I am a begineer to aws elb. Can someone help me to understand how elb automatically creates a new instance depending on the traffic or cpu usage. Also when it creates a new instnces how does it copies code from existing instance?
Any link/article will also be appreciated.
Thanks in adavnce.
How elb automatically creates a new instance depending on the traffic
or cpu usage?
ELB does not create the new instance the new instance is created by Launch configuration and Autoscaling group rules that you have set. https://docs.aws.amazon.com/autoscaling/latest/userguide/GettingStartedTutorial.html
Also when it creates a new instnces how does it copies code from
existing instance?
When a new instance gets created from the AMI you have to add the replication mechanism either using user data scripts (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/user-data.html) or running a cron job on that instance that will copy the files to that instance from a S3 bucket.
Related
I have a an Ubuntu-14.04 EC2 instance running with EBS volume
I regularly take snapshot
I launched a new instance Ubuntu-16.04.
I detach the root volume
I created a EBS volume from snapshot above
I re-attached the volume.
I see all the data and my servers seem to work on the new instance. For eg. mongo, app servers etc.
My question is (other than app data):
What are the differences between the new instance and the instance launched via an existing EBS?
Is the existing-EBS-launched instance supposed to work like the old instance without any changes, out-of-the-box?
What are the differences between the new instance and the instance launched via an existing EBS?
Answer- first of all, understand what EBS is, in a simple language, it is a block storage volume for use with Amazon EC2 Instance.
So Whenever you launch a new Instance via an existing EBS, all the stuff/ any manual changes on the disk which you have done previously will be automatically reflected in your new Instance, as you are using the same disk (Block Storage). It's just when you want any kind of modification like wants to change the key pair at that time we detach the volume, do the modifications and again attach the volume (disk).
Is the existing-EBS-launched instance supposed to work like the old instance without any changes, out-of-the-box?
Answer- yes Existing EBS launched instance work as the old instance, its just what kind of modification you have provided to the new instance. Suppose while launching you have changed the Type of instance, key pair, attach different security group. So all these changes will be reflected and all the manual operations done on Disk will remains same.
Last day I wanted, according to AWS recommendations, put my ec2 instance inside of an autoscaling group. I created my ec2 instance by using the standard linux AMI instance and then I installed a full LAMP server.
The next morning I tried accessing my apache and guess what? My LAMP wasn't there anymore! Everything was wiped away.
I guess this is because, for some reason, the autoscaling group deleted my instance and recreated it vanilla.
Now I still want to autoscale my instance but, of course, I want to keep my LAMP and the stored data.
So here's my questions:
How to create a customized image starting from my actual instance?
Would it be correct to create the mysql DB using AWS RDS so to not keep it linked to my instance?Is it more or less expensive than dedicating a EBS storage?
I also want to keep my /var/www/html data somewhere shared between instances: while it is true that, on production, I won't update those files often it is also true that I don't want to lose them just because the autoscaling resets my instance state. I also don't want to re-create an image each time I update said files... What's the best way?Maybe an s3 bucket? Or, still, an EBS storage shared between instances?
I would assume that the reason that your "LAMP [server] wasn't there anymore" was because the web server failed health checks and was terminated and replaced by AutoScaling.
Elastic Beanstalk would be a good way to manage some of the complexity here. If that's not an option then you should read up on AutoScaling, ALB, and health checks.
In response to your specific questions:
you can create an Amazon Machine Image (AMI) from an instance. When you, or AutoScaling, launch a new instance from that AMI, you can get the instance up to date by running a script in userdata
move the DB from the web/app server to RDS, or to a DB server that you manage yourself
maintain the html/js/css etc. in S3 and sync them to your web server periodically (there are other options, but that's simple)
I am running amazon AWS ECS container which creates one single instance of EC2. I made sure that it is 1 instance when I created ECS.
My issue is that I have another instance running in EC2 and amazon has sent me an email that I am using double of the free quota and will be charged.
But I am not sure why this second EC2 instance is coming from.
I have terminated it many times but it is recreated. When I terminate it, this is the prompt i receive which advises me that it is created from EBS but there is no app in EBS
On an EBS-backed instance, the default action is for the root EBS volume to be deleted when the instance is terminated.
Storage on any local drives will be lost.
This name of the instance is.
ECS Instance - amazon-ecs-cli-setup-ecs-cricketscorer
Please help.
check if you have any Auto Scaling Groups that you do not recognize. It is most probably being created because of it. If not, change your account password and deactivate/delete your existing AccessKeys.
I setup one mail server in one EC2 instances. I want to copy the whole instance and launch as another new instance.
I'm very confused about snapshot and AMI, so please suggest how to do it.
When talking about creating a copy or clone of an instance, there's two aspects to consider:
The configuration of the instance itself, such as Instance Type, Security Group, IAM Role and network subnet
The contents of the disk volume(s)
To launch an instance with the same instance configuration, use the Launch More Like This option in the actions menu, which can launch a new instance with the same configuration. This will also select the original AMI used to launch the initial instance -- please note that this means it will have the same disk as sued when launching the initial instance, but will not have a copy of all data stored/changed on the initial instance since it was first started.
If you wish to make a perfect copy of the instance, including the contents of the disk volume(s), then create an AMI (see documentation for Linux and Windows). This will make a copy of the disk volume(s) so that any instance launched from the AMI will have the same data on disk. Then, launch a new instance from that AMI.
Is it possible to do AutoScaling with Static IPs in AWS ? The newly created instances should either have a pre-defined IP or pick from a pool of pre-defined IPs.
We are trying to setup ZooKeeper in production, with 5 zooKeeper instances. Each one should have a static-IP which are to hard-coded in the Kafka's AMI/Databag that we use. It should also support AutoScaling, so that if one of the zooKeeper node goes down, a new one is spawned with the same IP or from a pool of IPs. For this we have decided to go with 1 zoo-keeper instance per AutoScaling group, but the problem is with the IP.
If this is the wrong way, please suggest the right way. Thanks in advance !
One method would be to maintain a user data script on each instance, and have each instance assign itself an elastic IPs from a set of EIPs assigned for this purpose. This user data script would be referenced in the ASGs Launch Configuration, and would run on launch.
Say the user script is called "/scripts/assignEIP.sh", using the AWS CLI you would have it consult the pool to see which ones are available and which ones are not (already in use). Then it would assign itself one of the available EIPS.
For ease of IP management, you could keep the pool of IPs in a simple text properties file on S3, and have the instance download and consult that list when the instance starts.
Keep in mind that each instance will need an to be assigned IAM instance profile that will allow each instance to consult and assign EIPs to itself.