Nowadays, multi-tenancy is a burning issue in the Kubernetes world. It is a tough nut to crack in respect of Kubernetes. A survey conducted regarding it showed that 74% of respondents mentioned separate cluster usage for special teams and projects. The reason behind it is the security isolation challenges coming with multi-tenant Kubernetes clusters. Sit tight; in this post, we will review the conceptions of Kubernetes Multi-Tenancy and multi-tenants and identify the possible challenges that you need to cope with.
What is a Kubernetes Tenancy?
The Kubernetes Tenant indicates a tenant representing a bunch of Kubernetes users having access to a branch of group resources, including compute, networking, storage, and control plane. And, also resource limits and quotas that design tenant boundaries. These boundaries expand to the control plane that allows for the grouping of the resources that were owned by the tenant.
What is multi-tenancy in Kubernetes?
Multi-tenant Kubernetes groups share cluster resources among the tenants. As we described earlier, tenants might be anything from users to distributed teams, applications, customers, or projects. Kubernetes clusters are shared among various customers, and multiple workloads share a cluster’s resources.
There are two types of multi-tenancy in Kubernetes- one is Soft, and the other is Hard multi-tenancy.
Soft multi-tenancy keeps faith in tenants for being fine actors and supposes them to be non-spiteful. It is focused on minimizing accidents and handle the effect if they do.
Hard multi-tenancy presumes tenants to be spiteful, and that’s why recommends no belief between them. Tenant resources are separated, and entrance to others’ resources is prohibited. Clusters are set up to isolate tenant resources and hinder access to other tenant’s resources.
Kubernetes Multi-tenancy Best Practices:
Let’s go over to multi-tenancy best practices in respect of Kubernetes. We will sketch below the best practices for cluster managers who operate multi-tenant Kubernetes clusters:
Categories of Namespaces:
A newbie best practice with regard to Kubernete’s multi-tenancy is categorizing namespaces among groups. Three such namespace groups are mentioned below:
- System namespaces: Only for system pods.
- Service namespaces: Service namespaces are supposed to run applications accessible by services in other namespaces in the clusters.
- Tenant Namespaces: These namespaces need to be rotated to run applications. And, these applications need not be accessible by services from other namespaces.
Kubernetes has been posted on AWS nearly since its beginning. It is well-known as EKS, On AWS. The Amazon Kubernetes service provides a flexible stage for controlling your containers without compelling you to manage the administration infrastructure.
Why Amazon EKS?
Well, there are various advantages if you can configure Kubernetes Multi-tenancy with Amazon EKS. A few of these advantages are described below:
- Being a managed service, Amazon EKS indicates that you need not hire an expert to supervise your infrastructure.
- EKS offers you an available and scalable ingredient to your master nodes. That’s why it becomes easier for the infrastructure manager to give full focus on the cluster.
- EKS also supports Elastic Load Balancer (ELB), making an automatic load distribution and equal processing of the applications.
- You need not install or upgrade any types of plugins with Amazon EKS. You can use all the tools and the plugins without any cost from the Kubernetes community, as it is an authorized conformant.
Problems you might face while building Kubernetes multi-tenant architecture:
Before discussing the challenges for Kubernetes multi-tenant SaaS applications on EKS, we need to understand first what multi-tenancy is. The success of any application depends on its serviceability.
A successful application must serve several users simultaneously. As a result, the application’s processing ability should increase straight with the growing number of operators.
To scale-up, an application quickly, maintaining performance, durability, stability, and data isolation are so essential. This multi-tenant architecture allows simultaneous processing. It also separates the application and data from user-to-user.
So, now, let’s try to figure out the challenges while building a Kubernetes multi-tenant architecture by an easy example:
Suppose in an apartment you have to provide full isolation to the residents living inside. In this case, all the apartments should be isolated from one another. If a person has to go through another person’s apartment to go to the washroom, this type of architectural design sounds nasty, right? In the same way, all the tenants need to be isolated sufficiently.
Similarly, you should, of course, make sure that every person has enough access to the necessary resources in the building while sharing resources. You cannot provide the water in one apartment while the water is turned off in another apartment. It indicates that all the residents must have access to all the resources.
Isolation Layers in EKS:
There are various layers in EKS providing a particular layer of isolation for a Kubernetes multi-tenancy SaaS application. Some layers are mentioned below that you can apply in your design:
- Container: Though a container provides a basic layer of isolation, it doesn’t isolate the network. It also provides an isolation level from the noisy neighbors.
- Pod: These pods are a group of containers. Kubernetes network strategies help this type of micro-partition of containers.
- Node: A node is a physical or virtual machine. The machine includes a group of pods. This node can leverage devoted hardware for the separation of resources.
- Cluster: It is a gathering of nodes as well as a control plane. This cluster is the control layer for the containers. Plus, clusters can provide intense network isolation.
Multi-tenancy best practices:
There are several best practices regarding the application of EKS multi-tenancy. Here, we are going to let you know some best practices for this application:
Enabling RBAC or Role-Based Access Control aids to control Kubernetes APIs for a variety of users. Using this technique, the admins could establish distinct roles for distinct users, such as one role can be for admin, and another one could be for a tenant.
Namespace isolation using Network Policy:
Admins might have the better authority of the networking among pods that are making use of Network Policies. So, by using this method, Tenant namespaces could be isolated with ease.
We have pointed out some of the best thoughts regarding Kubernetes multi-tenancy applications using Amazon EKS. We tried to cover various issues about computing, networking, and storage. It is also essential to mention here that the design’s price or intricacy shouldn’t measure these policies. Depending on the SaaS service, any of the application models discussed above can meet your design needs.
Originally published at https://www.linkedin.com.