Re: access instance storage

From: sebastian rooks <no email>
Date: Tue, 9 Aug 2011 17:14:20 +0200

Thank you a lot again Justin, that solves my problem.

For other potential users, the actual command line I used looks like:
ec2-run-instances -K ~/.starcluster/pk-....pem -C
~/.starcluster/cert-....pem MY_AMI_ID --instance-type cc1.4xlarge
--block-device-mapping '/dev/sda1=SNAP-FOR-AMI:true'
--block-device-mapping '/dev/xvdb=ephemeral0' --block-device-mapping
'/dev/xvdc=ephemeral1' -k key_pair_name

One could use /dev/sdb and /dev/sdc but in the end on the machine they
are transformed as /dev/xvdb and /dev/xvdc

/dev/xvdb is automatically mounted as /mnt
/dev/xvdc is not mounted but one might be able to use a starcluster
plugin for that.

Sebastian


On Mon, Aug 8, 2011 at 8:35 PM, Justin Riley <jtriley_at_mit.edu> wrote:
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> Also, for your immediate needs, you can launch an instance of the
> Alestic HVM 11.04 AMI manually and specify the block mapping including
> the ephemeral storage device(s). Using ebsimage on an instance launched
> with a custom block device mapping should create the new AMI with an
> identical block device mapping. Let me know if you need help with this.
> Basically the launch command should look something like:
>
> ec2-run-instances <ami id> -k <your keypair name> --block-device-mapping
> '/dev/sdb1=ephemeral0' --block-device-mapping '/dev/sdc1=ephemeral1'
> - --block-device-mapping '/dev/sdd1=ephemeral2' --block-device-mapping
> '/dev/sde1=ephemeral3'
>
> ~Justin
>
> On 08/08/2011 02:01 PM, Justin Riley wrote:
>> Hi Sebastian,
>>
>> Unfortunately this is not possible when creating a new HVM image
>> using the ebsimage command. This is a limitation imposed by EC2's
>> 'create-image' API call. The 'create-image' call does not support
>> specifying a block device mapping that's different from the image
>> host's block device mapping. This is why you don't see the ephemeral
>> storage on your new 11.04 HVM image; the original alestic HVM didn't
>> have it in the block device mapping. To make matters worse the EC2
>> API documentation specifically states that an HVM image must be
>> created from an existing HVM instance in order for the AMI to be
>> HVM-compatible:
>>
>> http://docs.amazonwebservices.com/AWSEC2/latest/UserGuide/using_cluster_computing.html#using_cluster_computing_hvm_ami_running_instance
>>
>>  There may be a way around this though. It is possible to manually
>> specify a block device mapping when launching the instances. This
>> would allow StarCluster to override the default block device mapping
>> specified by a given AMI and always provide ephemeral storage even if
>> the original AMI creator did not include it when registering the
>> image. I'll experiment with this and see what I can come up with.
>> I've created a github issue to keep track of this:
>>
>> https://github.com/jtriley/StarCluster/issues/46
>>
>> Thanks for reporting,
>>
>> ~Justin
>>
>> On 08/08/2011 09:30 AM, sebastian rooks wrote:
>>> Hello Justin,
>>
>>> I would like to use the instance storage (2x 840G disks) that comes
>>>  with the cluster compute instance type. This is again for an
>>> Ubuntu 11.04 hvm AMI.
>>
>>> The scratch space is not mounted on /mnt:
>>> root_at_master:/mnt/sgeadmin# df -h Filesystem            Size  Used
>>> Avail Use% Mounted on /dev/sda1             7.9G  4.0G  3.5G  54% /
>>> none 12G  144K   12G   1% /dev none                   12G     0
>>> 12G   0% /dev/shm none                   12G   60K   12G   1%
>>> /var/run none 12G     0   12G   0% /var/lock /dev/xvdz1
>>> 20G  618M   19G 4% /home
>>
>>> The block devices are indeed not available on my AMI:
>>
>>> ec2-describe-images ami-ab5197c2 -K ~/.starcluster/pk-....pem -C
>>> ~/.starcluster/cert-....pem IMAGE    ami-ab5197c2    11-04-hvm       available
>>> private              x86_64  machine   ebs   hvm BLOCKDEVICEMAPPING  /dev/sda1
>>> snap-8f055aee        8
>>
>>> Nor are they on Alestic's public one:
>>
>>> ec2-describe-images ami-1cad5275 -K ~/.starcluster/pk-....pem -C
>>> ~/.starcluster/cert-....pem IMAGE    ami-1cad5275
>>> 099720109477/hvm/ubuntu-images/ubuntu-natty-11.04-amd64-server-20110426
>>>
>>>
> 099720109477    available       public          x86_64  machine ebs     hvm
>>> BLOCKDEVICEMAPPING   /dev/sda1               snap-b1ad2dde   8
>>
>>> Would it be possible to add the local instance storage during the
>>> AMI creation with ebsimage ?
>>> http://docs.amazonwebservices.com/AWSEC2/2011-01-01/UserGuide/index.html?Using_AddingDefaultLocalInstanceStorageToAMI.html
>>
>>>  Regards,
>>
>>> Sebastian _______________________________________________
>>> StarCluster mailing list StarCluster_at_mit.edu
>>> http://mailman.mit.edu/mailman/listinfo/starcluster
>>
>> _______________________________________________ StarCluster mailing
>> list StarCluster_at_mit.edu
>> http://mailman.mit.edu/mailman/listinfo/starcluster
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Received on Tue Aug 09 2011 - 11:14:21 EDT