Question

I’m trying to set some custom AWS CloudWatch metrics using the Java SDK.

I can’t seem to find anything in the documentation describing how to get certain pieces of data, nor what data I need to include.

MetricDatum datum = new MetricDatum()
    .withDimensions(
        new Dimension()
            .withName("InstanceType").withValue(/* 1 */),
        new Dimension()
            .withName("InstanceId").withValue(/* 2 */)
        /* 3 */
    .withMetricName("My metric").withTimestamp(new Date())
    .withUnit("Percent").withValue(new Double(55.0));

So, questions (for each of the commented numbers in the code above):

1. Where do I get the data to put here, using the Java AWS SDK?
2. Where do I get the data to put here, using the Java AWS SDK?
3. What other data do I need to include in order to ensure I can aggregate by auto-scaling group?
   (aggregating by security group would also be fine)

For #1, I’ve seen that I can make a regular HTTP call to http://169.254.169.254/latest/meta-data/instance-id to get the instance-id, but I’m hoping to do this all via the AWS SDK, if there are methods available to do so.

Answer 1

I posted the question to the Amazon support team.

The EC2 documentation gives a list of URLs that can be called to grab a bunch of meta-data, including the InstanceType (question 1), the InstanceId (question 2), and the security group (question 3).

The auto-scaling group can be obtained using the AWS SDK for Java, by getting a list of all the auto-scaling groups, and then iterating through that list until you find the instance with your own instanceId (that was retrieved using the URL listed above):

String instanceId = "Your-InstanceId";
AmazonAutoScalingClient amazonAutoScalingClient = new AmazonAutoScalingClient(new BasicAWSCredentials(accessKey, secretKey));
DescribeAutoScalingGroupsResult describeAutoScalingGroupsResult = amazonAutoScalingClient.describeAutoScalingGroups();
for(AutoScalingGroup autoScalingGroup : describeAutoScalingGroupsResult.getAutoScalingGroups()) {
    for(Instance instance : autoScalingGroup.getInstances()) {
        if(instance.getInstanceId().equals(instanceId)) {
            return autoScalingGroup.getAutoScalingGroupName();
        }
    }
}