Push Based Vs Pull Based CM
- In PUll Based CM, on the nodes we need to install software agents of CM Server who will be responsible for communication
- In Push based CM, no agents are required on the nodes.
- In Push based CM, CM Server needs to have
- a list of nodes to communicate
- credentials to login
- Communication Protocol (SSH/Winrm) enabled on nodes
- In both pull based and push based CM, we would have the following properties
- Idempotance: Result of execution of the script should be same (desired state) irrespective of execution count.
- Advantages of Push based CM
- Simpler to use
- Control over the entire system
- No agents are required to be installed on nodes
- Advantages of Pull Based CM
- Easier to Scale
- No need of credentials of nodes
Installing Ansible:
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Ansible is written in Python, To run ansible we need python to be installed on Ansible Control Server (CM Server) and also nodes
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Ansible Control Server can be installed on
- Linux
- FreeBSD
- macOS
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Nodes can be
- Linux
- Free BSD
- MacOS
- Windows
- Network Switches
- Routers
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Lets install ansible based on the below architecture
-
Configure Windows Terminal Refer Here
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Installing ansible on
- Ubuntu Refer Here
- Redhat, Centos , Fedora Refer Here
- Refer Here for all the possibilities
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Lets create a ubuntu vm
- AWS Refer Here
- Azure Refer Here
-
Login in to the ubuntu instance and execute the following commands
sudo apt update
sudo apt install software-properties-common
sudo apt-add-repository --yes --update ppa:ansible/ansible
sudo apt install ansible -y
python --version
ansible --version
- Create an ubuntu 18 node in aws/azure as mentioned above
- The only requirement for any machine to be ansible node is python should be installed.
- For today lets try to install the same version of python as in ansible control server.
sudo apt update
sudo apt install software-properties-common
sudo apt-add-repository --yes --update ppa:ansible/ansible
sudo apt install python -y
- Now we have node and ansible control server ready, so lets try to understand what ansible does to connect to a node
- Ansible needs to have ipaddress/dns name of the node in a file which is referred as inventory
- Ansible needs the credentials of the node (username & password) or (username and key)
- So lets create a inventory is
172.31.45.255
- Now create a file called as inventory in /home/ubuntu/inventory with the following content
172.31.45.255
- At this moment lets run the test command to verify if ansible can communicate with the node
ansible -i inventory -m ping all
- Lets understand how ansible works and resolve the error in the next class
