icinga-aws-autoscaling

Dynamic management of AWS Auto-Scaling Group inventory in Icinga.

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* Copy ./config.json.example to ./config.json. Replace the settings inside with those applicable to your setup.
* See the "Config values" section below for more details.
* Run: rm -rf node_modules && npm install --production
* Build the Lambda ZIP by running: npm run build
* This will produce a zip file in the ./build folder for you to upload to AWS Lambda.

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* icinga_host, icinga_port, icinga_user, and icinga_pass are all required.
* icinga_host_name_property - Optional, defaults to "instance_id". Determines what to set the name of the host to in Icinga. One of: "instance_id", "public_dns", "public_ip", "private_dns", or "private_ip".
* icinga_host_vars - Optional. Set to an object where each key is the host var vars.KEY, and each value is the host var's value.
* EG: "icinga_host_vars": {"os": "Linux"} would set vars.os to "Linux".
* This is useful for dynamically assigning host groups (see ./examples/icinga_configs/host_group.conf).

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#### Creating the SNS Topic
* Enter a topic name and display name.
* This is how we will feed Auto-Scaling Group scale events into our Lambda function.

#### Creating the Lambda Function
* Create a new Lambda function, using the "Blank Function" blueprint.
* For the trigger, choose "SNS", then choose the SNS topic created earlier.
* You do not need to enable the trigger yet.
* Enter a name and description for the function, then choose a runtime of "Node.js 6.10".
* For the Lambda function code, choose "Upload a .ZIP file", then select the zip of this repo that we created earlier.
* For the "function handler", enter index.handler
* For the "function role", you will need to create a new IAM role. Choose "Create a custom role".
* This will open a new window where you can create a new IAM role.
* Enter an appropriate Role Name.
* Edit the Policy Document so that it contains JSON below. It is a combination of the AWSLambdaBasicExecutionRole and AmazonEC2ReadOnlyAccess roles.
``json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"logs:CreateLogGroup",
"logs:CreateLogStream",
"logs:PutLogEvents"
],
"Resource": "*"
},
{
"Effect": "Allow",
"Action": "ec2:Describe*",
"Resource": "*"
},
{
"Effect": "Allow",
"Action": "elasticloadbalancing:Describe*",
"Resource": "*"
},
{
"Effect": "Allow",
"Action": [
"cloudwatch:ListMetrics",
"cloudwatch:GetMetricStatistics",
"cloudwatch:Describe*"
],
"Resource": "*"
},
{
"Effect": "Allow",
"Action": "autoscaling:Describe*",
"Resource": "*"
}
]
}
`
* Add any tags you need, and change any of the advanced settings you would like to.
* I have found the default memory and timeout of 128mb and 3sec work fine.
* Click the Create Function button to finish this step.
* You should enable this Lambda Function BEFORE you configure your Auto-Scaling Group to publish to the SNS Topic.

#### Configuring your Auto-Scaling Group to publish to the SNS Topic
* Go to your ASG, and open the "Notifications" tab.
* Create a new notification.
* Select "use existing topic", and select the SNS Topic we created earlier.
* Select the "Launch" and "Terminate" events. This code does not yet support the other event types ("fail to launch" and "fail to terminate").
* Save the new notification.

#### All together now!
* Create the SNS topic (see above).
* Create the Lambda Function (see above).
* Configure your ASG to publish to the SNS Topic (see above).
* You should now be able to scale your ASG, and see instances added/removed in Icinga 2.

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* The first place to look is the logs for the Lambda Function.
* Go to Cloudwatch -> Logs. Choose the log group for your Lambda Function.
* If you do not see any Node.js errors, there is not much I can help with. Check your config, check your security groups, etc.
* If you DO see Node.js errors, it is likely they are related to the requests sent to Icinga 2. Read them and determine if you have a config or security group issue.
* Issues with the code in this repo should result in a bug ticket being filed.

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* Install all dependencies using: rm -rf ./node_modules && npm install
* Open a Node.js REPL using: node
* You can simulate an ASG Launch/Terminate event using:
`js
let index = require('./index')

const launchEvent = {Records: [{Sns: {Message: "{\"Event\": \"autoscaling:EC2_INSTANCE_LAUNCH\", \"Details\": {\"Availability Zone\": \"us-west-2a\"}, \"EC2InstanceId\": \"i-08fa737d84cf6651b\"}"}}]}
index.handler(launchEvent, {}, function() {});

const terminateEvent = {Records: [{Sns: {Message: "{\"Event\": \"autoscaling:EC2_INSTANCE_TERMINATE\", \"Details\": {\"Availability Zone\": \"us-west-2a\"}, \"EC2InstanceId\": \"i-08fa737d84cf6651b\"}"}}]}
index.handler(terminateEvent, {}, function() {});
`
* Don't forget to replace the Availability Zone and EC2 Instance ID.

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* Run tests: npm run test
* Run tests w/ coverage: npm run test:coverage`

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* Add full event payload to fixtures.