Platform engineers at Form3 build highly available distributed systems using infrastructure as code. Our take home test is designed to evaluate real world activities that are involved with this role. We recognise that this may not be as mentally challenging and may take longer to implement than some algorithmic tests that are often seen in interview exercises. Our approach however helps ensure that you will be working with a team of engineers with the necessary practical skills for the role (as well as a diverse range of technical wizardry).
The sample application consists of four services:
┌─────────────┐ ┌──────────────┐ ┌──────────────┐ ┌──────────────┐
│ │ │ │ │ │ │ │
│ payment │ │ account │ │ gateway │ │ frontend │
│ │ │ │ │ │ │ │
└─────────┬───┘ └──────┬───────┘ └──────┬───────┘ └──────────────┘
│ │ │
│ │ │
│ ▼ │
│ ┌──────────────┐ │
│ │ │ │
└────────►│ vault │◄──────────┘
│ │
└──────────────┘
Three of those services connect to vault to retrieve database credentials. The frontend container serves a static file.
The project structure is as follows:
.
├── docker-compose.yml
├── form3.crt
├── README.md
├── run.sh
├── Vagrantfile
├── services
│ ├── account
│ ├── gateway
│ └── payment
└── tf
└── main.tf
- Refactoring the Terraform code found in the tf directory is the primary focus of this test.
Vagrantfile,run.shanddocker-compose.ymlare used to bootstrap this sample application; refactoring these files is not part of the test, but these files may be modified if your solution requires it.form3.crtis used to ease sandboxed running of the submission by Form3 staff and can be ignored.- The
servicescode is used to simulate a microservices architecture that connects to vault to retrieve database credentials. The code and method of connecting to vault can be ignored for the purposes of this test.
If you are using an M1 Mac then you need to install some additional tools:
- Multipass install the latest release for your operating system
- Multipass provider for vagrant
- Make sure you have installed the vagrant prerequisites
- In a terminal execute
vagrant up - Once the vagrant image has started you should see a successful terraform apply:
default: vault_audit.audit_dev: Creation complete after 0s [id=file]
default: vault_generic_endpoint.account_production: Creation complete after 0s [id=auth/userpass/users/account-production]
default: vault_generic_secret.gateway_development: Creation complete after 0s [id=secret/development/gateway]
default: vault_generic_endpoint.gateway_production: Creation complete after 0s [id=auth/userpass/users/gateway-production]
default: vault_generic_endpoint.payment_production: Creation complete after 0s [id=auth/userpass/users/payment-production]
default: vault_generic_endpoint.gateway_development: Creation complete after 0s [id=auth/userpass/users/gateway-development]
default: vault_generic_endpoint.account_development: Creation complete after 0s [id=auth/userpass/users/account-development]
default: vault_generic_endpoint.payment_development: Creation complete after 1s [id=auth/userpass/users/payment-development]
default:
default: Apply complete! Resources: 30 added, 0 changed, 0 destroyed.
default:
default: ~
Verify the services are running
vagrant sshdocker psshould show all containers running:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6662939321b3 nginx:latest "/docker-entrypoint.…" 3 seconds ago Up 2 seconds 0.0.0.0:4080->80/tcp frontend_development
b7e1a54799b0 nginx:1.22.0-alpine "/docker-entrypoint.…" 5 seconds ago Up 4 seconds 0.0.0.0:4081->80/tcp frontend_production
4a636fcd2380 form3tech-oss/platformtest-payment "/go/bin/payment" 16 seconds ago Up 9 seconds payment_development
3f609757e28e form3tech-oss/platformtest-account "/go/bin/account" 16 seconds ago Up 12 seconds account_production
cc7f27197275 form3tech-oss/platformtest-account "/go/bin/account" 16 seconds ago Up 10 seconds account_development
caffcaf61970 form3tech-oss/platformtest-payment "/go/bin/payment" 16 seconds ago Up 8 seconds payment_production
c4b7132104ff form3tech-oss/platformtest-gateway "/go/bin/gateway" 16 seconds ago Up 13 seconds gateway_development
2766640654f3 form3tech-oss/platformtest-gateway "/go/bin/gateway" 16 seconds ago Up 11 seconds gateway_production
96e629f21d56 vault:1.8.3 "docker-entrypoint.s…" 2 minutes ago Up 2 minutes 0.0.0.0:8301->8200/tcp, :::8301->8200/tcp vagrant-vault-production-1
a7c0b089b10c vault:1.8.3 "docker-entrypoint.s…" 2 minutes ago Up 2 minutes 0.0.0.0:8201->8200/tcp, :::8201->8200/tcp vagrant-vault-development-1
Imagine the following scenario, your company is growing quickly 🚀 and increasing the number services being deployed and configured.
It's been noticed that the code in tf/main.tf is not very easy to maintain 😢.
We would like you to complete the following tasks:
- Improve the Terraform code to make it easier to add/update/remove services
- Add a new environment called
stagingthat runs each microservice - Add a README detailing:
- Your design decisions, if you are new to Terraform let us know
- How your code would fit into a CI/CD pipeline
- Anything beyond the scope of this task that you would consider when running this code in a real production environment
- Create a private GitHub repository containing the content of this repository
- Complete the Task 🎉
- Invite @form3tech-interviewer-1 to your private repo
- Let us know you've completed the exercise using the link provided at the bottom of the email from our recruitment team
- Use only plain Terraform in your solution, i.e. anything supported by the Terraform CLI installed by the
run.shscript, but not external tooling or libraries that wrap or extend Terraform, such as Terragrunt or tfenv - Only modify files in the
tf/directory,run.sh, anddocker-compose.yml - Keep the current versions of the services running in
developmentandproductionenvironments - Structure your code in a way that will segregate environments
- 🚨 All environments (including staging) should be created when you run
vagrant upand the apps should printservice startedand the secret data in their logs 🚨 - Structure your code in a way that allows engineers to run different versions of services in different environments
- Do not use external tools that extend Terraform, such as Terragrunt.
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