Resolve "Add application instance scaling support"

Related to #254

src/main/java/net/geant/nmaas/nmservice/deployment/containerorchestrators/kubernetes/components/helm/commands/HelmUpgradeCommand.java

@@ -3,6 +3,7 @@ package net.geant.nmaas.nmservice.deployment.containerorchestrators.kubernetes.c
 import com.google.common.base.Strings;
 import net.geant.nmaas.nmservice.deployment.containerorchestrators.kubernetes.components.helm.HelmCommand;
 
+import java.util.List;
 import java.util.function.Predicate;
 
 public class HelmUpgradeCommand extends HelmCommand {
@@ -78,4 +79,27 @@ public class HelmUpgradeCommand extends HelmCommand {
         return o -> !o.startsWith("Error");
     }
 
+    public static HelmUpgradeCommand commandWithSetValues(String helmVersion, String namespace, String releaseName, List<String> setValues, boolean enableTls) {
+        if (!HELM_VERSION_3.equals(helmVersion)) {
+            throw new IllegalArgumentException("Upgrades are not supported for Helm v2");
+        }
+        if (releaseName == null || releaseName.isEmpty()) {
+            throw new IllegalArgumentException("Name of the release can't be null or empty");
+        }
+
+        StringBuilder sb = new StringBuilder();
+        sb.append(HELM)
+                .append(SPACE).append(UPGRADE)
+                .append(SPACE).append(OPTION_NAMESPACE).append(SPACE).append(namespace)
+                .append(SPACE).append(releaseName);
+
+        for (String setValue : setValues) {
+            sb.append(SPACE).append("--set").append(SPACE).append(setValue);
+        }
+
+        addTlsOptionIfRequired(helmVersion, enableTls, sb);
+        return new HelmUpgradeCommand(sb.toString());
+    }
+
+
 }