03_check_docker_containers.yml - Usage Guide

Read-Only Docker

Purpose

This playbook checks whether Docker is installed on the inventory hosts. If Docker is present, it runs a docker ps -a-style command and prints a table of container names, health/uptime (Status/Uptime), and published ports. It also generates clickable browser links for ports bound to the public address (0.0.0.0).

Requirements

  • Docker should be installed on the target hosts. (If it is not, the playbook does not fail; it only reports that Docker is missing.)
  • Your Ansible inventory must define the relevant groups (for example workers, master).

The container table is collected separately with Docker’s own table format (for display). Link generation uses structured JSON from docker ps --format '{{json .}}' (replacing the earlier sed regex approach). That way every published port on a multi-port container gets its own link; the old approach captured only the first port per line.

How to run 

# Run on all servers (master + workers + datanode):
ansible-playbook -i inventories/musteri_a/hosts.ini playbooks/03_check_docker_containers.yml

# Limit to the workers group (worker1, worker2, worker3):
ansible-playbook -i inventories/musteri_a/hosts.ini playbooks/03_check_docker_containers.yml --limit workers

Sample output

A ping connectivity test runs first. If Docker is installed, a formatted container list is printed:

TASK [Ping connectivity test] **************************************************
ok: [192.168.1.21]

TASK [Check if Docker is installed] ********************************************
ok: [192.168.1.21]

TASK [Get Docker containers info as table] *************************************
ok: [192.168.1.21]

TASK [Display Docker containers status] ****************************************
ok: [192.168.1.21] => {
    "msg": "NAMES                  STATUS                  PORTS\nnginx-proxy            Up 4 days (healthy)     0.0.0.0:80->80/tcp, :::80->80/tcp\npayment-api            Up 2 hours              0.0.0.0:8080->8080/tcp\nold-container          Exited (0) 5 days ago   "
}

TASK [Get Docker containers info as JSON] **************************************
ok: [192.168.1.21]

TASK [Parse container JSON output] *********************************************
ok: [192.168.1.21]

TASK [Generate browser accessible links for containers] ************************
ok: [192.168.1.21] => (item=nginx-proxy)
ok: [192.168.1.21] => (item=payment-api)
ok: [192.168.1.21] => (item=old-container)

TASK [Display container links] *************************************************
ok: [192.168.1.21] => {
    "msg": "You can reach the following container ports in a browser:\n\n- nginx-proxy -> http://192.168.1.21:80\n- payment-api -> http://192.168.1.21:8080"
}

TASK [Docker not found message] ************************************************
skipping: [192.168.1.21]