Merge pull request #1462 from jenting/fix-kubectl-server-side-dry-run…

…-flag

Fix kubectl server-side dry-run flag

internal/pkg/skuba/addons/addons.go

@@ -375,7 +375,11 @@ func (addon Addon) applyPreflight(addonConfiguration AddonConfiguration, rootDir
  "-f", preflightManifestPath,
  }
  if dryRun {
- kubectlArgs = append(kubectlArgs, "--dry-run=server")
+ flag, err := kubectlServerSideDryRunFlag()
+ if err != nil {
+ return true, err
+ }
+ kubectlArgs = append(kubectlArgs, flag)
  }
  cmd := exec.Command("kubectl", kubectlArgs...)
  var stderr bytes.Buffer
@@ -441,7 +445,11 @@ func (addon Addon) Apply(client clientset.Interface, addonConfiguration AddonCon
  "-k", addon.addonDir(),
  }
  if dryRun {
- kubectlArgs = append(kubectlArgs, "--dry-run=server")
+ flag, err := kubectlServerSideDryRunFlag()
+ if err != nil {
+ return err
+ }
+ kubectlArgs = append(kubectlArgs, flag)
  }
  cmd := exec.Command("kubectl", kubectlArgs...)
  var stderr bytes.Buffer
@@ -509,3 +517,24 @@ func updateSkubaConfigMapWithAddonVersion(client clientset.Interface, addon kube
  skubaConfiguration.AddonsVersion[addon] = addonVersion
  return skuba.UpdateSkubaConfiguration(client, skubaConfiguration)
 }
+
+func kubectlServerSideDryRunFlag() (string, error) {
+ // If k8s client version < v1.18.0, the server-side dry-run flag is `--server-dry-run`
+ // If k8s client version >= v1.18.0, the server-side dry-run flag is `--dry-run=server`
+ cmd := exec.Command("kubectl", "version", "--client", "--short")
+ combinedOutput, err := cmd.CombinedOutput()
+ if err != nil {
+ return "", err
+ }
+
+ var clientVersion string
+ _, err = fmt.Sscanf(string(combinedOutput), "Client Version: %s", &clientVersion)
+ if err != nil {
+ return "", err
+ }
+
+ if version.MustParseSemantic(clientVersion).LessThan(version.MustParseSemantic("v1.18.0")) {
+ return "--server-dry-run", nil
+ }
+ return "--dry-run=server", nil
+}