In this post I want to inform you about some of the new activities I am trying to do.
In order to make you equipped with more practical scenarios, I have decided to start #AWS #Question #Scenario series in which I would post a question on LinkedIn and Youtube community page. After few hours or next day, I shall reply as well. All are invited to participate and polish the understanding further. I request you to connect with me on LinkedIn - https://www.linkedin.com/in/knowledgeindia
Also, the YouTube feed is great and it is enabled for our channel now. If you look at your Subscriptions in Youtube mobile app, you can see content from KnowledgeIndia. Or, you can also visit - https://www.youtube.com/user/knowledgeindia/community
A new series of video tutorials is coming which would be focused on practical scenarios only. Looking forward to hear from all of you. Check out the videos added recently and kindly help us by sharing the videos and content on LinkedIn.
Hi Guys,
I have got some good questions on ELB for the given tutorial --
1. you had mentioned that the ELB internally creates instances to manage traffic. Just to expand a little on this, So When this ELB creates the internal instance(i assume its not visible to us ) and it consumes the private IP's too right, Does the internal instance gets created per availability zone or per instance? Coz, I attach an ELB to the instance not to the A.Z ?right? I assume it's something like an agent which gets installed per instance and sort of polling the Domain LB? pls, correct my understanding?
ANS: Yes, those instances won't be visible to users as ELB is a managed service. These instances do use ENIs (and hence Private IPs) from the respective subnets. ELB creates one instance in every subnet (you choose while ELB creation). There is no agent running on your instances (e.g. web server). Also, you register your instances to an ELB and hence tell ELB that it could send traffic to these instances.
2. Under Load balancers / instances, down the page under availability zone, ELB had created 2 AZ's. whereas I had all 3 of my instances in the same A.Z, though I can edit it and remove the other A.Z, why does it create an another AZ reference point when all my instances are in only one AZ? pls assist
ANS: While creating ELB, you can clearly choose which subnets you want it to handle. It is recommended that you give 2 subnets in 2 different AZs (based on principle of HA). ELB will launch an internal instance in the subnets you choose while creating ELB.
3. Under health check, the ping target, I gave the path index.html. let's assume I have 2 instances and if I want the index.html to reside in a different location for all the 2 instance, let's assume for the 1st one, it's under var/www/HTML and for the second one if its under var/www ..does the ping target as the intelligence to check the file irrespective if its location?
ANS: Given the fact that all the instances behind an ELB are generally kept identical, the path of the file has to be same. Though, if you have some specific use-case for the above scenario, it could be achieved using Application Load Balancer. But, in Classic ELB, it has to be same path.
Most of us are pretty excited to learn and work on AWS. Thanks to AWS that there is Free Tier available to practice as well. But, most of the learners end up getting bill even after being cautious.
I have picked up following query from my YouTube channel for AWS. I have got many similar queries earlier as well.
I am following your all videos from the beginning on AWS sysops
tutorials and its fantastic the way you explain.
here i have a small doubt on free tier account.
750 hours of ec2 instance... how is that calculated?
Is that only one instance limit for 750 hours or many instances
multiplied with number of hours used..?
Actually i have used 2 instances while practicing with 30GB of EBS each
and i could see the amount in some dollars month to date in billing
console. Is that amount i need to pay.. i mean am i crossed the free
tier limits.
kindly clarify me this please... i have tried contacting aws support but
again that also need to subscribed it seems every where they are trying
to grab from us :(
Thanks in advance.
___________________
ANS: In order to understand above scenario, consider following points --
1. In case of an EC2, there are multiple cost factors - EC2 instance charges, EBS charge, Data-out charges, Elastic IP charges etc.
As explained in FAQ, you can use 750 hours of Linux AND750 hours of Windows EC2. You can have 2 EC2 Linux running 375 hours each as well. They would look at the aggregate hours only.
But, in the above case the cost would have been incurred because of EBS usage. For EBS, AWS gives "30 GB of Amazon Elastic Block Storage in any combination of General Purpose (SSD) or Magnetic".
As the user has run 2 Windows instances, EBS usage would have gone more than Free Tier allowed limits (each Windows EC2 takes 30 GB minimum EBS). Also, remember that EBS continues to cost you after creation, till it is terminated (because your data is consuming the storage on Cloud, right!!). EC2 instance costs you only if it is running. There is no charge when it is in stopped state.
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I got following questions from one of our viewers and I thought of answering it here -- Please SUBSCRIBE to this blog by entering and VERIFYING your email on right side.
1. Can we limit versioning, Meaning to ask, versioning if enabled keeps all the modified files, can I limit it to the last 3 modifications? ANS: You can limit it by time. E.g. that versions of last 3 days would remain there. You can move older versions to different storage classes with help Lifecycle Policies. In another case, you can write your custom Lambda function which gets invoked every time an object gets created and it could check and keep last 3 versions of that object and delete anything older.
2.When I choose s3 from the console, it doesn't allow me to choose a region from the console, Whereas after going into S3, it allows me to choose a region? why is that? ANS: Many people have got that confusion. In case of S3, you see all your buckets (irrespective of their region) in one UI. That's why you cannot choose region at top. But, an S3 bucket belongs to one region only, hence you need to choose that when you are creating an S3 bucket.
3.What is the need to mandate versioning in cross-region replication? Any theory behind it?
4.When I give a user named trinity, full S3 admin access in IAM, and then I create a bucket named Skynet only for few users, will trinity(user) still have full access over Skynet(bucket) ? ANS: How are you ensuring that Skynet is created for few users? When you create a resource, you don't create it for a user, rather you use IAM to control which user can access that resource. In the above case Trinity has full S3 access and hence she would be able to access Skynet. But, you can explore the opportunity of denying her access at Bucket Policy level (defined at Skynet bucket).
5. After enabling cross region replication , if i delete the content in the source or destination , that deletion is not getting replicated . i can still see the file intact in my destination folder ? [In my case, though i replicated only a part of the file from the source, [replication was successful] , But when i deleted the whole source bucket, the files still where intact in my destination ?
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