Add simple capability for filtering existing nodegroups

pkg/cfn/manager/tasks.go

@@ -3,6 +3,8 @@ package manager
 import (
 	"sync"
 
+	"k8s.io/apimachinery/pkg/util/sets"
+
 	"github.com/kris-nova/logger"
 
 	api "github.com/weaveworks/eksctl/pkg/apis/eksctl.io/v1alpha4"
@@ -65,23 +67,38 @@ func (c *StackCollection) CreateClusterWithNodeGroups() []error {
 		return errs
 	}
 
-	return c.CreateAllNodeGroups()
+	return c.CreateAllNodeGroups(false)
 }
 
 // CreateAllNodeGroups runs all tasks required to create the node groups;
 // any errors will be returned as a slice as soon as one of the tasks
 // or group of tasks is completed
-func (c *StackCollection) CreateAllNodeGroups() []error {
+func (c *StackCollection) CreateAllNodeGroups(ignoreExisting bool) []error {
 	errs := []error{}
 	appendErr := func(err error) {
 		errs = append(errs, err)
 	}
 
+	existing := sets.NewString()
+
+	if ignoreExisting {
+		existingStacks, err := c.DescribeNodeGroupStacks()
+		if err != nil {
+			return []error{err}
+		}
+		for _, s := range existingStacks {
+			existing.Insert(getNodeGroupName(s))
+		}
+	}
 	createAllNodeGroups := []Task{}
 	for i := range c.spec.NodeGroups {
+		ng := c.spec.NodeGroups[i]
 		t := Task{
 			Call: c.CreateNodeGroup,
-			Data: c.spec.NodeGroups[i],
+			Data: ng,
+		}
+		if existing.Has(ng.Name) {
+			continue
 		}
 		createAllNodeGroups = append(createAllNodeGroups, t)
 	}

pkg/ctl/create/nodegroup.go

@@ -20,8 +20,9 @@ import (
 )
 
 var (
-	updateAuthConfigMap bool
-	nodeGroupFilter     = ""
+	updateAuthConfigMap     bool
+	nodeGroupFilter         = ""
+	nodeGroupIgnoreExisting bool
 )
 
 func createNodeGroupCmd(g *cmdutils.Grouping) *cobra.Command {
@@ -54,6 +55,7 @@ func createNodeGroupCmd(g *cmdutils.Grouping) *cobra.Command {
 		fs.StringVarP(&clusterConfigFile, "config-file", "f", "", "load configuration from a file")
 		fs.StringVarP(&nodeGroupFilter, "only", "", "",
 			"select a subset of nodegroups via comma-separted list of globs, e.g.: 'ng-*,nodegroup?,N*group'")
+		fs.BoolVar(&nodeGroupIgnoreExisting, "ignore-existing", false, "ignore all existing nodegroups")
 		cmdutils.AddUpdateAuthConfigMap(&updateAuthConfigMap, fs, "Remove nodegroup IAM role from aws-auth configmap")
 	})
 
@@ -290,7 +292,7 @@ func doCreateNodeGroups(p *api.ProviderConfig, cfg *api.ClusterConfig, nameArg s
 
 	{
 		logger.Info("will create a CloudFormation stack for each of %d nodegroups in cluster %q", len(cfg.NodeGroups), cfg.Metadata.Name)
-		errs := stackManager.CreateAllNodeGroups()
+		errs := stackManager.CreateAllNodeGroups(nodeGroupIgnoreExisting)
 		if len(errs) > 0 {
 			logger.Info("%d error(s) occurred and nodegroups haven't been created properly, you may wish to check CloudFormation console", len(errs))
 			logger.Info("to cleanup resources, run 'eksctl delete nodegroup --region=%s --cluster=%s --name=<name>' for each of the failed nodegroup", cfg.Metadata.Region, cfg.Metadata.Name)