aws: Add check for multiple worker pools

Add validation check for multiple worker pools, to avoid conflicting
port values in aws_lb_listener. User has to set unique values for
lb_http_port and lb_https_port.

Signed-off-by: knrt10 <kautilya@kinvolk.io>

pkg/platform/aws/aws.go

@@ -278,6 +278,7 @@ func (c *config) checkValidConfig() hcl.Diagnostics {
 	diagnostics = append(diagnostics, c.checkNotEmptyWorkers()...)
 	diagnostics = append(diagnostics, c.checkWorkerPoolNamesUnique()...)
 	diagnostics = append(diagnostics, c.checkNameSizes()...)
+	diagnostics = append(diagnostics, c.checkDifferentPortForMuliplePools()...)
 
 	if c.OIDC != nil {
 		_, diags := c.OIDC.ToKubeAPIServerFlags(c.clusterDomain())
@@ -287,6 +288,28 @@ func (c *config) checkValidConfig() hcl.Diagnostics {
 	return diagnostics
 }
 
+// checkDifferentPortForMuliplePools checks if user is using multiple worker
+// pools, then they should have lb_http_port and lb_https_port flag set
+// with different values.
+func (c *config) checkDifferentPortForMuliplePools() hcl.Diagnostics {
+	var diagnostics hcl.Diagnostics
+
+	// check only if using multiple worker pools.
+	if len(c.WorkerPools) > 1 {
+		for _, wp := range c.WorkerPools {
+			if wp.LBHTTPPort == 0 && wp.LBHTTPSPort == 0 {
+				diagnostics = append(diagnostics, &hcl.Diagnostic{
+					Severity: hcl.DiagError,
+					Summary:  "Unique values required",
+					Detail:   fmt.Sprintf("Values lb_http_port and lb_https_port not set for worker pool %s", wp.Name),
+				})
+			}
+		}
+	}
+
+	return diagnostics
+}
+
 // checkNameSizes checks the size of names since AWS has a limit of 32
 // characters on resources.
 func (c *config) checkNameSizes() hcl.Diagnostics {