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< Heat
Revision as of 23:30, 17 February 2013 by Ryan Lane (talk | contribs) (Text replace - "__NOTOC__" to "")

Note: the current cloud watch implementation is incomplete (it's only sufficient for [HA](https://github.com/heat-api/heat/wiki/Using-HA)). But should be easy to make more generally useful.

To use cloud watch you need the following in your template:

    "MyOwnAlarm": {
     "Type": "AWS::CloudWatch::Alarm",
     "Properties": {
        "AlarmDescription": "Restart the WikiDatabase if httpd fails > 3 times in 10 minutes",
        "MetricName": "ServiceFailure",
        "Namespace": "system/linux",
        "Statistic": "SampleCount",
        "Period": "300",
        "EvaluationPeriods": "1",
        "Threshold": "2",
        "AlarmActions": [ { "Ref": "WebServerRestartPolicy" } ],
        "ComparisonOperator": "GreaterThanThreshold"

Note: Currently the only Action that is supported is HEAT::HA::Restarter

Then you need to call this from in your vm: /opt/aws/bin/cfn-push-stats --watch MyOwnAlarm [other args]

To see this all together look at the HA template

CloudWatch API

An AWS-compatible API to the heat CloudWatch alarms and metrics is in-progress. Not all AWS actions are supported (yet), but you can do the following:

  • List Alarms
  • List Metrics (related to alarms only, generic Metric datapoints not yet supported)
  • Create Metric Datapoints (similar to current cfn-push-stats functionality but authenticated)
  • Set Alarm state (temporarily, useful for testing alarm actions)

Status of API actions as they are implemented will be tracked in the API roadmap page(https://github.com/heat-api/heat/wiki/Roadmap-Feature:-cloudwatch-api)

You can use the Cloudwatch API by doing the following:

heat-api-cloudwatch -d &
tail -f /var/log/heat/api-cloudwatch.log

Note that it is not currently necessary to run heat-api-cloudwatch for HA and autoscaling to work correctly - instances still report Cloudwatch metric data via the metadata server (for the time being at least..)

CloudWatch Client "**heat-watch**"

A client has been created to demonstrate the CloudWatch API - it is **heat-watch**

Usage examples:

List Alarms:

heat-watch describe

List Metrics Datapoints:

heat-watch metric-list

Create Metric Datapoints:

heat-watch metric-put-data HttpFailureAlarm system/linux ServiceFailure Count 1

Set Alarm state:

heat-watch -d set-state HttpFailureAlarm ALARM