Yaml files example

If we use a single space or double space, it has different meanings in YAML. Spaces change the meaning of data structure. YAML is case sensitive. YAML is language independent. In the starting, YAML was very useful and friendly to people who work with data. YAML uses Unicode printable characters. In Unicode, some provide the information of structure, and others contain the data itself. Using the minimization of structural characters, a unique cleanness can be achieved by YAML.

YAML is used to show the data itself in a meaningful and natural way. For example, bullet lists are created by dashes, key: value pairs are separated by a colon, and structure may be used by indentation. In YAML, the data structure has myriad flavors. Using the three basic primitives, the data structure can be adequately represented. The basic primitives are mapping, sequences, and scalars. YAML leverages these primitives, and if we want to form a complete language for data serialization, it adds an easy typing system and aliasing mechanism.

YAML is used by most of the programming languages for data serialization. But YAML excels in working with the languages that are built around the primitives like mapping, sequences, and scalars. To work well with the common use cases, YAML language was specialty designed. Common-use cases are cross-language data sharing, log files, debugging of complex data structure, interprocess messaging, object persistence, and configuration files.

The programming becomes an easy task when data is easy to understand and view. Format of Prolog Consider the following text: Javatpoint is the best website. How to create a kubernetes Pod using YAML To create a Kubernetes pod with YAML, you first create an empty file, assign it the necessary access permissions, and then define the necessary key-value pairs.

The important ones are the apiVersion, the kind pod , name, and the containers within the pod. For instance, below is the YAML code to create a pod named mywebapp1 that has 2 containers: One is a web server and the other is a database server. It is also assigned to a specific volume named websvr-storage:. YAML apiVersion: v1 kind: Pod metadata: name: mywebapp1 labels: role: webserver-role app: nginx spec: containers: - name: webserver1 image: nginx You can define many more parameters and values for a pod.

For example, you can specify extra parameters to assign CPU resources, configure quality-of-service for a pod, configure service accounts, configure pod initialization, assign a pod to a specific node, and many more tasks as listed in the official Kubernetes documentation.

How to create a Kubernetes Deployment using YAML Remember that in the case of a deployment , we are creating a set of resources to be managed as a unit. And also keep in mind that one of the reasons to use Kubernetes is for redundancy of our resources, mainly achieved via replicas and replicasets.

The mandatory specifications to be included when defining our deployment via YAML are apiVersion, kind, metadata, and spec. Because deployments are sets of objects, we must specify what objects are to be created by this deployment.

This is done under the template: specification. And to ensure we are creating only the correct pods in this deployment, we use the. In this case, only those pods that match our desired label which is app:nginx will be included in this deployment. We have also specified that we want 2 pods to be created in this deployment. These pods are webserver1 and database-server.

And their respective specs are also included here, just as they were when creating the individual pods. And this should be transparent to any application or other pods trying to access this pod-set. The request should still be acknowledged and fulfilled as usual. YAML files are nowadays being used extensively for defining properties of tools and applications due to the very human-readable syntax.

It's not meant to be a replacement for the current solutions and is mainly used for configuration files due to the fact that it's both easy to read and edit, and supports comments, making it a lot more team-friendly. Here's an example of a YAML file:. After defining a few properties such as the name , wage , and position , a list is included, again, indented with each list item beginning with a -.

You can shorten dictionaries and form more complex collections, though that's out of the scope of this tutorial. Most formatting languages display data in a non-human readable format. Even JSON, the most popular data format in use, has poor code readability. This article will introduce you to the YAML markup language. We cover the basic concepts behind this markup language, explain its key features, and show what YAML offers to DevOps teams.

YAML is a data serialization language. It is not a programming language in the true sense of the word. YAML files store information, so they do not include actions and decisions. Users can write code for reading and generating YAML in any programming language.

The extensions in YAML are. Both extensions stand for the same file type. Users can add multiple documents to a single YAML file. Separate different documents with three dashes , like this:. YAML allows users to add comments to their code.

YAML comments start with the symbol and do not have to be on a separate line:. There are no usual format symbols, such as braces, square brackets, closing tags, or quote marks.

The syntax is clean and easy to scan through. It is good practice to display whitespace characters in your text editor to prevent accidental uses of tabs.