I have a golden image pipeline running without problem backed by an EBS volume, but trying to create the same for an instance store backed ami seems to always produce the same error. The issue is that the imagebuilder pipeline continuously attempts to tag a non-existent EBS volume and therefore fails;
Reason for failure:
You cannot specify tags for EBS volumes if there are no EBS volumes being created by the request.
The base image is ami-08d82c356d670cf9c which has the root device type INSTANCE-STORE, and there are no tags applied anywhere in the pipeline (not in the configuration, distribution, recipe or infrastructure). There is little documentation regarding a golden image using instance storage and any attempt to create one results in the same failure.
Does anyone have an idea on where this application of tags is taking place in the process in order to avoid it?
Thanks
Confirmed with AWS that Image Builder does not support the use of AMIs backed by instance store, as they use ec2:CreateImage which does not support it, and also requires the instance to be shut down to create an image.
Related
Does Creating an Image of an Amazon EC2 Linux instance cause any downtime? Can I image a running server?
Already answered correctly, but I wanted to add a couple of caveats:
--no-reboot, no guarantee: When you create an image of a AMI with EBS backed root device, you may opt for --no-reboot, but AWS warns about this. It does not guarantee integrity of the file system. If it's really busy instance and heavy RW operations going on, you may get a corrupted image.
Instance Store, no reboot: Creating an instance store backed image never required reboot to me. It's three simple steps -- bundle-image, upload to S3, and register the image without any rebooting in this whole process.
It is my opinion that No Reboot should prevent the image creation from rebooting.
If you are the api user, it also provides argument --no-reboot to do it.
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 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
So, in a simple situation, if there is only one instance, then I can store the data into a EBS volume mounted on that instance. e.g. /mnt/db
However, how does it work if I scale and have multiple instance (either static or dynamic scaling)?
Because one EBS can only attach to one instance, if I have multiple instance, does it mean that I have to attach an EBS volume for each instance? If that's the case, the data on each Instance's EBS volume will be different.
It is obvious that I want all instances to access (R & W) a single volume (as data-storage). and the data in the volume will constantly grow and there is no downtime.
What is the solution? Is there a way that I don't mount the device (EBS), and just call it for accessing the data?
Here is what I can think of:
1) if each instance has its own EBS volume, then each time interval (e.g. 1 hour), all instances will unmount & detach the EBS volume,and attach a new one. Then there is one powerful instance that mount all the EBS volumes just detached, and aggregate all the data.
2) or similar to 1), instead of detach and attach, I just take a snapshot on all volumes for all instances. Then the powerful instance aggregateness the data from the snapshot. And save the result into either another EBS or S3.
These two approach seem to be working.. but require a lot of work. is there a smarter way to approach this problem? thanks.
by the way, because of performance issue, I cannot have the instance writes data to S3. :)
OH how about this
3) First, all instances have their own EBS and write data into the EBS. and then each hour, data will be sent to S3. Then another instance will aggregate them.
how about having ang NFS instance which can be mounted to the other instances?
It seems that you need to create an EBS snapshot of your most up to date EC2 instance. This will create an EBS backed AMI. You would then need to terminate all your EC2 instances that are not up to date and launch a new stack of instances from your newly created AMI. If you had a load balancer running then you would have to attach these new instances to your load balancer also.
It seems a little long-winded but it can all be done programmatically. At least this is how I think scaling in the cloud with Amazon works and far as propagating changes across multiple instances goes. Somebody else with more experience verify this. I plan to test it out myself later on.
I spent the day experimenting with AWS for the first time. I've got an EC2 instance running and I mounted an Elastic Block Store (EBS) to keep the MySQL databases.
Does it make sense to also put my web application files on the EBS, or should I just deploy them to the normal EC2 file system?
When you say your web application files, I'm not sure what exactly you are referring to.
If you are referring to your deployed code, it probably doesn't make sense to use EBS. What you want to do is create an AMI with your prerequisites, then have a script to create an instance of that AMI and deploy your latest code. I highly recommend you automate and test this process as it's easy to forget about some setting you have to manually change somewhere.
If you are storing data files, that are modified by the running application, EBS may make sense. If this is something like user-uploaded images or similar, you will likely find that S3 gives you a much simpler model.
EBS would be good for: databases, lucene indexes, file based CMS, SVN repository, or anything similar to that.
EBS gives you persistent storage so if you EC2 instance fails the files still exist. Apparently their is increased IO performance but I would test it to be sure.
If your files are going to change frequently (like a DB does) and you don't want to keep syncing them to S3 (or somewhere else), then an EBS is a good way to go. If you make infrequent changes and you can manually (or scripted) sync the files as necessary then store them in S3. If you need to shutdown or you lose your instance for whatever reason, you can just pull them down when you start up the new instance.
This is also assuming that you care about cost. If cost is not an issue, using the EBS is less complicated.
I'm not sure if you plan on having a separate EBS for your DB and your web files but if you only plan on having one EBS and you have enough empty space on it for your web files, then again, the EBS is less complicated.
If it's performance you are worried about, as mentioned, it's best to test your particular app.
Our approach is to have a script pre-deployed on our AMI that fetches the latest and greatest version of the code from source control. That makes it very straightforward to launch new instances quickly, or update all running instances (we take them out of the load balancing rotation one at a time, run the script, and put them back in the rotation).
UPDATE:
Reading between the lines it looks like you're mounting a separate EBS volume to an instance-store backed instance. AWS recently introduced EBS backed instances that have a ton of benefits vs. the old instance-store ones. I still mount my MySQL data on a separate EBS partition, though, so that I can easily mount it to a different server if needed.
I strongly suggest an EBS backed instance with a separate EBS volume for the MySQL data.