问开发中的nova诊断技术

EN

from oslo.utils import units
from ceilometer.compute.pollsters import util


  def inspect_memory_usage(self, instance, duration=None):  
        instance_name = util.instance_name(instance)    
        domain = self._lookup_by_name(instance_name)    
        state = domain.info()[0]    
        if state == libvirt.VIR_DOMAIN_SHUTOFF: 
            LOG.warn(_('Failed to inspect memory usage of %(instance_name)s, '  
                       'domain is in state of SHUTOFF'),    
                     {'instance_name': instance_name})  
            return  
        try:    
            memory_stats = domain.memoryStats() 
            if (memory_stats and    
                    memory_stats.get('available') and   
                    memory_stats.get('unused')):    
                memory_used = (memory_stats.get('available') -  
                               memory_stats.get('unused'))  
                # Stat provided from libvirt is in KB, converting it to MB.     
                memory_used = memory_used / units.Ki    
                return virt_inspector.MemoryUsageStats(usage=memory_used)   
            else:   
                LOG.warn(_('Failed to inspect memory usage of ' 
                           '%(instance_name)s, can not get info from libvirt'), 
                         {'instance_name': instance_name})  
        # memoryStats might launch an exception if the method   
        # is not supported by the underlying hypervisor being   
        # used by libvirt   
        except libvirt.libvirtError as e:   
            LOG.warn(_('Failed to inspect memory usage of %(instance_name)s, '  
                       'can not get info from libvirt: %(error)s'), 
                                 {'instance_name': instance_name, 'error': e})