[FIX] store hostAliases in label to persist them across cluster stop/start (#1029)

cmd/cluster/clusterStart.go

@@ -58,6 +58,17 @@ func NewCmdClusterStart() *cobra.Command {
 						l.Log().Fatalf("failed to gather info about cluster environment: %v", err)
 					}
 					startClusterOpts.EnvironmentInfo = envInfo
+
+					// Get pre-defined clusterStartOpts from cluster
+					fetchedClusterStartOpts, err := client.GetClusterStartOptsFromLabels(c)
+					if err != nil {
+						l.Log().Fatalf("failed to get cluster start opts from cluster labels: %v", err)
+					}
+
+					// override only a few clusterStartOpts from fetched opts
+					startClusterOpts.HostAliases = fetchedClusterStartOpts.HostAliases
+
+					// start the cluster
 					if err := client.ClusterStart(cmd.Context(), runtimes.SelectedRuntime, c, startClusterOpts); err != nil {
 						l.Log().Fatalln(err)
 					}

pkg/client/cluster.go

@@ -25,6 +25,7 @@ import (
 	"bytes"
 	"context"
 	_ "embed"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"sort"
@@ -377,6 +378,18 @@ ClusterCreatOpts:
 	}
 	clusterCreateOpts.GlobalLabels[k3d.LabelClusterToken] = cluster.Token
 
+	/*
+	 * Extra Labels
+	 */
+	if len(clusterCreateOpts.HostAliases) > 0 {
+		hostAliasesJSON, err := json.Marshal(clusterCreateOpts.HostAliases)
+		if err != nil {
+			return fmt.Errorf("error marshalling hostaliases: %w", err)
+		}
+
+		clusterCreateOpts.GlobalLabels[k3d.LabelClusterStartHostAliases] = string(hostAliasesJSON)
+	}
+
 	/*
 	 * Nodes
 	 */
@@ -762,6 +775,22 @@ func populateClusterFieldsFromLabels(cluster *k3d.Cluster) error {
 	return nil
 }
 
+func GetClusterStartOptsFromLabels(cluster *k3d.Cluster) (k3d.ClusterStartOpts, error) {
+	clusterStartOpts := k3d.ClusterStartOpts{
+		HostAliases: []k3d.HostAlias{},
+	}
+	for _, node := range cluster.Nodes {
+		if len(clusterStartOpts.HostAliases) == 0 {
+			if hostAliasesJSON, ok := node.RuntimeLabels[k3d.LabelClusterStartHostAliases]; ok {
+				if err := json.Unmarshal([]byte(hostAliasesJSON), &clusterStartOpts.HostAliases); err != nil {
+					return clusterStartOpts, fmt.Errorf("error unmarshalling hostaliases JSON from node %s label: %w", node.Name, err)
+				}
+			}
+		}
+	}
+	return clusterStartOpts, nil
+}
+
 var ClusterGetNoNodesFoundError = errors.New("No nodes found for given cluster")
 
 // ClusterGet returns an existing cluster with all fields and node lists populated

pkg/types/types.go

@@ -75,25 +75,26 @@ var ClusterExternalNodeRoles = []Role{
 
 // List of k3d technical label name
 const (
-	LabelClusterName          string = "k3d.cluster"
-	LabelClusterURL           string = "k3d.cluster.url"
-	LabelClusterToken         string = "k3d.cluster.token"
-	LabelClusterExternal      string = "k3d.cluster.external"
-	LabelImageVolume          string = "k3d.cluster.imageVolume"
-	LabelNetworkExternal      string = "k3d.cluster.network.external"
-	LabelNetwork              string = "k3d.cluster.network"
-	LabelNetworkID            string = "k3d.cluster.network.id"
-	LabelNetworkIPRange       string = "k3d.cluster.network.iprange"
-	LabelRole                 string = "k3d.role"
-	LabelServerAPIPort        string = "k3d.server.api.port"
-	LabelServerAPIHost        string = "k3d.server.api.host"
-	LabelServerAPIHostIP      string = "k3d.server.api.hostIP"
-	LabelServerIsInit         string = "k3d.server.init"
-	LabelRegistryHost         string = "k3d.registry.host"
-	LabelRegistryHostIP       string = "k3d.registry.hostIP"
-	LabelRegistryPortExternal string = "k3s.registry.port.external"
-	LabelRegistryPortInternal string = "k3s.registry.port.internal"
-	LabelNodeStaticIP         string = "k3d.node.staticIP"
+	LabelClusterName             string = "k3d.cluster"
+	LabelClusterURL              string = "k3d.cluster.url"
+	LabelClusterToken            string = "k3d.cluster.token"
+	LabelClusterExternal         string = "k3d.cluster.external"
+	LabelImageVolume             string = "k3d.cluster.imageVolume"
+	LabelNetworkExternal         string = "k3d.cluster.network.external"
+	LabelNetwork                 string = "k3d.cluster.network"
+	LabelNetworkID               string = "k3d.cluster.network.id"
+	LabelNetworkIPRange          string = "k3d.cluster.network.iprange"
+	LabelClusterStartHostAliases string = "k3d.cluster.start.hostaliases"
+	LabelRole                    string = "k3d.role"
+	LabelServerAPIPort           string = "k3d.server.api.port"
+	LabelServerAPIHost           string = "k3d.server.api.host"
+	LabelServerAPIHostIP         string = "k3d.server.api.hostIP"
+	LabelServerIsInit            string = "k3d.server.init"
+	LabelRegistryHost            string = "k3d.registry.host"
+	LabelRegistryHostIP          string = "k3d.registry.hostIP"
+	LabelRegistryPortExternal    string = "k3s.registry.port.external"
+	LabelRegistryPortInternal    string = "k3s.registry.port.internal"
+	LabelNodeStaticIP            string = "k3d.node.staticIP"
 )
 
 // DoNotCopyServerFlags defines a list of commands/args that shouldn't be copied from an existing node when adding a similar node to a cluster