Canary step weighting scenarios

[aackerman]

I'm interested in more complicated step weighting.

Currently steps are defined with a maxWeight and a stepWeight. This doesn't allow for a scenario I'm looking for where you would want a slow ramp up and then total cut over.

I'm interested in a weighting scenario that would be like 1, 2, 3, 5, 15, 25, 50, 100, more like a logarithmic scale. A proposed API could be to add a weightStrategy key, with the current behavior having a value of step-weights, and add new behavior with a weightStrategy like static-weights and add a key for staticWeights that could be an array of values similar to the weights I laid out above.

Like

maxWeight: 100
weightStrategy: "static-weights"
staticWeights:
- 1
- 2
- 3
- 5
- 15
- 25
- 50
- 100

... or

staticWeights: "1,2,3,5,15,25,50,100" 

I also posted about manual gating in #163, so it may be worth considering handling both of these scenarios with one consistent API that's different from my proposal.

[Imaskar]

This is also interesting for us. We're looking into migrating from Beanstalk to k8s+Flagger. We currently have "0.1,1,10,30,70,100" for weights and current Flagger schema looks very limiting. Are there any plans in this direction?

[robq99]

We needed similar functionality but a little bit more granual: expected weights were 0.01%, 0.1%, 1%, 10%...
I created (working) proposal with some documentation:
https://github.com/robq99/flagger/blob/master/docs/gitbook/tutorials/rollout-weights.md

Could you please share your thoughts on this?

edited: link updated

[ta924]

@stefanprodan curious if there has been any thoughts around entertaining this issue? Not sure if this would lead to changes on the Canary CRD or a dedicated CRD to handle dynamic scenarios.

[stefanprodan]

Implemented in v1.3.0