[libvirt-users] can't establish more than 1000 connections with virsh

Hi: I'm trying to connect with libvirtd with virsh from a remote PC,but only can establish 1000 connections. If try more connections,prompt: "error: failed to connect to the hypervisor error: Failed to open file '/etc/libvirt/libvirt.conf': Too many open files" I tried in another PC,also get the same prompt. Anybody know why? Thanks! environment: libvirt:libvirt-2.0.0-10.el7 OS:centos7.3