#ansibleja

1. Dynamic inventory:
No more host list!
#ansibleja Ansible勉強会#1
2014/06/10
@tagomoris
14年6月10日火曜日

2. TAGOMORI Satoshi (@tagomoris)
LINE Corp.
14年6月10日火曜日

3. Ansible
Batch server operations
add routing table entry
deploy ssh keys
update openssl
Install/update middleware
Hadoop, Presto, Fluentd (and its config/code ...)
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4. Ansible: good points
Minimal managed node requirements
Simple tool chain and files
YAML
and many built-in modules
Less stress of shell scripts
Dynamic inventory
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5. Ansible: bad points
Less japanese case-studies
Less japanese books and blog entries
Less japanese users? -> No!
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6. Inventory
Hosts and groups
Host variables / Group variables
Group of groups
‘group_vars/’ and ‘host_vars/’
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7. Inventory: example
mail01.local globalip=192.168.0.11
[blog]
www[01:30].blog.local virtualip=203.0.113.63
app[01:50].blog.local
master01.db.blog.local server_id=....
slave0[1:4].blog.local server_id=..????
[linenantoka]
www[01:10].nantoka.line.local
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8. ROLEs and TYPEs
Roles (web, app, db, hadoop, ...)
Groups (service-names, ...)
OSs, Server models, Disk types (HDD, SSD, ioDrive, ...)
IP addrs (local, global, virtual)
... and many more
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9. Yabitz
Our host management tool/server:
WebUI and WebAPI (json)
hostname[s], status, service, CPU, memory, disk,
rack position, size, local/global/virtual IPs, virtual/
parent server, ....
tags
changes(history, diff)
anything
links to other internal web tools
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10. Dynamic inventory
Dynamic inventory plugins
Cobbler external inventory script
Example for linux install server
AWS EC2 external inventory script
Digital Ocean, Google Compute Engine, Linode,
Zabbix, ...
Mix inventories (static and dynamic)
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11. Custom dynamic inventory
Original scripts AS dynamic inventory
“Developing Dynamic Inventory Sources”
http://docs.ansible.com/developing_inventory.html
executable program
implement `--list`
implement `--host HOSTNAME`
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12. JSON: for `--list`
Dynamic inventory: output
{
"databases": {
"hosts": [ "host1.local", "host2.local" ],
"vars": {
"a": true
}
},
"webservers": [ "host2.local", "host3.local" ],
"tokyo": {
"hosts": [ "host1.local", "host4.local", "host5.local" ],
"vars": {
"b": false
},
"children": [ "shibuya", "ebisu" ]
},
"shibuya": [ "host6.local" ],
"ebisu": [ "host7.local" ]
}
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13. JSON: for `--host HOSTNAME`
Dynamic inventory: output
{
“localip”: “192.0.2.53”,
“virtualip”: “203.0.113.53”,
“global_fqdn”: “tagomoris.example.com”,
}
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14. Dynamic inventory reference
1. inventory --list
2. inventory --host host1.local
3. inventory --host host2.local
4. inventory --host host4.local
5. ...
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15. Playbook execution
$ ansible-playbook PLAYBOOK_PATH.yml
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16. Yabitz inventory
ansible-playbook
bin/yabitz_inventory
Yabitz
playbooks/PLAYBOOK.yaml
Servers
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17. Role based playbooks
Flat playbook directory
playbooks/*.yaml
playbooks/SERVICE_NAME/*.yaml
“hosts” are always roles
hosts: centos
hosts: centos6
hosts: hadoop-slave
hosts: hadoop-all-nodes:fluentd-all-nodes
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18. Yabitz tags and ROLEs
Tags
Server-type-tag (by studio3104 crawler)
centos
centos5, centos6
Role-based-tag
hadoop-all-nodes
hadoop-master, service-hadoop-master2
hadoop-slave
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19. Implementation examples
ansible.cfg
[defaults]
hostfile=/path/to/bin/yabitz_inventory
commands
$ ansible-playbook playbooks/update-openssl.yaml
$ TARGET_HOSTS=host1.local,host2.local
ansible-playbook playbooks/SERVICE/foo.yaml
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20. No more host lists!
Ansible inventory is very simple and understandable
But we cannot use it for real world operations
especially for hundreds or thousands of hosts...
Use dynamic inventory!
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21. Role based playbook testing
Serverspec
testing without breaking operations
providing double check (beside of ansible)
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22. Serverspec directories
from http://serverspec.org/tutorial.html
host based spec directory tree
spec/
SERVERNAME/
function_spec.rb
and exec (`rake spec`)
“How to share serverspec tests among hosts”
http://serverspec.org/advanced_tips.html
static file based test sharing
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23. Specs and roles
Role based provisioning
roles-to-hosts resolution MUST be done dynamically
Helper command to get roles from playbooks
and role based spec directory
bin/kick-spec
spec/ROLE/*_spec.rb
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24. Implementation example(2)
$ bin/kick-spec playbooks/BOOK.yaml
$ bin/kick-spec playbooks/BOOK.yaml
--host host1.local --host host2.local
$ bin/kick-spec --role latest_openssl
--host host5.local
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25. Conclusion
DO NOT write same data in 2 or more files
USE master data from anywhere
Dynamic inventory makes it possible!
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26. NO MORE HOST
LISTS!!!!!!!!
Thanks!
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27. Appendix: “_meta”(1)
Special attribute of JSON for `--list`
To include host variables in single JSON result
No more exec: `--host HOST`
{
“shibuya”: [ “host6.local” ],
“ebisu”: [ “host7.local” ],
“_meta”: {
“hostvars”: {
“host6.local”: { “var1”: “value1”, “var2”: “value2” },
“host7.local”: { .... }
}
}
}
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28. Without `_meta`:
`--list` x1 and `--host` x1000 !
With `_meta`:
`--list` x1 only!
Appendix: “_meta”(2)
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29. Benchmark: time before task starts
w/ yabitz_inventory
for thousands of hosts
Appendix: “_meta”(3)
w/o _meta w/ _meta
Elapsed time 18min! 10sec!!!!
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