A fully dockerized environment to play with ansible.

Prerequisites:

• Docker
• Docker Compose
• [ kubectl ]

Lab Architecture :

Nodes

This Lab consists of 5 containers:

• 1 control node container (control-node).

• 4 managed hosts as containers :

  • Alpine with SSH connection (ansible_connection=ssh)
  • RHEL8 with docker connection (ansible_connection=docker)
  • CentOS7 with docker connection (ansible_connection=docker)
  • Alpine+systemd with docker connection (ansible_connection=docker)

All these containers are defined in docker-compose.yml

Playbook Sample

The playbook sample is under playbook-example/hello.yml.

It consists of 4 plays:

• First play: target all managed hosts to create a simple file

• Second play: targets the alpine node to run NodeJS app (running inside container on port 3000, running externally on port 3001 - check docker-compose )

• Third play: targets both RedHat containers ( rhEL8, centos7) to run nginx (conclude exposed ports from docker-compose )

• Fourth play: target Alpine-systemd container to run Apache Web server ( external port 8083)

Configuration

• RHEL8 and CentOS7 containers does not need pre configuration as it used ansible_connection=docker.

• Alpine container requires pre-configuration as ansible connects to it thru SSH :

• Generate SSH key pair in ./secrets directory:

ssh-keygen -t rsa -N "" -f secrets/id_rsa

Using compose

Setup

docker-compose up -d

Play

## 
docker-compose exec controlnode ash
########
/playbook $ ansible all --list-hosts
## alpinesystemd-example-com
## alpine-example-com
## centos7-example-com
## rhel8-example-com

/playbook $ ansible all -m ping

## 
docker-compose exec controlnode ash
########

# run the playbook sample:
/playbook $ ansible-playbook hello.yml

Validation

on your host, navigate to :

• http://localhost:3001 , app (node) run in alpine node

• http://localhost:8081 , app (nginx) runs in rhel8 node

• http://localhost:8082 , app (nginx) runs in centos7

• http://localhost:8083 , app (apache) runs in alpine-systemd

Cleanup

docker-compose down

Using Kubernetes + compose

Setup

export stackname=infra-ansible
export DOCKER_STACK_ORCHESTRATOR=kubernetes
docker stack deploy -c docker-compose.yml ${stackname}

Play

# Get podID of control node
controlnode_podid=$(kubectl get pods -lcom.docker.service.id=${stackname}-controlnode -o jsonpath='{.items[0].metadata.name}')
kubectl exec -it ${controlnode_podid} ash

########
/playbook $ ansible all --list-hosts 
/playbook $ ansible alpine-example-com -m ping
# run the playbook sample:
/playbook $ ansible-playbook hello.yml

Cleanup

docker stack rm ${stackname}