tests/network: use ethX naming to preserve NIC order by CCW devno on s390x

Signed-off-by: Nikita Dubrovskii <[email protected]>

Author: nikita-dubrovskii

mantle/kola/tests/misc/network.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"runtime"
 	"strings"
 	"time"
 
@@ -503,6 +504,10 @@ func setupMultipleNetworkTest(c cluster.TestCluster, primaryMac, secondaryMac st
 			AdditionalNics: 2,
 		},
 	}
+	// On s390x, multiple NICs are ordered by the CCW device number. Use classic ethX names to ensure consistent and ordered naming.
+	if runtime.GOARCH == "s390x" {
+		options.AppendKernelArgs = "net.ifnames=0"
+	}
 
 	var userdata = conf.Ignition(fmt.Sprintf(`{
 		"ignition": {