app-katas

This is a collection of "app katas" to practice deploying complex applications using open-source DevOps tools.

Kata is a Japanese word (型 or 形) meaning "form". It refers to a detailed choreographed pattern of martial arts movements made to be practised alone. [...] It is practised in Japanese martial arts as a way to memorize and perfect the movements being executed. (Wikipedia - Kata)

The idea of "code katas" comes from Dave Thomas, one of the authors of the Agile Manifesto, as a way to bring that element of disciplined practice into software development.

Here we apply the idea of code katas to DevOps practice, by deploying various apps using a common DevOps tech stack. Those are the "app katas" included in the present repo.

Stack

The stack is comprised of the following tools:

Installation and configuration of these tools is outside the scope of this document.

Deployment

Pre-requisites:

Terraform and Ansible must be installed in the operator machine.

Terraform and Ansible credentials must have been configured for the cloud provider of choice.

Create an inventory file from (for example, if using GCP) _config/inventory/example.gcp.yml and set the GCP project ID.

Set up any needed environment variables for the app containers in <app>/app/.env, as in the example whoami/app/.env.example.

(TODO: add more instructions)

Create infra (example):

Individual app modules are instantiated in (for example, GCP) _infra/gcp/main.tf.

pushd ./_infra/gcp
terraform init
terraform plan
terraform apply
popd

(Grab the Terraform outputs to configure DN.)

DNS:

Add DNS records pointing to the instance IPs output in the previous step.

Deploy docker app (example):

Example:

pushd ./_config
ansible-galaxy install -r requirements.yml
./playbooks/docker-app.gcp.yml -i inventory/yourinventory.gcp.yml -e upgrade_system=true -e app=whoami
popd

Example: k3s single node on Hetzner Cloud

export HCLOUD_TOKEN="examplehcloudtoken"

pushd ./_infra/hcloud
terraform init
terraform plan
terraform apply
popd

pushd ./_config
./playbooks/k3s.yml --inventory inventory/hcloud.yml
popd

export KUBECONFIG=/tmp/k3s.yaml
export SERVER_IP="<SERVER_IP_HERE>"
kubectl apply -f ./k3s/hello-world/
curl "${SERVER_IP}"

pushd ./_infra/hcloud
terraform destroy
popd

Example: AWS w/ SSM session manager plugin

.envrc:

export APP_NAME="example"
export X_TAG="vm_tag_${APP_NAME}"
export X_AWS_SSM_BUCKET_NAME="example-bucket"

Ping:

pushd ./_config

ansible "${X_TAG}" --inventory ./inventory/aws_ec2.yml -m ping \
  --extra-vars "ansible_connection=aws_ssm" \
  --extra-vars "ansible_aws_ssm_region=${AWS_REGION}" \
  --extra-vars "ansible_aws_ssm_bucket_name=${X_AWS_SSM_BUCKET_NAME}"

popd

Deploy:

pushd ./_config

./playbooks/docker-app.aws.yml --inventory inventory/aws_ec2.yml \
  --extra-vars "app=${APP_NAME}" \
  --extra-vars "ansible_connection=aws_ssm" \
  --extra-vars "ansible_aws_ssm_region=${AWS_REGION}" \
  --extra-vars "ansible_aws_ssm_bucket_name=${X_AWS_SSM_BUCKET_NAME}"

popd

Authors

Andre Silva - @andreswebs

License

This project is licensed under the Unlicense.

Acknowledgements

Dave Thomas, http://codekata.com/

andreswebs/app-katas