Hi. Does Amazon Elastic Load Balancing incorporate auto scaling?
That is: when the traffic drops to a low level from a high level, does it scale down?
Yes, it does.
According to the ELB product description,
Elastic Load Balancing automatically scales its request handling capacity in response to incoming application traffic.
Auto Scaling with Elastic Load Balancing
Let’s say that you want to make sure that the number of healthy Amazon EC2 instances behind an Elastic Load Balancer is never fewer than two. You can use Auto Scaling to set these conditions, and when Auto Scaling detects that a condition has been met, it automatically adds the requisite amount of Amazon EC2 instances to your Auto Scaling Group. Or, if you want to make sure that you add Amazon EC2 instances when latency of any one of your Amazon EC2 instances exceeds 4 seconds over any 15 minute period, you can set that condition, and Auto Scaling will take the appropriate action on your Amazon EC2 instances — even when running behind an Elastic Load Balancer. Auto Scaling works equally well for scaling Amazon EC2 instances whether you’re using Elastic Load Balancing or not.
As per the Auto Scaling feature description:
Auto Scaling allows you to scale your Amazon EC2 capacity up or down automatically according to conditions you define. With Auto Scaling, you can ensure that the number of Amazon EC2 instances you’re using increases seamlessly during demand spikes to maintain performance, and decreases automatically during demand lulls to minimize costs. Auto Scaling is particularly well suited for applications that experience hourly, daily, or weekly variability in usage.
Features of Auto Scaling
Scale out Amazon EC2 instances seamlessly and automatically when demand increases.
Shed unneeded Amazon EC2 instances automatically and save money when demand subsides.
Scale dynamically based on your Amazon CloudWatch metrics, or predictably according to a schedule that you define.
Yes, You can attach Amazon Auto Scaling with Amazon Elastic Load Balancing. In event an Load increases, new EC2 can be launched by Amazon Auto Scaling and it will seamlessly get attached to Amazon ELB. In event traffic reduces, Auto scaling will terminate EC2 instances which will be deregistered from ELB. This scheme works both in Amazon Classic cloud and Amazon VPC.
Related
Is there a way like assigning a specific tag for the EC2 instances to automatically attached to the load balancer on AWS?
I believe I had done that in the past but unable to find that option now.
Since you say you've done it in the past, I believe you're thinking of a feature offered by EC2 auto-scaling groups (ASGs). ASG is a capability of the EC2 infrastructure that scales machine counts up and down based on workload or maintains a set number of healthy instances always running (destroying and replacing failed instances). When an ASG is attached to a load balancer, the instances controlled by the ASG are automatically registered and deregistered from the balancer.
Amazon EC2 Auto Scaling integrates with Elastic Load Balancing to enable you to attach one or more load balancers to an existing Auto Scaling group. After you attach the load balancer, it automatically registers the instances in the group and distributes incoming traffic across the instances.
https://docs.aws.amazon.com/autoscaling/ec2/userguide/attach-load-balancer-asg.html
Is there an easy way to automatically deploy a CodeStar application to a persistent spot instance every time the request is fulfilled? The pipeline only runs when the code is changed and requires that the codedeploy agent already be installed. I've searched online and can't seem to find anything regarding using CodeStar with spot instances.
Seems totally possible, please read Deploying AWS CodeDeploy Applications to Auto Scaling Groups
AWS CodeDeploy supports Auto Scaling, an AWS service that can launch Amazon EC2 instances automatically according to conditions you define. These conditions can include limits exceeded in a specified time interval for CPU utilization, disk reads or writes, or inbound or outbound network traffic. Auto Scaling terminates the instances when they are no longer needed. For more information, see What Is Auto Scaling?.
When new Amazon EC2 instances are launched as part of an Auto Scaling
group, AWS CodeDeploy can deploy your revisions to the new instances
automatically. You can also coordinate deployments in AWS CodeDeploy
with Amazon EC2 instances registered with Elastic Load Balancing load
balancers. For more information, see Integrating AWS CodeDeploy with
Elastic Load Balancing and Set Up a Classic Load Balancer in Elastic
Load Balancing for AWS CodeDeploy Deployments.
Good luck
Does anyone know what the difference between Automatic Load-based Scaling vs having explicit auto scaling groups on OpsWorks is?
this: http://docs.aws.amazon.com/opsworks/latest/userguide/workinginstances-autoscaling-loadbased.html
vs https://aws.amazon.com/blogs/devops/auto-scaling-aws-opsworks-instances/
With load-based instances, how does one add one to a target group?
Can you have multiple auto scaling groups in one layer of OpsWorks?
I’m looking at going with an ALB to route our traffic, which cannot act as an independent layer in Opsworks.
So I would need to pipe requests to 1 auto scaling group for one type of requests and the rest to the other other auto scaling group.
I just am not sure what load-based instances are and am perplexed by them not providing a default number of machines to start with.
Which one should I use for ALB routing traffic between the two groups?
OpsWorks is a configuration management tool that utilises Chef to configure your infrastructure. OpsWorks utilises a different approach when it comes to scaling out than a auto-scaling group.
Unlike an auto-scaling group, you have these instances pre-defined on your OpsWorks stack (layer) and they are being launched when a certain metric (threshold) is triggered (CloudWatch data: CPU, memory, load... etc).
OpsWorks will not spawn (create) any new instances, but will only be capable of starting instances you have previously created and set them as load-based instances. This is also only available for OpsWorks and cannot be used for any other service outside of OpsWorks.
AWS EC2 auto-scaling actually can launch very large number of instances (instances which do not need to be created beforehand) into your AWS environment, and same as the OpsWorks load-based scaling, can be triggered by CloudWatch alarms (CPU, memory, Load... etc).
Auto-scaling is not by default available on OpsWorks, and there is no build in way to have an auto-scaling group associated with your OpsWorks stack, but it's possible with a bit of work. Read about it here.
Let me divide the answer for you.
Does anyone know what the difference between Automatic Load-based
Scaling vs having explicit auto scaling groups on OpsWorks is?
Automatic Load-based Scaling:
Amazon Opsworks Service provides you the the feature, automatic load-based scaling where you can add instances to your layer in stack and set the auto scaling configuration policies directly.
Load based scaling scales up or down the instances based upon the load you have set to handle. You need to set the threshold, using the parameters and define the scaling policies.
Explicit Auto Scaling groups on OpsWorks:
Amazon Opsworks Service allows you to add existing instances to your layer in stack. Which means You can set an autoscaling launch configuration and set the scale up and scale down events based on the load. Then create an Autoscaling group and launch instances in it. Then you can go to Opsworks and add these existing instances to your layer in stack. So when the load increases or decreases more or less than the threshold set, the Autoscaling group handles the scaling.
With load-based instances, how does one add one to a target group?
Once you have the Load based Instances Ready either you have launched then directly from Automatic Load-based Scaling in Opsworks or Explicitly using Auto Scaling groups on OpsWork, you can go to Application Load balancer in EC2 Console and configure with necessary configurations and then register the load based instances you have just created with ALB in Register targets TAB.
Can you have multiple auto scaling groups in one layer of OpsWorks?
Yes, you can have multiple auto scaling groups in one layer of OpsWorks.
Which one should I use for ALB routing traffic between the two groups?
You can use any of the group.
so that you can pipe requests to 1 auto scaling group for one type of
requests and the rest to the other other auto scaling group.
Please Refer Autoscaling once.
I just am not sure what load-based instances are
Load Based Instances are the instances which are configured with Load based scaling configuration. You need to set the threshold,configuration and the events to define when to scale up and scale down.
EX: Suppose, If you have 5 instances running at initial stage and as you want your application to be running even your load increases to minimize your downtime, you will set autoscaling configuration such that if average CPU utilization of instances increase more than 70% launch 2 more instances. You can set scale up and scale down on many more factors.
Hope it Helps:)
I am new to AWS. I would like to activate load balancing. I need to know that should I create multipl ec2 instance with the same files? Or only one instance is enough?. What will happen while heavy traffic?
AWS Elastic Load balancer (ELB) is for distributing traffic across multiple EC2 instances. You will be registering the instances with the ELB. Even when instances fail and new instances are added to ELB, the traffic is evenly distributed among the remaining active registered instances. Please see the documentation: AWS Elastic Load Balancing
If you have only one instance, ELB will send traffic only to that. But, what is the use of ELB then? It serves no purpose to have only 1.
If you need to scale out as the traffic increases, you need to use AWS Auto Scaling : AWS Auto Scaling
I have read that we can configure Auto Scaling to used CloudWatch metrics to scale in/or a pool of EC2 instances.
I'm curious to understand how ELB gets to know there is an EC2 instance added/removed to the Auto Scaling Group, so it does send workload to the newly added instance ? (or stop sending workload to the instance that has been removed?)
Regards,
Pascal
When you set them up, you associate the Auto Scaling group with the Elastic Load Balancer. The Auto Scaling Group then notifies the Elastic Load Balancer when instances are added or removed.