netscaler / nitrox

Configure Citrix Netscaler Loadbalancing for container platforms

Nitrox

Configure Citrix NetScaler loadbalancing for container platforms such as Docker Swarm, Mesos Marathon, Kubernetes and Consul.

Theory of Operation

1. Containers that form a load-balanced backend for an app/microservice are labeled with the same label (e.g., com.citrix.lb.appname=AccountService, or AccountService) or name
2. Information (host IP and port) from the container platform (such as Docker Swarm) API for the labeled containers are used to configure a NetScaler loadbalancer.
3. The NetScaler admin creates the "frontend" lb vserver with the label/name used in #1

NetScaler Pre-requisites

1. Credentials for a running Citrix NetScaler (VPX/MPX/SDX/CPX). On the host where you run the container/code, replace with your own:

   export NS_IP=10.220.73.33
   export NS_USER=nsroot
   export NS_PASSWORD=useyourownnspassword
   

2. List of microservices / apps that have to be load balanced. For example, 'AccountService', 'ProductCatalog', 'ShoppingCart', etc.

3. NetScaler that has been configured with VIP(s) for above apps. For example, lets say there is a microservice/app called 'AccountService' with a load balanced IP of 10.220.73.222. On the NetScaler:

   add lb vserver AccountService HTTP 10.220.73.222 80 -persistenceType COOKIE -lbMethod LEASTCONNECTION
   

   Alternatively, if the lb_ip and lb_port are included in the APP_INFO env variable, the lb vserver is configured automatically with some default options (ROUNDROBIN)

4. (for developers) The NetScaler Python SDK (can be downloaded here https://www.citrix.com/downloads/netscaler-adc/sdks.html or copied from the NetScaler)

#Container Platforms

Docker Swarm

[Docker Swarm] (https://docs.docker.com/swarm/) is a clustered container manager. Instructions are here

Marathon

[Marathon] (https://mesosphere.github.io/marathon/) is a PAAS framework that can run containerized workloads. Instructions are here

Kubernetes

[Kubernetes] (https://kubernetes.io/) is an open source orchestration system for Docker containers. It . Instructions are here

Consul-template

[consul-template] (https://github.com/hashicorp/consul-template) provides a convenient way to populate values from Consul. Instructions are here