Dockerzie SSH and Configure Webserver in Docker with Ansible

Hello ?? ! Here is my Article to configure Webserver inside a Docker Container with Ansible Playbook

In this article, I am going to.

• Dockerize SSH - Install SSH and Enable SSH Service in Docker
• Configure WebServer in Docker with Ansible

Dockerize SSH

Ansible works on SSH protocol and we need SSH enabled in the managed node. In our case, we are Configuring Docker so, Our Managed node is Docker Container we should Enable SSH inside the Docker Container

Pre-Configuration :

• Install Docker and Ansible

Follow this Article to Install Docker and Ansible :

Launch the Docker Container :

docker run -it -p 2222:22 --name <Container_Name> centos:latest 

This Docker command run a container in interactive terminal mode and expose the 22 port of Docker to 2222 port of Host Machine Where the Docker is running give a name to the container with --name tag with centos:latest container image

We now landed at the container terminal.

Inside Container

Install SSH :

SSH Server:

• We need to install SSH Server to allow ansible to configure with SSH

yum install openssh-server  -y 

SSH Client :

• To use SSH commands we need SSH Client Software

yum install openssh-client  -y 

Start SSH Server :

Before we start SSH Service we need some host keys and we have to generate host keys, The following command will do this: For each of the key types (rsa, dsa, ecdsa and ed25519) for which host keys do not exist, generate the host keys with the default key file path, an empty passphrase, default bits for the key type, and default comment.

ssh-keygen  -A

• systemctl command or service command doesn't work in Docker so we need to find which file will run when we start service with systemctl.
• For SSH we have to run /usr/sbin/sshd with these options: do not detach (-D), log to stderr (-e), passthrough other arguments

/usr/sbin/sshd  -D  -e  "$@"

SSH is working great !!

Escape from the container with ctrl+p+q because when we start service the terminal become non-interactive and we have to make SSH Service Permanent Now, When we restart the container the SSH should not have to stop

• The command will execute the terminal of the Container we specified

docker exec  -it  Container_Name  bash

Make SSH Service Permanent :

Add the command - /usr/sbin/sshd -D -e "$@" at last in file /root/.bashrc Because the file will run when we restart the container so our service also start again

We Miss One thing !!

• We are one step away to connect to SSH and we need a password to connect the SSH of Docker but Docker by default doesn't have any password

Let's activate the password for root in Docker :

• Install passwd command which helps us to set the password for root

yum install passwd  -y

• Set new password for root

The following command will prompt for a password and we have to use this password when we do SSH

passwd  root

Check SSH

• Find the IP of the container - Run this command from Host Machine Where Docker is Running

docker inspect  Container_Name | grep IP

IP is 172.17.0.2 , We know Password from the Previous Step and the user is root

Do SSH from Host Machine to Container :

ssh  [email protected]

This will prompt for password and enter the password you set, Don't Worry about Warnings ?

SSH Working Great !!

If we do SSH to the container, we can easily configure Webserver in Container with Ansible

Configure WebSever in Container with Ansible

Ansible Configuration :

• In /etc/ansible/ansible.cfg give the inventory location where the hosts present

Inventory : /etc/asible/hosts

• Inventory has the list of hosts and the credentials to log in to Managed Node with SSH

Playbook

• Playbook has the tasks to do configuration. hosts keyword specify where to do configuration

- hosts: docker
  tasks:

Install httpd :

• This task will install httpd package

  - name: Install httpd
    package:
      name: httpd
      state: present

Copy WebPages to the Document root :

• This task will copy index.html to /var/www/html

  - name: Copy Website
    copy:
      src: index.html
      dest: /var/www/html

Start Service :

• The Service module doesn't work in the docker container. We can run that with the command module or shell module

Check Service State:

The shell keyword is to run command and the command s to get the status of a webserver with status code

  - name: check Service
    shell: curl  -o /dev/null  -s  -w  '%{http_code}'  https://localhost
    ignore_errors: true
    register: httpd_status

The command to get httpd status :

The curl command is to get the webpage and we are extracting the httpd_code of webserver.

curl  -o /dev/null  -s  -w  '%{http_code}'  https://localhost

If httpd_status.stdout = "200" then the webserver is running. The task of Staring the Web server will Skip

Playbook

- hosts: docker
  tasks:
  - name: Install httpd
    package:
      name: httpd
      state: present
  - name: Copy Website
    copy:
      src: index.html
      dest: /var/www/html
  - name: check Service
    shell: curl  -o /dev/null  -s  -w  '%{http_code}'  https://localhost
    ignore_errors: true
    register: httpd_status
  - name: Print Status
    debug:
      var: httpd_status
  - name: Start Service
    command: "/usr/sbin/httpd"
    when: httpd_status.stdout != "200"

Run the Playbook :

ansible-playbook  FileName.yml

• The error is because the webserver is not running and the status code is 000

Check Webpages

curl  172.17.0.2

Done this task under the guidance of Mr.Vimal Daga Sir in ARTH.

Thank you Vimal Daga sir.

Thank you for Reading, Please Drop a message If you have any questions about this article. Happy to Help!