How can I create several executors for a job in Circle CI orb? - continuous-integration

Question

NOTE: The actual problem I am trying to solve is run testcontainers in Circle CI.
To make it reusable, I decided to extend the existing orb in my organisation.
The question, how can I create several executors for a job? I was able to create the executor itself.
Executor ubuntu.yml:
description: >
The executor to run testcontainers without extra setup in Circle CI builds.
parameters:
# https://circleci.com/docs/2.0/configuration-reference/#resource_class
resource-class:
type: enum
default: medium
enum: [medium, large, xlarge, 2xlarge]
tag:
type: string
default: ubuntu-2004:202010-01
resource_class: <<parameters.resource-class>>
machine:
image: <<parameters.tag>>
One of the jobs itself:
parameters:
executor:
type: executor
default: openjdk
resource-class:
type: enum
default: medium
enum: [small, medium, medium+, large, xlarge]
executor: << parameters.executor >>
resource_class: << parameters.resource-class >>
environment:
# Customize the JVM maximum heap limit
MAVEN_OPTS: -Xmx3200m
steps:
# Instead of checking out code, just grab it the way it is
- attach_workspace:
at: .
# Guessing this is still necessary (we only attach the project folder)
- configure-maven-settings
- cloudwheel/fetch-and-update-maven-cache
- run:
name: "Deploy to Nexus without running tests"
command: mvn clean deploy -DskipTests
I couldn't find a good example of adding several executors, and I assume that I will need to add ubuntu and openjdk for every job. Am I right?
I continue looking into other orbs and documentation but cannot find a similar case to mine.

Answer 1

As it is stated in Circle CI documentation, executors can be defined like this:
executors:
my-executor:
machine: true
my-openjdk:
docker:
- image: openjdk:11
Side note, there can be many executors of any type such as docker, machine (Linux), macos, win.
See, StackOverflow question how to invoke executors from CircleCI orbs.