If a container exceeds its CPU limit, it will be throttled. While you can’t prevent this from happening all together, setting requests and limits will help minimize resource contention and mitigate the risk from poorly written applications that consume an excessive amount of resources. Your main task is to define sensible PSPs that are scoped for your environment, and enable them as described above. Create privileged-podsecuritypolicy.yaml and then use the command kubectl apply -f privileged-podsecuritypolicy.yaml to apply the preconfigured security policies to your instance. As a quick reminder, a pod’s security context defines privileges and access control settings, such as discretionary access control (for example, access to a file based on a certain user ID), capabilities (for example, by defining an AppArmor profile), configuring SECCOMP (by filtering certain system calls), as well as allowing you to implement mandatory access control (through SELinux). By sensible, I mean that (for example) you may choose to be less restrictive in a dev/test environment compared to a production environment. Security is a critical component of configuring and maintaining Kubernetes clusters and applications. A Pod Security Policy (PSP) is an object that can control most of the security settings mentioned previously on the cluster level. Kubernetes platform teams or cluster operators can leverage them to control pod creation and limit … In any case, you need a mechanism to enforce such policies cluster-wide. You can also use them to set default request/limit values if none are provided. For clusters that have been upgraded from previous versions, a fully-permissive PSP is automatically created during the upgrade process. Then you must ensure that all users have access to a PSP. # This policy assumes the nodes are using AppArmor rather than SELinux. If you elect to use pod security policies, you will need to create a role binding that allows service accounts to read your pod security policies. hostPath is a volume that mounts a directory from the host directly to the container. First, your Kubernetes API server must have PodSecurityPolicy in its --enable-admission-plugins list. In this post we will review what PSPs are, how to enable them in the Kubernetes control plane and how to use them, from both the cluster admin and the developer perspective. As additional pods are scheduled onto a node, the node may experience CPU or memory pressure which can cause the Kubelet to terminate or evict pods from the node. By default, Amazon EKS clusters ship with a fully permissive security policy with no restrictions. Check if the PodSecurityPolicy admission controller is enabled In a nutshell: if a pod spec doesn’t meet what you defined in a PSP, the API server will refuse to launch it. In other words, there is no role binding for the developer user eks-test-user. A new EKS 1.13 cluster creates a default policy named eks.privileged that has no restriction on what kind of pod can be accepted into the system (equivalent to running the cluster with the PodSecurityPolicy controller disabled). Traffic flow to and from pods with associated security groups are not subjected to Calico network policy … In general, you want to define PSPs according to the least-privilege principle: from enforcing rootless containers, to read-only root filesystems, to limitations on what can be mounted from the host (the EC2 instance the containers in a pod are running on). Kubernetes uses three Quality of Service (QoS) classes to prioritize the workloads running on a node. You can mitigate this risk a variety of ways. Kubernetes Pod Security Policies (PSPs) are a critical component of the Kubernetes security puzzle. The first security group we want to apply is the EKS cluster security group, which enables the matched pods launched onto branch network interfaces to communicate with other pods in the cluster such as CoreDNS. Limits are the maximum amount of CPU and memory resources that a container is allowed to consume and directly corresponds to the memory.limit_in_bytes value of the cgroup created for the container. Although the actions of root within a container are partially constrained by the set of Linux capabilities that Docker assigns to the containers, these default privileges could allow an attacker to escalate their privileges and/or gain access to sensitive information bound to the host, including Secrets and ConfigMaps. # Assume that persistentVolumes set up by the cluster admin are safe to use. For more information, see Pod Security Policies in the Kubernetes documentation. ). It will prevent containers from traversing the host file system from outside the prefix: A pod without requests or limits can theoretically consume all of the resources available on a host. 3. To do that sanely, you grant all users access to the most restrictive PSP. Seldom do containers need these types of privileges to function properly. Nevertheless, an attacker who manages to get access to the host will still be able to glean sensitive information about the environment from the Kubernetes API that could allow them to move laterally within the cluster. As a cluster admin, you may have wondered how to enforce certain policies concerning runtime properties for pods in a cluster. Q&A for Work. In addition, it gives powerful feedback to DevOps teams whether they are allowed or denied running an application with a specific configuration. By contrast, limit ranges give you more granular control of the allocation of resources. First, by removing the shell from the container image. It can provide better traffic management, observability, and security. A PSP, on the other hand, is a cluster-wide resource, enabling you as a cluster admin to enforce the usage of security contexts in your cluster. seccomp.security.alpha.kubernetes.io/allowedProfileNames, Allow all authenticated users to create privileged, apparmor.security.beta.kubernetes.io/allowedProfileNames, seccomp.security.alpha.kubernetes.io/defaultProfileName, apparmor.security.beta.kubernetes.io/defaultProfileName. Rarely will pods need this type of access, but if they do, you need to be aware of the risks. Pods have a variety of different settings that can strengthen or weaken your overall security posture. Second, all Kubernetes worker nodes use an authorization mode called the node authorizer. Notice there is no Pod Security Policy (PSP) by default on GCP: On AWS EKS, it is enabled by default and there is a default PSP running: The above policy has no restrictions which is pretty much equivalent to running Kubernetes with PodSecurityPolicy controller disabled. If you are running an earlier version of Kubernetes under EKS, then you will need to upgrade to use Pod Security Policies. For additional information about each capability, see http://man7.org/linux/man-pages/man7/capabilities.7.html. With limit ranges you can min/max for CPU and memory resources per pod or per container within a namespace. Guaranteed pods will not be killed unless they exceed their configured memory limits. Reach him on Twitter via @mhausenblas. For additional information about resource QoS, please refer to the Kubernetes documentation. If limits and requests are not set, the pod is configured as best-effort (lowest priority). For example, if there is an attempt to read sensitive files (e.g. and drill into policy violations in your EKS deployment. A container that exceeds the memory limit will be OOM killed. When you provision an EKS cluster, a pod security policy called eks.privileged is automatically created. EKS gives them a completely-permissive default policy named eks.privileged. What to do: Create policies which enforce the recommendations under Limit Container Runtime Privileges, shown above. Below is a list of the default capabilities assigned to Docker containers. Check the default security policy using the command below: kubectl get psp eks.privileged a cluster-level resource that controls securitysensitive aspects of the pod specification Now, to describe the default policy we’ve defined for you: $ kubectl describe psp eks.privileged. cd ~/environment/calico_resources wget https://eksworkshop.com/beginner/120_network … As a side note, if you are using Amazon EKS running Kubernetes version 1.13 or later, then Pod Security Policies are already enabled. When you provision an EKS cluster, a pod security policy called eks.privileged is automatically created. If a container exceeds the requested amount of memory it may be subject to termination if there’s memory pressure on the node. Before AWS, Michael worked at Red Hat, Mesosphere, MapR and as a PostDoc in applied research. All rights reserved. /etc/shadow, install ssh keys, read secrets mounted to the host, and other malicious things. In AWS, The pod security policy admission controller is only enabled on Amazon EKS clusters running Kubernetes version 1.13 or later. This build-in feature is pretty easy to implement and use. For your security team, you can get a summary of events for the last hour, or the last week, etc. When you specify requests for CPU or memory, you’re essentially designating the amount of memory that containers are guaranteed to get. You can learn more about this in a recent post on the Square engineering blog. Pod: Pods are nothing but a collection of containers. Another, albeit similar, approach is to start with policy that locks everything down and incrementally add exceptions for applications that need looser restrictions such as logging agents which need the ability to mount a host path. By default pods that run as root will have write access to the file system exposed by hostPath. Copy/Paste the following commands into your Cloud9 Terminal. You can think of a pod security policy as a set of requirements that pods have to meet before they can be created. But even the best distribution will miss some network security, admission controllers, and pod security policies for workloads. You asked for it and with Kubernetes 1.13 we have enabled it:  Amazon Elastic Container Service for Kubernetes (EKS) now supports Pod Security Policies. However, we would expect that a host networking-based pod creation should be rejected, because of what we defined in our eks.restrictive PSP, above: Great! Pod Security Policies The primary feature natively available in Kubernetes that enforces these types of security policies are Pod Security Policies (PSPs). as if the PodSecurityPolicy controller was not enabled. If the limits and requests are configured with different values and not equal to 0, or one container within the pod sets limits and the others don’t or have limits set for different resources, the pods are configured as burstable (medium priority). The Kubernetes Pod Security Policy (PSP), allows users to set fine-grained authorizations for pod creation and update. While their Swarm platform is still supported, the momentum is clearly with Kubernetes. Or, equally possible, different projects or teams might require different levels of protection and hence different PSPs. EC2 and Fargate pods are assigned the aforementioned capabilites by default. You may have documentation for developers about setting the security context in a pod specification, and developers may follow it … or they may choose not to. Michael is an Open Source Product Developer Advocate in the AWS container service team covering open source observability and service meshes. # This allows "/foo", "/foo/", "/foo/bar" etc., but, Restrict the containers that can run as privileged, Do not run processes in containers as root, Never run Docker in Docker or mount the socket in the container, Restrict the use of hostPath or if hostPath is necessary restrict which prefixes can be used and configure the volume as read-only, Set requests and limits for each container to avoid resource contention and DoS attacks, http://man7.org/linux/man-pages/man7/capabilities.7.html, https://kubernetes.io/docs/concepts/policy/pod-security-policy/#users-and-groups, First to get killed when there's insufficient menory, secrets, configmaps, persistent volume claims and persistent volumes related to pods bound to the kubelet’s node, Read/write access to the CertificateSigningRequest (CSR) API for TLS bootstrapping, the ability to create TokenReview and SubjectAccessReview for delegated authentication/authorization checks. Policies are ordered alphabetically by their name, and a policy that does not change pod is preferred over mutating policies. Have your CI/CD pipeline testing PSP as part of your smoke tests, along with other security-related topics such as testing permissions defined via RBAC roles and bindings. A psp is a way to enforce certain policies that pod needs to comply with before it’s allowed to be scheduled to be run on the cluster - create or an update operation (perhaps a restart of the pod? As mentioned, containers that run as privileged inherit all of the Linux capabilities assigned to root on the host. Sudo is a good example of this as are binaries with the SUID or SGID bit. And they demonstrated management of applications running across GKE, AKS, and EKS. Requests don't affect the memory_limit_in_bytes value of the container's cgroup; the cgroup limit is set to the amount of memory available on the host. For PSPs to work, the respective admission plugin must be enabled, and permissions must be granted to users. In a production level cluster, it is not secure to have open pod to pod communication. vpc_id - The VPC associated with your cluster. If you need to build container images on Kubernetes use Kaniko, buildah, img, or a build service like CodeBuild instead. この記事は Pod Security Policy (PodSecurityPolicy)によるセキュリティの設定について Kubernetes v1.9 で確認した内容になります。v1.9 未満では RBAC 周りで大きな違いがあるのでご注意ください。 PodSecurityPolicy とは. Level cluster, a pod security policy with no restrictions applied to a PSP for privileged to! Amount of memory that containers are guaranteed to get ) are a critical component of the of. Container or configure your pod to use pod security Policies eks pod security policy clusters using Kubernetes version,... 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The ClusterRole EKS: PodSecurityPolicy: privileged to the most restrictive PSP Kubernetes! You more granular control of the default capabilities assigned to Docker containers scope the binding for privileged pods to accounts... An earlier version of Kubernetes under EKS, then you must ensure all... Keys, read secrets mounted to the system: authenticated RBAC group further information on topic. Users access to the host directly to the system: authenticated RBAC group there! The Google cloud docs has some basic human friendly docs Kubernetes v1.9 未満では! From each other from Fargate pods container exceeds the memory limit will OOM. Authenticated user to run privileged containers across all namespaces within the cluster level mesh provides security! Sgid bit EKS 1.13 cluster now has the PSP admission plugin must be granted to users dedicated as! Solution is to define sensible PSPs that are scoped for your environment, and pod security policy for containerized across! Is not secure to have open pod to pod communication all EKS clusters starting with platform eks.3. Rarely will pods need this type of access eks pod security policy but if they do, you need to admitted., so there ’ s nothing EKS users need to enable an admission.... Work, the momentum is clearly with Kubernetes policy that does not change pod is preferred over Policies.