Deploying a Web Application with Docker Swarm

Overview

In today’s fast-paced tech landscape, deploying, scaling, and managing applications efficiently is crucial. To satisfy these expectations, containerization has become a crucial technology, encapsulating programs and their dependencies into lightweight, portable containers. Leading containerization platform Docker is becoming a standard tool for DevOps teams and engineers. Running a single container, though, is frequently only the first step. Orchestrating numerous containers over a cluster of servers is crucial for increasingly complicated applications, especially those that need to be highly available and scalable. Docker Swarm enters the picture here.

Introduction

Containerization has revolutionized the way we develop, deploy, and manage applications. Docker, a leading containerization platform, allows developers to package applications and their dependencies into containers, ensuring consistency across multiple environments. Docker facilitates the running of single containers, but a more advanced solution is needed to orchestrate numerous containers over a cluster of servers. One such technology that gives Docker containers native clustering and orchestration features is Docker Swarm. We’ll look at utilizing Docker Swarm to deploy a web application in this blog.

Docker-swarm

One virtual Docker host is created from a pool of Docker servers using Docker Swarm. It coordinates and oversees a group of real or virtual machines that serve as Docker nodes. Among the main attributes of Docker Swarm are:

• Scalability: We can add or remove containers to extend your applications horizontally.
• High Availability: This feature guarantees your application is constantly operating by automatically rescheduling failing containers.
• Load Balancing: Distributes incoming service requests among available containers using load balancing.
• Declarative Service Model: This model lets us specify the ideal condition for the services, and Swarm takes care of keeping them there.

Guide to host web application

• Installation of Docker Swarm:

1. Create the 3 AWS instances with the following name: Swarm master, Swarm worker-1, Swarm worker-2

2. In all three instances, inside the inbound rules, allow

• Custom TCP — 2377 — Anywhere IPv4
• Custom TCP — 8001 — Anywhere IPv4

3. Install the Docker in all the 3 instances:

4. Open your Swarm master node’s terminal and run the command:

5. Run this command in Worker instances:

Worker node 1:

Worker node 2:

6. To check about all the nodes in the manager, run:

Running Mern-Django Application using Docker Swarm

1. This is the react-django-based application’s docker image, which you should use Docker Swarm to launch. To accomplish that, a Docker service must be created:

The Docker service name—in this example, “django-app-service”—is specified with the option –name django-app-service.

–replicas 3: This instructs the service to have three replicas. This indicates that Docker Swarm will create and maintain three instances of the designated container.

800-publish: 800-01: This assigns the host’s port 8001 to the service container’s port 8001. It permits external users to access the host computer’s service.

2. To see the docker services, run the below command:

3. At this point, this service will create the Manager node’s container. Use this command to verify:

At this point, all three nodes will be operating this service. Simply take the IP address of any node and then port 8001 to verify this. Regarding <Any_ip_of_3_vms>:8001.

Removing the worker node

1. Simply execute the following to eliminate any node from the environment:

2. As we removed one of the workers and inside the status, we can see it’s down.

Conclusion

Because Docker Swarm makes administering containerized apps easier, it’s an effective solution for providing scalable and resilient services. Use Docker Swarm to improve application stability and expedite your deployment operations.

Drop a query if you have any questions regarding Docker Swarm and we will get back to you quickly.

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