Feature: Add min/max scale for auto-scaling - Swarm & external providers

[alexellis]

Signed-off-by: Alex Ellis alexellis2@gmail.com

Description

Feature: Add min/max scale for auto-scaling - Swarm & external providers

Motivation and Context

• I have raised an issue to propose this change (required)

See: #414

How Has This Been Tested?

With new tests and with Stefan via gateway and kubernetes

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have signed-off my commits with git commit -s
• I have added tests to cover my changes.
• All new and existing tests passed.

[ericstoekl]

Tried this out and at least can see that min is working, as the number of replicas for my function starts at 5. What's the recommended way to make the container scale up until it hits its max limit? Would using ab work?

[alexellis]

Yes that will work too with a high number or a bash loop. Doesn't need to be high figures for concurrency and you can monitor the alerts in Prometheus too

[ericstoekl]

Gotcha, I will try that out.

Confirmed that max works as well as min in Docker Swarm.

I will try this out on Kubernetes next.

Edit -- tried this out in faas-netes. Looks like it creates the specified number of replicas, and in faas-cli ls the number is shown correctly, but in kubectl get pods it shows a separate pod for each replica. Is this expected?

Replica list on Faas-Netes

[stefanprodan]

@ericstoekl this is how Kubernetes works, replicas refer to pods not containers

[alexellis]

@ericstoekl do this instead - kubectl get deploy that is where the replica count is stored.

[ericstoekl]

In that case, I see that the function has the correct number of replicas. Thanks 💯

[alexellis]

Thank you both for testing. I'll merge.