aws

package
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 Go to latest Published: Jun 28, 2023 License: Apache-2.0 Imports: 23 Imported by: 0

Documentation

Overview

package aws implements autoscaling integration for AWS cloud provider

Design ------ 

+-------------------------+           +--------------------------+
|                         |           |                          |
|                         |           |                          |
|   Gravity  Master Node  |           |    Auto Scaling Group    +---------------------------------+
|                         |           |                          |                                 |
|                         |           |                          |                                 |
++-----+------------------+           +--------------------------+                                 |
 |     |                                               +---------------+                           |
 |     |                                               |               |                           |
 |     | Publish Gravity  ELB address                  |               |                           |
 |     | Publish Encrypted Join Token                  |  AWS Instance |                           |

Read SQS notifications | | | | | Remove deleted nodes | | | | | 

|     |                                               +--------+------+                           |   Push Scale Up/Scale Down Events
|     |                                                        |                                  |   to SQS service
|     |              +--------------------------+              | Discover Gravity  ELB            |
|     |              |                          |              | Read Join Token                  |
|     +-------------->    SSM Parameter Store   <--------------+ Join the cluster                 |
|                    |                          |                                                 |
|                    +--------------------------+                                                 |
|                                                                                                 |
|                   +-------------------------------------------+                                 |
|                   |                                           |                                 |
|                   |     AWS Lifecycle Hooks/SQS notifications |                                 |
+------------------->                                           <---------------------------------+
                    |                                           |
                    +-------------------------------------------+
  • Autoscaler runs on master nodes
  • Autoscaler publishes the Gravity load balancer service and encrypted join token to the SSM (AWS systems manager) parameter store
  • Instances started up as a part of auto scaling group discover the cluster by reading SSM parameters from the parameter store.
  • Whenever ASG scales down it sends a notification to the SQS (Amazon Simple Queue Service)

queue associated with the cluster. * Autoscaler receives the notification on the scale down and removes the node from the cluster in forced mode (as the instance is offline by the time notification is received)

Index

Constants

View Source 
const (
	// InstanceLaunching is AWS instance launching lifecycle autoscaling event
	InstanceLaunching = "autoscaling:EC2_INSTANCE_LAUNCHING"
	// InstanceTerminating is AWS instance terminating lifecycle autoscaling event
	InstanceTerminating = "autoscaling:EC2_INSTANCE_TERMINATING"
)

Variables

This section is empty.

Functions

func ConvertError 

func ConvertError(err error, args ...interface{}) error

ConvertError converts errors specific to AWS to trace-compatible error

Types

type Autoscaler 

type Autoscaler struct {
	// Config is Autoscaler config
	Config
	// QueueURL is SQS queue name with notifications
	QueueURL string
	*log.Entry
	// contains filtered or unexported fields
}

Autoscaler is AWS autoscaler server, it enables nodes to discover cluster information via AWS Systems Manager (SSM) Parameter Store and Masters to add/remove nodes from the cluster as they join via discovery group

func New 

func New(cfg Config) (*Autoscaler, error)

New returns new instance of AWS autoscaler

func (*Autoscaler) DeleteEvent 

func (a *Autoscaler) DeleteEvent(ctx context.Context, event HookEvent) error

DeleteEvent deletes SQS message associated with event

func (*Autoscaler) DescribeInstance 

func (a *Autoscaler) DescribeInstance(ctx context.Context, instanceID string) (*ec2.Instance, error)

DescribeInstance returns information about instance with the specified ID.

func (*Autoscaler) DescribeInstancesWithSourceDestinationCheck 

func (a *Autoscaler) DescribeInstancesWithSourceDestinationCheck(ctx context.Context, instanceIDs []string) (result []*ec2.Instance, err error)

DescribeInstancesWithSourceDestinationCheck returns all instances from the specified list that have source/destination check enabled.

func (*Autoscaler) GetQueueURL 

func (a *Autoscaler) GetQueueURL(ctx context.Context) (string, error)

GetQueueURL returns queue URL associated with this cluster

func (*Autoscaler) GetServiceURLAndJoinToken 

func (a *Autoscaler) GetServiceURLAndJoinToken(ctx context.Context) (responseURL string, responseToken string, err error)

GetServiceURLAndJoinToken fetches and decrypts cluster service URL and join token from SSM parameter

func (*Autoscaler) ProcessEvents 

func (a *Autoscaler) ProcessEvents(ctx context.Context, queueURL string, operator Operator)

ProcessEvents listens for events on SQS queue that are sent by the auto scaling group lifecycle hooks.

func (*Autoscaler) PublishDiscovery 

func (a *Autoscaler) PublishDiscovery(ctx context.Context, operator ops.Operator)

PublishDiscovery periodically updates discovery information

func (*Autoscaler) TurnOffSourceDestinationCheck 

func (a *Autoscaler) TurnOffSourceDestinationCheck(ctx context.Context, instanceID string) error

TurnOffSourceDestinationCheck check turns off source destination check on the instance that is necessary for K8s to function properly

func (*Autoscaler) WaitUntilInstanceTerminated 

func (a *Autoscaler) WaitUntilInstanceTerminated(ctx context.Context, instanceID string) error

WaitUntilInstanceTerminated blocks until the instance with the specified ID is terminated.

Note: If an incorrect or non-existent ID is provided, the method will block indefinitely (or until timeout has been reached) so it is advised to query the instance using DescribeInstance method prior to calling it.

type Config 

type Config struct {
	// ClusterName is a Telekube cluster name,
	// used to discover configuration in the cluster
	ClusterName string
	// Client is an optional kubernetes client
	Client *kubernetes.Clientset
	// SSM is AWS systems manager parameter store,
	// metadata store used to store configuration
	SystemsManager SSM
	// Queue is Simple Queue Service, AWS pub/sub queue
	Queue SQS
	// Cloud is Elastic Compute Cloud, AWS cloud service
	Cloud EC2
	// AutoScaling is a client for the AWS AutoScaling service
	AutoScaling *autoscaling.AutoScaling
	// NewLocalInstance is used to retrieve local instance metadata
	NewLocalInstance NewLocalInstance
	// Region specifies the AWS region the gravity controllers are running in
	Region string
}

Config is autoscaler config

func (*Config) CheckAndSetDefaults 

func (cfg *Config) CheckAndSetDefaults() error

CheckAndSetDefaults checks and sets default values

type EC2 

type EC2 interface {
	ModifyInstanceAttributeWithContext(aws.Context, *ec2.ModifyInstanceAttributeInput, ...request.Option) (*ec2.ModifyInstanceAttributeOutput, error)
	DescribeInstancesWithContext(aws.Context, *ec2.DescribeInstancesInput, ...request.Option) (*ec2.DescribeInstancesOutput, error)
	WaitUntilInstanceTerminatedWithContext(aws.Context, *ec2.DescribeInstancesInput, ...request.WaiterOption) error
}

EC2 is an interface representing AWS Elastic Compute cloud

type HookEvent 

type HookEvent struct {
	// QueueURL is a queue this event belongs to
	QueueURL string `json:"-"`
	// ReceiptHandle is SQS receipt handle
	ReceiptHandle string `json:"-"`
	// InstanceID is AWS instance ID
	InstanceID string `json:"EC2InstanceId"`
	// Type is event type
	Type string `json:"LifecycleTransition"`
	// Token is the token to use when interacting with the lifecycle event
	Token string `json:"LifecycleActionToken"`
	// AutoScalingGroupName is the name of the AWS ASG
	AutoScalingGroupName string `json:"AutoScalingGroupName"`
	// LifecycleHookName is the name of the AWS Lifecycle hook
	LifecycleHookName string `json:"LifecycleHookName"`
}

HookEvent is a lifecycle hook event posted by autoscaling group

type NewLocalInstance 

type NewLocalInstance func() (*gaws.Instance, error)

type Operator 

type Operator interface {
	GetLocalSite(context.Context) (*ops.Site, error)
	CreateSiteShrinkOperation(context.Context, ops.CreateSiteShrinkOperationRequest) (*ops.SiteOperationKey, error)
	GetSiteOperationProgress(ops.SiteOperationKey) (*ops.ProgressEntry, error)
}

Operator is a simplified operator interface to mock in tests

type SQS 

type SQS interface {
	DeleteMessageWithContext(aws.Context, *sqs.DeleteMessageInput, ...request.Option) (*sqs.DeleteMessageOutput, error)
	ReceiveMessageWithContext(aws.Context, *sqs.ReceiveMessageInput, ...request.Option) (*sqs.ReceiveMessageOutput, error)
	GetQueueUrlWithContext(aws.Context, *sqs.GetQueueUrlInput, ...request.Option) (*sqs.GetQueueUrlOutput, error)
}

SQS is an interface representing AWS Queue Service

type SSM 

type SSM interface {
	GetParametersWithContext(aws.Context, *ssm.GetParametersInput, ...request.Option) (*ssm.GetParametersOutput, error)
	PutParameterWithContext(aws.Context, *ssm.PutParameterInput, ...request.Option) (*ssm.PutParameterOutput, error)
}

SSM is an interface representing AWS Systems Manager

Source Files

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