In today’s cloud-native landscape, Kubernetes has become a cornerstone for enterprises, especially with the rise of multi-cluster deployments. These architectures enhance disaster recovery, enable intelligent autoscaling, and strengthen identity management, providing organizations with greater resilience and flexibility. It automates deployment, scaling, and resilience while abstracting infrastructure complexity, enabling applications to be more agile, portable, and innovative making it a critical enabler for modern digital platforms. Complementing this, the NetScaler Ingress Controller (NSIC) adds enterprise-grade traffic management, security, and observability, providing advanced load balancing, application firewalling, and seamless integration with Kubernetes services to ensure reliable and secure application delivery in cloud-native deployments.
The NetScaler Ingress Controller (NSIC) supports multiple NetScaler form factors CPX, BLX, VPX, and MPX to efficiently manage and route traffic into Kubernetes clusters. By leveraging these capabilities, organizations can achieve high availability, improved resilience, and consistent performance across clusters.
NetScaler elevates Kubernetes ingress by delivering enterprise-grade traffic management through CRDs, including advanced rewrite and responder policies unavailable in native Kubernetes Ingress. It supports flexible topologies such as Single-Tier and Dual-Tier, ensuring smooth integration with Kubernetes environments. With NetScaler CPX, organizations can achieve advanced Layer 7 load balancing for East-West microservice traffic, surpassing Kubernetes’ default Layer 4 capabilities.
Understanding the Architecture
The architecture consists of two OpenShift clusters (DC 1 and DC 2), each with:
OpenShift Container Platform running applications.
NetScaler Ingress Controller (NSIC) managing ingress rules.
GSLB Controller handling DNS-based traffic distribution (Part 2).
IPAM Controller handling Ingress IP allocation.
NetScaler appliances acting as Tier-1 ingress points and synchronizing GSLB configuration.
Traffic Flow:
Ingress Configuration NetScaler Ingress Controller (NSIC) in both clusters configures ingress rules for exposed applications.
GSLB Entity Setup Each cluster’s GSLB controller configures GSLB entities on the primary site NetScaler (Hall 1). These include service groups, monitors, and DNS records.
GSLB Sync The GSLB configuration is synchronized automatically between the NetScaler’s deployed across datacenters over MEP (Metric Exchange Protocol).
DNS ResolutionA client’s DNS query for an application FQDN is directed to GSLB. Based on configured global traffic policies (round-robin, proximity, or availability), the GSLB resolves the query to an IP.
Client to Ingress VIPThe resolved IP corresponds to the ingress VIP on one of the NetScaler’s. The client’s traffic lands on this Tier-1 ingress point.
Application Access The NetScaler forwards the request to the appropriate OpenShift cluster, where it reaches the application service pods via NSIC and kube-proxy, responsible for routing requests within clusters that allow services to communicate with pods.
Deployments Prerequisites:
NetScaler ANY form factor, VPX, MPX, BLX (use existing NetScaler ADC available in the environment or set up VPX easily on compatible hypervisor. (For this setup, VPX 3000 is used).
Configure two SNIP IPs on each NetScaler for traffic management.
Keep free VIPs available to expose OpenShift applications externally.
Ensure SNIP-to-SNIP connectivity across VPXs in DCs with ports 22, 3008, 3009, 3011, and 443 allowed.
Open port 443 between VPX SNIPs and OpenShift node IPs for secure app communication.
Allow VPX SNIPs to reach OpenShift nodes over assigned NodePort service ports, or simply enable the full range 30000–32767 (TCP/UDP) for flexibility
OpenShift CLI for cluster management
Deployments: NSIC with OpenShift Multi-Site Multi-Cluster deployments
1. Deploy NetScaler VPXs in HA for each site 2. Create Namespace in OpenShift Cluster oc project dc1-apps 3. Deploy sample applications We are using HTTPBIN sample application to demonstrate in this blog end to end –
apiVersion: v1
kind: ServiceAccount
metadata:
name: httpbin
namespace: dc1-apps
---
apiVersion: v1
kind: Service
metadata:
name: httpbin
labels:
app: httpbin
service: httpbin
namespace: dc1-apps
spec:
type: NodePort
ports:
- name: http
port: 8000
targetPort: 8080
selector:
app: httpbin
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: httpbin
namespace: dc1-apps
spec:
replicas: 2
selector:
matchLabels:
app: httpbin
version: v1
template:
metadata:
labels:
app: httpbin
version: v1
spec:
serviceAccountName: httpbin
containers:
- image: quay.io/sample-apps/httpbin:latest
imagePullPolicy: IfNotPresent
name: httpbin
# Same as found in Dockerfile's CMD but using an unprivileged port
command:
- gunicorn
- -b
- 0.0.0.0:8080
- httpbin:app
- -k
- gevent
env:
# Tells pipenv to use a writable directory instead of $HOME
- name: WORKON_HOME
value: /tmp
ports:
- containerPort: 8080
4. Create self-signed certificates for securing the application and SSL termination on NetScaler
openssl genrsa -out httpbin_key.pem 2048
openssl req -new -key httpbin_key.pem -out httpbin_csr.pem -subj "/CN=*.httpbin.com"
openssl x509 -req -in httpbin_csr.pem -sha256 -days 365 -extensions v3_ca -signkey httpbin_key.pem -CAcreateserial -out httpbin_cert.pem
oc create secret tls httpbin --key httpbin_key.pem --cert httpbin_cert.pem
5. Create NetScaler login credentials for NSIC
oc create secret generic nslogin --from-literal=username='nsroot' --from-literal=password='cxalab@123' -n dc1-apps
6. Install NetScaler Operator from OpenShift Operator Hub in the project/namespace created. It is OpenShift native way to deploy and manage NetScaler’s inside OpenShift environment.
7. Install NetScaler Ingress Controller in the project created by NetScaler Operator. Set the parameters values like name, namespace, serviceClass, ingressClass and NetScaler ADC details etc.
8. Install IPAM controller from OpenShift operator hub or using Helm chart by creating values.yaml Use requires IPAM annotations when creating ingress.
helm install my-release netscaler/citrix-ipam-controller -f values.yaml
OR create ingress deployment and mention the listener IP manually like below:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingresshttpbin
annotations:
ingress.citrix.com/frontend-ip: 10.100.4.150
spec:
ingressClassName: ns-ingressclass
tls:
- secretName: httpbin
rules:
- host: 'bk.httpbin.com'
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: httpbin
port:
number: 8000
9. Deploy Ingress to expose OpenShift application and route the traffic. Below is output of ingress created under cluster –
Name: ingresshttpbin
Namespace: dc1-apps
Address: 10.100.4.150
TLS:
httpbin terminates
Rules:
Host Path Backends
---- ---- --------
bk.httpbin.com
/ httpbin:8000 (10.100.96.183:8080,10.100.98.61:8080)
Annotations:
ingress.citrix.com/frontend-ip: 10.100.4.150
Events:
<none>
Deployment Validation:
Login to NetScaler and check the configuration pushed by NISC through OpenShift
CS vServer
CS policy
CS action
SSL certificate and binding with CS vServer
LB vServer
LB ServiceGroup
Monitor (optional – health monitor needs to be part of ingress deployment)
> sh cs vserver redstorm-10.100.4.150_443_ssl
redstorm-10.100.4.150_443_ssl (10.100.4.150:443) - SSL
Type: CONTENT
State: UP
Last state change was at Mon Oct 13 20:11:43 2025
Time since last state change: 20 days, 08:42:45.680
Client Idle Timeout: 180 sec
Down state flush: ENABLED
Disable Primary Vserver On Down : DISABLED
Comment: uid=WJ7KNW35SB5ADSSIQGR7HWF7HT4RYPQOQ7U7F2WA3JTOCGHZUAJQ====
Appflow logging: ENABLED
DnsOverHttps: DISABLED
State Update: DISABLED
Default: Content
Precedence: RULE
Vserver IP and Port insertion: OFF
L2Conn: OFF
Case Sensitivity: ON
Authentication: OFF
401 Based Authentication: OFF
Push: DISABLED
Push VServer:
Push Label Rule: none
HTTP Redirect Port: 0
Dtls : OFF
Persistence: NONE
Listen Policy: NONE
IcmpResponse: PASSIVE
RHIstate: PASSIVE
Traffic Domain: 0
1) Content-Switching Policy: redstorm-httpbin_8000_csp_wbe5m6xaaqlb34bzjay24rrayadsyu6x
Rule: HTTP.REQ.HOSTNAME.SERVER.EQ("bk.httpbin.com") && HTTP.REQ.URL.PATH.SET_TEXT_MODE(IGNORECASE).STARTSWITH("/")
Priority: 200000008
Hits: 414195
Done
> sh lb vserver redstorm-httpbin_8000_lbv_wbe5m6xaaqlb34bzjay24rrayadsyu6x
redstorm-httpbin_8000_lbv_wbe5m6xaaqlb34bzjay24rrayadsyu6x (0.0.0.0:0) - HTTP
Type: ADDRESS
State: UP
Last state change was at Mon Oct 13 20:11:44 2025
Time since last state change: 20 days, 08:44:01.520
Effective State: UP
ARP:DISABLED
Client Idle Timeout: 180 sec
Down state flush: ENABLED
Disable Primary Vserver On Down : DISABLED
Comment: "rv:30411398,ing:ingresshttpbin,ingport:443,ns:dc1-apps,svc:httpbin,svcport:8000"
Appflow logging: ENABLED
Port Rewrite : DISABLED
No. of Bound Services : 2 (Total) 2 (Active)
Configured Method: LEASTCONNECTION
BackupMethod: ROUNDROBIN
Mode: IP
Persistence: NONE
Vserver IP and Port insertion: OFF
Push: DISABLED
Push VServer:
Push Multi Clients: NO
Push Label Rule: none
L2Conn: OFF
Skip Persistency: None
Listen Policy: NONE
IcmpResponse: PASSIVE
RHIstate: PASSIVE
New Service Startup Request Rate: 0 PER_SECOND, Increment Interval: 0
Mac mode Retain Vlan: DISABLED
DBS_LB: DISABLED
Process Local: DISABLED
Traffic Domain: 0
TROFS Persistence honored: ENABLED
Retain Connections on Cluster: NO
Order Sequence: ASCENDING
Current Active Order: 1
Bound Service Groups:
1) Group Name: redstorm-httpbin_8000_sgp_wbe5m6xaaqlb34bzjay24rrayadsyu6x
1) redstorm-httpbin_8000_sgp_wbe5m6xaaqlb34bzjay24rrayadsyu6x (10.100.2.152: 31264) - HTTP
State: UP
Weight: 1
Order: 1
2) redstorm-httpbin_8000_sgp_wbe5m6xaaqlb34bzjay24rrayadsyu6x (10.100.2.150: 31264) - HTTP
State: UP
Weight: 1
Order: 1
Benefits of using NetScaler as Ingress Controller for OpenShift and cloud native solutions:
Easy Deployment: NSIC can be deployed directly into OpenShift using the NetScaler Operator and Helm charts, enabling automated provisioning, scaling, and management of NetScaler instances without manual configuration, making it cloud-native and Kubernetes-friendly.
One Architecture: The NetScaler can be used as traditional ADC in delivering intelligent traffic management for traditional apps as well as modern applications.
Enterprise-Grade Load Balancing: NetScaler offers Layer 4–7 load balancing with intelligent traffic distribution, unlike the default OpenShift router.
Advanced Traffic Policies: Apply rewrite, responder, content switching, and AppQoE policies to optimize and control application traffic.
Secure Application Delivery: SSL/TLS offloading, Web Application Firewall (WAF), and DDoS protection ensure secure exposure of OpenShift apps.
High Availability & Resilience: NetScaler ensures HA across multiple nodes and clusters, providing failover and uninterrupted service.
Multi-Cluster Support: Enables traffic routing across multiple OpenShift clusters for disaster recovery, scalability, and geographic distribution.
Integration with OpenShift: Works with NetScaler Ingress Controller (NSIC) and CRDs for Kubernetes-native management, making deployment and configuration declarative and automated.
Enhanced Observability:Provides deep analytics and monitoring for application performance and end-user experience via ADM/AppFlow or integration with Elasticsearch, Prometheus etc.
Coming up part 2 – GSLB Controller for datacenter resiliency across OpenShift clusters…
