func (daemon *Daemon) checkLocaldns() error { resolvConf, err := resolvconf.Get() if err != nil { return err } if len(daemon.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) { log.Infof("Local (127.0.0.1) DNS resolver found in resolv.conf and containers can't use it. Using default external servers : %v", DefaultDns) daemon.config.Dns = DefaultDns } return nil }
func (container *Container) setupContainerDns() error { if container.ResolvConfPath != "" { return nil } var ( config = container.hostConfig daemon = container.daemon ) resolvConf, err := resolvconf.Get() if err != nil { return err } container.ResolvConfPath, err = container.getRootResourcePath("resolv.conf") if err != nil { return err } if config.NetworkMode != "host" && (len(config.Dns) > 0 || len(daemon.config.Dns) > 0 || len(config.DnsSearch) > 0 || len(daemon.config.DnsSearch) > 0) { var ( dns = resolvconf.GetNameservers(resolvConf) dnsSearch = resolvconf.GetSearchDomains(resolvConf) ) if len(config.Dns) > 0 { dns = config.Dns } else if len(daemon.config.Dns) > 0 { dns = daemon.config.Dns } if len(config.DnsSearch) > 0 { dnsSearch = config.DnsSearch } else if len(daemon.config.DnsSearch) > 0 { dnsSearch = daemon.config.DnsSearch } return resolvconf.Build(container.ResolvConfPath, dns, dnsSearch) } return ioutil.WriteFile(container.ResolvConfPath, resolvConf, 0644) }
// CreateBridgeIface creates a network bridge interface on the host system with the name `ifaceName`, // and attempts to configure it with an address which doesn't conflict with any other interface on the host. // If it can't find an address which doesn't conflict, it will return an error. func createBridge(bridgeIP string) error { nameservers := []string{} resolvConf, _ := resolvconf.Get() // we don't check for an error here, because we don't really care // if we can't read /etc/resolv.conf. So instead we skip the append // if resolvConf is nil. It either doesn't exist, or we can't read it // for some reason. if resolvConf != nil { nameservers = append(nameservers, resolvconf.GetNameserversAsCIDR(resolvConf)...) } var ifaceAddr string if len(bridgeIP) != 0 { _, _, err := net.ParseCIDR(bridgeIP) if err != nil { return err } ifaceAddr = bridgeIP } else { for _, addr := range addrs { _, dockerNetwork, err := net.ParseCIDR(addr) if err != nil { return err } if err := networkdriver.CheckNameserverOverlaps(nameservers, dockerNetwork); err == nil { if err := networkdriver.CheckRouteOverlaps(dockerNetwork); err == nil { ifaceAddr = addr break } else { log.Debugf("%s %s", addr, err) } } } } if ifaceAddr == "" { return fmt.Errorf("Could not find a free IP address range for interface '%s'. Please configure its address manually and run 'docker -b %s'", bridgeIface, bridgeIface) } log.Debugf("Creating bridge %s with network %s", bridgeIface, ifaceAddr) if err := createBridgeIface(bridgeIface); err != nil { return err } iface, err := net.InterfaceByName(bridgeIface) if err != nil { return err } ipAddr, ipNet, err := net.ParseCIDR(ifaceAddr) if err != nil { return err } if netlink.NetworkLinkAddIp(iface, ipAddr, ipNet); err != nil { return fmt.Errorf("Unable to add private network: %s", err) } if err := netlink.NetworkLinkUp(iface); err != nil { return fmt.Errorf("Unable to start network bridge: %s", err) } return nil }