Sooo .. You are monitoring a fleet of AWS EC2 hosts via Nagios, and have yet to find an easy way to manage their host definitions .. Good news (if you happen to be using Ansible dynamic inventories) !! I created an Ansible template that loops thru all your EC2s and creates them for you ..
In addition, you can easily define Nagios service dependencies, helping you zero in on the root problem more quickly ..
Afraid of having too many AWS EC2 images and/or snapshots, thus running up your bill ?? Fear not !! I have you covered:
Nagios Plugins to Check AWS EC2 Images
Nagios Plugin to Check AWS EC2 Snapshots
So you’ve met Hal — he’s my bud .. That said, I’ve never been a fan of how I “reply” to Hubot commands .. For example:
“Greg, what’s your problem ?? Hal brings you beer !!” .. True, true .. But I want more !! I want to be more like my developer friends and apply an MVC design pattern to my Hubot development .. Specifically, I want my “views” to be beautiful and maintainable, while having the ability to use complex data “models” ..
Hello Handlebars !! Long story short, I can easily build semantic templates, compile output, and send as a Hubot reply .. For example:
Here’s the template:
Here’s the Slack output:
So I have been using Ansible for over two years now .. I use it for damn near everything — provisioning infrastructure, configuring nodes, deploying Web applications, testing whatever I can, and other ad hoc tasks (sadly, I’m still working on a “get me beer” playbook) .. Long story short, it’s been a game changer .. Problem is, as my (and my team’s — hi guys !!) Ansible usage grows (50+ playbooks and 130+ roles) — so does my desire to organize it in a way that is scaleable ..
There are many ways you can setup your Ansible project (one, two, three, four, etc ..) — which is great !! That said, I love me some simplicity .. After trying out a few setups, I finally settled on one that works for me .. You can see it here ..
The view from 30,000 feet:
- All of my inventory files, static and dynamic, will be children of the inventories directory
- FULL DISCLOSURE: by design, I only have two inventory files — localhost and ec2.py .. every once in a blue moon we will add additional inventory files (PoCs, targeted testing, etc ..), but we always fallback to only the two
- Group and other variables
- the group_vars directory can be relative to an inventory file, no matter where the playbook is .. since I like to add some structure to my playbook organization, it makes sense to put it here
- variable files (i.e. Ansible Vault) that need to be explicitly loaded go in the vars directory
- IN THEORY: you could also put a host_vars directory here .. but as y’all know, host_vars are the devil
- Let me explain my logic here .. In my work, I essentially perform five functions: 1) provision infrastructure, 2) configure infrastructure, 3) deploy to infrastructure, 4) test infrastructure (and other things), and 5) save the world (i.e. ad hoc tasks) .. Knowing this:
- since the line between provisioning and configuring infrastructure can get murky, I combined the two “functions” into one directory
- the one-offs that don’t fit nicely anywhere — but here
- these are the bits and pieces that make up a useful piece of infrastructure .. for example, we have resource roles for AEM, Bitbucket, CPANm, .forward, Java (1.6, 1.7, and 1.8), Apache, Netcat, Nagios, NRPE, etc .. all solid implementations .. all reusable ..
- STYLE ALERT: we DON’T use Ansible Galaxy — directly .. we often refer to it for inspiration — but always end up using our own implementation
- this is a “completed”piece of infrastructure .. the sum of the (resource) parts .. the cherry on top .. for example, we have primary roles for user_web_api_server, internal_dns_server, aem_author_server, aem_publish_server, etc ..
- this is what I “do” to my infrastructure that doesn’t maintain any real “resource” …. for example, we have action roles for silencing/unsilencing Nagios, deploying code, restarting application servers, taking data centers offline, etc ..
The view from 30 feet:
- PROBLEM: “I want my playbooks to be able to refer to my roles in a way that is consistent and easy” .. Great idea !! The problem is, your playbooks and roles are gonna be all over the place — so you can’t take advantage of the “relative referencing” you can do in a traditional project structure .. Let’s also assume you don’t want to define an absolute path in the config file ..
- SOLUTION: Hello bootstrap !! Take a path that will always be consistent (inventory_dir) and use it to define other paths with some regex magic .. When finished, shove it all into a external variables file ..
- FINALLY: Refer to the bootstrap, early and often, in every playbook you create, ..
Again, this project setup works for me .. “Me” being myself and 4 other sys admins ..
Anywho — I need to get back to work on that “get me beer” playbook ..
This post is kinda dopey, but it might help one person out there in intertubes land .. That said, I have been using HipSaint for ……………….. 3 years ?? It’s great !! It posts Nagios alert information into HipChat:
- Log into Nagios
- Locate the host or service that is alerting
- Click the link
- View the details
- Acknowledge the alert, if needed
Y’all know I’m lazy though –right ?? I wish the HipChat message would just give me the links I want .. Well, now it can:
As you will see, I am simply appending the status and acknowledgement links to the Nagios “service output” .. I also use Ansible to populate variables such as:
- HipChat token
- HipChat room
- Nagios hostname
Now I can be as lazy as I want to be:
Hal is my Hubot chatbot .. He’s awesome !! He gets me beer !!
hal beer me
He also does things like restart app servers, deploy code, and show me pictures of grumpy cats .. He’s so cool, I’ve started making non-humans to talk to him .. “Greg, what do you mean ??” .. Well, let me show you ..
- I have a Nagios server
- It monitors (allthethings)
- When the “logged in users” alert is triggered, Nagios sends a message to my chat service using hipsaint
- “logged in users” is a monitor I have that alerts me when more than 3 users are logged into a server
- I see the alert and the server in question
- I SSH into the server
- I type who
- I then determine if I need to care
- If not, move on with my life
- If so, dig deeper
The thing is, I have more than 1,200 active monitors .. That means Nagios can and will send many, many messages to my chat service — depending on the day .. So how can I make my life easier ??
Here’s an easy one: ask Hal who’s on a server ..
hal whos on
hal whos on
My stack is HipChat -> Hubot -> Jenkins -> Ansible .. That means I can damn near do anything I want, all from my chat client ..
Remember what I said earlier — about making non-humans talk to Hal ?? What I did was create a Nagios event handler that sends a message to my chat service using HipChat CLI .. Therefore, I AM NOT asking Hal who’s on a server, it’s NAGIOS WHO IS doing it ..
nagios hal whos on
It doesn’t stop there !! You can create scripted Splunk alerts as well .. Before you know it, you will be making (allthethings) talk to Hal ..
OMG !! It’s still hip to say that — right ??
Anyway .. While I consider myself to be reasonably intelligent, I still find myself doing dopey things from time to time .. For example: saying OMG .. Another dopey thing I have been doing for a very, very long time — are run-on sentence notes for my Nagios service definitions .. I am ashamed to admit how many times I have tried to “fix” this — but always errored out during the pre-flight check .. Yes — I am aware of Google, but I’ve never found anything definitive ..
And then it hit me like a bolt of lightening — Bash style line breaks ..
So obvious, yet so elusive ..