Introduction to Ansible
RECRUIT
1. What is Ansible?
Ansible is a newly emerging automation operation and maintenance tool developed based on Python, which integrates the advantages of many operation and maintenance tools (puppet, chef, func, fabric) to achieve functions such as batch system configuration, batch program deployment, and batch command execution.
Ansible is developed based on paramiko and works on a modular basis; it does not have the capability for batch deployment by itself. The real batch deployment capability comes from the modules that Ansible runs; Ansible merely provides a framework. Ansible does not require the installation of clients/agents on remote hosts because it communicates with remote hosts via SSH. Ansible has now been officially acquired by Red Hat.
2. Ansible Management Method
Ansible is a model-driven configuration manager that supports multi-node deployment and remote task execution. It uses SSH for remote connections by default. There is no need to install additional software on the managed nodes, and it can be extended using various programming languages. The Ansible management system consists of a control host and a group of managed nodes. The control host directly controls the managed nodes via SSH, and the managed nodes are grouped and managed through Ansible’s inventory.
3. Ansible Architecture
4. Ansible Task Execution Modes
The operations of the control host on the managed nodes can be divided into two categories: ad-hoc and playbook:
(1) Ad-hoc mode (point-to-point mode)
Using a single module, it supports batch execution of a single command. An ad-hoc command is a command that can be quickly entered and does not need to be saved. It is equivalent to a one-liner shell command in bash.
(2) Playbook mode (script mode)
This is the main management method of Ansible and the key to Ansible’s powerful functionality. Playbooks complete a type of function through multiple task collections, such as the installation and deployment of web services, or batch backups of database servers. A playbook can be simply understood as a configuration file that combines multiple ad-hoc operations.
5. Ansible Execution Process
Ansible Deployment
RECRUIT
1. Install RHEL9 Version Virtual Machine
Configure IP information
2. Configure Local Yum Repository, Create server.repo in /etc/yum.repos.d/ Directory, Then Configure.
mount /dev/cdrom /mnt
vim /etc/yum.repos.d/server.repo
[aa]
name=aa1
baseurl=file:///mnt/BaseOS
enabled=1
gpgcheck=0
[bb]
name=bb1
baseurl=file:///mnt/AppStream
enabled=1
gpgcheck=0
Save and Exit
3. Install Software Package Groups
yum group install “Virtualization Client” “Virtualization Hypervisor” “Virtualization Tools” -y
4. Restart libvirtd Service and Set to Start on Boot
Systemctl restart libvirtd
Systemctl enable libvirtd
5. Upload Local RHEL9.2 Image to Virtual Machine
6. Use virt-manager to Open Virtual Console for System Installation
7. Clone 5 Nodes + One Just Installed, Total 6 Hosts
192.168.122.100 master.example.com
192.168.122.10 node1.example.com
192.168.122.20 node2.example.com
192.168.122.30 node3.example.com
192.168.122.40 node4.example.com
192.168.122.50 node5.example.com
8. For All Hosts, When Configuring IP, Pay Attention to Remove the UUID from the Network Configuration File
9. For All Hosts, Edit /etc/hosts
192.168.122.1 ansible.example.com ansible
192.168.122.100 master.example.com master
192.168.122.10 node1.example.com node1
192.168.122.20 node2.example.com node2
192.168.122.30 node3.example.com node3
192.168.122.40 node4.example.com node4
192.168.122.50 node5.example.com node5
10. Configure Passwordless Login for Master Host
(1) Operate with root user and student user separately
ssh-keygen Press Enter until Finished
(root user)
for i in node{1..5}
do ssh-copy-id -i ~/.ssh/id_rsa.pub root@$i
done
for i in node{1..5}
do ssh-copy-id -i ~/.ssh/id_rsa.pub student@$i
done
(student user)
for i in node{1..5}
do ssh-copy-id -i ~/.ssh/id_rsa.pub root@$i
done
for i in node{1..5}
do ssh-copy-id -i ~/.ssh/id_rsa.pub student@$i
done
11. Configure Yum Repository
Configure local yum repository on the host machine ansible, then install
httpd service
Upload package files to /var/www/html/ directory, then
Restart httpd service and set to start on boot
Turn off firewall, selinux
12. Deploy Yum Repository on Master Host
vi /etc/yum.repos.d/server.repo
[aa]
name=aa1
baseurl=http://ansible.example.com/rhel9/BaseOS
enabled=1
gpgcheck=0
[cc]
name=cc1
baseurl=http://ansible.example.com/rhel9/AppStream
enabled=1
gpgcheck=0
[dd]
name=dd1
baseurl=http://ansible.example.com/ansible-automation-platform
enabled=1
gpgcheck=0
13. Grant Privileges to Student User
vim /etc/sudoers.d/student
student ALL=(ALL) NOPASSWD: ALL
14. Install Ansible
Switch to student user su – student
sudo yum -y install ansible-core ansible-navigator
