pkg

Documentation

Index

• Constants
• type ElectorConfig
  • func (conf *ElectorConfig) Log()
• type ElectorNode
  • func NewElectorNode(config *ElectorConfig) *ElectorNode
  • func (node *ElectorNode) IsLeader() bool
  • func (node *ElectorNode) Run() error

Constants

const (
	// EnvPodName is the environment variable which is checked for the Pod name.
	EnvPodName = "ELECTOR_POD_NAME"

	// ResourcePathPodLabel is the path to the Pod label metadata which is used
	// for updating Pod label values for election status.
	//
	// Note that the label key is the last element in the path. Since the key
	// contains a "/", it is escaped as "~1".
	ResourcePathPodLabel = "/metadata/labels/k8s-elector~1status"

	// StatusStandby is the standby status annotation value.
	StatusStandby = "standby"

	// StatusLeader is the leader status annotation value.
	StatusLeader = "leader"
)

Types

type ElectorConfig

type ElectorConfig struct {
	// Address is the HTTP address[:port] that the elector will host an endpoint
	// on (at '/') to provide information on the node and if it is the leader. If
	// not set, an HTTP endpoint will not be set up.
	Address string

	// The ID of the elector node participating in the election. This is required
	// for an election and must be unique. If not specified, the elector will try
	// using the HOSTNAME as its ID.
	ID string

	// PodName is the name of the Pod which the elector is running in. This is
	// found via the ELECTOR_POD_NAME environment variable. If not set, this defaults
	// to the hostname.
	PodName string

	// KubeConfig is the path to the kubeconfig file to use for setting up the
	// elector node's Kubernetes client. If no kubeconfig is specified, the node
	// will default to using in-cluster configuration.
	KubeConfig string

	// LockType specifies the kind of Kubernetes object to use as the lock mechanism
	// to determine node leadership. If not specified, the node will use "leases"
	// by default.
	//
	// The valid LockTypes are: "endpoints", "configmaps", and "leases".
	LockType string

	// The Name of the election. The election name gets used as the name for the
	// Kubernetes object used as the election lock. This is required by the node
	// to join or create an election.
	Name string

	// The Namespace in Kubernetes to run the election in. The Kubernetes object
	// used as the election lock will be created in this namespace. If not specified,
	// "default" is used.
	Namespace string

	// The TTL for the election determines the lease duration (the time non-leader
	// candidates will wait to force acquire leadership), the renew deadline (the
	// duration that the acting master will retry refreshing leadership), and the
	// retry period (the duration that elector nodes should wait between retry
	// actions).
	TTL time.Duration
}

ElectorConfig contains the configuration values for the elector node.

func (*ElectorConfig) Log

func (conf *ElectorConfig) Log()

Log logs the ElectorConfig values at INFO level.

type ElectorNode

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

ElectorNode is a participant node in an election.

func NewElectorNode

func NewElectorNode(config *ElectorConfig) *ElectorNode

NewElectorNode creates a new instance of an elector node which will participate in an election.

func (*ElectorNode) IsLeader

func (node *ElectorNode) IsLeader() bool

IsLeader checks whether the elector node is currently the leader.

func (*ElectorNode) Run

func (node *ElectorNode) Run() error

Run the elector node.

This is the entry point that kicks off all of the elector node setup and run logic.