Changes between Version 1 and Version 2 of virtual-machines

02/03/12 16:08:22 (7 years ago)
pruth (IP:



  • virtual-machines

    v1 v2  
    1 test 
     1= Virtual Machine Images = 
     3Known ORCA images can be found here:  [wiki:neuca-images images] 
     5!ImageProxy: [wiki:image-proxy-with-orca Using ImageProxy with ORCA] 
     7== !ImageProxy == 
     9Virtual Machine images can be made available to ORCA by placing them (and their metadata) at well known URLs.  An ORCA service called !ImageProxy will manage staging and caching all images at the appropriate cloud site(s).    !ImageProxy identifies each image by its URL and the SHA-1 hash of the image and requires an xml metadata file with the identifying information. 
     11Sample metadata file. Node element names and keywords representing image type are case sensitive: 
     15        <image> 
     16                <type>FILESYSTEM</type> 
     17                <signature>FS_IMAGE_HASH</signature> 
     18                <url>http://url_filesystem_image</url> 
     19        </image> 
     20        <image> 
     21                <type>KERNEL</type> 
     22                <signature>KERNEL_IMAGE_HASH</signature> 
     23                <url>http://url_kernel_image</url> 
     24        </image> 
     25        <image> 
     26                <type>RAMDISK</type> 
     27                <signature>RAMDISK_IMAGE_HASH</signature> 
     28                <url>http://url_ramdisk_image</url> 
     29        </image> 
     33The metadata file itself also needs to be hosted. Provided with the URL for the metadata file and its signature (SHA1 hash), !ImageProxy associated with a cloud site can download and install the required images and provide ORCA with site-specific image ids (AMI/EMI, AKI/EKI, ARI/ERI) that can be used to create guest VMs on that site.  
     35The documentation for the latest metafile format is maintained on the [ ImageProxy wiki]. 
     37== Compressed Images == 
     39The image provider can reduce the amount of data transfered across the network by compressing the virtual machine images and modifying the metadata file to indicate that the image is compressed.   The file system type should be set to "ZFILESYSTEM".  
     43        <image> 
     44                <type>ZFILESYSTEM</type> 
     45                <signature>FS_IMAGE_HASH</signature> 
     46                <url>http://url_to_compressed_filesystem_image</url> 
     47        </image> 
     48        <image> 
     49                <type>KERNEL</type> 
     50                <signature>KERNEL_IMAGE_HASH</signature> 
     51                <url>http://url_kernel_image</url> 
     52        </image> 
     53        <image> 
     54                <type>RAMDISK</type> 
     55                <signature>RAMDISK_IMAGE_HASH</signature> 
     56                <url>http://url_ramdisk_image</url> 
     57        </image> 
     61Currently, ZFILESYSTEM can handle .gz, .bz2, and .xz. images compressed with these tools can have any name. 
     63In addition, ZFILESYSTEM can handle images that are tarred before they are compressed with the tools above extending the allowed formats to include .tgz, .tbz2, and .txz.    However, images that are tarred and gzipped must conform to the expected naming convention by naming the image file "filesystem".  The tarball can have any name. 
     65== Sparse Images == 
     71$ dd if=/dev/zero of=myimage.img bs=1 count=1 seek=2G