I have seen this answer for growing EBS volumes, but I would like to shrink one.
The default Ubuntu Server images are 15 GB while I really need only 2 GB max (I use a different volume for data). Is there a way to shrink the size of the volume?
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I had the same question as you, so I worked out how to do it.
First, I did this from the Ubuntu 32-bit EBS-backed ami from the US-East region, other OS's or images may work differently. However, I suspect that you should be ok, as long as you are using an ext* filesystem. It might work on other filesystems, but you'll have to figure out how to resize them on your own.
The steps are basically:
You first need to get some information from the ami you want to shrink. In particular, you need the kernel ID and ramdisk ID, if any (the image I shrunk didn't have a ramdisk). All this information should be available from the aws management console ,in the AMI window.
The kernel ID looks like kia-xxxxxxxx, and the snapshot ID looks like snap-xxxxxxxx, and ramdisk IDs look like RIA-xxxxxxxx.
Next, launch a linux instance. I launched a Ubuntu instance. You can use a t1.micro instance if you like. It doesn't take much power to do these next steps.
After the machine is running, attach the snapshot you wrote down from the first step. In my case, I attached it to /dev/sdf
Then, create a new volume, having the size you want. In my case, I created a 5GB volume, as that's the size I wanted to shrink it to. Don't create this new volume from a snapshot. We need a new blank volume. Next, attach it to the running instance, in my case I attached it as /dev/sdg
Next, ssh into the machine but don't mount the attached volumes.
At this point, I erred on the side of paranoia, and I opted to check the file system on the large volume, just to make sure there were no errors. If you are confident that there are none, you can skip this step:
Next, I resized the file system on the large volume so that it was only as big as the data on the disk:
The -M shrinks it, and the -p prints the progress.
The resize2fs should tell you how large the shrunkin filesystem is. In my case, it gave me the size in 4K blocks.
We now copy the shrunkin file system to the new disk. We're going to copy the data in 16MB chunks, so we need to figure out how many 16MB chunks we need to copy. This is where that shrunken file system size comes in handey.
In my case, the shrunk file system was just over 1 GB, because I had installed a lot of other programs on the basic Ubuntu system before taking a snapshot. I probably could have gotten away with just copying the size of the file system rounded up to the nearest 16MB, but I wanted to play it safe.
So, 128 times 16MB chunks = 2GB:
I copied in blocks of 16MB because with EBS, you pay for each read and write, so I wanted to minimize the number of them as much as possible. I don't know if doing it this way did so, but it probably didn't hurt.
We then need to resize the file system we just copied to the new volume so that it uses all the available space on the volume.
Finally, check it, to make sure everything is well:
That's all we need to do in this machine, though it couldn't hurt to mount the new volume, just as a test. However, this step is almost certainly optional, as e2fsck should have caught any problems.
We now need to snapshot the new volume, and create an AMI based on it. We're done with the machine, so you can terminate it if you like.
Make sure the small volume is unmounted if you mounted it, and then take a snapshot of it. Again, you can do this in the management console.
We use the ec2-register application to register an AMI based on the snapshot you just took, so write down the snap-xxxxxxxx value from the snapshot you just took.
You should then use a command like:
You of course need to replace the kernel ID with the one you wrote down at the beginning and the snapshot ID with the one you created in the previous step. You also need to point it at your secret key (called sk.pem) above, and your x509 cert (called cert.pem). You can of course choose whatever you want for the name and description.
Hope this helps.
Yeah, I've wondered this too. The following tutorial is overkill, but I think it contains the necessary tools: http://www.linuxconfig.org/Howto_CREATE_BUNDLE_UPLOAD_and_ACCESS_custom_Debian_AMI_using_ubuntu
Instead of install onto a new disk image as above, it should be possible to fire up the large AMI, create a new EBS, attach EBS to the running instance, and copy the running AMI over to the new EBS. Finally, register the new EBS as an AMI.
Take a look at this blog-post for some more background, especially the comment by freremark: http://alestic.com/2010/01/public-ebs-boot-amis-for-ubuntu-on-amazon-ec2
On a final note, the euca2ools seems like a great replacement for ec2-ami-tools - euca2ools include actual manpages! They have all the same names as the ec2-* commands, just with the euca- prefix. http://open.eucalyptus.com/wiki/Euca2oolsUsing