does nightscout VM in Google Cloud require Premium Tier networking to be free of charge?

[krsummersBA]

I created a VM instance in my google account using these detailed step-by-step instructions: https://navid200.github.io/xDrip/docs/Nightscout/VirtualMachine.html. These instructions are meant to set up for a “Free Tier” machine. I was seeing some very small network and “VM manager” charges. After some research, we found that the 1GB outbound data free limit does not apply to the “Standard Network Tier”. You must use “Premium Network Tier” for the "Always Free usage limits" to apply.
The documentation seems contradictory in places, but this page says:
Standard Tier pricing
Egress pricing is per GiB delivered. Egress pricing is based on the source region of the traffic. Ingress pricing is still free. Always Free usage limits do not apply to Standard Tier.

So .. the Premium Tier (which is more expensive per GiB) gives you the free tier benefits, while Standard Tier (which is cheaper per GiB) charges for all egress traffic from the first byte. The bottom line for nightscout users is that if your system is going to stay below 1GB of outbound traffic per day, you need to select the Premium Tier network service or you will be subject to some charges on egress traffic.

I also added some "Custom metadata" variables to turn off some osconfig features that I thought might be contributing to the "VM Manager" charges. I will keep checking the billing info to make sure my config is remaining free.

[Navid200]

Create a cost table and we can find out why you have been charged: https://navid200.github.io/xDrip/docs/Nightscout/NS_FreeTier.html

We don't add anything to the guide just because we have had an idea. If you see something in guide, that means it's been tested.

I am more than happy to improve the guide if needed.

If you are interested to join a few of us who discuss ideas and test them before release, you can join this Facebook group: https://m.facebook.com/groups/google.cloud.nightscout/

[krsummersBA]

My setup is brand new, only about a week of use. I am in the free-trial period of 90 days, so the charges are not really billed to me. I am just monitoring it to understand the network traffic and make sure I have set it up correctly to not be charged. I am glad to hear it's been in use for 3 years. I must have something else set up incorrectly. Google doesn't allow me to do a Cost table since my project is only a week old - it only has June as an invoice option.
I am a member of the Facebook group. I will post there for this type of question.
Thank you!

[Navid200]

When we started this project, we went with the default network service tier.

At the time, we would get charged $0.01-$0.02 a month because of the crawlers in China causing traffic to where the free tier was excluded (China and Australia). Someone suggested switching the network service tier to standard. Looking at the free tier guide, I made the conclusion you have made and ignored the suggestion.
So, we put up with a cost of about $0.02 a month dues to the crawlers in China.

For December of 2024, many of us were charged about $0.50. After a lot of investigation, we discovered that there were some scanners in Brazil creating extensive traffic by constantly scanning us. This means they had caused traffic to go over 1GB for the month.
That was when we started working on firewalls to deal with the extra cost.
Someone again suggested why don't we switch to standard network tier.
I decided to add that to my batch of test machines that were testing different firewall implementations because we were not sure which was the best solution.

At the end of the month, the test results showed the best solution was switching the network service tier.
I then asked other users in the facebook group to test it. Several tested. I was not sure if we would experience a degradation of performance. Neither was I sure if the cost would be zero.
Month after month, the tests proved no degradation in performance and zero cost.

There are rounding errors in Google Cloud that results in a cost of about $0.02 some months. The next month, you will be given a credit. So, the overall annual cost is 0. But, the monthly cost is a max of $0.02.

[Navid200]

There are currently two possible mistakes one can make while building a setup that could cause a cost. One is to leave the network service tier as premium and possibly get hit by a scanner. The other is to leave the automatically set up snapshoting active. Snapshots are not free and since a few months ago, any new machine is set up to automatically create snapshots.

The page that goes over different reasons one may be charged goes over both of those: https://navid200.github.io/xDrip/docs/Nightscout/NS_FreeTier.html

The service tier specifically is explained here: https://navid200.github.io/xDrip/docs/Nightscout/GCNS/SwitchNetworkTier.html

The snapshot issue is described here: https://navid200.github.io/xDrip/docs/Nightscout/GCNS/DeleteSnapshotSchedule.html

I admit that there are so many pages in the guide. I have intentionally made the guide broken into many smaller pages because I believe a very large document like the user manual of a car is something you leave in the glove compartment and never look at. I wanted to create something that would be like a dictionary that you would refer to when you need to only get the answer you needed.

There is no perfect solution. Any style has pros and cons.
I would like to keep improving the guide and appreciate suggestions and criticism.

Thanks for asking and please let me know if you have any questions.

[krsummersBA]

Thank you for all the detailed info on the test environments. It does not look like my VM had a snapshot schedule by default, so that is not a problem. I have modified my machine back to Standard Tier networking.
I do not have any suggestions for the guide. It is extremely helpful.

[Navid200]

If you have created your machine less than a few months ago, there will be automatic snapshots scheduled. Unless, Google has made a recent change again.
I will need to create a new machine to confirm.
Thanks

[Navid200]

Of course, if you followed the guide to install less less than a month or so ago, the guide is already updated walking you through disabling the automated snapshot creation.

Only for a few months after Google introduced automated snapshots, we were not aware and new installs had it. And it is easy to disable it if that is the case.