Kubernetes is an open-source container orchestration system designed to run distributed services and applications massively. A K8s cluster or Kubernetes cluster comprises a variety of components that comprise a portion of the Kubernetes control plane or Kubernetes Control Plane or Kubernetes nodes. In recent times, Kubernetes has emerged as the most talked about topic in the DevOps space and is among the top platforms used by developers. Because they are widely utilized to accommodate a variety of use cases and applications, cluster security is now a major issue for many companies. The increasing use of Kubernetes has led to attacks targeting and utilizing various parts of the system. Because Kubernetes isn’t protected from potential threats, like insecure configuration, it is essential to adopt robust measures to increase overall security. It is noteworthy that the Linux Foundation CKA is a sought-after Kubernetes Certification. CKA is a well-known certification that showcases the candidate’s Kubernetes management and administration abilities. Additionally, you will gain an advantage over your peers with no certification, as employers and recruiters are searching for certified experts.
It is essential to ensure that your Kubernetes Control plan and components of nodes are safe, particularly when you use it to meet compliance or for business motives.
In this article, we’ll review some of the crucial steps you can take to secure you and your Kubernetes deployments.
Let’s dive right in.
Basics of the Kubernetes Design
There are three main elements to solid Kubernetes policies for the network. The Kubernetes cluster needs to be:
- Expandable The cluster should be able to be customized and not solely favor one provider.
- Simple to use Create the cluster so that it can be operated with only a few commands.
- Secure The cluster must follow the most recent pod security guidelines and best practices.
Understanding the components of the Kubernetes Cluster and How to secure them
In essence, you could classify Kubernetes clusters in two areas: the control plane and the nodes or computers.
Control planes are accountable for controlling the cluster. Serving as the nerve center of the Kubernetes cluster, The control plane is responsible for managing the state of the cluster and configuration information. Control plane components ensure that your containers are running in sufficient numbers with all the required resources.
But it is susceptible to attack by attackers since it’s not simple to set up. While many companies set up their clusters in the way they want, some holes allow attackers to breach the security of the controller plane.
To ensure Your Kubernetes Control Plane, verify the following parts and ensure that you execute the specified actions.
, etc.
Configuration information and data about the state of the cluster is stored in the database called etcd. It’s a key-value store database, designed to be fault-tolerant and distributed so that it can be the sole source of truth about the cluster. To verify whether the database is secure, enter your command below:
- ps -ef | grep etcd
Then, modify the etcd pod specification file located at /etc/kubernetes/manifests/etcd.yaml
Then, execute using the below command see whether encryption has been disabled:
-encryption-provider-config
kube-controller-manager
The kube-controller-manager is responsible for running the cluster and controlling its functions. It makes sure that the right number of pods are operating continuously. If one of the pods is down the controller notices it and immediately takes the appropriate action.
To check if your kube-controller-manager is configured securely, first run the following command on your master node:
- ps -ef | grep kube-controller-manager
On the output page, review and change these arguments
- Set –use-service-account-credentials argument to true. This, in conjunction with RBAC will ensure that control loops are running by the minimum permissions.
- Set –service-account-private-key-file argument using a separate public/private key pair for signing service account tokens.
- Make sure the file with the –root argument is available. Set the –root-ca-file as a certificate file that contains the root cert, which is the API Server’s serving certificate that allows pods to validate the API Server’s server cert before making a connection.
- Set RotateKubeletServerCertificate to true. Ensure the argument is in place for cubelets that get their certificates from the API Server. API Server and only.
- Set the the –address at 127.0.0.1 and ensure your controller manager isn’t tied to insecure non-loopback addresses.
kube-scheduler
The theKube-schedulertakes responsibility for the health of the cluster. It determines if your cluster requires new containers and supplies these following the requirements, thus ensuring that your pod is able to meet its demands for resources in any time.
To determine if the kube-scheduler is securely configured To verify that it is configured securely, run an following script on the master server:
- ps -ef | grep kube-scheduler
If you see the output of your program, review and change the following arguments whenever required:
- Configure the –profiling for Falseto minimize the surface of attack.
- Set the the –address at 127.0.0.1 to ensure that controller manager isn’t restricted to insecure addresses that are not loopback-safe.
kube-apiserver
The Kube-apiserver serves as the interface to the control plane which handles internal and external requests. The Kube-apiserver is the one that validates requests and then sends them to processing. Try contacting the Kube-apiserver through an external IP and see whether it’s secure. If Kube-apiserverresponds this way, it’s a sign that other machines can perform the same thing unless you’ve restricted access to an API server only to your own IP. To make sure it is secure that your Kube-apiserver isn’t publicly accessible and visible to the public you must restrict the access of your Kubernetes cluster to GKE by adjusting setting the network master settings performing these commands
gcloud container clusters create –enable-master-authorized-networks –master-authorized-networks=CIDR
ps -ef | grep kube-apiserver
How do you set up RBAC within the Kubernetes cluster?
Making sure you configure RBAC correctly can go an enormous way to preventing your cluster safe from compromise. With RBAC you can restrict users and pods to CRUD actions they are able to perform within the cluster. It gives you a more precise overview of the components of the cluster the user or pod can access, as well as limiting the threat surface for your cluster.
You can enable RBAC in your Kubernetes cluster via the kube-apiserver at startup with the flag: -authorization-mode=RBAC
An intruder can easily disable RBAC. To determine whether RBAC has been disabled, try this command:
ps -ef | grep kube-apiserver
Another method to ensure that RBAC is secure is to impersonate users or groups of users manually via personas of the user. Users impersonation lets administrators test and validate an authorization policy through temporarily impersonating the identity of another user. It is also a good practice to record users who are not recognized and track their activities throughout the network.
Securing node components
When the control plane can be regarded as the nerve’s center, the node components constitute the Kubernetes cluster’s muscles. These nodes are accountable for controlling and running all containers, pods, and pods within the cluster. While there’s no requirement to set up worker nodes, it’s recommended to have at minimum one worker running and controlling all containers as well as pods on the same network as the control plane can make things complicated.
The main elements of a node include the runtime engine for containers and the Kubeletand the kube-proxy.
- The engine for running containers is responsible for running containers within your cluster.
- The Kubelet is a small agent responsible for ensuring that your containers and nodes are operating.
- The Kube-proxy helps Kubernetes network services, which handles the network’s communications inside and outside the cluster.
To ensure the security of your node components, look over these components to see what’s in the list below.
Container runtime engine
Every computes node within the Kubernetes cluster is equipped with an engine for running containers. Most Kubernetes applications employ Docker as an engine for running containers but Kubernetes also supports other runtime engines, such as CRI-O and containersd. Configuring your container runtime engine depends on adhering to security best practices as outlined that are imposed by the engine you choose to use. Setting up your engine according to the guidelines provided by your provider will ensure you are ensuring that the Kubernetes containers are secure from attack.
Kubelet
The Kubelet can be described as an agent, which is running on each of the cluster’s nodes and ensures the containers in your cluster are operating. It also has the responsibility of making changes to configuration whenever needed. A kubelet that is not configured correctly is a risk for a misconfigured kubelet.can create a backdoor to hackers to access your cluster.
You can either make use of an kubelet-specific configuration file or use arguments from the executable of the running kubelet in order to set up your Kubelet. You can locate the configuration file for your kubelet by using the following command, and then looking at it. “-config” parameter:
Ps -ef Kubelet
Then, execute an identical command over every node:
Ps -ef Kubelet
The output will verify and alter the following arguments whenever needed:
- Set the –anonymous-auth parameter on the false value to disable requests that are not authenticated.
- Set –rotate-certificates to true. If you’re using a kubelet configuration file, set RotateKubeletServerCertificate to true. If you still need to do this, make sure that your kubelets obtain their certificates from the API Server. API Server.
- Set –tls-cert-file and –tls-private-key-file appropriately. If you’re using Kubelet’s configuration file, then set the tlsCertFile along with TLSPrivateKeyFile so that all connections to the Kubelets occur via TLS.
kube-proxy
Kube-proxy is an internet proxy that is running on every node within your cluster, ensuring the network rules for these nodes. It makes sure that your nodes are able to connect with both external and internal resources in the manner that is required and permitted.
Secure Kube-proxy is a matter of making sure that you are able to ensure that you are able to ensure the security as well as integrity of the Kubeconfig file. To make sure that your Kube-proxy data is safe, first identify the Kubeconfig file used by starting:
Google Kube-proxy
Make sure to use the option –kubeconfig to locate the Kube-proxy configuration file’s location and then execute the following command for each worker node:
stat -c percenta
From the output, verify that permissions are set at 644 or more stringent to help keep the integrity of the file.
Then, execute the following command on each worker node , using exactly the same Kube-proxy configuration file:
stat -c %U:%G
In the output you will see the output, change access rights to root:root to stop unauthorised access to the file.
The Final Words
Maintaining the Kubernetes Control plane and node component safe is now basic. Although configuring every component of your cluster might be daunting, it can help protect your deployments and applications from threats and attacks that could harm your system. Following these recommended configurations, you can dramatically minimize the attack risk and avoid common mistakes.
