Ah, I think I understand what you are looking for now (instances to scale up in the specific region where soft limit has been reached). Indeed, the existing documentation did describe this kind of region-aware behavior:
Standard: Instances of the application, up to the minimum count, are evenly distributed among the regions in the pool. They are not relocated in response to traffic. New instances are added where there is demand, up to the maximum count.
I dug into this recently, and found that our current (nomad-based) autoscaler implementation was deployed around Sept 2021, but this documentation was originally written for an earlier system that had somewhat different behavior. Most notably, thereās only one āmodeā in the current autoscaling system (and I believe the scaling action is a simple adjustment of the total instance count), so setting ābalancedā mode no longer has any effect.
Apologies for the confusion our quite out-of-date documentation has caused on this. Iāve prepared some updates to the documentation and flyctl that should clarify the current behavior a bit better moving forward.
That said, it does look like the current autoscaler is not quite capable of what youāre looking for. Our current efforts have been focused on adding features to Machines to help manage more advanced scaling requirements like this. Autoscaling apps on machines isnāt quite ready yet, but itās something weāre actively working on and should eventually be able to better handle your use-case.
Ok, I think we will disable autoscaling for launch and revisit the topic later then. We donāt have too much traffic for now so we can totally live with a fixed set of VMs in specific spots around the globe (the main goal being optimal latency).
However Iām not sure how to do that. I have this set of regions configured:
Region Pool:
cdg
hkg
lax
maa
scl
syd
Backup Region:
ams
sjc
How can I start a VM in each of these regions? I tried to disable autoscaling and to set the VM count to 6 with flyctl scale count 6, hoping it would fill the spots, but instead it started 4 in lax and hkg:
Instances
ID PROCESS VERSION REGION DESIRED STATUS HEALTH CHECKS RESTARTS CREATED
6a3dd886 app 950 hkg run pending 0 8s ago
10cbf6c9 app 950 lax run pending 0 8s ago
2c3a79e6 app 950 lax run pending 0 8s ago
dd84e7c3 app 950 hkg run pending 0 8s ago
d24f1a6d app 950 scl run running 2 total, 2 passing 0 2h24m ago
784474bd app 950 cdg run running 2 total, 2 passing 0 2022-10-21T13:20:11Z
I also tried switching back to autoscaling with a min count of 6 but got the same result.
Flyās main selling point is, for us, starting VMs close to users, how can I do that?
The --max-per-region option to flyctl scale count is probably what youāre looking for. For example flyctl scale count 6 --max-per-region 1 should start a single VM in each of 6 different regions.
Thanks that should work for us. Do you have plans for the autoscaling that would better fit our needs? Is there an issue, a changelog, or a Twitter account I can track to keep updated on this subject?
