Introduction to Ansible

This is an introduction to Ansible I gave at cfgmgmtcamp 2014

Transcript

1. ANSIBLE ANSIBLE INTRODUCTION TO ANSIBLE INTRODUCTION TO ANSIBLE Mattias Gees / @MattiasGees
2. WHAT IS ANSIBLE? WHAT IS ANSIBLE? Started in February 2012 By Michael DeHaan More than 600 Contributors Orchestration Engine Con guration Management Application Deployment Continuous Delivery
3. ONLINE RESOURCES ONLINE RESOURCES
4. WEBSITE WEBSITE
5. DOCUMENTATION DOCUMENTATION
6. MAILING LISTS MAILING LISTS ansible-announce ansible-project ansible-devel
7. IRC IRC #ANSIBLE #ANSIBLE
8. GITHUB GITHUB HTTPS://GITHUB.COM/ANSIBLE/ANSIBLE HTTPS://GITHUB.COM/ANSIBLE/ANSIBLE
9. BENEFITS BENEFITS
10. NO AGENT REQUIRED NO AGENT REQUIRED SSH SSH
11. EASY TO INSTALL EASY TO INSTALL # EPEL repo yum install ansible # Available through a PPA apt-get install ansible pip install ansible
12. REQUIREMENTS REQUIREMENTS Control machine: Python 2.6 Managed node: Python 2.4 python-simplejson libselinux-python
13. YAML SYNTAX YAML SYNTAX --- - yum: name= state=installed with_items: - app_server - acme_software - service: name=app_server state=running enabled=yes - template: src=/opt/code/templates/foo.j2 dest=/etc/foo.conf notify: - restart app server
14. SCALABLE SCALABLE
15. CUSTOMIZABLE CUSTOMIZABLE
16. COMMANDS COMMANDS ansible ansible-playbook ansible-pull ansible-doc ansible-galaxy
17. MODULES MODULES Run on remote host Control system resources, executing system commands Noti cation Easy to write new modules
18. MODULES MODULES Cloud Commands Database Files Internal Inventory Messaging Monitoring Net Infrastructure Network Noti cation Packaging Source Control System Utilities Web Infrastructure
19. INVENTORY INVENTORY Contains all the managed hosts Can contain variables Flat le(s) or script (dynamic inventory) Can interact with your own CMDB Multiple inventory sources
20. INVENTORY INVENTORY mail.example.com [webservers] foo.example.com bar.example.com [dbservers] one.example.com two.example.com three.example.com [servers:children] webservers dbservers
21. INVENTORY INVENTORY jumper ansible_ssh_port=5555 ansible_ssh_host=192.168.1. [webservers] www[01:50].example.com [webserver:vars] port=80
22. ANSIBLE ANSIBLE Basic tasks Information from system(s) Execute one module Usage: ansible host-pattern [options]
23. ANSIBLE ANSIBLE ansible all -m ping -o ansible demo -m setup ansible foo.example.com -a “/usr/sbin/reboot” ansible demo -m file -a "dest=/srv/foo/a.txt mode=600" -o ansible demo-one -m yum -a "name=httpd state=installed" ansible demo-one -m service -a "name=httpd state=started"
24. PLAYBOOKS PLAYBOOKS Execution of tasks One task is one module Variables Handlers Idempotent
25. ANSIBLE ANSIBLE --- - hosts: http remote_user: user sudo: yes vars: in_ports: - 80 tasks: - name: install httpd action: yum name=httpd state=latest - name: copy httpd.conf action: template src=httpd.conf.j2 dest=/etc/httpd/conf/httpd.conf owner=root group=root
26. ROLES ROLES Reusable list of tasks Has one goal (eg deploy apache) Reusable --- - hosts: demo gather_facts: False connection: local serial: 1 vars: in_ports: - 80 roles: - httpd - mysql - iptables
27. TEMPLATES TEMPLATES Jinja2 templating engine Use of variables in les Loops, Conditionals, Filters, ... < Proxy balancer://{{ balancer_name }}> {% for host in groups['demo-web'] %} BalancerMember http://{{ hostvars[host].ansible_eth1.ipv4.address }} {% endfor %} Order allow,deny Allow from all < /Proxy>
28. ANSIBLE-PLAYBOOK ANSIBLE-PLAYBOOK Execute a playbook Set-up a whole environment / host(s) Usage: ansible-playbook playbook.yml -i inventory -l limit to host / group
29. EXTRA FEATURES EXTRA FEATURES
30. ACCELERATED MODE ACCELERATED MODE --- - hosts: all accelerate: true # default port is 5099 accelerate_port: 10000
31. ASYNCHRONOUS ACTIONS AND POLLING ASYNCHRONOUS ACTIONS AND POLLING --- - hosts: all remote_user: root tasks: - name: simulate long running op (15 sec), wait for up to 45, poll every 5 command: /bin/sleep 15 async: 45 poll: 5
32. CHECK MODE CHECK MODE Usage: ansible-playbook foo.yml --check --- tasks: - name: this task is run even in check mode command: /something/to/run --even-in-check-mode always_run: yes Usage: ansible-playbook foo.yml --check --diff --limit foo.example.com
33. ROLLING UPDATES ROLLING UPDATES --- - name: test play hosts: webservers serial: 3 MAX FAILURE PERCENTAGE MAX FAILURE PERCENTAGE --- - hosts: webservers max_fail_percentage: 30 serial: 10
34. DELEGATION DELEGATION --- - hosts: webservers serial: 5 tasks: - name: take out of load balancer pool command: /usr/bin/take_out_of_pool {{ inventory_hostname }} delegate_to: loadbalancer.example.com - name: actual steps would go here yum: name=acme-web-stack state=latest - name: add back to load balancer pool command: /usr/bin/add_back_to_pool {{ inventory_hostname }} delegate_to: loadbalancer.example.com
35. LOCAL ACTIONS/PLAYBOOKS LOCAL ACTIONS/PLAYBOOKS --- # ... tasks: - name: recursively copy files from management server to target local_action: command rsync -a /path/to/files {{ inventory_hostname }}:/pa Usage: ansible-playbook playbook.yml --connection=local --- - hosts: demo connection: local
36. ERROR HANDLING / OVERRIDING OUTPUT ERROR HANDLING / OVERRIDING OUTPUT --- - name: this will not be counted as a failure command: /bin/false ignore_errors: yes - name: this command prints FAILED when it fails command: /usr/bin/example-command -x -y -z register: command_result failed_when: "'FAILED' in command_result.stderr" - shell: /usr/bin/billybass --mode="take me to the river" register: bass_result changed_when: "bass_result.rc != 2"
37. LOOKUPS LOOKUPS --- - hosts: all tasks: - debug: msg="{{ lookup('env','HOME') }} is an environment variable" - debug: msg="{{ item }} is a line from the result of this command" with_lines: - cat /etc/motd - debug: msg="{{ lookup('pipe','date') }} is the raw result of running th - debug: msg="{{ lookup('redis_kv', 'redis://localhost:6379,somekey') }} - debug: msg="{{ lookup('dnstxt', 'example.com') }} is a DNS TXT record f
38. PROMPTS PROMPTS --- - hosts: all remote_user: root vars: from: "camelot" vars_prompt: name: "what is your name?" quest: "what is your quest?" vars_prompt: - name: "release_version" prompt: "Product release version" default: "1.0"
39. TAGS TAGS --- tasks: - yum: name={{ item }} state=installed with_items: - httpd - memcached tags: - packages - template: src=templates/src.j2 dest=/etc/foo.conf tags: - configuration Usage: ansible-playbook example.yml --tags "configuration,packages" --- roles: - { role: webserver, port: 5000, tags: [ 'web', 'foo' ] } --- - include: foo.yml tags=web,foo
40. BEST PRACTICES BEST PRACTICES 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 # "" site.yml # master playbook webservers.yml # playbook for webserver tier dbservers.yml # playbook for dbserver tier roles/ common/ # this hierarchy represents a "role" tasks/ #
41. ANSIBLE-PULL ANSIBLE-PULL Host gets Ansible con guration Git SVN NFS ... Runs the playbook on itself No central machine needed Enforcing of con guration Usage: ansible-pull [options] playbook.yml
42. ANSIBLE-DOC ANSIBLE-DOC View documentation of modules Usage: ansible-doc yum -M module_path
43. ANSIBLE-GALAXY ANSIBLE-GALAXY Download roles http://galaxy.ansible.com Usage: ansible-galaxy install bennojoy.nginx
44. THANK YOU THANK YOU MATTIAS GEES MATTIAS GEES / @MattiasGees mattias.gees@btr-services.be