How to monitor website status with AWS Lambda and CloudWatch? - amazon-web-services

I have to monitor a website if it works - response looks like following:
{"response":
{"time": 1457564305},
"stat": "OK"
}
And need sending mail alert to me if stat is not OK.
Seems this can be done with Lambda using node.js and CloudWatch.
I tried to create Lambda function and execute through CloudWatch but only see the function was triggered. Seems I need to push some metrics?
I'm newbie to node.js and Lambda (handler, metrics, etc.).
Would anyone share some hints on where I should start with?
Thanks a lot.

Not sure what you mean by "only see the function was triggered".
Yes, you can cause a Lambda function to be invoked on a schedule. That Lambda function could issue a request to the website and trigger a notification to an SNS topic if it believes the site to be down. You would subscribe (by email address or SMS) to the SNS topic for notifications. Here's an example of how to do this.

Related

Alert on Lambda failure with detailed info

I have a cloudWatch alert setup on all lambdas sending data to a an SNS topic
Using the metric as
sum(errors) across all functions
I get the notification as expected, but there is no information in there to identify which amongst my lambdas triggered the alarm or in other words which one failed
If I setup the alarm individually on each lambda, then I get the information on which one failed under Dimensions. But I have a lot of them and plan to add more and this process will become painful
How can I leverage cloudWatch to alert me on all lambda failures and also provide info on which lambda failed and the error message ?
Should this be implemented in a different way ?
The AWS Cloud Operations & Migrations Blog has a post published on this topic.
Instead of using CloudWatch Alarms as you are doing now, you can use a CloudWatch Logs subscription. Whenever a log entry matches a specific pattern that you specify, it will trigger a new Lambda function that can notify you however you choose. In the blog post, the Lambda uses SNS to send an email notification.
You can control what information gets included in the body of the notification by adjusting what the Lambda function sends to SNS. The log group name, log stream, and the error message itself can be included.

AWS Eventbridge Notifications Does Not Work Using SNS topic

I want to receive notifications from AWS Eventbridge when there's a scheduled event for my Amazon Elastic Compute Cloud (Amazon EC2) instance.
I created an Eventbridge rule and set the target to an already working SNS topic. The SNS topic is subscribed to a working Lambda function that is used for other "Cloudwatch to slack" alarms already. The eventbridge setting is as follows:
{
"source": ["aws.health"],
"detail-type": ["AWS Health Event"],
"detail": {
"service": ["EC2"],
"eventTypeCategory": ["scheduledChange"]
}
}
I already got an EC2 scheduled maintenance(reboot) notification as e-mail from AWS, but this eventbridge I created did not trigger for that and did not send any notification to the slack channel.
I am unsure now if I am missing something in the setting. I am setting it for the first time and no way to simply test it with fake input. It is supposed to work even if there is a single schedule event that appears in the top bell icon(as shown in the screenshot above), correct?
In order to find out the root cause of this issue, I suggest to take a look a the CloudWatch usage metrics for SNS. SNS reports the following metrics which might be useful for you: NumberOfMessagesPublished, NumberOfNotificationsDelivered NumberOfNotificationsFailed. If you find these metrics reported an they have a value different than 0, this means that SNS receives events from Event Bridge and the problem is somewhere else.
If you are using a Lambda to send messages to Slack, you should take a look at the logs in CloudWatch to see if the Lambda did execute successfully. You might want to check out the setup for Lambda recommended by AWS: (link)
For further debugging you may want to check out test-event-pattern CLI command.
It is supposed to work even if there is a single schedule event that appears in the top bell icon(as shown in the screenshot above), correct?
Yeah, it supposed to work even if there already is an event.
I'm having a similar issue with eventbridge rule being built with cloudformation. I had to manually go into the eventbridge rule via the AWS console and go to the trigger and select the SNS topic again. It now works. It took me a while to figure out. Can you confirm that the fix did that for you as I'm not sure how to fix this...

How can I get aws cloudwatch to fire alarm notifications repeatedly

We have aws alarms set up to email on alarm but we would like to continue to get the alarm notification even if the state is in Alarm without a state change. How could I achieve this (would be happy to use a lambda but no idea how to do it)
Amazon CloudWatch alarm notifications are only sent when the state of the alarm changes. It is not possible to configure CloudWatch to continually send notifications while in the ALARM state.
You would need to write your own code to send such notifications. This could be accomplished via a cron job, scheduled AWS Lambda function or your own application.
Try with a script using Cloudwatch API for example with Boto3 + Python or a Lambda running every X minutes. I have a python script to get values from cloudwatch you can adapt it. http://www.dbigcloud.com/cloud-computing/230-integrando-metricas-de-aws-cloudwatch-en-zabbix.html
One alternative is, to create a Lambda function to send email and host that function using CloudWatch Rule with Scheduled option and target as Lambda function that you have created. In Schedule option, you can set the frequency of time that you expect to receive email. In defined frequency, the Rule will trigger Lambda Function to send email.

send notification alert when AWS Lambda function has an error

I have a AWS Lambda function running some process in my infrastructure. The Lambda is triggered every 8 hours using a CloudWatch rule. I am trying to raise a notification if any error happens into the Lambda process. I tried to use SES but that service is not available in that Region.
I will like to know any suggestions for this problem:
How to setup notifications when an error occurs in my Lambda functions ?
I am looking for suggestions. This questions never asked for doing my task. I will appreciate any official documentation but either way, any help is welcome.
Some suggestions:
Dead Letter Queues:
If your error causes failed invocations, you can use a Lambda Dead Letter Queue to send the event to an SNS topic or an SQS queue. If you send it to an SNS topic, you can directly subscribe to the topic via SNS or Email to get notified any time a message is published to that topic.
Multi-region SES:
If you're really set on using SES directly, SES clients can be instantiated with an explicit region provided -- as long as your lambda's execution role has the appropriate permissions, you can send email to SES from a different region. Here's documentation for instantiating the JS SES Client.
CloudWatch Logs:
If your error does not cause the invocation to fail, another option is using a CloudWatch Logs metric filter to aggregate failures and potentially alarm on them. If you're using NodeJS, you can simply log out via console.log(), console.error(), etc. and it will be written out to CWLogs. More details here.
You can subscribe an SNS topic to CloudWatch Alarms, and notify yourself in the same way as the DLQ.
As you gain experience with the error and learn how to process common errors, you could also subscribe another lambda to the SNS topic from the DLQ/CWLogs example to process it as it happens.

Can you send SNS push notification from lambda function in Amazon AWS?

I am developing an application with Amazon AWS and what I am trying to achieve is to attach a lambda function to DynamoDB table, so after a new row is added ,the lambda function is triggered.
In the above mentioned lambda function I want to add the functionality to send a push notification with Amazon SNS service, but I could not find any information in their documentation if that is possible and if it is, what exactly needs to be done to get it working? What I found in their documentation is that you can attach lambda function trigger to a SNS topic, which means that after a notification is pushed then the function is called, but what I am interested in is to send a push notification directly from lambda function. I would appreciate if someone shed some light on this topic for me.
Yes, you can call any of the API functions from Lambda. Perhaps if you posted some code and the errors you are getting you could get more specific help.