I understand that when I launch an instance on ec2, that the instance has to be located on a particular data center, and that after launching you can't change that. I also understand that an AMI is created from an instance.
But what I dont understand, is when I launch an instance from an AMI, why can't I specify what region I want it to run on? Seems like it shouldnt matter, once the AMI is created you should be able to launch it in any region. What does the AMI contain that ties it to a region and why?
Kernels. The kernel IDs change across regions (don't ask me why).
Meaning an AMI which specifies a kernel ID to be booted with can only be booted in the region this kernel ID exists.
AMI is region specific because AMI basically contains a software configuration (for example, an operating system, an application server, and applications). From an AMI, you launch an instance, which is a copy of the AMI running as a virtual server in the cloud. And if we consider AMI a global service, it means all AMIs are stored in one place and have access to all regions. For this, it will take more time to pull and then create instances. So if it is available in a region(region-specific), then we can quickly launch instances fast without time delay.
Related
What is the different between starting an AWS Image and Instances?
Example:
I do notice when I am running AWS image using boto, I can only stop the Image while running AWS instance using boto, I can only terminate.
Think of an EC2 instance as a single running server with CPU, memory, hard disk, networking, etc. Any changes you make to that instance affect only that instance.
Think of an AMI (Amazon Machine Image) as an exact copy of the root file system that gets copied to the hard disk when you start a new instance. The AMI is a hard disk sitting on a shelf. You make an exact copy of the hard disk on the shelf, install the new hard disk in a server, and turn the server on. You can do this for as many servers as you'd like to start without affecting the master copy.
The AMI defines the initial state of each instance. Each instance changes as it runs, but you can never change the original AMI once it has been created (other than to delete it).
There are more details that refine this conceptual model, but that's the basics.
Specific to the wording in your question:
Sometimes we say we're "starting an AMI" sometimes we say we're "starting an instance". We mean the same thing. We're really starting an instance using an AMI as the template.
We never say we're "stopping/terminating an image" or "stopping an ami" as, once started, it's really the instance that's running.
You can have one or more instances running that are derived from an image (AMI). Here is a good little tutorial, that's a bit old mind you, talking about how you can convert an Instance to an AMI ... which you can then redeploy one or many times:
http://webkist.wordpress.com/2010/03/16/creating-an-amazon-ec2-ebs-ami-from-a-running-instance/
What is an AMI: Amazon Machine Image
http://en.wikipedia.org/wiki/Amazon_Machine_Image
Technically, you can't start an AMI. You can start an instance that is derived from an AMI.
I know it is a newbie question but the documentation is really not clear about that.
I have successfully launched a Cluster Instances Amazon Linux AMI 2011.02.1 cc1.4xlarge instance. I need to upload and process a 15 GB text file and I don't know how to activate the "additional" storage.
By default, I have just 8 GB of storage. Can someone help me writing simple and clear instruction on how to activate all the storage (1690 GB) I should have?
Thanks a lot in advance.
Regards,
Eugenio
You should be able to mount your ephemeral drives by following this guide.
Cheers.
It's a very common question and there's a large confusion that everyone has around this when starting to work with AWS EC2.
There are 2 things to have in mind here :
Instance Type
AMI (Amazon Machine Image, basically a disk snapshot with some operating system)
Each AMI has some requirements that will dictate parts of the configuration of your created instance.
Here we're concerned with the Root Device type of an AMI :
EBS-backed AMI
These AMI's only work on instances that have an EBS volume attached. And therefore if you choose an EBS-backed AMI, the wizard will by default add an EBS volume (usually of size 8 GiB) without you noticing, and you'll be charged for this EBS separately in addition to the EC2 hourly charge. In this case when you ssh to your instance you will only find 8 GiBs of storage and not the large storage you're promised when you view the EC2 Pricing table at https://aws.amazon.com/ec2/pricing/ . And that is confusing.
If you also want to use your -usually large- instance store with these AMIs, then when you create that instance you have to explicitly add a volume and select Instance Store 0 from Volume Type (in Step 4 - Add Storage). You may have more than 1 drives assigned to your instance type, you need to add all of them in this case (Instance Store 0,1,..etc). These volumes can only be added at creation time. If the volumes were automatically mounted then you'll find them at /media/ephemral*, if not, you'll have to mount them manually.
Instance-Store-backed AMI
Those images use the Instance Storage as their root device (the OS will be installed on the instance store at / ). I think the confusion comes from the fact that these AMI's are not instantly viewable in the Quick Start tab of Step 1 at which you choose the AMI. All AMIs in the Quick Start tab are EBS-backed, and Instance Store AMIs are very uncommon these days, everyone uses EBS-backed AMIs because of their various speed and persistence benefits, and that's recommended by Amazon as well.
If you want an instance-store-backed AMI to avoid dealing with any EBS whatsoever, then in Step 1, choose the tab Community AMIs, and filter them by Root Device Type = Instance Store, then choose your AMI. Whether or not you add Instance Store 0 in Step 4 - Add Storage, the instance store will be available.
Check what Amazon Linux AMI type you're launching the image as. In my experience, if you launch with the "EBS-backed" AMI type, it won't mount the ephemeral storage. If you switch to the "Instance Store" type, it will mount it for you at /media/ephemeral0
http://aws.amazon.com/amazon-linux-ami/
I have ec2 instance set up where mysql DB is mounted on separate volume.
(as detailed in http://aws.amazon.com/articles/1663 )
I want to duplicate this instance set up where my application servers on duplicated instances share the DB volume which is attached to the already running ec2 instance.(I can specify mysql ip through configuration file)
Since almost every set up except the mysql ip is identical, i'd like to create an ami from the first instance and slightly modify to create 2nd,3rd instances.
The question is, the mount information stored in the first instance will take effect when I launch the 2nd instance.
I can elaborate the question,
1. I read that a volume can not be attached to more than one ec2 instance at the same time.
2. the running instance attaches/mount an volume to itself on start up.(so it seems)
3. if I were to create an ami from first instance and use that to initiate other instances, how would auto attach/mount information(which I assume, will be stored in the ami) will affect the other instances.
Eugene,
Mounting the same device to several servers is not possible, so you better forget about this option.
The best solution is to:
Create a copy of your master instance.
Detach the created mount volume. We are going to create an image from this new instance, and you don't want the useless drive copy to be re-created every time.
Change the settings that you need to change, in order to make this server rely on the remote (master) mysql server.
Once you are satisfied with the outcome, create an image from this instance.
Good luck!
Dotan
Or is it absolutely necessary to have an EBS backed storage? Does anyone have manuals/Howtos?
I am following the manual given on this site.
You can create an AMI from either an EBS or S3-backed running instance. The simplest way is to use the AWS Management Console to select the instance and click 'Create Image' from the Instance Actions menu.
This will create either an EBS or S3-backed AMI, depending on the type of instance.
Be aware that creating an AMI from a Running instance is inherently potentially unsafe - the storage is not imaged as a hard 'point-in-time' snapshot, so changes to the filesystem whilst the image is being created may not be recorded, and may even result in a compromised image. You should quiesce the OS as far as possible before starting.
Note also that your instance will reboot during the image-creation process, so make sure you're prepared for any temporary loss of service from the VM.
If you bundle a Windows EBS instance while it is running, its Administrator password will be reset by Amazon's rebundling tools - so you'll have to use the EC2 "get Admin password" function with instances launched from the new AMI.
If you stop your Windows instance before rebundling, its Administrator password will remain intact through the rebundling process.
I don't know if this is documented anywhere, but it's certainly been my experience with Windows 2003 instances.
you will to refer the manual for the three commands:
ec2-bundle-vol, ec2-upload-bundle, ec2-register.
Keep at hand your private and certificate key (eg. pk.pem, cert.pem files) and your access and shared key. Download the ec2 ami tools and setup the environment variables for the ec2 ami tools. This site might give you the details on how to bundle the volume, create the images, upload them to S3 and finally register it as your own ami.
http://alestic.com/2009/06/ec2-ami-bundle
It is possible to create an AMI from an EBS running instance using the AWS management console. as mentioned by Eight-Bit Guru by clicking 'Create Image' from the Instance Actions menu.
For the S3 backed instance it is currently not possible without bundling the instance.
If you are using a linux ami then you have two ways as explained in this guide:
Creating an AMI from S3 backed instance - For Linux
For windows based S3 backed instance you can follow other guide
Creating an AMI from S3 backed instance - For Windows
Hope this will help for creating an AMI for S3 backed intances.
I am new to Amazon web services. I need to create a server image with a few software packages pre installed on the EC2 instances.
One option I am considering is to create an EBS volume with these packages and then use them to launch EC2 instances.
The other option I am thinking of is to create a private AMI and then use them to launch the EC2 instances.
I am not sure which option is better.
One other slightly related question I have is can I create a private EBS volume and share it with some other account.
You should create your own AMI, as it's probably more efficient. In order to create an instance, you must specify an AMI. Specifying an EBS snapshot as the root device in addition to specifying the AMI (if this even works, I haven't tested it) would just result in the EC2 cloud launching your instance with the AMI, followed by overwriting it with the EBS snapshot for the root volume.
It's easy enough to keep the AMIs laying around as prototypes.