使用virsh連線到別的伺服器時，使用的是tcp連線

virsh -c qemu+tcp://host/system

如果目標伺服器沒有開啟libvirtd的tcp埠監聽時，會出現

error: unable to connect to server at 'host:16509':Connection refused
error: failed to connect to the hypervisor

ubuntu下解決方法

sed -i 's/#listen_tls = 0/listen_tls = 0/g'/etc/libvirt/libvirtd.conf
sed -i 's/#listen_tcp = 1/listen_tcp = 1/g'
 
/etc/libvirt/libvirtd.conf
sed -i 's/#auth_tcp = "sasl"/auth_tcp = "none"/g'/etc/libvirt/libvirtd.conf

vi /etc/default/libvirt-bin 修改為libvirt_opts ="-d -l"增加-l監聽tcp

service libvirt-bin restart

centos下解決方法

sed -i 's/#listen_tls = 0/listen_tls = 0/g'/etc/libvirt/libvirtd.conf
sed -i 's/#listen_tcp = 1/listen_tcp = 1/g'
 
/etc/libvirt/libvirtd.conf
sed -i 's/#auth_tcp = "sasl"/auth_tcp = "none"/g'/etc/libvirt/libvirtd.conf
sed -i 's/#LIBVIRTD_ARGS="--listen"/LIBVIRTD_ARGS="--listen"/g'/etc/sysconfig/libvirtd

service libvirtd restart