormation
- Benefits of Elastic Beanstalk
- Working with OpsWorks
- OpsWorks for Chef Automate and Puppet Enterprise