DEV Community: DIZZ

Introduction to Kubernetes

DIZZ — Sun, 02 Jan 2022 06:31:52 +0000

The rise of microservices caused an increased usage of container technology. Containers are the best option to host microservices as they can host small independent services on each container. With microservices, the applications which used to be monolith are now shifted to microservices generating hundreds and thousands of containers. Managing these containers in several different environments manually or with self-made scripts is a cumbersome task. Hence there should be a solution to mitigate this issue.

What is Kubernetes?

It is an open-source container orchestration tool developed by Google. It has been developed to address the above-discussed issue by providing an easy way or a tool to manage the growing population of containers.

Features of Kubernetes

High availability and Less down time
Disaster recovery and self healing capabilities
Scalability (Horizontal)
Load balancing
Rolling update and rollback
Resource monitoring and logging

Kubernetes Basic Architecture

The master node runs the Kubernetes processes, necessary to run and manage clusters properly
Worker nodes are the places where actual work happens
API Server: Entry point to K8s cluster
Controller Manager: Keeps track of what is happening in the cluster
Scheduler: Responsible for scheduling containers on different worker nodes based on the workload and available resources in each node. It decides on which worker node the next container should be scheduled on.
etcd: Holds data as key-value pairs. This holds the current state of the Kubernetes cluster. Also contains all the configuration data and status data of each container in the worker nodes AKA snapshots.

Pods in K8s

In K8s you only work with pods
Pod: This is the smallest unit you could find in Kubernetes and works as a wrapper to a container
Each node can have multiple pods
Each pod can have multiple containers
Usually, one pod is used for a one application
Each pod has its own IP address.
Pods communicate with each other using internal IP addresses
Pod gets a new IP address when created
To get a static IP address to a pod Service can be used
Service has main two features,
- Permanent IP address
- Load Balancing

Wanna know more?👇

Useful Resources

Introduction to ELK Stack

DIZZ — Sun, 12 Dec 2021 07:39:10 +0000

The systems have to be monitored to ensure that there are minimum possibilities for outages and downtimes. Indeed, many tools are out there for monitoring, but not every tool can provide centralized, comprehensive monitoring. This is where the ELK Stack comes into play.

The ELK Stack is an open-source log management solution that is used for collecting, searching, analyzing, and visualizing large volumes of data generated by various sources. It mainly comprises of 3 products.

Elasticsearch
Logstash
Kibana

ELK Stack Architecture

How does ELK Stack work?

Logstash accepts logs in a variety of formats and through a variety of protocols, over the network, or wherever they originate on your network.
After that, these logs are sent to Elasticsearch. Here you can perform analysis and real-time search of data gathered.
Kibana allows you to visualize the data in Elasticsearch in a comprehensive manner by representing it in charts and graphs.

More On Logstash

Logstash collects data inputs and feeds them into the Elasticsearch. It gathers different types of data to unify and normalize them for analytical and visualization purposes.
Basically, Logstash contains 3 components,

Input: Transferring logs to be processed into a machine-readable format.
Filters: It is a series of conditions that must be met to carry out a specific action or event.
Output: Processed event or log decision maker.

Advantages of Logstash

Capable of analyzing a large variety of structured/unstructured data.
Offers plugins to connect various types of input sources.
Can be used for centralized data processing.

More on Elasticsearch

Elasticsearch is a NoSQL database. It offers advanced queries to perform detailed analysis and stores all the data centrally.
You can also use Elasticsearch to store, search, and analyze large amounts of data. It's primarily utilized as the backend engine for applications that fulfill search needs. In addition to a simple search, the tool includes comprehensive analytics and a number of advanced capabilities.

Advantages of Elasticsearch

Utilize data record by record with the help of multi-document APIs.
Perform data filtering and querying.
Helps to scale vertically and horizontally.
Store schema-less data while creating a schema for the data.

More on Kibana

Kibana is a data visualization tool. This tool is used to visualize Elasticsearch documents and provides developers with a quick overview. To visualize complex queries, the Kibana dashboard provides a variety of interactive diagrams, geospatial data, and graphs.
In Kibana there are different search types,

Free text searches: Specific strings can be searched.
Field-level searches: String within a specific field can be searched.
Logical statements: Combine searches into a logical statement.
Proximity searches: Search for terms with specific character proximity.

Advantages of Kibana

Visualization of data is easy.
Real-time analysis, charting, summarization, and debugging are offered.
User-friendly interface provided.
Allows sharing of snapshots of the logs.
Integrated with Elasticsearch.

Wanna know more?👇

Useful Resources

ELK Docs

Thanks for reading.. 🙌

Introduction to Ansible

DIZZ — Wed, 24 Nov 2021 08:22:27 +0000

Ansible is an Open-Source IT automation engine which allows provisioning, configuration management and application deployment tool enabling infrastructure as code(Iac).

Why Ansible?

At the beginning of the network computing, system administrators managed servers manually. But the reliability and the efficiency of such practices were an issue. Eventually, data centres grew, the hosted applications in them became more complex and cumbersome to handle. Therefore doing complex configurations in thousands of servers manually was not efficient practice. Therefore IT personnel needed a tool to do these server configuration tasks effectively and efficiently.
The tool that they came up with is Ansible.

Why is this Popular?

There are indeed other tools that do the same as Ansible. If that is true, why do professionals use Ansible? There are several factors for that. Let's dive in 🐋,

Ansible is simple and human-readable, which allows any user level to grasp it relatively quickly.
Since Ansible is agentless, it does not stick to a platform.
It's capable of handling tens of thousands of nodes at a time.
More secure since it runs on SSH(on Linux)
For provisioning, configuration management, orchestration, and deployment, there are different tools available. But Ansible can provide all these services by itself.

Ansible Terms

Controller Machine: There server where Ansible is installed, This is responsible for provisioning.
Inventory: This contains the information of the servers that are managed.
Module: This is a reusable, standalone script that Ansible runs on your behalf locally or remotely.
Task: Defines a single procedure to be executed.
Playbook: Is the blueprint of automation tasks. Playbooks are written in YAML format.
Role: A series of actions for configuring a host to perform a certain function, such as configuring a service.
Play: Execution of a playbook.
Facts: Global variables which keep data gathered about target nodes.
Handlers: Are special tasks which only get executed when triggered via the notify directive.
Ansible Tower: Web-based interface to manage Ansible.

Ansible Architecture

Wanna know more?👇

Useful Resources

Thanks for reading.. 🙌

Introduction to Docker

DIZZ — Tue, 02 Nov 2021 16:05:22 +0000

Have you ever encountered an issue where your code works on your machine but does not work on another machine? Most of you should probably have faced this issue.But what if we could remove this platform dependency somehow. This is where docker comes into play.

What is Docker?

Docker is a platform as a service (PaaS) that uses OS-Level Virtualization to deliver software packages in containers which helps to build, test and deploy an application in any environment.

Docker Ideology

Let's say we want to assemble a car in one country, For that, we have to bring all the required parts from another country. If those components are shipped as individual components, sometimes some of them might get lost, leaving us with an uncompleted car. But if the person who sends, could send them packing the components into the container, the risk of losing the parts is minimum.
It is the same in the software development world, If the software developer could send the source code with all the dependencies and libraries, it ensures that the code works as expected in another environment, Docker enables this through containerization.

Containers VS VMs

Let's see the differences briefly..

Virtual Machines

In simple terms, VMs are emulations of physical machines. VMs provide hardware-level virtualization and have their own Operating System aka OS. To communicate with the host it uses a software layer called Hypervisor.

Containers

Containers are more lightweight than VMs. Provides OS-level virtualization and share the host OS. Since it does not have to spin up an entire VM to run Boot Up times are generally around milliseconds.

Docker Terminology

Before getting an idea about the Docker workflow, it is better to know the terminology. 👇

Dockerfile: File that contains the instructions to build a Docker image.
Docker Image: Has all the instructions to build a Docker container. Also it contains application code, libraries, tools, dependencies and other files to make the application run.These images can be stored in Docker Hub which is a remote repository.
Docker Container: A runtime instance of a Docker image.

Docker Workflow

Must Know Docker Commands

docker images : list down all the docker images
docker ps : list down all running docker containers
docker ps -a : list down all the docker containers
docker start <container name or id> : start a container
docker stop <container name or id> : stop a container
docker run <image name or id> : create a container using a docker image

Wanna know more? 👉 References

Useful Resources

Thanks for reading.. 🙌