In this guide, we will talk about setting up a Selenium Grid using Docker Swarm on any of the cloud services like GCP or AWS.
Let’s start with the basics first, i.e. what is Selenium Grid and Docker Swarm.
What is Selenium Grid?
Selenium Grid allows the execution of WebDriver scripts on remote machines (virtual or real) by routing commands sent by the client to remote browser instances. It aims to provide an easy way to run tests in parallel on multiple machines.
Selenium Grid allows us to run tests in parallel on multiple machines, and to manage different browser versions and browser configurations centrally (instead of in each individual test).
Selenium Grid purposes and main functionalities
- A central entry point for all tests
- Management and control of the nodes/environment where the browsers run
- Scaling
- Running tests in parallel
- Load balancing
Now a question comes “When to use Grid”?
Generally speaking, there are two reasons why you might want to use Grid.
- To run your tests against multiple browsers, multiple versions of browsers, and browsers running on different operating systems.
- To reduce the time it takes for the test suite to complete a test pass.
Grid is used to speed up the execution of a test pass by using multiple machines to run tests in parallel. For example, if you have a suite of 100 tests, but you set up Grid to support 4 different machines (VMs or separate physical machines) to run those tests, your test suite will complete in (roughly) one-fourth the time as it would if you ran your tests sequentially on a single machine.
What is Docker Swarm?
Docker swarm is a container orchestration tool, meaning that it allows the user to manage multiple containers deployed across multiple host machines.
One of the key benefits associated with the operation of a docker swarm is the high level of availability offered for applications. In a docker swarm, there are typically several worker nodes and at least one manager node that is responsible for handling the worker nodes’ resources efficiently and ensuring that the cluster operates efficiently.
What are the two types of Docker Swarm mode services?
Docker Swarm has two types of services: replicated and global.
**Replicated services: **Swarm mode replicated services functions by you specifying the number of replica tasks for the swarm manager to assign to available nodes.
**Global services: **Global services function by using the swam manager to schedule one task to each available node that meets the services constraints and resource requirements.
#docker-swarm #docker #selenium #docker swarm
