The microservices that make up today’s modern infrastructure are almost always launched using containers, and these microservices are used to deploy today’s modern infrastructure. Containers might be used in large numbers by an organization. In order for these containers to be readily deployed and managed, it is necessary for them to have management software, or a management platform.
Kubernetes is a platform that is portable, adaptable, and open source. It is used for managing containerized workloads and services, and it enables declarative setup while also facilitating automation. It has a big ecology that is expanding at a rapid rate. There is a significant amount of availability for Kubernetes services, support, and tools.
In terms of the security provided by Kubernetes, they just implemented a new admissions controller, which will be of great assistance in ensuring that the security measures are carried out in the most effective manner. Kubernetes clusters can have their operations defined and governed with the assistance of admission controllers.
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Admission controllers are a collection of different types of plugins. Usually, they act as the gatekeepers, processing requests received to the Kubernetes API server before the object data is either executed or put into the distributed key-value store. The kubernetes admission controller has the ability to wholly reject, approve, or modify requests, as well as the request objects themselves.
It is quite simple to switch on the admission controller in Kubernetes. It consists of a number of distinct plugins. This plugin ensures that the infrastructure is protected appropriately. It comes pre-installed with some default plugins like ResourceQuota and podsecurity, both of which receive updates on a regular basis.
Tips to Secure the Pods with Admission Controller
There are a lot of different plugins within Kubernetes admission controller, and all of them can be used to protect pods (a bunch of containers) from a wide variety of threats. All these things may be utilized in the process of securing the pods.
Admitting Pod Based on Security Standard
There are essentially three distinct pod policy standards, and they are referred to as privileged, baseline, and restricted respectively. The cumulative effect of these rules might range from being extremely permissive to quite restrictive. This admission controller responds to the creation or change of a pod and decides if it should be admitted depending on the pod security standards.
For example, the restricted policy is targeted at implementing current pod hardening best practices at the expense of some compatibility—such as pods with this security policy will not be allowed for privilege escalation whereas the users inside the containers will not have root privileges. If any pod that is being admitted doesn’t follow the policy then it will not be admitted. Hence, it maintains the security posture of pods.
Enforcing Containers to Always Pull Images
When we talk about containers, we are typically referring to them as having a base image such as Linux or Ubuntu. When you deploy a pod, it is absolutely necessary for all of the containers included within the pod to be operating with the most recent images possible. It is the responsibility of this controller to ensure that the most recent builds of the container images are consistently downloaded.
Though performance takes a hit whenever a node pulls and uses new images, it is essential to run container images that are up to date. This is because utilizing outdated images carries a threat. The packages of dependencies that are being used in that image might be susceptible—that is, they might contain vulnerabilities that, if exploited, can compromise the entire cluster.
Managing Resource Quota
When Kubernetes clusters are being deployed and numerous teams or users are using a cluster with a fixed number of nodes, it is likely that there is a concern that one team could utilize more than its fair share of resources. This is because the number of nodes in the cluster is fixed.
In the event that the allocated amount of resources is depleted, it is possible that the pods or containers will become unavailable. As a result, this admission controller is going to basically keep an eye on all of the requests that are coming in, and it is going to make sure that those requests do not violate any of the restrictions that are listed in the ResourceQuota object that is stored in a Namespace. So if a lot of teams are using the clusters then it is important to impose the ResourceQuota.
Conclusion
As organizations are increasingly reliant on microservices and containers, Kubernetes has become a vital component for any enterprise. Given the large number of clusters and resources that it oversees, it is essential that it has adequate security.
Since there are many plugins that can be configured and simply protect the entire deployment, the admission controller makes this process very simple and straightforward for users. If the clusters are not configured correctly, it is possible that an attacker might take advantage of the vulnerabilities or misconfiguration. Therefore, it is necessary to implement and maintain a high level of security within Kubernetes.
