ansible使用8-Best Practices

Content Organization

production                # inventory file for production servers
stage                     # inventory file for stage environment

group_vars/
   group1                 # here we assign variables to particular groups
   group2                 # ""
host_vars/
   hostname1              # if systems need specific variables, put them here
   hostname2              # ""

library/                  # if any custom modules, put them here (optional)
filter_plugins/           # if any custom filter plugins, put them here (optional)

site.yml                  # master playbook
webservers.yml            # playbook for webserver tier
dbservers.yml             # playbook for dbserver tier

roles/
    common/               # this hierarchy represents a "role"
        tasks/            #
            main.yml      #  <-- tasks file can include smaller files if warranted
        handlers/         #
            main.yml      #  <-- handlers file
        templates/        #  <-- files for use with the template resource
            ntp.conf.j2   #  <------- templates end in .j2
        files/            #
            bar.txt       #  <-- files for use with the copy resource
            foo.sh        #  <-- script files for use with the script resource
        vars/             #
            main.yml      #  <-- variables associated with this role
        defaults/         #
            main.yml      #  <-- default lower priority variables for this role
        meta/             #
            main.yml      #  <-- role dependencies

    webtier/              # same kind of structure as "common" was above, done for the webtier role
    monitoring/           # ""
    fooapp/               # ""

Use Dynamic Inventory With Clouds

Dynamic Inventory

How to Differentiate Stage vs Production

# file: production

[atlanta-webservers]
www-atl-1.example.com
www-atl-2.example.com

[boston-webservers]
www-bos-1.example.com
www-bos-2.example.com

[atlanta-dbservers]
db-atl-1.example.com
db-atl-2.example.com

[boston-dbservers]
db-bos-1.example.com

# webservers in all geos
[webservers:children]
atlanta-webservers
boston-webservers

# dbservers in all geos
[dbservers:children]
atlanta-dbservers
boston-dbservers

# everything in the atlanta geo
[atlanta:children]
atlanta-webservers
atlanta-dbservers

# everything in the boston geo
[boston:children]
boston-webservers
boston-dbservers

# 按主机、区域、数据中心划分

Group And Host Variables

---
# file: group_vars/atlanta
ntp: ntp-atlanta.example.com
backup: backup-atlanta.example.com

---
# file: group_vars/webservers
apacheMaxRequestsPerChild: 3000
apacheMaxClients: 900

---
# file: group_vars/all
ntp: ntp-boston.example.com
backup: backup-boston.example.com

---
# file: host_vars/db-bos-1.example.com
foo_agent_port: 86
bar_agent_port: 99

# 注意主机变量＆组变量的覆盖

Top Level Playbooks Are Separated By Role

---
# file: site.yml
- include: webservers.yml
- include: dbservers.yml

---
# file: webservers.yml
- hosts: webservers
  roles:
    - common
    - webtier

ansible-playbook site.yml --limit webservers
ansible-playbook webservers.yml

Task And Handler Organization For A Role

---
# file: roles/common/tasks/main.yml

- name: be sure ntp is installed
  yum: pkg=ntp state=installed
  tags: ntp

- name: be sure ntp is configured
  template: src=ntp.conf.j2 dest=/etc/ntp.conf
  notify:
    - restart ntpd
  tags: ntp

- name: be sure ntpd is running and enabled
  service: name=ntpd state=running enabled=yes
  tags: ntp

---
# file: roles/common/handlers/main.yml
- name: restart ntpd
  service: name=ntpd state=restarted

What This Organization Enables (Examples)

ansible-playbook -i production site.yml
ansible-playbook -i production site.yml --tags ntp
ansible-playbook -i production webservers.yml

ansible-playbook -i production webservers.yml --limit boston
ansible-playbook -i production webservers.yml --limit boston[0-10]
ansible-playbook -i production webservers.yml --limit boston[10-20]

ansible boston -i production -m ping
ansible boston -i production -m command -a '/sbin/reboot'

# confirm what task names would be run if I ran this command and said "just ntp tasks"
ansible-playbook -i production webservers.yml --tags ntp --list-tasks

# confirm what hostnames might be communicated with if I said "limit to boston"
ansible-playbook -i production webservers.yml --limit boston --list-hosts

Deployment vs Configuration Organization

Stage(test) vs Production

Rolling Updates

Delegation, Rolling Updates, and Local Actions.

Always Mention The State

Group By Roles

Operating System and Distribution Variance