AWS charging for Cloud Watch 0.5 Alarms

[lunaSnowflake]

I recently got a notification stating that I was charged $0.02 for a CLoud Watch Service. While the charges isn't bank breaking, I wanted to understand what are all the Cloud Watch bill components actually mean.
I had a total of 30 alarms out of which I've deleted 6, remaining 24 Alarms out of which 6 are in the "In alarm" state (what does this "In alarm" means? -- I understood it to be those Alarms which could not be completely executed).
All alarms are filled with Target tracking "Provisioned Capacity" and "Consumed Capacity". But all these alarms were created automatically when I made DynamoDB Tables. (All tables were created in same month)

If I am getting it right, I had 30 alarms out of which 10 should be free, which leaves me with extra 20 Alarms for which I should be charged. Then what is the component "Usage Quality" of "0.182" shows? -- and why it's in Decimal instead of a whole number?

After approaching AWS support, I came to know I'll get charged every time I make a new DynamoDB Table. Is that True?

They Have been a really good help!

Update: Now in total I've charged for $0.05

[gockle]

Hi @lunaSnowflake We will look into this and provide more information, meanwhile can you confirm if you selected Yes for the CloudWatch Parameter Enable CloudWatch Metrics? refer to the documentation here Step 5 for more information

Can you also provide which version of the solution you installed?

[lunaSnowflake]

No, I did not.

[CrypticCabub]

Thanks @lunaSnowflake!

Amazon CloudWatch is a service for monitoring key metrics and logs across your AWS account. Each individual alarm watches a specific metric and can be configured to go "into alarm" when the metric meets a specific criteria (such as less than or greater than some value). You can find out more about CloudWatch here

Cloudwatch Alarm metrics are often created automatically by services such as DynamoDB to track critical metrics related to the service. DynamoDB in particular will deploy the alarms you mention alongside provisioned databases so that it can use them to manage autoscaling (see documentation here).
Note: DynamoDB does not create these alarms for on-demand tables

In the context of Instance Scheduler Specifically, we use CloudWatch to store logging output and trigger scheduling events on a periodic timer (every 5 minutes by default), we do not deploy any CloudWatch alarms ourselves, but any provisioned DynamoDB tables you create will deploy those alarms as part of the deployment

[lunaSnowflake]

Thanks for lighting fast replies!
I've gone deep into this lately, and understand what is going on here. What I did not understand is when I created DynamoDB tables it created a total of 30 Alarms out of which 10 should be free and 20 should be chargeable, Am I correct?
If so why I am getting charged for 0.5 Alarms and not for 20? And why it is even is fractions like 0.5?

[CrypticCabub]

The billing is in "alarm months" so if you were to have 15 alarms for a full month you would get charged for 15 "alarm months" , but if you had those same 15 alarms for only half of the month you would get get billed for 7.5 "alarm months" (15 * .5)

[lunaSnowflake]

Ahh! I see that's what I was not enlightened about. Thanks that helped! I was not thinking straight probably too much confusion all over the internet.
Last question, how much time does it take for my "Alarm" bills to get reflected in my account? I am assuming it does not reflect at the beginning of each new month, because my alarms were created somewhere beginning of this month only (Jan 2023)?

[CrypticCabub]

I'm not sure I follow the question exactly.

If you mean being able to see an estimate for your bill at the end of the month you should be able to see those in Amazon Cost Explorer or CloudWatch Billing Metrics within a day or two

If you mean the bill itself, the alarms themselves would start accumulating costs immediately and should be included with the bill at the end your current billing period (thus how it is possible to have 15 alarms for only half of a month)

[lunaSnowflake]

I got my answer somewhere between those lines.
Again you guys were a huge help, Thanks a lot!😀