We need documents for human, not for robots.
What is ansible?
Ansible is a tool for DevOps. It can be used to：
- define server groups in inventory
- control a group of servers like localhost
- setup environments on servers
- install, update, remove apps
- write, copy files
- execute command on servers
- use playbooks to execute a series of tasks
- use others’ playbooks as roles from ansible galaxy
The easiest way to learn how to use ansible is learning from examples. Only when you find some key words that confuse you that you need to check the official documents with search engines.
Here I’d like to give you some simple introductions.
TOML like file that defines the group of servers. If you already defined some hosts in
$HOME/.ssh/config, you can use the host name instead of IP address.
[master] 10.0.0.1 [worker] 10.0.10.1 10.0.10.2 10.0.10.3
In the file above, we define two groups of servers. Then you can use
all as group name. Save this file as
/etc/ansible/hosts so you can use it anywhere.
Ping all the servers:
ansible all -m ping.
Run a live command:
ansible worker -a "/bin/echo $USER"
Playbooks and roles
You can execute a series of tasks defined in the playbooks. First of all, check if there exists roles that already done the same thing you need. Roles can be found from Ansible Galaxy.
Playbooks is defined in yaml file.
- hosts: all become: yes roles: - nvidia.nvidia_driver - nvidia.nvidia_docker tasks: - name: turn off swap command: swapoff -a when: ansible_swaptotal_mb > 0 - name: add k8s GPG key apt_key: url=https://packages.cloud.google.com/apt/doc/apt-key.gpg - name: install kubectl kubelet kubeadm apt: name: ['kubelet','kubectl','kubeadm'] state: present update_cache: yes
For each task, you can do almost everything like
replace. Find what you need with search engines.
ansible-playbook -i inventory k8s.yml
This is almost everything you need to know about ansible as a beginner :)
As usual, GitHub and StackOverflow are still your best friends.