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main:faq:vo_image_list_format

Introduction

AppDB produces image list files in order to provide third parties with information regarding particular virtual appliance versions (a.k.a. VM image versions), or groups thereof. There are two types of image lists; the first one is the standalone image list, generated while publishing a virtual appliance version, containing a single image. In this case, the image list is made publicly available and accessible through AppDB, with the exception of private virtual appliances, which are only accessible by the VM authors.

The second type of image list is the VO-wide image list, which is a collection of VM versions that a VO manager has endorsed. It gets generated each time a VO manager publishes a list of endorsed VM versions and is accessible only by authorized parties, such as cloud providers (instructions).

The format of the image list follows the HEPiX image list format and, therefore, is interoperable with the vmcatcher and the cloudkeeper clients. All of the generated image lists are signed by the AppDB service. An example of the image list structure can be found here

Image list schema

Field names prefixed with ad: are AppDB-specific extensions to the HEPiX format.

Field Name Description
dc:date:created Date in year-month-dayTHour:Minute:SecondTimezone format, e.g. 2021-10-06T14:37:28Z
dc:date:expires Date in year-month-day format, after which the Virtual Machine Image List should no longer be trusted, e.g. 2499-12-31T22:00:00Z
dc:description Description of the Virtual Machine Image List, e.g. “This is a VO-wide image list for vo.access.egi.eu VO.”
dc:identifier RFC 4122 UUID for the Virtual Machine Image List, for unique identification purposes, e.g. 488dcdc4-9ab1-4fc8-a7ba-b7a5428ecb3d
dc:source Source of the image list, its default value is “https://appdb.egi.eu/
dc:title Title of the Virtual Machine Image List, e.g. “VO vo.access.egi.eu image list.”
ad:num_of_images Number of images contained in this list, e.g. 8
ad:publisher:fullname Full name of image list publisher, as taken from the AppDB user profile
ad:publisher:guid Unique identifier of image list publisher as taken from the AppDB user profile
ad:publisher:uri Link to the publisher's AppDB user profile
ad:vo The name of the VO this list pertains to, e.g. vo.access.egi.eu. In the case of a standalone image list, the value is always “appdb-general”
hv:uri URL to retrieve this image list, e.g. “https://vmcaster.appdb.egi.eu/store/vo/vo.access.egi.eu/image.list”. In the case of VO wide image lists, the URL is not publicly accessible.
hv:version The version of this image list (auto-generated from AppDB per VO), e.g. 20210913143728
hv:endorser/hv:x509 Placeholder for endorser metadata
hv:images The images referenced by this image list

Endorser schema

The schema of hv:endorser/hv:x509 object describing the endorser service. In our case this is the AppDB service itself.

Field Name Description
hv:ca Standard hash id for the Certification Authorities
hv:dn x.509 DN of the endorser
hv:email Email address of the endorser
dc:creator Name of the endorser

Image item schema

The schema of the image data objects contained in the “hv:images” list. In the case of VO wide image lists, this information is meant to be processed by a subscription service (e.g. cloudkeeper), in order to populate a cloud provider VM catalog (e.g. OpenStack Glance).

Field Name Optional Description
dc:description NO Free text describing the image
dc:identifier NO RFC 4122 UUID for image unique identification purposes
dc:title NO Title of image. Default value gets auto-generated by AppDB, if not provided by user
dc:date:expires NO The expiration date of the specific VM version. The value is user-defined and may span any of 3, 6, 9, or 12 months after the publication of the image version
ad:appid NO AppDB ID referencing the virtual appliance the image belongs to
ad:mpuri NO AppDB URL referring to the VM version in relation to the specific VO image list version. In the case of a standalone image list, this value will be the same as ad:base_mpuri
Note: In the case of VO-wide image lists, this information is important, as it relates the specific virtual appliance version with the specific VO image list version. Moreover, storing it in a cloud provider catalogue helps identify the distribution of the particular image.
ad:base_mpuri NO AppDB URL referring to the VM version
ad:group NO Obsolete. Used in the past to group many VMs of the same virtual appliance version. Now, each virtual appliance version corresponds to a single VM, and the value defaults to “General group”. May be ignored
hv:hypervisor NO Typically set to reflect the supported Virtualization technology, e.g. Xen, KVM.
The list of all possible values may be retrieved from the AppDB API
hv:format NO The image format, e.g. OVA. User defined
hv:uri NO URI pointing to the location of this image.
hv:version NO The version of the image, so that updates can share the same metadata. It does not follow a specific pattern and it is up to the user to provide, although AppDB enforces values to be unique per virtual appliance
hv:size NO Size of the image in bytes, as measured by AppDB during checksum computation
sl:checksum:sha512 NO Computed sha512 checksum of the image from AppDB upon publication by user
sl:comments NO User comments for the specific VM version.
sl:arch NO Architecture of the image, typically ’x86_64’
The list of all possible values may be retrieved from the AppDB API
sl:os NO The operating system family the image runs, examples include “Linux”, “BSD”, “Windows”
The list of all possible values may be retrieved from the application:osfamily elements of the AppDB API
sl:osname NO The operating system the image runs, examples include “Ubuntu”
The list of all possible values may be retrieved from the application:os elements of the AppDB API, as long as their familyid attribute corresponds to the sl:os value
sl:osversion NO The operating system version the image runs, examples include “20.04”
hv:ram_minimum YES Minimum number of RAM required to run the virtual machine image, expressed as an integer in bytes.
ad:ram_recommended YES Recommended number of RAM required to run the virtual machine image, expressed as an integer in bytes.
hv:core_minimum YES Minimum number of virtual cores required to run the virtual machine image, expressed as an integer.
AppDB constraints the value to 1,2,4,8,16 or 32 cores
ad:core_recommended YES Recommended number of virtual cores required to run the virtual machine image, expressed as an integer.
AppDB constraints the value to 1,2,4,8,16 or 32 cores
ad:accel_type YES The accelerator type the VM supports.
Currently, the only supported value is “GPU”.
ad:accel_minimum YES Minimum accelerator cores. Only available if accel_type is defined]
AppDB constraints the value to 1,2,4,8,16 or 32 cores
ad:accel_recommended YES Recommended accelerator cores. Available if accelerator type is defined
AppDB constraints the value to 1,2,4,8,16 or 32 cores
ad:traffic_in YES List of inbound network traffic rules that the VM needs to function, as defined by the user,
ad:traffic_out YES List of outbound network traffic rules that the VM needs to function, as defined by the user,
ad:context_format YES The contextualization format. Reserved for future use and may be ignored. Only supported option is “cloud-init”
ad:default_access YES The default method to access the VM. Reserved for future use and may be ignored. Defaults to “None”
ad:user:fullname NO Full name of image version publisher as taken from the AppDB user profile
ad:user:guid NO Unique identifier of image version publisher as taken from the AppDB user profile
ad:user:uri NO Link to image version publisher's AppDB user profile

Network traffic schema

Below are the fields of objects of ad:traffic_in and ad:traffic_out lists in the image items.

Field Name Description
ad:net_protocol The type of network protocol.
Possible values are “TCP”, “UDP”, or “ICMP”
ad:net_port The port number the rule applies to, or a range of ports seperated by “:“
e.g. “80”, “8000:8088”
ad:net_range Reserved for future use for IP Ranges. Always defaults to “0.0.0.0/0” and may be ignored
main/faq/vo_image_list_format.txt · Last modified: 2021/10/07 15:25 by 84f464f99bd105183e28266cde96f6d7bdc2804663c23b97e7bde0520f656155@egi.eu