Add new check pdb-unhealthy-pod-eviction-policy (#855) (#856)

Author: wissamir

docs/generated/checks.md

@@ -446,6 +446,15 @@ strategyTypeRegex: ^(RollingUpdate|Rolling)$
 **Remediation**: Change the PodDisruptionBudget to have minAvailable set to a number lower than the number of replicas in the related deployment-like objects. Refer to https://kubernetes.io/docs/tasks/run-application/configure-pdb/ for more information.
 
 **Template**: [pdb-min-available](templates.md#no-pod-disruptions-allowed---minavailable)
+## pdb-unhealthy-pod-eviction-policy
+
+**Enabled by default**: Yes
+
+**Description**: Indicates when a PodDisruptionBudget does not explicitly set the unhealthyPodEvictionPolicy field.
+
+**Remediation**: Set unhealthyPodEvictionPolicy to AlwaysAllow. Refer to https://kubernetes.io/docs/tasks/run-application/configure-pdb/#unhealthy-pod-eviction-policy for more information.
+
+**Template**: [pdb-unhealthy-pod-eviction-policy](templates.md#.spec.unhealthypodevictionpolicy-in-pdb-is-set-to-default)
 ## privilege-escalation-container
 
 **Enabled by default**: Yes

docs/generated/templates.md

@@ -564,6 +564,15 @@ KubeLinter supports the following templates:
 **Supported Objects**: PodDisruptionBudget
 
 
+## .spec.unhealthyPodEvictionPolicy in PDB is set to default
+
+**Key**: `pdb-unhealthy-pod-eviction-policy`
+
+**Description**: Flag PodDisruptionBudget objects that do not explicitly set unhealthyPodEvictionPolicy.
+
+**Supported Objects**: PodDisruptionBudget
+
+
 ## Ports
 
 **Key**: `ports`

e2etests/bats-tests.sh

@@ -648,6 +648,20 @@ get_value_from() {
   [[ "${count}" == "3" ]]
 }
 
+@test "pdb-unhealthy-pod-eviction-policy" {
+
+  tmp="tests/checks/pdb-unhealthy-pod-eviction-policy.yaml"
+  cmd="${KUBE_LINTER_BIN} lint --include pdb-unhealthy-pod-eviction-policy --do-not-auto-add-defaults --format json ${tmp}"
+  run ${cmd}
+
+  message1=$(get_value_from "${lines[0]}" '.Reports[0].Object.K8sObject.GroupVersionKind.Kind + ": " + .Reports[0].Diagnostic.Message')
+
+  [[ "${message1}" == "PodDisruptionBudget: unhealthyPodEvictionPolicy is not explicitly set" ]]
+  count=$(get_value_from "${lines[0]}" '.Reports | length')
+  [[ "${count}" == "1" ]]
+
+}
+
 @test "privilege-escalation-container" {
   tmp="tests/checks/privilege-escalation-container.yml"
   cmd="${KUBE_LINTER_BIN} lint --include privilege-escalation-container --do-not-auto-add-defaults --format json ${tmp}"

internal/defaultchecks/default_checks.go

@@ -36,5 +36,6 @@ var (
 		"unsafe-sysctls",
 		"unset-cpu-requirements",
 		"unset-memory-requirements",
+		"pdb-unhealthy-pod-eviction-policy",
 	)
 )

pkg/builtinchecks/yamls/pdb-unhealthy-pod-eviction-policy.yaml

@@ -0,0 +1,7 @@
+name: "pdb-unhealthy-pod-eviction-policy"
+description: "Indicates when a PodDisruptionBudget does not explicitly set the unhealthyPodEvictionPolicy field."
+remediation: "Set unhealthyPodEvictionPolicy to AlwaysAllow. Refer to https://kubernetes.io/docs/tasks/run-application/configure-pdb/#unhealthy-pod-eviction-policy for more information."
+scope:
+  objectKinds:
+    - PodDisruptionBudget
+template: "pdb-unhealthy-pod-eviction-policy"

pkg/templates/all/all.go

@@ -36,6 +36,7 @@ import (
 	_ "golang.stackrox.io/kube-linter/pkg/templates/nonisolatedpod"
 	_ "golang.stackrox.io/kube-linter/pkg/templates/pdbmaxunavailable"
 	_ "golang.stackrox.io/kube-linter/pkg/templates/pdbminavailable"
+	_ "golang.stackrox.io/kube-linter/pkg/templates/pdbunhealthypodevictionpolicy"
 	_ "golang.stackrox.io/kube-linter/pkg/templates/ports"
 	_ "golang.stackrox.io/kube-linter/pkg/templates/privileged"
 	_ "golang.stackrox.io/kube-linter/pkg/templates/privilegedports"

pkg/templates/pdbunhealthypodevictionpolicy/internal/params/gen-params.go

@@ -0,0 +1,5 @@
+package params
+
+// Params represents the params accepted by this template.
+type Params struct {
+}

pkg/templates/pdbunhealthypodevictionpolicy/internal/params/params.go

@@ -0,0 +1,42 @@
+package pdbunhealthypodevictionpolicy
+
+import (
+	"golang.stackrox.io/kube-linter/pkg/check"
+	"golang.stackrox.io/kube-linter/pkg/config"
+	"golang.stackrox.io/kube-linter/pkg/diagnostic"
+	"golang.stackrox.io/kube-linter/pkg/lintcontext"
+	"golang.stackrox.io/kube-linter/pkg/objectkinds"
+	"golang.stackrox.io/kube-linter/pkg/templates"
+	"golang.stackrox.io/kube-linter/pkg/templates/pdbunhealthypodevictionpolicy/internal/params"
+	pdbV1 "k8s.io/api/policy/v1"
+)
+
+const (
+	templateKey = "pdb-unhealthy-pod-eviction-policy"
+)
+
+func init() {
+	templates.Register(check.Template{
+		HumanName:   ".spec.unhealthyPodEvictionPolicy in PDB is set to default",
+		Key:         templateKey,
+		Description: "Flag PodDisruptionBudget objects that do not explicitly set unhealthyPodEvictionPolicy.",
+		SupportedObjectKinds: config.ObjectKindsDesc{
+			ObjectKinds: []string{
+				objectkinds.PodDisruptionBudget},
+		},
+		Parameters:             params.ParamDescs,
+		ParseAndValidateParams: params.ParseAndValidate,
+		Instantiate: params.WrapInstantiateFunc(func(_ params.Params) (check.Func, error) {
+			return func(_ lintcontext.LintContext, object lintcontext.Object) []diagnostic.Diagnostic {
+				pdb, ok := object.K8sObject.(*pdbV1.PodDisruptionBudget)
+				if !ok {
+					return nil
+				}
+				if pdb.Spec.UnhealthyPodEvictionPolicy == nil {
+					return []diagnostic.Diagnostic{{Message: "unhealthyPodEvictionPolicy is not explicitly set"}}
+				}
+				return nil
+			}, nil
+		}),
+	})
+}

pkg/templates/pdbunhealthypodevictionpolicy/template.go

@@ -0,0 +1,60 @@
+package pdbunhealthypodevictionpolicy
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/suite"
+	"golang.stackrox.io/kube-linter/pkg/diagnostic"
+	"golang.stackrox.io/kube-linter/pkg/lintcontext/mocks"
+	"golang.stackrox.io/kube-linter/pkg/templates"
+	"golang.stackrox.io/kube-linter/pkg/templates/pdbunhealthypodevictionpolicy/internal/params"
+	pdbv1 "k8s.io/api/policy/v1"
+)
+
+func TestUnhealthyPodEvictionPolicyPDB(t *testing.T) {
+	suite.Run(t, new(UnhealthyPodEvictionPolicyPDBTestSuite))
+}
+
+type UnhealthyPodEvictionPolicyPDBTestSuite struct {
+	templates.TemplateTestSuite
+
+	ctx *mocks.MockLintContext
+}
+
+func (s *UnhealthyPodEvictionPolicyPDBTestSuite) SetupTest() {
+	s.Init(templateKey)
+	s.ctx = mocks.NewMockContext()
+}
+
+func (s *UnhealthyPodEvictionPolicyPDBTestSuite) TestNoUnhealthyPodEvictionPolicy() {
+	s.ctx.AddMockPodDisruptionBudget(s.T(), "test-pdb-no-unhealthy-pod-eviction-policy")
+	s.ctx.ModifyPodDisruptionBudget(s.T(), "test-pdb-no-unhealthy-pod-eviction-policy", func(pdb *pdbv1.PodDisruptionBudget) {
+		pdb.Spec.UnhealthyPodEvictionPolicy = nil
+	})
+	s.Validate(s.ctx, []templates.TestCase{
+		{
+			Param: params.Params{},
+			Diagnostics: map[string][]diagnostic.Diagnostic{
+				"test-pdb-no-unhealthy-pod-eviction-policy": {{Message: "unhealthyPodEvictionPolicy is not explicitly set"}},
+			},
+			ExpectInstantiationError: false,
+		},
+	})
+}
+
+func (s *UnhealthyPodEvictionPolicyPDBTestSuite) TestUnhealthyPodEvictionPolicyIsSet() {
+	s.ctx.AddMockPodDisruptionBudget(s.T(), "test-pdb-unhealthy-pod-eviction-policy-is-set")
+	s.ctx.ModifyPodDisruptionBudget(s.T(), "test-pdb-unhealthy-pod-eviction-policy-is-set", func(pdb *pdbv1.PodDisruptionBudget) {
+		var policy pdbv1.UnhealthyPodEvictionPolicyType = "AlwaysAllow"
+		pdb.Spec.UnhealthyPodEvictionPolicy = &policy
+	})
+	s.Validate(s.ctx, []templates.TestCase{
+		{
+			Param: params.Params{},
+			Diagnostics: map[string][]diagnostic.Diagnostic{
+				"test-pdb-unhealthy-pod-eviction-policy-is-set": nil,
+			},
+			ExpectInstantiationError: false,
+		},
+	})
+}