# More configuration options for EC2 dynamic inventories **URL:** \ **Category:** Ansible Developer\ **Tags:** aws\ **Created:** [June 17, 2014, 9:22pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486 "2014-06-17T21:22:08Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Michael\_Peters](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@Michael\_Peters](https://forum.ansible.com/u/Michael_Peters)\ **Post date:** [June 17, 2014, 9:22pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/1 "2014-06-17T21:22:08Z")
All, I've recently begun using the ec2.py dynamic inventory script and I've thought of some relatively simple optional enhancements that would be driven by the ec2.ini configuration file and wanted to see if there was any interest in having them included. I'd rather not maintain a company specific fork and I think these features are generic enough to be useful to others. And since they would be optional and only take effect if explicitly configured then they won't impact folks that don't want them. 1) All of the built-in ec2\_\* facts are lowercase, but because some of the keys are dynamic from user data in EC2 they can be a mish-mash of cases. I propose a config setting that would allow them to be either coerced into the same case or allow aliases (eg, have ec2\_tag\_Name and ec2\_tag\_name point to identical lists). 2) Allow host aliases from other fields. I'm using EC2 inside of VPCs and the private\_ip\_address makes sense as the destination\_variable and unique host name. But having a bunch of 10.0.0.\* IPs flash across the screen as tasks are executed isn't ideal since I don't memorize them. It would be nice to be able to have something like "destination\_alias" (and vpc\_destination\_alias) that would let me pick some other field like ec2\_tag\_Name or ec2\_tag\_ShortName, etc. This would also make it easier to target a specific host from the command line with "-l app1" instead of "-l 10.0.0.123" after having to look up the private IP from AWS. 3) Group aliases. I'm using a VPC for each environment for production, staging, etc but local development takes place on local virtual machines (using vagrant). If my hosts criteria becomes "ec2\_tag\_role\_web" instead of just "web" then it makes it harder to manage environments that aren't in EC2. So being able to have a way to create an alias for a group would be nice. I'm not totally sure of the right way to present this as configuration so that it's dynamic, but if there's interest I can come up with a couple of ideas and see what people think. Anyways, thanks for reading this far. ---
**Author:** ![Michael\_Peters](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@Michael\_Peters](https://forum.ansible.com/u/Michael_Peters)\ **Post date:** [June 18, 2014, 1:25pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/2 "2014-06-18T13:25:11Z")
I’ve thought of another feature that would be helpful. I have several similar, isolated environments running in their own VPC and some random machines running in EC2 classic. It would be helpful (and faster) if the dynamic inventor could be restricted to only machines in the subnet where ansible is running. So, if I submitted some of these as pull requests would anyone else be interested? ---
**Author:** ![Michael\_DeHaan1](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael\_DeHaan1](https://forum.ansible.com/u/Michael_DeHaan1)\ **Post date:** [June 18, 2014, 3:43pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/3 "2014-06-18T15:43:25Z")
> All, > > I've recently begun using the ec2.py dynamic inventory script and I've > thought of some relatively simple optional enhancements that would be > driven by the ec2.ini configuration file and wanted to see if there > was any interest in having them included. > > I'd rather not maintain a company specific fork and I think these > features are generic enough to be useful to others. And since they > would be optional and only take effect if explicitly configured then > they won't impact folks that don't want them. The inventory plugins are in fact examples so if there become too many different customization options that are idiomatic, maintaining someone's own copy is ok. > 1) All of the built-in ec2\_\* facts are lowercase, but because some of > the keys are dynamic from user data in EC2 they can be a mish-mash of > cases. I propose a config setting that would allow them to be either > coerced into the same case or allow aliases (eg, have ec2\_tag\_Name and > ec2\_tag\_name point to identical lists). These are pretty much coming from Boto - though we don't want to create different groups as that would bloat the number of groups. An option like downcase\_facts=False # default False would be reasonable > 2) Allow host aliases from other fields. I'm using EC2 inside of VPCs > and the private\_ip\_address makes sense as the destination\_variable and > unique host name. But having a bunch of 10.0.0.\* IPs flash across the > screen as tasks are executed isn't ideal since I don't memorize them. > It would be nice to be able to have something like "destination\_alias" > (and vpc\_destination\_alias) that would let me pick some other field > like ec2\_tag\_Name or ec2\_tag\_ShortName, etc. This would also make it > easier to target a specific host from the command line with "-l app1" > instead of "-l 10.0.0.123" after having to look up the private IP from > AWS. I'm finding the sprawling of aliases to be somewhat confusing, but it should also be the case that users should not get attached to EC2 hostnames (treat machines like cattle, not pets -- don't give them names). I guess my resistance here is this starts to make it very confusing as to what someone should set up to get started. I am perhaps persuadable on this topic but it would require more documentation explaining in in a really simple easy to understand way with suggestions. > 3) Group aliases. I'm using a VPC for each environment for production, > staging, etc but local development takes place on local virtual > machines (using vagrant). If my hosts criteria becomes > "ec2\_tag\_role\_web" instead of just "web" then it makes it harder to > manage environments that aren't in EC2. So being able to have a way to > create an alias for a group would be nice. I'm not totally sure of the > right way to present this as configuration so that it's dynamic, but > if there's interest I can come up with a couple of ideas and see what > people think. In the above I think I'm reading that "ec2-tag\_role\_" starting the tag is too much typing. I am not sure I believe this makes them harder to manage. I believe it is important that we continue to indicate which things come from tags rather than making things automagic, especially when it's not an EC2 convention. As such, I'd suggest we not do this at this time. I do understand what you say about your Vagrant groups not being named ec2\_tag\_foo, but a way to solve this would be to make ec2\_tag\_foo a child group of a group with a different name. ---
**Author:** ![Michael\_Peters](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@Michael\_Peters](https://forum.ansible.com/u/Michael_Peters)\ **Post date:** [June 18, 2014, 4:31pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/4 "2014-06-18T16:31:38Z")
> The inventory plugins are in fact examples so if there become too many > different customization options that are idiomatic, maintaining someone's > own copy is ok. While I agree in principle, if I have some feature requests that seem generic and reusable to others, I usually default to trying to get those changes into the project itself and not my fork. > These are pretty much coming from Boto - though we don't want to create > different groups as that would bloat the number of groups. > An option like downcase\_facts=False # default False > > would be reasonable Yeah, I definitely understand about group bloat since there are already so many. I'll go with the downcase\_facts route. > I'm finding the sprawling of aliases to be somewhat confusing, but it should > also be the case that users should not get attached to EC2 hostnames (treat > machines like cattle, not pets -- don't give them names). I guess my > resistance here is this starts to make it very confusing as to what someone > should set up to get started. I agree with the cattle/pets analogy, but sometimes it's just useful to be able to see something like   ok: [web25]   failed: [web26] vs just   ok: [10.0.0.123]   failed: [10.0.0.321] And it shouldn't change what you need to get started. It just might make it more like static inventories which allow aliases. > I am perhaps persuadable on this topic but it would require more > documentation explaining in in a really simple easy to understand way with > suggestions. If I add this to my version I'll see how useful it is and see if I can come up with more real life examples. > In the above I think I'm reading that "ec2-tag\_role\_" starting the tag is > too much typing. I am not sure I believe this makes them harder to manage. More typing is just a minor nit. > I believe it is important that we continue to indicate which things come > from tags rather than making things automagic, especially when it's not an > EC2 convention. As such, I'd suggest we not do this at this time. > > I do understand what you say about your Vagrant groups not being named > ec2\_tag\_foo, but a way to solve this would be to make ec2\_tag\_foo a child > group of a group with a different name. I'm fine with this too if it could be automated in some way in the dynamic inventory. When I switched away from a static inventory I had to edit all kinds of playbooks, roles and templates to change "search" to "tag\_role\_search". Not a big deal in itself, but it's not something that will be easy to "downgrade" for my vagrant setups. I thought about using multiple group names when selecting hosts in playbooks (having "hosts: tag\_role\_web:web") but that only works for playbook hosts. It doesn't work in templates or tasks where I need to get specific host vars from certain groups. Did you have a better way to solve this that I'm missing? Thanks ---
**Author:** ![Michael\_DeHaan1](https://avatars.discourse-cdn.com/v4/letter/m/5e9695/32.png) [@Michael\_DeHaan1](https://forum.ansible.com/u/Michael_DeHaan1)\ **Post date:** [June 19, 2014, 9:41pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/5 "2014-06-19T21:41:36Z")
“Did you have a better way to solve this that I’m missing?” What I said about putting the tag group in the other group, possibly. This may require the (not quite yet applied) patch from Serge that allows mixing inventory groups and hosts between dynamic and static sources in directory form, i…e -i \ ec2.py group\_info # ini and in group\_info you put the ec2\_tag\_foo\_bar group in a group named foo ---
**Author:** ![Michael\_Peters](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@Michael\_Peters](https://forum.ansible.com/u/Michael_Peters)\ **Post date:** [June 20, 2014, 3:02pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/6 "2014-06-20T15:02:56Z")
I've made a pull request for this: [https://github.com/ansible/ansible/pull/7867](https://github.com/ansible/ansible/pull/7867) ---
**Author:** ![Michael\_Peters](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@Michael\_Peters](https://forum.ansible.com/u/Michael_Peters)\ **Post date:** [June 20, 2014, 3:08pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/7 "2014-06-20T15:08:52Z")
Yeah, that sounds like a good solution for my problem. I'm guessing it's this pull request? [https://github.com/ansible/ansible/pull/6379](https://github.com/ansible/ansible/pull/6379) ---
**Author:** ![Michael\_Peters](https://avatars.discourse-cdn.com/v4/letter/m/c2a13f/32.png) [@Michael\_Peters](https://forum.ansible.com/u/Michael_Peters)\ **Post date:** [June 24, 2014, 2:30pm UTC](https://forum.ansible.com/t/more-configuration-options-for-ec2-dynamic-inventories/15486/8 "2014-06-24T14:30:24Z")
I've created a pull request to take care of this part too. I added a same\_vpc\_only boolean option, which if true will only return hosts that are in the same VPC where the inventory script is running. [https://github.com/ansible/ansible/pull/7916](https://github.com/ansible/ansible/pull/7916)