vultr

README

Cluster Autoscaler for Vultr

The cluster autoscaler for Vultr scales nodes in a VKE cluster.

Vultr Kubernetes Engine

Vultr Kubernetes Engine (VKE) is the managed kubernetes solution provided by Vultr.

VKE lets users create Node Pools, i.e. groups of nodes each of the same type.

The size of a Node Pool can be configured at any moment. The user cannot select specific nodes to be deleted when downsizing a Node Pool, rather, VKE will randomly select nodes to be deleted to reach the defined size, even if a node is not healthy or has been manually deleted.

Nodes in a Node Pool are considered disposable: they can be deleted and recreated at any moment, deleting a single node outside of VKE will be recreated by Vultr after a small amount of time.

Configuration

It is mandatory to define the cloud configuration file cloud-config. You can see an example of the cloud config file at examples/cluster-autoscaler-secret.yaml, it is an INI file with the following fields:

The (JSON) configuration file of the Vultr cloud provider supports the following values:

• cluster_id: the ID of the VKE cluster.
• token: the Vultr API key literally defined.

Configuring the autoscaler such as if it should be monitoring node pools or what the minimum and maximum values. Should be configured through the Vultr API. The autoscaler will pick up any changes and adjust accordingly.

Development

Make sure you are inside the cluster-autoscaler path of the autoscaler repository.

Create the docker image:

make container

tag the generated docker image and push it to a registry.

Documentation

Index

• func BuildVultr(opts config.AutoscalingOptions, do cloudprovider.NodeGroupDiscoveryOptions, ...) cloudprovider.CloudProvider
• type Config
• type NodeGroup
  • func (n *NodeGroup) AtomicIncreaseSize(delta int) error
  • func (n *NodeGroup) Autoprovisioned() bool
  • func (n *NodeGroup) Create() (cloudprovider.NodeGroup, error)
  • func (n *NodeGroup) Debug() string
  • func (n *NodeGroup) DecreaseTargetSize(delta int) error
  • func (n *NodeGroup) Delete() error
  • func (n *NodeGroup) DeleteNodes(nodes []*apiv1.Node) error
  • func (n *NodeGroup) Exist() bool
  • func (n *NodeGroup) GetOptions(defaults config.NodeGroupAutoscalingOptions) (*config.NodeGroupAutoscalingOptions, error)
  • func (n *NodeGroup) Id() string
  • func (n *NodeGroup) IncreaseSize(delta int) error
  • func (n *NodeGroup) MaxSize() int
  • func (n *NodeGroup) MinSize() int
  • func (n *NodeGroup) Nodes() ([]cloudprovider.Instance, error)
  • func (n *NodeGroup) TargetSize() (int, error)
  • func (n *NodeGroup) TemplateNodeInfo() (*framework.NodeInfo, error)

Functions

func BuildVultr

func BuildVultr(opts config.AutoscalingOptions, do cloudprovider.NodeGroupDiscoveryOptions, rl *cloudprovider.ResourceLimiter) cloudprovider.CloudProvider

BuildVultr builds the Vultr cloud provider.

Types

type Config

type Config struct {
	ClusterID string `json:"cluster_id"`
	Token     string `json:"token"`
}

Config is the configuration of the Vultr cloud provider

type NodeGroup

type NodeGroup struct {
	// contains filtered or unexported fields
}

NodeGroup implements cloudprovider.NodeGroup interface. NodeGroup contains configuration info and functions to control a set of nodes that have the same capacity and set of labels.

func (*NodeGroup) AtomicIncreaseSize

func (n *NodeGroup) AtomicIncreaseSize(delta int) error

AtomicIncreaseSize is not implemented.

func (*NodeGroup) Autoprovisioned

func (n *NodeGroup) Autoprovisioned() bool

Autoprovisioned returns true if the node group is autoprovisioned. An autoprovisioned group was created by CA and can be deleted when scaled to 0.

func (*NodeGroup) Create

func (n *NodeGroup) Create() (cloudprovider.NodeGroup, error)

Create creates the node group on the cloud provider side. Implementation optional.

func (*NodeGroup) Debug

func (n *NodeGroup) Debug() string

Debug returns a string containing all information regarding this node group.

func (*NodeGroup) DecreaseTargetSize

func (n *NodeGroup) DecreaseTargetSize(delta int) error

DecreaseTargetSize decreases the target size of the node group. This function doesn't permit to delete any existing node and can be used only to reduce the request for new nodes that have not been yet fulfilled. Delta should be negative. It is assumed that cloud provider will not delete the existing nodes when there is an option to just decrease the target.

func (*NodeGroup) Delete

func (n *NodeGroup) Delete() error

Delete deletes the node group on the cloud provider side. This will be executed only for autoprovisioned node groups, once their size drops to 0. Implementation optional.

func (*NodeGroup) DeleteNodes

func (n *NodeGroup) DeleteNodes(nodes []*apiv1.Node) error

DeleteNodes deletes nodes from this node group (and also increasing the size of the node group with that). Error is returned either on failure or if the given node doesn't belong to this node group. This function should wait until node group size is updated. Implementation required.

func (*NodeGroup) Exist

func (n *NodeGroup) Exist() bool

Exist checks if the node group really exists on the cloud provider side. Allows to tell the theoretical node group from the real one. Implementation required.

func (*NodeGroup) GetOptions

func (n *NodeGroup) GetOptions(defaults config.NodeGroupAutoscalingOptions) (*config.NodeGroupAutoscalingOptions, error)

GetOptions returns NodeGroupAutoscalingOptions that should be used for this particular NodeGroup. Returning a nil will result in using default options.

func (*NodeGroup) Id

func (n *NodeGroup) Id() string

Id returns an unique identifier of the node group.

func (*NodeGroup) IncreaseSize

func (n *NodeGroup) IncreaseSize(delta int) error

IncreaseSize increases the size of the node group. To delete a node you need to explicitly name it and use DeleteNode. This function should wait until node group size is updated.

func (*NodeGroup) MaxSize

func (n *NodeGroup) MaxSize() int

MaxSize returns maximum size of the node group.

func (*NodeGroup) MinSize

func (n *NodeGroup) MinSize() int

MinSize returns minimum size of the node group.

func (*NodeGroup) Nodes

func (n *NodeGroup) Nodes() ([]cloudprovider.Instance, error)

Nodes returns a list of all nodes that belong to this node group. It is required that Instance objects returned by this method have ID field set. Other fields are optional.

func (*NodeGroup) TargetSize

func (n *NodeGroup) TargetSize() (int, error)

TargetSize returns the current target size of the node group. It is possible that the number of nodes in Kubernetes is different at the moment but should be equal to Size() once everything stabilizes (new nodes finish startup and registration or removed nodes are deleted completely). Implementation required.

func (*NodeGroup) TemplateNodeInfo

func (n *NodeGroup) TemplateNodeInfo() (*framework.NodeInfo, error)

TemplateNodeInfo returns a framework.NodeInfo structure of an empty (as if just started) node. This will be used in scale-up simulations to predict what would a new node look like if a node group was expanded. The returned NodeInfo is expected to have a fully populated Node object, with all of the labels, capacity and allocatable information as well as all pods that are started on the node by default, using manifest (most likely only kube-proxy). Implementation optional.