How does the AWS EC2 Auto Scaling synchronisation work automatically? - amazon-web-services

We started our wordpress blog some time ago with only one single EC2 Instance and a Multi-AZ RDS Database.
The traffic increased with heavy ups and downs (up to 1.500 user per minute), so we decided to use EC2 Auto Scaling. Here is our problem: Every time we changed some code, we have to create a new AMI for the Auto Scaling Group and terminate all instance so new instances will start with the new AMI Data.
Is there a easy way to synchronize all instance automatically, when changing some code on one of them? Perhaps Opsworks could to that but I haven't experience with this. I already searched a couple of days for a tutorial, but could not find anything helpful.

You could configure your AMI to download the latest code on startup, so that you don't have to constantly update the AMI.
Or you could just use Elastic Beanstalk and let it manage all this stuff for you.

If you want an easy way to deploy changes to instances in your autoscaling group, I would recommend using Code Deploy.
Code Deploy integrates nicely with Autoscaling. If a scaling up event occurs, it will start a deployment to the newly launched instance and won't bring that instance into service in the AutoScaling group until the deployment has finished.
The deployments can be as simple as changing the code or else they can involve more thanks to Code Deploys deployment hooks.
Also you can have Code Deploy grab your code from S3, Github or CodeCommit.
Code Deploy is pretty easy to set up and the documentation is great:
Docs AutoScaling Integreation

Related

Deploying to bare EC2 instances in an ASG?

I have a service that needs to run on our own EC2 instances, since it requires some support from the kernel. My previous experience is all with containers in AWS. The application itself is distributed as a single JAR file and I'm looking for advice for how I should automate deployments. The architecture is:
An ALB in front of the ASG.
EC2 instance running a single Java application.
Any open sockets are open for an hour tops and to not cause any trouble, we have to drain the connections to the EC2 instances before performing an update, so a hard requirement is for the ALB to stop opening new connections for an hour before updating the software. The application is mission critical and ECS has had some issues last year, so I want to minimize the AWS services I depend on. While I could do what I want on my own ECS cluster with custom AMIs, I don't want to do it, since I will run a single instance of the app per host and don't need the extra layer.
My question: What is the simplest method to achieve this using CodePipeline? My understanding is that I need to use a CodeDeploy deployment step to push something to bare EC2 instances. How does draining with an ALB work in this case? We're using CloudFormation for the deployment.
You need to use codedeploy. You can find tutorial on AWS codedeploy documentation.
Codedeploy deployment lifecycle hooks for EC2.
https://docs.aws.amazon.com/codedeploy/latest/userguide/reference-appspec-file-structure-hooks.html#appspec-hooks-server

AWS EC2 Auto scaling philosophy

Hello there!
I'm at beginning of the investigation of AWS, but one of the concepts looks unclear to me. Based on it I want to ask for assistance with an understanding of functionality.
I have a web application on PHP installed on EC2.
My application is huge loaded and I need to use a load balancer for the best performance. How to do and set up this is clear. The Code of my application is hosted on Gitlab.
After EC2 and load balancer setup did I want to use Autoscaling.
So, I need to use the autoscale group.
Main question: what I should do next? As I understand I need somehow create a new instance, but I need a correct image for the instance with all dependencies and source code.
Code auto-deploy is also a big question. When the new feature merged I need to run the GitLab pipeline and delivery code somehow to the new EC2.
So what do I need to read and investigate to have the ability to deploy new code to the new EC2 instance automatically? Is AWS provide some tools for this?
Thank you for the help with my journey.
Regards,
Mavis.
You can begin with this link https://docs.aws.amazon.com/autoscaling/ec2/userguide/create-asg-from-instance.html which explains to you how to create an autoscaling group based on an EC2 instance.
In short you can generate an AMI ( Amazon machine Image) from your current EC2 (host php) and create a launch configuration/launch template for your autoscaling group.
Next, you may add a load balancer to distribute traffic to theses instances, you can associate it with target groups and your Autoscaling goup https://docs.aws.amazon.com/autoscaling/ec2/userguide/attach-load-balancer-asg.html
For the Auto deploy, you can automate within your pipeline to create a new launch configuration or to get the last version of your code PHP from S3 or another location in the user data part. You may use gitlab ci or CodeDeploy which is the perfect candidate for this kind of stuff
Be aware also, that the autoscaling group is statless(create/terminate instances) and you must store your images and assets in a shared location like S3, DB or EFS, because if an instance is unhealthy or terminated by the ASG, you may lose data.

AWS EC2 instances with auto scaling staying in sync

I have a Node.js web application currently running on a single EC2 instance on AWS. I am thinking of using auto scaling with 2 or more EC2 instances since the load on the application is increasing.
I have been trying to understand something with AWS Auto Scaling for a couple hours now but I cant seem to find an answer anywhere.
Currently, at many instances I SSH into my Ubuntu EC2 instance to modify some things or to run a deploy command (which grabs latest code from github). How does this work when you have, let's say 4 instances running under the auto scaling?
So if I SSH into a server and change the server.js file, what happens to the other 3 instances?
If that is not possible what are my choices? I have seen many people seeing that using S3 is the way to keep things in Sync but I don't fully get that. So I have to keep all my source code in S3 and do my edits from there?
You won't be able to modify files directly on the server once they are in an auto-scaling group. Changing something on one server won't be reflected on the other servers, and even if you manually updated all the currently running servers, any servers added by auto-scaling actions will not have those changes.
There are many methods to solve this, for example using AWS Code Deploy.
You could also configure something via an EC2 User-Data script in your auto-scaling configuration which will run on each server when they are created. That script could checkout the latest code from Git, or pull the latest build artifact from S3, and then start the app. When you have an update ready to deploy, you would simply flag the current instances as "unhealthy" and wait for the Auto-Scaling group to automatically replace them with new, updated instances.
You could use AWS EFS to host your application code and all web servers will get content from EFS instead of individual server. This way you don't have to worry about modifying individual server content.
One way you can do it is using github. you can update your code and push it to github and then terminate your existing instances and let the auto-scaling group spin up new instances with the updated code. here is a youtube tutorial video that has detailed steps on how to do it: https://www.youtube.com/watch?v=lB3Ip0Yn-Zs

how to deploy code on multiple instances Amazon EC2 Autocaling group?

So we are launching an ecommerce store built on magento. We are looking to deploy it on Amazon EC2 instance using RDS as database service and using amazon auto-scaling and elastic load balancer to scale the application when needed.
What I don't understand is this:
I have installed and configured my production magento enviorment on an EC2 instance (database is in RDS). This much is working fine. But now when I want to dynamically scale the number of instances
how will I deploy the code on the dynamically generated instances each time?
Will aws copy the whole instance assign it a new ip and spawn it as a
new instance or will I have to write some code to automate this
process?
Plus will it not be an overhead to pull code from git and deploy every time a new instance is spawned?
A detailed explanation or direction towards some resources on the topic will be greatly appreciated.
You do this in the AutoScalingGroup Launch Configuration. There is a UserData section in the LaunchConfiguration in CloudFormation where you would write a script that is ran when ever the ASG scales up and deploys a new instance.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-as-launchconfig.html#cfn-as-launchconfig-userdata
This is the same as the UserData section in an EC2 Instance. You can use LifeCycle hooks that will tell the ASG not to put the EC2 instance into load until everything you want to have configured it set up.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-as-lifecyclehook.html
I linked all CloudFormation pages, but you may be using some other CI/CD tool for deploying your infrastructure, but hopefully that gets you started.
To start, do check AWS CloudFormation. You will be creating templates to design how the infrastructure of your application works ~ infrastructure as code. With these templates in place, you can rollout an update to your infrastructure by pushing changes to your templates and/or to your application code.
In my current project, we have a github repository dedicated for these infrastructure templates and a separate repository for our application code. Create a pipeline for creating AWS resources that would rollout an updated to AWS every time you push to the repository on a specific branch.
Create an infrastructure pipeline
have your first stage of the pipeline to trigger build whenever there's code changes to your infrastructure templates. See AWS CodePipeline and also see AWS CodeBuild. These aren't the only AWS resources you'll be needing but those are probably the main ones, of course aside from this being done in cloudformation template as mentioned earlier.
how will I deploy the code on the dynamically generated instances each time?
Check how containers work, it would be better and will greatly supplement on your learning on how launching new version of application work. To begin, see docker, but feel free to check any resources at your disposal
Continuation with my current project: We do have a separate pipeline dedicated for our application, but will also get triggered after our infrastructure pipeline update. Our application pipeline is designed to build a new version of our application via AWS Codebuild, this will create an image that will become a container ~ from the docker documentation.
we have two triggers or two sources that will trigger an update rollout to our application pipeline, one is when there's changes to infrastructure pipeline and it successfully built and second when there's code changes on our github repository connected via AWS CodeBuild.
Check AWS AutoScaling , this areas covers the dynamic launching of new instances, shutting down instances when needed, replacing unhealthy instances when needed. See also AWS CloudWatch, you can design criteria with it to trigger scaling down/up and/or in/out.
Will aws copy the whole instance assign it a new ip and spawn it as a new instance or will I have to write some code to automate this process?
See AWS ElasticLoadBalancing and also check out more on AWS AutoScaling. On the automation process, if ever you'll push through with CloudFormation, instance and/or containers(depending on your design) will be managed gracefully.
Plus will it not be an overhead to pull code from git and deploy every time a new instance is spawned?
As mentioned, earlier having a pipeline for rolling out new versions of your application via CodeBuild, this will create an image with the new code changes and when everything is ready, it will be deployed ~ becomes a container. The old EC2 instance or the old container( depending on how you want your application be deployed) will be gracefully shut down after a new version of your application is up and running. This will give you zero downtime.

Do I need to duplicate code on every EC2 instance running behind an ELB?

Hi this is a very noob question, but I am trying to deply my Node JS API server on AWS.
Everything is working fine with one m1.large instance that my Front End running on S3 connects to.
Now I want to Scale and put my EC2 instance and possibly many more behing and ELB and an Auto Scaling Group.
Do I need to duplicate my server code on every EC2 instance?
If so , I assume I'll have to create a seperate DB server which all of the EC2 instances will connect to.
Am I right,anyone experienced in Amazon AWS can answer this, I tried googling but most of the links point to detailed tutorials which however don't answer my question.
Any help would be much appreciated. Thanks
yep. that's basically correct. the code needs to be on all instances fronted by the load balancer. for the database you may want to look into RDS.
Of course NOT.. But sure you can do..
That's why there are EFS volumes, which are shared volumes to more than one EC2 instance, but you have to choose a region that support them since they are available on certain regions. As a candidate AWS certified architect I would recommend you more than two options.
You can follow your first approach and create an EC2 instance put your code inside and then create an AMI and use this AMI to launch your upcoming EC2s through autoscaling group. In my opinion bad decision since on any code change you have to go on each one and put the new code and then create a new AMI and a new Auto scaling configuration..Lot's of stuff to do, but it will work.
Second approach, following the first approach but do not create an AMI, instead upload your code on a private (I suppose) Repo like github, bitbucket, install SSM and the appropriate roles for managing EC2 and on every code changes push them to repo and pull them on your EC2, using SSM. Of course you may write a webhook to bitbucket to call an api and run the git pull command on each EC2. Probably the last sentence could be a third approach but needs more coding!!!
Last but not least!! Use an EFS volume put your code there, mount this volume on your EC2, add a auto mount command on every boot, alter your apache httpd main document to point on this EFS/folder and create an AMI with this configuration. Voila! every new EC2 will use the same code which located on this shared/network volume. Whenever you need to change something you have to log in on a third instance outside of your autoscaling group for a certain amount of time upload your changes and then turn it off and all of your EC2 will take immediately the new code. Of course you may pull the changes from a repo following the third approach.
Maybe there are more approaches, I'm using the third one with private repos of course and until now I haven't faced any problem (Fingers crossed)!
One other option is to use Elastic Beanstalk to Deploy NodeJs applications. Here is the guide specific to NodeJs. This will take care of most of the stuff which you would need to do otherwise if you only use EC2 For example: ELB, Autoscaling Cloudwatch etc.
For Database, you may want to use the Master Slave with Read Replicas. Another option is to evaluate NoSql Databases like DynamoDB if it fits your use case. The scalability of DynamoDB tables is managed by AWS so you dont need to worry about it.