Bug 1003610 - RFE: capabilities: Expose xen blktap support
RFE: capabilities: Expose xen blktap support
Product: Virtualization Tools
Classification: Community
Component: libvirt (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Libvirt Maintainers
Depends On:
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Reported: 2013-09-02 09:30 EDT by Cole Robinson
Modified: 2016-03-20 18:26 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2016-03-20 18:26:14 EDT
Type: Bug
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RHEL 7.3 requirements from Atomic Host:
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Description Cole Robinson 2013-09-02 09:30:37 EDT
virt-install/virt-manager have had this check forever:

def is_blktap_capable(conn):
    # Ideally we would get this from libvirt capabilities XML
    if conn.is_remote():
        return False

    f = open("/proc/modules")
    lines = f.readlines()
    for line in lines:
        if line.startswith("blktap ") or line.startswith("xenblktap "):
            return True
    return False

If True, we use driver name='tap' for <disk> XML. As the comment above suggestions, libvirt should expose some tag in capabilities so we know a
host supports blktap, and tools don't need to probe lsmod or similar.
Comment 1 Cole Robinson 2016-03-20 18:26:14 EDT
blktap is apparently not the favored xen driver anymore, as detailed in bug 1171550, so while in theory libvirt should provide this info I don't think anyone practically cares about it anymore.

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