Load Balancing in Kubernetes

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As an example, consider an image-processing backend which is running with 3 replicas. This Service definition, for example, maps the my-service Service in the prod namespace to my. Which backend Pod to use is decided based on the SessionAffinity of the Service. Mohsen, Not at the moment.

In Rancher, we wanted to make things easy for users who are just getting familiar with Kubernetes, and who simply want to deploy their first workload and try to balance traffic to it. I would be interested to understand the use case. Given the Load Balancer is external to the cluster, the service has to be of a NodePort type.

Kubernetes service

There are two different types of load balancing kubernetes service loadbalancer Kubernetes. These services generally expose an internal cluster ip and port s that can be referenced internally as an environment variable to each pod. A service can load balance between these containers with a single endpoint. Allowing for container failures and even node failures within the cluster while preserving accessibility of the application. External — Services can also kubernetes service loadbalancer as external load balancers if you wish through a NodePort or LoadBalancer type. NodePort will expose a high level port externally on every node in the cluster. By default somewhere between 30000-32767. When scaling this up to 100 or more nodes, it becomes less than stellar. Its also not great because who hits an application over high level ports like this. So now you need another external load balancer to do the port translation for you. The pods get exposed on a high range external port and the load balancer routes directly to the pods. This bypasses the concept of a service in Kubernetes, still requires high kubernetes service loadbalancer ports to be exposed, allows for no segregation of duties, requires all nodes in the cluster to be externally routable at minimum and will end up causing real issues if you have more than X number of applications to expose where X is the range created for this task. Because services were not the long-term answer for external routing, some contributors came out with Ingress and Ingress Controllers. This in my mind is the future of external load balancing in Kubernetes. So lets take a high level look at what this thing does. Ingress — Collection of rules to reach cluster services. It also listens on its assigned port for external requests. In the diagram above we have an Ingress Controller listening on :443 consisting of an nginx pod. This pod looks at the kubernetes master for newly created Ingresses. It then parses each Ingress and creates a backend for each ingress in nginx. With this combination we get the benefits of a full fledged load balancer, listening on normal ports for traffic that is fully automated. Creating new Ingresses are quite simple. I would use this as a template by which to create your own. Its written in Go but you could quite easily write this in whatever language you want. Its a pretty simple little program. For more information here is the link to at Kubernetes project. Mohsen, Not at the moment. I would be interested to understand the use case. There are a number of possible scenarios which could accomplish this.

This is the default ServiceType. So now you need another external load balancer to do the port translation for you. That means ipvs redirects traffic much faster, and has much better performance when syncing proxy rules. Its also not great because who hits an application over high level ports like this? Because services were not the long-term answer for external routing, some contributors came out with Ingress and Ingress Controllers. To see which policies are available for use, run the awscli command: metadata: name: my-service annotations: service.