< Previous : https://knowledgehunter.code.blog/2020/10/10/getting-ready-n-ansible-ping/

Introduction to Playbook

Ansible playbook is the place where we can setup multiple tasks to get executed through Ansible.

This is mainly happens through playbook.yml file.

Note : The syntax and format follow in this YAML file and other relevant YAML file is VERY IMPORTANT. They must exactly follow the formats otherwise the application will misbehave

[ref : https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html]

You need to create this playbook.yml in the place that you run the ansible commands

(Don’t worry about the file_store.yml file at this moment it is for one tasks to provide the directory names to create the directories in remote ansible hosts)

This is how the tasks defines in the playbook.yml.

Note : Please note the name ‘playbook’ is optional you can use anyother name also for that.

In this case, the playbook file part contains the tasks, hosts etc is called as a “play”. You can define multiple plays in a play book and you can give them a name also. And the connecting user also you can define in there.

eg:

- name: play1
  hosts: webServers
  remote_user: ubuntu
  tasks:
    - name: install httpd # going to install apache
      yum:
        name: httpd
        state: latest
- name: play2
  hosts: dbServers
  remote_user: centos
  tasks:
    - name: install httpd # going to install apache
      yum:
        name: httpd
        state: latest

The hosts parameter refers the Ansible hosts that the play is going to execute on. eg : you can mention the particular server group also in this case. Or you can mention them as all where it will effect to all of the servers in the host file.

eg :

[servers]
server1 ansible_host=192.168.1.15

[all:vars]
ansible_python_interpreter=/usr/bin/python3

Zooooming on tasks..

Let’s closer look at the each task

task#1 : Obtaining vars

  - name: obtaining vars
    include_vars: file_store.yml

This is a builtin angular module to load the variables that was stored in external file file_store.yml.

In this case variables are stored as above in that file and they can be loaded as “{{ dirList[‘path’] }}”. This is used in task#4.

[ref : https://docs.ansible.com/ansible/latest/collections/ansible/builtin/include_vars_module.html]

task #2 : Ansible create directory

  - name: ansible create directory example
    file: 
      path: /home/ubuntu/Desktop/newDir1
      state: directory

Ansible builtin file module is used for this and state directory is to create a directory in the path mentioned (newDir1 is the new direcotory name). If you are using the relative paths, path will be created related to the user directory.

(eg : if the path is path: newParent/newDir1, directory will be created under /home/ubuntu/newParent/newDir1)

[ref : https://docs.ansible.com/ansible/latest/collections/ansible/builtin/file_module.html]

task #3 : Create multiple directories

  - name: ansible create Multiple directories
    file: 
      path: "{{ item }}"
      state: directory
    with_items:
      - '/home/ubuntu/Desktop/newDir2'
      - '/home/ubuntu/Desktop/newDir3'
      - '/home/ubuntu/Desktop/newDir4'

In this case file path is given using the list of items mentioned in with_items

[ref : https://docs.ansible.com/ansible/latest/user_guide/playbooks_loops.html]

task#4 : Create directory taking the file name from external source

  - name: ansible create directory from External File
    file: 
      path: "{{ dirList['path'] }}"
      state: directory

In this case, we load the path from the external file as discussed in task#1

task#5 : Create directory with timestamp adding to the name

  - name: ansible create directory with timestamp
    file: 
      path: /home/ubuntu/Desktop/newDir_{{ansible_date_time.date}}
      state: directory

In this case we have used an ansible playbook variable ansible_date_time to get the date appended to the directory name.

[ref:https://docs.ansible.com/ansible/2.5/user_guide/playbooks_variables.html]

task#6 : Delete directory

  - name: ansible delete directory
    file: 
      path: /home/ubuntu/Desktop/newDir3
      state: absent

In this case we delete a created directory using the state as absent

task#7 : Copy files

  - name: Copy files
    copy:
      src: /home/user/Fun/integration-server/standalone/configuration/logging.properties
      dest: /home/ubuntu/Desktop/newDir4/logging.properties

In this case, we copy logging.properties file from Ansible Control Node – Local PC to newDir4 in the remote Ansible Host. For this we have used ansible builtin copy module.

[refer : https://docs.ansible.com/ansible/latest/collections/ansible/builtin/copy_module.html]

task#8 : Execute shell command

  - name: Execute the command in remote shell; stdout goes to the specified file on the remote
    shell: df >> somelog.txt

In this case we execute a shell command. eg : get the disck usage and writ to a file. We have used Ansible builtin shell module for this.

[ref : https://docs.ansible.com/ansible/latest/collections/ansible/builtin/shell_module.html]

Run the playbook.

Now you can simply run the playbook using below command

$ ansible-playbook -u ubuntu -i inventory/ playbook.yml

Response :

PLAY [all] *

TASK [Gathering Facts] *
ok: [server1]

TASK [obtaining vars] **
ok: [server1]

TASK [ansible create directory example]
changed: [server1]

TASK [ansible create Multiple directories] ***
changed: [server1] => (item=/home/ubuntu/Desktop/newDir2)
changed: [server1] => (item=/home/ubuntu/Desktop/newDir3)
changed: [server1] => (item=/home/ubuntu/Desktop/newDir4)

TASK [ansible create directory from External File] *
changed: [server1]

TASK [ansible create directory with timestamp] *
changed: [server1]

TASK [ansible delete directory]
changed: [server1]

TASK [Copy files]
changed: [server1]

TASK [Execute the command in remote shell; stdout goes to the specified file on the remote] **
changed: [server1]

PLAY RECAP *
server1 : ok=9 changed=7 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

Note :

You can use prefix ANSIBLE_DEBUG=1 to get debug information.

eg : $ ANSIBLE_DEBUG=1 ansible-playbook -u ubuntu -i inventory/ playbook.yml

Further readings :

• https://docs.ansible.com/ansible/latest/collections/ansible/builtin
• https://www.digitalocean.com/community/tutorial_series/how-to-manage-remote-servers-with-ansible
• https://www.tutorialspoint.com/ansible/ansible_playbooks.htm
• https://techrideradmin.blogspot.com/2018/09/create-directory-in-ansible.html
• https://www.mydailytutorials.com/ansible-create-directory/
• https://www.youtube.com/watch?v=EcnqJbxBcM0&t=141s

#ansible, #config-management

<< Previous : https://knowledgehunter.code.blog/2020/10/10/setup-ansible-in-local/

In the previous aritcle we setup our VM and installed Ansible.

First ssh to the VM to see the user, password and ip is ok. You must be able to log with password.

eg : ssh ubuntu@192.168.1.20

Note : you can get the IP by running the ifconfig on the VM’s terminal.

Get ready…

Let’s try to run some basic Ansible commands.

First of all, to run Ansible, you need to have

1. One Ansible Control Node : machine we’ll use to connect to and control the Ansible hosts over SSH
2. One or more Ansible Hosts : any machine that your Ansible control node is configured to automate

In this case, our local PC is the Ansible Control Node and VM is the Ansible Host.

There are some prerequisites fulfilled before start playing with Ansible…

1. Ansible Control Node must have a non-root user with sudo privileges.
2. Ansible Control Node must have SSH keypair associated with this user.

Note : In this case, you must have been already setup the SSH Keys on the local PC. Otherwise refer : https://www.digitalocean.com/community/tutorials/how-to-set-up-ssh-keys-on-ubuntu-20-04,

Or you can generate SSH Keys using IDE’s also like eclipse

[Windows > Preferences > General > Network Connection > SSH2 > Key Management> Generate RSA Key]

3. The Ansible control node’s SSH public key must have been added to Ansible Host’s authorized_keys for a system user.

You can easily do this by using ssh-copy-id in ssh-copy-id username@remote_host format

eg : $ssh-copy-id ubuntu@192.168.1.20

Note :

Sometimes you may get below like error

sign_and_send_pubkey: signing failed for RSA “/home/user/.ssh/id_rsa” from agent: agent refused operation

In this case, you must add the ssh keys to Agent using $ ssh-add.

Here. if you get below like warning, you must change the access of the .ssh/id_rsa by running chmod 600 ~/.ssh/id_rsa since the private key has been exposed. Otherwise again ssh-copy-id will fail.

Warining : Permissions 0664 for ‘/home/namal/.ssh/id_rsa’ are too open.
It is required that your private key files are NOT accessible by others.
This private key will be ignored.

Once above done, run ssh-copy-id ubuntu@192.168.1.20 again and you should see a success message.

Then try to run ssh ubuntu@192.168.1.20 again this time you must be able to connect without giving the password. This is password less login

Now environment is ready to do Ansible ping..

Do Ansible ping..

Ansible ping means running a connectivity test using Ansible’s built-in ping module. The ping module will test:

• if hosts are accessible;
• if you have valid SSH credentials;
• if hosts are able to run Ansible modules using Python.

Hosts file…

You must define the host detail (IPs) in the file called .

The default location for hosts file is /etc/ansible/hosts. But you can define the hosts file in any location you want.

You must define the hosts IPs in the hosts file as mentioned below

[servers]
server1 ansible_host=203.0.113.111
server2 ansible_host=203.0.113.112
server3 ansible_host=203.0.113.113

These server1, server2, and server3 are custom aliases.

Note :

You can define all:vars subgroup also there as mentioned below.

[all:vars]
ansible_python_interpreter=/usr/bin/python3

This parameter makes sure the remote server uses the /usr/bin/python3 Python 3 executable instead of /usr/bin/python (Python 2.7), which is not present on recent Ubuntu versions.

Once the hosts file is defined you can run below command to list the inventories

ansible-inventory –list -y

Note :

If you run any ansible command having specific hosts file (not the generic on in /etc/ansible/hosts), you must give the path (absolute or relative path) using -i flag as follows

if the host file is in the same location that ansible command is executing : -i .

otherwise : -i

eg :

1. ansible-inventory –list -y -i .

2. ansible-inventory –list -y -i inventory

3. ansible-inventory –list -y -i /home/user/ansibleProjects/inventory

If everything is ok you’ll see success response as mentioned below

all:
  children:
    servers:
      hosts:
        server1:
          ansible_host: 103.0.113.111
        server2:
          ansible_host: 103.0.113.112
        server3:
          ansible_host: 103.0.113.113
    ungrouped: {}

Execute…

Then we can run the ansible ping command

ansible all -m ping -u

eg : ansible all -m ping -u ubuntu

For the success responses you’ll get pong for ping as mentioned below.

Outputserver1 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
server2 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}
server3 | SUCCESS => {
    "changed": false, 
    "ping": "pong"
}

Note : this all will execute the ansible module in all the hosts. If you want to execute it only on certain hosts you can mention those specifically. eg :ansible server1 -m ping -u ubuntu

reference : https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-ansible-on-ubuntu-20-04

https://knowledgehunter.code.blog/2020/10/11/lets-play-ansible-book/ Next >>

#ansible, #config-management