If you’re serving up a static website from S3, especially if you have larger assets stored there, you may want to put monitoring on the requests or bytes downloaded from S3, just to make sure someone’s not running up terabytes of transfers or millions of requests.
Enabling Metrics on S3
You will have to enable metrics on S3 in order to get CloudWatch alarms on them.
Go to Services -> S3 -> Buckets and select the bucket for your static site.
Select Management tab and [Metrics] and then click on the pencil icon next to the bucket icon.
Once enabled, the metrics will take a bit to populate.
First, you’re going to want to be notified. Go to Services -> Simple Notification Service to set up a pathway for that to happen.
Next, click “Topics” and then [Create topic]
Name your topic something that adequately describes the purpose (I just used domainname-com)
Scroll down to [Create Topic]
Set up a subcription
Under “Amazon SNS” left sidebar, click “Subscriptions” and [Create Subscription]
Click on the Topic ARN field and you should be able to see an ARN with your topic name as the last part of the ARN. Click that ARN
Under Protocol, select your preferred method of notification (I’m going with SMS.
Under Endpoint, enter your cell number, including country code (+18005551212 for (800) 555-1212 in the US)
Setting up a CloudWatch Alarm
Go to Services -> CloudWatch -> Alarms and [Create alarm]
[Select metric] and select S3
If you don’t see “Request Metrics per Filter” then the metrics haven’t started populating yet.
Check “GetRequests” or “BytesDownloaded” and [Select Metric]
Set conditions as you would like to have flag any anomalies and click [Next]
Choose “In Alarm” and “Select an existing SNS topic” and click in the box below “Send Notification To…” to get suggestions and select the SNS topic corresponding to the notification method you set up. Click [Next]
Ok, so you’ve created a lovely static site and/or set up a CloudFront distribution for https for it. But CloudFront bills by the GB. What if somebody decides your assets are perfect to hotlink to or just straight up makes an insane boatload of requests? How do you protect yourself from getting a frightening bill before AWS Budget can even notify you?
Setting up Simple Notification Service (SNS)
Set up a topic
First, you’re going to want to be notified. Go to Services -> Simple Notification Service to set up a pathway for that to happen.
Next, click “Topics” and then [Create topic]
Name your topic something that adequately describes the purpose (I just used domainname-com)
Scroll down to [Create Topic]
Set up a subcription
Under “Amazon SNS” left sidebar, click “Subscriptions” and [Create Subscription]
Click on the Topic ARN field and you should be able to see an ARN with your topic name as the last part of the ARN. Click that ARN
Under Protocol, select your preferred method of notification (I’m going with SMS.
Under Endpoint, enter your cell number, including country code (+18005551212 for (800) 555-1212 in the US)
Get Notified
Go to Services -> CloudFront -> Alarms
[Create Alarm]
Under Metric, choose the threshold that you want to detect on… maybe it’s Requests, maybe it’s Bytes Downloaded…
Select the distribution that you want to watch ( domainname.com should be mentioned in the dropdown)
For “Send a notification to”, select the SNS topic that corresponds to the notification method you set up.
Since mine is a dev/test site, I don’t expect more than a request/second so
Finally, [Create Alarm]
Testing the Alarm
If you have a low enough threshold you can probably just hold down F5 (or whatever your refresh key is) for a few seconds. (Word of caution: Don’t do this with a page that downloads a lot of assets!)
In bash you can also do the following.
for i in {1..61}
do
curl https://domainname.com
done
If your notifications are working, you should get an message through your preferred notification method.
Under Services -> CloudWatch -> Alarms, you should also see your Alarm count be > 0.
In the window that opens from “Request or Import a Certificate with ACM”, enter your domain name (domainname.com) and click [Next]
Select DNS validation and click [Next]
Click [Review]
Click [Confirm and Request] if the details look correct.
Expand the domain in validation:
Click [Create record in Route 53] and confirm by clicking [Create] again.
You’ll be waiting from several minutes to half an hour for the validation to happen, during which time status will display as “Pending validation”
Click [Continue] to finish the request process and go back to the Certificate Manager main screen.
Click the (refresh icon) button to update status, and when status turns to “Issued” you are ready to use it in CloudFront.
Pending validationReady for use
Setting up a CloudFront distribution
In the AWS Console, go to Services → Cloudfront
Click [Create Distribution]
Click [Get Started] under Web
Create Distribution
Under “Origin Domain Name” select the selection under “Amazon S3 buckets” that corresponds to your static web site bucket. (e.g., domainname.com.s3.amazonaws.com)
Optional: Restrict Bucket Access [Yes] so that you can control access through the CloudFront distribution alone.
Set “Origin Access Identity” to “Create a new identity”
Set “Grant Read Permissions on Bucket” to “Yes, Update Bucket Policy”
Under Viewer Protocol Policy I select “Redirect HTTP to HTTPS” just to keep things uniform.
Set up SSL
Under Alternate Domain Names, enter your domain name (e.g., domainname.com)
Select “Custom SSL Certificate”
Click “Request or Import a Certificate with ACM”
If you go back to CloudFront you should be able to select “Custom SSL Certificate” now and the certificate corresponding to your domain name should show up in suggestions:
Scroll down and leave defaults until you get to “Default Root Object”. You’ll want to set this to the name of the document to bring up (e.g., index.html) if the user browses to / on the domain.
Optional: I set Logging to On and selected my logging bucket that I used for the static site as the bucket, adding a log prefix for it.
To finish, click [Create Distribution]
You may be waiting quite a while for changes to propagate to the edge locations, but at some point before the “In Progress” changes to “Deployed” you will be able to pull up via the domain listed under the “Domain Name” column in your list of CloudFront Distributions.
Pointing the domain name at your distribution
Go back to Route 53 and go into the hosted zone for your domain name
Check the checkbox next to your A record and then go up to Actions -> Edit
Change “Value/Route traffic to” from “Alias to S3 endpoint” to “Alias to CloudFront distribution” in the “Choose Distribution” input box.
Enter the domain name (“asdfkjdfasoiadsf9u.cloudfront.net.”) as your domain name. (The new interface wasn’t suggesting distributions like the last version of the interface did… it may change next week, of course.)
Locking down S3
If you selected “Restrict bucket access” and had CloudFront update your S3 policy, your public access setting on the bucket is still unaffected. You’ll want to remove that:
Go back to Services -> Amazon S3
Go to your domainname.com bucket
Click Permissions
Click Block public access
Check “Block all public access” and click [Save]
Some other details
If you want to have JavaScript and forms function properly You’ll want to set up CORS configuration by going to your S3 bucket, then selecting Permissions tab and clicking CORS configuration:
A certificate for *.domainname.com does not cover domainname.com. You have to add both if you want wildcard and domainname.com itself covered.
Next up… preventing someone from running up a $1,000 AWS bill by hammering your site (i.e., monitoring your site’s access… with better granularity than AWS Budgets…
