Use the slrip4netns dns in the rootless cni ns
If a user only has a local dns server in the resolv.conf file the dns
resolution will fail. Instead we create a new resolv.conf which will use
the slirp4netns dns.
@@ -24,6 +24,7 @@ import (
"github.com/containers/podman/v3/libpod/network"
"github.com/containers/podman/v3/pkg/errorhandling"
"github.com/containers/podman/v3/pkg/netns"
+ "github.com/containers/podman/v3/pkg/resolvconf"
"github.com/containers/podman/v3/pkg/rootless"
"github.com/containers/podman/v3/pkg/util"
"github.com/containers/storage/pkg/lockfile"
@@ -134,9 +135,14 @@ func (r *rootlessCNI) Do(toRun func() error) error {
return errors.Wrap(err, "failed to mount netns directory for rootless cni")
}
+ // mount resolv.conf to make use of the host dns
+ err = unix.Mount(filepath.Join(r.dir, "resolv.conf"), "/etc/resolv.conf", "none", unix.MS_BIND, "")
+ if err != nil {
+ return errors.Wrap(err, "failed to mount resolv.conf for rootless cni")
+ }
+
// also keep /run/systemd if it exists
- // many files are symlinked into this dir, for example systemd-resolved links
- // /etc/resolv.conf but the dnsname plugin needs access to this file
+ // many files are symlinked into this dir, for example /dev/log
runSystemd := "/run/systemd"
_, err = os.Stat(runSystemd)
if err == nil {
@@ -348,6 +354,29 @@ func (r *Runtime) getRootlessCNINetNs(new bool) (*rootlessCNI, error) {
return nil, err
}
+ // build a new resolv.conf file which uses the slirp4netns dns server address
+ resolveIP := slirp4netnsDNS
+ if netOptions.cidr != "" {
+ _, cidr, err := net.ParseCIDR(netOptions.cidr)
+ if err != nil {
+ return nil, errors.Wrap(err, "failed to parse slirp4netns cidr")
+ }
+ // the slirp dns ip is always the third ip in the subnet
+ cidr.IP[len(cidr.IP)-1] = cidr.IP[len(cidr.IP)-1] + 3
+ resolveIP = cidr.IP.String()
+ }
+ conf, err := resolvconf.Get()
+ if err != nil {
+ return nil, err
+ }
+ searchDomains := resolvconf.GetSearchDomains(conf.Content)
+ dnsOptions := resolvconf.GetOptions(conf.Content)
+
+ _, err = resolvconf.Build(filepath.Join(cniDir, "resolv.conf"), []string{resolveIP}, searchDomains, dnsOptions)
+ if err != nil {
+ return nil, errors.Wrap(err, "failed to create rootless cni resolv.conf")
+ }
+
// create cni directories to store files
// they will be bind mounted to the correct location in a extra mount ns
err = os.MkdirAll(filepath.Join(cniDir, "var"), 0700)
