Orbiter is a multi-vendor autoscaler designed for Docker Swarm, aiming to create a streamlined application management experience without the complexities of autoscaling. It provides an HTTP API for scaling services, integrates with various metrics and alerting tools, and simplifies communication with Docker's API. The tool is intended to function solely within Docker Swarm, making it accessible for users and easier to manage services through well-defined configurations.

1. github.com/gianarb/orbiter

2. Gianluca Arbezzano
@gianarb
Building clouds at InfluxDB (SRE)

3. Why?
● To create a use case around metrics, InfluxDB and Docker.
● Docker Swarm at the moment doesn’t provider autoscale capabilities.
● To design an application easy to manage and well integrated in Docker Swarm.

4. Orbiter is a general-purpose multi vendor autoscaler

5. Orbiter is a general-purpose multi vendor autoscaler
Orbiter is a Docker Swarm autoscaler

6. swarm cluster
manager
get metrics:
● cadvidor
● telegraf
● ….
alert:
● custom
● kapacitor
● alert
manager

7. Why Docker Swarm doesn’t have autoscaling?
● I don’t know.
● As you can see the architecture required is not small.
● Probably it will have autoscaling at some point.

8. Orbiter is designed to be Only-Swarm
● To make it easy to start
● To remove abstractions
● Because less is more! cit unknown but for sure a lazy person

9. What does it?
● It lists all your services and it gets only who has label orbiter=true
● Expose and HTTP API to trigger up and down scale event
○ curl -X POST -v http://$(IP):8081/v1/orbiter/handle/autoswarm/stack_micro/up
○ curl -X POST -v http://$(IP):8081/v1/orbiter/handle/autoswarm/stack_micro/down
● It uses Docker Swarm Api to keep in sync the managed services
● You can configure a service via label orbiter.up=3, orbiter.donw=2, orbiter.cooldown = 2

10. Requirement:
● Deploy it in a manager.

11. Deploy it as service in
Docker Swarm
version: '3'
services:
orbiter:
image: gianarb/orbiter
command: daemon
ports:
- 8081:8000
volumes:
- /var/run/docker.sock:/var/run/docker.sock
deploy:
placement:
constraints:
- node.role == manager
mode: replicated
replicas: 1

12. How Orbiter communicate with Swarm
func NewSwarmProvider(c map[string]string) (autoscaler.Provider, error) {
var p autoscaler.Provider
client, err := docker.NewEnvClient()
if err != nil {
logrus.WithField("error", err).Warn("problem to communicate with docker")
return p, err
} else {
logrus.Info("Successfully connected to a Docker daemon")
}
p = SwarmProvider{
dockerClient: client,
}
return p, nil
}

14. Scale a service - 1.Find the service
service, _, err := p.dockerClient.ServiceInspectWithRaw(ctx, serviceId, types.ServiceInspectOptions{
InsertDefaults: true,
})
if err != nil {
logrus.WithFields(logrus.Fields{
"error": err.Error(),
"provider": "swarm",
}).Debugf("Service %s didn't scale. We didn't get it from docker.", serviceId)
return err
}
filters := filters.NewArgs()
filters.Add("service", serviceId)
tasks, err := p.dockerClient.TaskList(ctx, types.TaskListOptions{Filters: filters})
if err != nil { … }
err = p.isAcceptable(tasks, target, direction)

15. Scale a service - 2.Update the Spec
spec := service.Spec
var ptrFromSystem uint64
base := p.calculateActiveTasks(tasks)
if direction == true {
ptrFromSystem = uint64(base + target)
} else {
ptrFromSystem = uint64(base - target)
}
spec.Mode.Replicated.Replicas = &ptrFromSystem
_, err = p.dockerClient.ServiceUpdate(ctx, serviceId, service.Version, spec, types.ServiceUpdateOptions{})
if err != nil {...}

16. Background job to sync services with Docker
services, err := dockerClient.ServiceList(ctx, types.ServiceListOptions{})
if err != nil {
logrus.WithField("error", err).Debug("Bad communication with Docker.")
return
}
prov, _ := provider.NewSwarmProvider(map[string]string{})
for _, service := range services {
s, err := getAutoscalerByService(prov, service.Spec.Annotations)
if err != nil {
continue
}
c.Autoscalers[fmt.Sprintf("autoswarm/%s", service.Spec.Annotations.Name)] = s
}

17. Is orbiter just a wrapper on Docker Swarm API?
Let’s put that in a cooler way.
Orbiter provides easy to use rest API to
scale your services up and down.

18. T-shirt time

19. Demo

21. Thanks a lot
https://twitter.com/gianarb
https://github.com/gianarb
https://gianarb.it