Automatically adjust Elastic Agent hostPath permissions #6599
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -13,8 +13,6 @@ spec: | |
| serviceAccountName: elastic-agent | ||
| containers: | ||
| - name: agent | ||
| env: | ||
| - name: NODE_NAME | ||
| valueFrom: | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
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@@ -14,8 +14,6 @@ spec: | |
| spec: | ||
| containers: | ||
| - name: agent | ||
| volumeMounts: | ||
| - mountPath: /var/log | ||
| name: varlog | ||
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| Original file line number | Diff line number | Diff line change |
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@@ -11,8 +11,6 @@ spec: | |
| spec: | ||
| containers: | ||
| - name: agent | ||
| config: | ||
| id: 488e0b80-3634-11eb-8208-57893829af4e | ||
| revision: 2 | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,153 @@ | ||
| // Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one | ||
| // or more contributor license agreements. Licensed under the Elastic License 2.0; | ||
| // you may not use this file except in compliance with the Elastic License 2.0. | ||
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| package agent | ||
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| import ( | ||
| corev1 "k8s.io/api/core/v1" | ||
| "k8s.io/apimachinery/pkg/api/resource" | ||
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| "github.com/blang/semver/v4" | ||
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| agentv1alpha1 "github.com/elastic/cloud-on-k8s/v2/pkg/apis/agent/v1alpha1" | ||
| container "github.com/elastic/cloud-on-k8s/v2/pkg/controller/common/container" | ||
| "github.com/elastic/cloud-on-k8s/v2/pkg/controller/common/version" | ||
| "github.com/elastic/cloud-on-k8s/v2/pkg/utils/pointer" | ||
| ) | ||
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| const ( | ||
| hostPathVolumeInitContainerName = "permissions" | ||
| ) | ||
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| var ( | ||
| hostPathVolumeInitContainerResources = corev1.ResourceRequirements{ | ||
| Requests: map[corev1.ResourceName]resource.Quantity{ | ||
| corev1.ResourceMemory: resource.MustParse("128Mi"), | ||
| corev1.ResourceCPU: resource.MustParse("100m"), | ||
| }, | ||
| Limits: map[corev1.ResourceName]resource.Quantity{ | ||
| corev1.ResourceMemory: resource.MustParse("128Mi"), | ||
| corev1.ResourceCPU: resource.MustParse("100m"), | ||
| }, | ||
| } | ||
| ) | ||
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| // maybeAgentInitContainerForHostpathVolume will return an init container that ensures that the host | ||
| // volume's permissions are sufficient for the Agent to maintain state if the Elastic Agent | ||
| // has the following attributes: | ||
| // | ||
| // 1. Agent volume is not set to emptyDir. | ||
| // 2. Agent version is above 7.15. | ||
| // 3. Agent spec is not configured to run as root. | ||
| func maybeAgentInitContainerForHostpathVolume(spec *agentv1alpha1.AgentSpec, v semver.Version) (initContainers []corev1.Container) { | ||
| // Only add initContainer to chown hostpath data volume for Agent > 7.15 | ||
| if !v.GTE(version.MinFor(7, 15, 0)) { | ||
| return nil | ||
| } | ||
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| image := spec.Image | ||
| if image == "" { | ||
| image = container.ImageRepository(container.AgentImage, spec.Version) | ||
| } | ||
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| if !dataVolumeEmptyDir(spec) && !runningAsRoot(spec) { | ||
| initContainers = append(initContainers, corev1.Container{ | ||
| Image: image, | ||
| Command: hostPathVolumeInitContainerCommand(), | ||
| Name: hostPathVolumeInitContainerName, | ||
| SecurityContext: &corev1.SecurityContext{ | ||
| RunAsUser: pointer.Int64(0), | ||
| }, | ||
| Resources: hostPathVolumeInitContainerResources, | ||
| VolumeMounts: []corev1.VolumeMount{ | ||
| { | ||
| Name: DataVolumeName, | ||
| MountPath: DataMountPath, | ||
| }, | ||
| }, | ||
| }) | ||
| } | ||
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| return initContainers | ||
| } | ||
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| // hostPathVolumeInitContainerCommand returns the container command | ||
| // for maintaining permissions for Elastic Agent. | ||
| func hostPathVolumeInitContainerCommand() []string { | ||
| return []string{ | ||
| "/usr/bin/env", | ||
| "bash", | ||
| "-c", | ||
| `#!/usr/bin/env bash | ||
| set -e | ||
| if [[ -d /usr/share/elastic-agent/state ]]; then | ||
| chmod g+rw /usr/share/elastic-agent/state | ||
| chgrp 1000 /usr/share/elastic-agent/state | ||
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| if [ -n "$(ls -A /usr/share/elastic-agent/state 2>/dev/null)" ]; then | ||
| chgrp 1000 /usr/share/elastic-agent/state/* | ||
| chmod g+rw /usr/share/elastic-agent/state/* | ||
| fi | ||
| fi | ||
| `} | ||
| } | ||
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| // runningAsRoot will return true if either the Daemonset or Deployment for | ||
| // Elastic Agent has a security context set where the container will run as root. | ||
| func runningAsRoot(spec *agentv1alpha1.AgentSpec) bool { | ||
| if spec.DaemonSet != nil { | ||
| templateSpec := spec.DaemonSet.PodTemplate.Spec | ||
| if templateSpec.SecurityContext != nil && | ||
| templateSpec.SecurityContext.RunAsUser != nil && *templateSpec.SecurityContext.RunAsUser == 0 { | ||
| return true | ||
| } | ||
| return containerRunningAsUser0(templateSpec) | ||
| } | ||
| if spec.Deployment != nil { | ||
| templateSpec := spec.Deployment.PodTemplate.Spec | ||
| if templateSpec.SecurityContext != nil && | ||
| templateSpec.SecurityContext.RunAsUser != nil && *templateSpec.SecurityContext.RunAsUser == 0 { | ||
| return true | ||
| } | ||
| return containerRunningAsUser0(templateSpec) | ||
| } | ||
| return false | ||
| } | ||
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| // containerRunningAsUser0 will return true if the Agent container | ||
| // has its pod security context set to run as root. | ||
| func containerRunningAsUser0(spec corev1.PodSpec) bool { | ||
| for _, container := range spec.Containers { | ||
| if container.Name == "agent" { | ||
| if container.SecurityContext == nil { | ||
| return false | ||
| } | ||
| if container.SecurityContext.RunAsUser != nil && *container.SecurityContext.RunAsUser == 0 { | ||
| return true | ||
| } | ||
| return false | ||
| } | ||
| } | ||
| return false | ||
| } | ||
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| // dataVolumeEmptyDir will return true if either the Daemonset or Deployment for | ||
| // Elastic Agent has it's Agent volume configured for EmptyDir. | ||
| func dataVolumeEmptyDir(spec *agentv1alpha1.AgentSpec) bool { | ||
| if spec.DaemonSet != nil { | ||
| return volumeIsEmptyDir(spec.DaemonSet.PodTemplate.Spec.Volumes) | ||
| } | ||
| if spec.Deployment != nil { | ||
| return volumeIsEmptyDir(spec.Deployment.PodTemplate.Spec.Volumes) | ||
| } | ||
| return false | ||
| } | ||
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| func volumeIsEmptyDir(vols []corev1.Volume) bool { | ||
| for _, vol := range vols { | ||
| if vol.Name == DataVolumeName && vol.VolumeSource.EmptyDir != nil { | ||
| return true | ||
| } | ||
| } | ||
| return false | ||
| } | ||
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I think this is still required for the container's CA bundle to be updated, see:
cloud-on-k8s/pkg/controller/agent/pod.go
Lines 360 to 366 in 379c19a