- \n
- Integrating Lambda With CloudWatch (Scheduled Event)<\/li>\n<\/ul>\n
- \n
- Creating SNS Topic and Subscriptions<\/li>\n<\/ul>\n
- \n
- Integrating CloudWatch With SNS\u00a0<\/b>for Notification<\/li>\n<\/ul>\n
Why use Lambda?<\/strong><\/p>\n
Lambda will be an effective solution, when there are events that are need to be performed in a periodic manner. It will also help in infrastructure automation.<\/p>\n
Example Use Cases.<\/strong><\/p>\n
- \n
- Taking AMIs or Snapshots in a regular interval of time.<\/li>\n<\/ul>\n
- \n
- Adding 2 servers morning at 8.00am when no of servers running is lesser than 30. etc,.<\/li>\n<\/ul>\n
Cost Comparision<\/strong><\/p>\n
For a scheduled running of a program that triggers the API’s, a dedicated Linux Cron machine is commonly used.<\/p>\n
Though the program runs few times a day, the instance must be running throughout the year.<\/p>\n
Cost of a (t1.micro) EC2 machine running for a month = $ 14.64 <\/b>
![\"m1\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/m1.png\")
<\/p>\n<\/p>\n
Cost of running the same for a year =$ 14.64 * 12 = $ 175.56 <\/b><\/p>\n
![\"g\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/AAEAAQAAAAAAAAjEAAAAJDNhNjBjOWUwLTk3YTYtNDEzZS1hODhjLTYwNDE0Yzc0ZWM4Zg.png\")
<\/p>\nPoints to Ponder<\/b><\/p>\n
- \n
- You are responsible for your Linux Cron instance and must take necessary steps for Scaling, Patching, Administration<\/strong><\/li>\n<\/ul>\n
- \n
- You must also ensure that, another machine is backing up when cron instance goes down.<\/strong><\/li>\n<\/ul>\n
Most often, when your Lambda function runs for few minutes, few times a day, it will come under the free tier*.<\/p>\n
For Lambda Pricing and free tier information, click the following link.<\/p>\n
https:\/\/aws.amazon.com\/lambda\/pricing\/<\/a><\/p>\n
Creating Lambda Function<\/b>[showhide type=”qs” more_text=”For Steps to Create A Lambda function, Click Here” less_text=”Hide Details” hidden=”yes”]<\/p>\n
Step 1:<\/b> In the AWS Dashboard, Click Lambda<\/b> to get into the Lambda Console.
![\"1\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/147.png\")
<\/a><\/p>\n<\/b> Step 2: <\/b>\u00a0Click the Get Started Now <\/b>button to create a Lambda Function.<\/p>\n
![\"2\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/220.png\")
<\/a><\/p>\nStep 3: \u00a0<\/b>There are various inbuilt Lambda Functions that can be utilized. Also, specify the type of Language <\/b>you want to choose from. If you want to use your own Lambda Function, click the Skip <\/b>button in the bottom right corner.<\/p>\n
<\/p>\n
![\"3\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/318.png\")
<\/a> Step 4: <\/b>\u00a0Enter the Name <\/b>you want to provide to \u00a0Lambda Function along with Description. <\/b>You will have to choose the method by which you want to use your program code. In our case, we are using the Edit code inline <\/b>option. You will have to use Upload a .Zip<\/b> file or Upload a .Zip from Amazon S3 <\/b>if you have dependencies in your program.<\/p>\n![\"4\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/48.png\")
<\/a><\/p>\nStep 5: <\/b>You must choose a Lambda Role for authorization, that will \u00a0perform the actions you want via the code you provide. You must provide necessary permissions by creating a new role in IAM, for Lambda to access SNS, CloudWatch and EC2. Choose VPC <\/b>if you require. Click Next <\/b>complete creation of Lambda Function.<\/p>\n
![\"5\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/test-prep-e1477043709154.png\")
<\/a><\/p>\n[\/showhide]<\/p>\n
Important Note:<\/strong><\/p>\n
- \n
- Although AWS Lambda can perform actions in various regions, CloudWatch and Lambda are region-specific.<\/strong><\/li>\n<\/ul>\n
- \n
- So make sure that CloudWatch Rule is in the same region, with the created Lambda Function.<\/strong><\/li>\n<\/ul>\n
Integrating Lambda With CloudWatch<\/b><\/p>\n
Although, Lambda is basically Event-driven, Lambada can also be Scheduled<\/b> to take place in a particular time or particular interval of time.<\/p>\n
![\"6\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/67.png\")
<\/a>\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0<\/strong><\/p>\n\u00a0\u00a0<\/strong><\/p>\n
[showhide type=”qp” more_text=”For Steps to Create a Scheduled Event, Click Here” less_text=”Hide Details” hidden=”yes”]<\/span><\/p>\n
Step 1: <\/b>To Configure, click the CloudWatch<\/b> Service from the AWS dashboard.<\/p>\n
![\"7\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/77.png\")
<\/a><\/p>\nStep 2: \u00a0<\/b>Click Create Rule <\/b>in the Events Tab to create an event.<\/p>\n
![\"9\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/910.png\")
<\/a><\/p>\nStep 3: \u00a0<\/b>Click Schedule <\/b>in the Select event source<\/b> tab. The Event Selector is the source for invoking the target.<\/p>\n
![\"10\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/106.png\")
<\/a><\/p>\nStep 4: \u00a0<\/b>Click in the Fixed Rate of<\/b> tab and also select Interval Period. It may be the frequency in Minutes, Hours or Days. <\/b>You can \u00a0also specify a Simple Cron Expression. Click Add target <\/b>button from the Targets tab.<\/p>\n
For more information on how to schedule an event based on specific time, please click the following link<\/p>\n
https:\/\/docs.aws.amazon.com\/AmazonCloudWatch\/latest\/DeveloperGuide\/ScheduledEvents.html<\/a><\/p>\n
<\/p>\n
![\"11\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/1113.png\")
<\/a><\/p>\nStep 5: \u00a0<\/b>From the Targets Section, Click Select target type <\/b>and select Lambda function. <\/b>Click Configure details<\/b> to proceed.<\/p>\n
![\"12\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/1210.png\")
<\/a><\/p>\nStep 6: <\/b>Enter the Name and Description<\/b> and check the status <\/b>if it is enabled. Click Create rule <\/b>to complete the rule creation. \u00a0\u00a0
![\"16\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/163.png\")
<\/p>\n[\/showhide]<\/p>\n
Integrating CloudWatch With SNS<\/b><\/p>\n
CloudWatch can trigger SNS, if an event is completed or when there is a change in the state of EC2 or when an action is performed in Auto Scaling Group or even when an API call.<\/p>\n
For example<\/b>, we are configuring SNS \u00a0to send Email and Email-Json notification when a Lambda function gets executed or when an event is completed successfully.<\/p>\n
![\"22\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/222.png\")
<\/a> \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\u00a0<\/b><\/p>\n[showhide type=”qq” more_text=”For Steps to Create an SNS Topic with Subscriptions, Click Here” less_text=”Hide Details” hidden=”yes”]<\/span><\/p>\n
Step 1: \u00a0<\/b>Select SNS<\/b> from the AWS services dashboard for creation of \u00a0SNS Topic.
![\"Capture\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/Capture7.png\")
<\/a> Step 2: \u00a0<\/b>Select Create Topic <\/b>from SNS Home tab<\/p>\n![\"17\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/173.png\")
<\/a><\/p>\nStep 3: \u00a0<\/b>Enter the Topic name <\/b>and Display name <\/b>and click Create Topic <\/b>button.<\/p>\n
![\"18\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/182.png\")
<\/a><\/p>\nStep 4: \u00a0<\/b>Click Create Subscription <\/b>in the Subscriptions tab<\/p>\n
![\"19\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/192.png\")
<\/a><\/p>\nStep 5: \u00a0<\/b>Select the type of Protocol by which you want to notify. The protocols are<\/p>\n
- \n
- \n
- \n
- Email –<\/b> Normal Mail format<\/li>\n
- Email-JSON –<\/b> You will get the data in Key-Value pairs<\/li>\n
- Amazon SQS – <\/b>\u00a0You can forward the output to Amazon Queue for further operations<\/li>\n
- HTTP, HTTPS – You can use these protocols for web page operations such as POST etc.<\/span><\/b><\/li>\n
- Application<\/strong> – You can forward the data to an application.<\/li>\n
- AWS Lambda<\/strong> – You can also invoke Lambda Function.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
![\"23\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/232.png\")
<\/a><\/p>\nStep 6:<\/strong> Create the Subscription under a specific Topic or manually enter Topic ARN<\/b>. Select Email <\/b>from the Protocol drop-down menu.<\/p>\n
![\"20\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/203.png\")
<\/a><\/p>\nStep 7: <\/b>You will receive a PendingConfirmation<\/b> message. You can confirm either by activating subscription by clicking the link received via e-mail or manually clicking Confirm Subscription <\/b>or providing Subscription confirmation URL. <\/b>Click Confirm Subscription.<\/b><\/p>\n
![\"21\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/219.png\")
<\/a><\/p>\n[\/showhide]<\/p>\n
Important Note:<\/b><\/p>\n
- \n
- CloudWatch is region-specific. So make sure that CloudWatch Rule is in the same region, with the created SNS Topics.<\/b><\/li>\n<\/ul>\n
- \n
- If Lambda performs events in various regions, CloudWatch and SNS have to be created for every region to get all notifications<\/b><\/li>\n<\/ul>\n
Configuring CloudWatch to Trigger SNS<\/strong><\/p>\n
[showhide type=”qr” more_text=”For Steps to Configure CloudWatch with SNS, Click Here” less_text=”Hide Details” hidden=”yes”]<\/span><\/p>\n
Step 1<\/strong>: Click Create Rule <\/b>in the Events Tab to create an event.<\/p>\n
<\/p>\nStep 2: \u00a0\u00a0<\/b>Select \u00a0the Service name <\/b>from the various available services.<\/p>\n
- If Lambda performs events in various regions, CloudWatch and SNS have to be created for every region to get all notifications<\/b><\/li>\n<\/ul>\n
- Email-JSON –<\/b> You will get the data in Key-Value pairs<\/li>\n
- Email –<\/b> Normal Mail format<\/li>\n
- \n
- So make sure that CloudWatch Rule is in the same region, with the created Lambda Function.<\/strong><\/li>\n<\/ul>\n
- Although AWS Lambda can perform actions in various regions, CloudWatch and Lambda are region-specific.<\/strong><\/li>\n<\/ul>\n
- You must also ensure that, another machine is backing up when cron instance goes down.<\/strong><\/li>\n<\/ul>\n
- You are responsible for your Linux Cron instance and must take necessary steps for Scaling, Patching, Administration<\/strong><\/li>\n<\/ul>\n
- Adding 2 servers morning at 8.00am when no of servers running is lesser than 30. etc,.<\/li>\n<\/ul>\n
- Taking AMIs or Snapshots in a regular interval of time.<\/li>\n<\/ul>\n
- Integrating CloudWatch With SNS\u00a0<\/b>for Notification<\/li>\n<\/ul>\n
- Creating SNS Topic and Subscriptions<\/li>\n<\/ul>\n
![\"Capture1\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/Capture12.png\")
<\/a><\/p>\n![\"Capture2\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/Capture23.png\")
\u00a0 \u00a0 ![\"Capture3\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/Capture31.png\")
<\/p>\n![\"Capture4\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/Capture41.png\")
<\/p>\n![\"Capture6\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/Capture61.png\")
<\/a><\/p>\n![\"m\"](\"https:\/\/content.cloudthat.com\/resources\/wp-content\/uploads\/2022\/11\/m.png\")
Thus, whenever Lambda gets triggered in a scheduled manner through CloudWatch, we will receive notification.<\/p>\n