Flexible VM - Weekly reboot

[Tom Stuart]

What is the minimum number of instances required for App Engine Flexible to maintain 100% uptime?

As per the documentation:

All flexible instances are restarted on a weekly basis. During restarts, critical, backwards-compatible updates are automatically rolled out to the underlying operating system. Your application's image will remain the same across restarts.

Does this mean that the minimum number of instances is 2?

Or would I be able to maintain 100% uptime using just 1 instance and Google App Engine starts a new instance to deal (and I pay for 2 instances for a short period of time)?

[Digil(Google Cloud Platform Support)]

Google doesn’t guarantee 100%  up-time even if you use 2 instances or more, instead we do have an SLA agreement with the customers where we provide a monthly up-time percentage of a range between 99.00% – < 99.95% as mentioned in this document.

That being said, it is recommended to use automatic scaling to ensure that your application is always serving with enough instances to meet your traffic needs.

If you are using manual scaling, it is recommended to at least have two instances in case of automatic updates, and to follow the ‘Best Practices’ guide to avoid instance downtime.