Properly share UTS namespaces in a pod

Sharing a UTS namespace means sharing the hostname. Fix situations where a container in a pod didn't properly share the hostname of the pod.

Signed-off-by: Peter Hunt <pehunt@redhat.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/pkg/spec/spec.go b/pkg/spec/spec.go
index c94746767..c16696ffe 100644
--- a/pkg/spec/spec.go
+++ b/pkg/spec/spec.go
@@ -174,10 +174,20 @@ func (config *CreateConfig) createConfigToOCISpec(runtime *libpod.Runtime, userM
 	}
 
 	hostname := config.Hostname
-	if hostname == "" && (config.NetMode.IsHost() || config.UtsMode.IsHost()) {
-		hostname, err = os.Hostname()
-		if err != nil {
-			return nil, errors.Wrap(err, "unable to retrieve hostname")
+	if hostname == "" {
+		if utsCtrID := config.UtsMode.Container(); utsCtrID != "" {
+			utsCtr, err := runtime.GetContainer(utsCtrID)
+			if err != nil {
+				return nil, errors.Wrapf(err, "unable to retrieve hostname from dependency container %s", utsCtrID)
+			}
+			hostname = utsCtr.Hostname()
+		} else if config.NetMode.IsHost() || config.UtsMode.IsHost() {
+			hostname, err = os.Hostname()
+			if err != nil {
+				return nil, errors.Wrap(err, "unable to retrieve hostname of the host")
+			}
+		} else {
+			logrus.Debug("No hostname set; container's hostname will default to runtime default")
 		}
 	}
 	g.RemoveHostname()
@@ -606,6 +616,9 @@ func addUTSNS(config *CreateConfig, g *generate.Generator) error {
 	if utsMode.IsHost() {
 		return g.RemoveLinuxNamespace(string(spec.UTSNamespace))
 	}
+	if utsMode.IsContainer() {
+		logrus.Debug("using container utsmode")
+	}
 	return nil
 }