文章目录
- 1. 介绍
- 2. Install OPA
- 3. Deny All Policy
- 3. Enforce Namespace Labels
- 4. Enforce Deployment replica count
- 5. The Rego 练习
- 在这里插入图片描述 [rego playgroud](https://play.openpolicyagent.org/) 
1. 介绍
2. Install OPA
root@master:~/cks/opa# k create -f gatekeeper.yaml
namespace/gatekeeper-system created
Warning: apiextensions.k8s.io/v1beta1 CustomResourceDefinition is deprecated in v1.16+, unavailable in v1.22+; use apiextensions.k8s.io/v1 CustomResourceDefinition
customresourcedefinition.apiextensions.k8s.io/configs.config.gatekeeper.sh created
customresourcedefinition.apiextensions.k8s.io/constraintpodstatuses.status.gatekeeper.sh created
customresourcedefinition.apiextensions.k8s.io/constrainttemplatepodstatuses.status.gatekeeper.sh created
customresourcedefinition.apiextensions.k8s.io/constrainttemplates.templates.gatekeeper.sh created
serviceaccount/gatekeeper-admin created
role.rbac.authorization.k8s.io/gatekeeper-manager-role created
clusterrole.rbac.authorization.k8s.io/gatekeeper-manager-role created
rolebinding.rbac.authorization.k8s.io/gatekeeper-manager-rolebinding created
clusterrolebinding.rbac.authorization.k8s.io/gatekeeper-manager-rolebinding created
secret/gatekeeper-webhook-server-cert created
service/gatekeeper-webhook-service created
deployment.apps/gatekeeper-audit created
deployment.apps/gatekeeper-controller-manager created
Warning: admissionregistration.k8s.io/v1beta1 ValidatingWebhookConfiguration is deprecated in v1.16+, unavailable in v1.22+; use admissionregistration.k8s.io/v1 ValidatingWebhookConfiguration
validatingwebhookconfiguration.admissionregistration.k8s.io/gatekeeper-validating-webhook-configuration created
root@master:~/cks/opa# k get ns
NAME STATUS AGE
default Active 2d5h
gatekeeper-system Active 48s
kube-node-lease Active 2d5h
kube-public Active 2d5h
kube-system Active 2d5h
root@master:~/cks/opa# k get pod,svc -n gatekeeper-system
NAME READY STATUS RESTARTS AGE
pod/gatekeeper-audit-65f658df68-jql6v 1/1 Running 0 74s
pod/gatekeeper-controller-manager-5fb6c9ff69-srvg7 1/1 Running 0 39m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/gatekeeper-webhook-service ClusterIP 10.98.47.59443/TCP 39m
参考链接：
Dynamic Admission Control
3. Deny All Policy
任务
root@master:~/cks/opa# k get crd
NAME CREATED AT
bgpconfigurations.crd.projectcalico.org 2021-05-14T08:50:42Z
bgppeers.crd.projectcalico.org 2021-05-14T08:50:42Z
blockaffinities.crd.projectcalico.org 2021-05-14T08:50:42Z
clusterinformations.crd.projectcalico.org 2021-05-14T08:50:42Z
configs.config.gatekeeper.sh 2021-05-16T14:33:44Z
constraintpodstatuses.status.gatekeeper.sh 2021-05-16T14:33:44Z
constrainttemplatepodstatuses.status.gatekeeper.sh 2021-05-16T14:33:44Z
constrainttemplates.templates.gatekeeper.sh 2021-05-16T14:33:44Z
felixconfigurations.crd.projectcalico.org 2021-05-14T08:50:42Z
globalnetworkpolicies.crd.projectcalico.org 2021-05-14T08:50:42Z
globalnetworksets.crd.projectcalico.org 2021-05-14T08:50:42Z
hostendpoints.crd.projectcalico.org 2021-05-14T08:50:42Z
ipamblocks.crd.projectcalico.org 2021-05-14T08:50:42Z
ipamconfigs.crd.projectcalico.org 2021-05-14T08:50:42Z
ipamhandles.crd.projectcalico.org 2021-05-14T08:50:42Z
ippools.crd.projectcalico.org 2021-05-14T08:50:42Z
kubecontrollersconfigurations.crd.projectcalico.org 2021-05-14T08:50:42Z
networkpolicies.crd.projectcalico.org 2021-05-14T08:50:43Z
networksets.crd.projectcalico.org 2021-05-14T08:50:43Z
root@master:~/cks/opa# k get constrainttemplates
No resources found
root@master:~/cks/opa# vim template.yaml
apiVersion: templates.gatekeeper.sh/v1beta1
kind: ConstraintTemplate
metadata:
name: k8salwaysdeny
spec:
crd:
spec:
names:
kind: K8sAlwaysDeny
validation:
# Schema for the `parameters` field
openAPIV3Schema:
properties:
message:
type: string
targets:
- target: admission.k8s.gatekeeper.sh
rego: |
package k8salwaysdeny
violation[{"msg": msg}] {
1 > 0
msg := input.parameters.message
}
root@master:~/cks/opa# k create -f template.yaml
constrainttemplate.templates.gatekeeper.sh/k8salwaysdeny created
root@master:~/cks/opa# k get k8salwaysdeny
No resources found
root@master:~/cks/opa# k get constrainttemplates
NAME AGE
k8salwaysdeny 90s
root@master:~/cks/opa# vim constraint.yaml
apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sAlwaysDeny
metadata:
name: pod-always-deny
spec:
match:
kinds:
- apiGroups: [""]
kinds: ["Pod"]
parameters:
message: "ACCESS DENIED!"
root@master:~/cks/opa# k get k8sAlwaysDeny
NAME AGE
pod-always-deny 19s
root@master:~/cks/opa# k run pod --image=nginx
Error from server ([denied by pod-always-deny] ACCESS DENIED!): admission webhook "validation.gatekeeper.sh" denied the request: [denied by pod-always-deny] ACCESS DENIED!
root@master:~/cks/opa# vim constraint.yaml
apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sAlwaysDeny
metadata:
name: pod-always-deny
spec:
match:
kinds:
- apiGroups: [""]
kinds: ["Pod"]
parameters:
message: "NO WAY!" #修改此行
root@master:~/cks/opa# k -f constraint.yaml replace
k8salwaysdeny.constraints.gatekeeper.sh/pod-always-deny replaced
root@master:~/cks/opa# k run pod --image=nginx
Error from server ([denied by pod-always-deny] NO WAY!): admission webhook "validation.gatekeeper.sh" denied the request: [denied by pod-always-deny] NO WAY!
root@master:~/cks/opa# k describe k8sAlwaysDeny pod-always-deny
Name: pod-always-deny
Namespace:
Labels: <none>
Annotations: <none>
API Version: constraints.gatekeeper.sh/v1beta1
Kind: K8sAlwaysDeny
Metadata:
Creation Timestamp: 2021-05-20T06:10:39Z
Generation: 2
Managed Fields:
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:spec:
.:
f:match:
.:
f:kinds:
f:parameters:
.:
f:message:
Manager: kubectl-create
Operation: Update
Time: 2021-05-20T06:10:39Z
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:spec:
f:parameters:
f:message:
Manager: kubectl-replace
Operation: Update
Time: 2021-05-20T06:14:29Z
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:status:
f:auditTimestamp:
f:byPod:
f:violations:
Manager: gatekeeper
Operation: Update
Time: 2021-05-20T06:15:24Z
Resource Version: 80590
UID: 064073ac-19fd-4eaa-96d3-d97a640c4f57
Spec:
Match:
Kinds:
API Groups:
Kinds:
Pod
Parameters:
Message: NO WAY!
Status:
Audit Timestamp: 2021-05-20T06:18:31Z
By Pod:
Constraint UID: 064073ac-19fd-4eaa-96d3-d97a640c4f57
Enforced: true
Id: gatekeeper-audit-65f658df68-jql6v
Observed Generation: 2
Operations:
audit
status
Constraint UID: 064073ac-19fd-4eaa-96d3-d97a640c4f57
Enforced: true
Id: gatekeeper-controller-manager-5fb6c9ff69-srvg7
Observed Generation: 2
Operations:
webhook
Total Violations: 16
Violations:
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: app
Namespace: default
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: gatekeeper-audit-65f658df68-jql6v
Namespace: gatekeeper-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: gatekeeper-controller-manager-5fb6c9ff69-srvg7
Namespace: gatekeeper-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: calico-kube-controllers-57fc9c76cc-t45js
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: calico-node-jkfm9
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: calico-node-lrkbp
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: calico-node-pdwqm
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: coredns-74ff55c5b-gmfsj
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: coredns-74ff55c5b-s6lt8
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: etcd-master
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: kube-apiserver-master
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: kube-controller-manager-master
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: kube-proxy-6m8q6
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: kube-proxy-8vprs
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: kube-proxy-b6r2s
Namespace: kube-system
Enforcement Action: deny
Kind: Pod
Message: NO WAY!
Name: kube-scheduler-master
Namespace: kube-system
Events: <none>
root@master:~/cks/opa# cat template.yaml
apiVersion: templates.gatekeeper.sh/v1beta1
kind: ConstraintTemplate
metadata:
name: k8salwaysdeny
spec:
crd:
spec:
names:
kind: K8sAlwaysDeny
validation:
# Schema for the `parameters` field
openAPIV3Schema:
properties:
message:
type: string
targets:
- target: admission.k8s.gatekeeper.sh
rego: |
package k8salwaysdeny
violation[{"msg": msg}] {
1 > 0
1 > 2 #添加此行
msg := input.parameters.message
}
root@master:~/cks/opa# k -f template.yaml replace
constrainttemplate.templates.gatekeeper.sh/k8salwaysdeny replaced
root@master:~/cks/opa# k run pod --image=nginx
pod/pod created
root@master:~/cks/opa# k describe k8sAlwaysDeny pod-always-deny
Name: pod-always-deny
Namespace:
Labels: <none>
Annotations: <none>
API Version: constraints.gatekeeper.sh/v1beta1
Kind: K8sAlwaysDeny
Metadata:
Creation Timestamp: 2021-05-20T06:10:39Z
Generation: 2
Managed Fields:
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:spec:
.:
f:match:
.:
f:kinds:
f:parameters:
.:
f:message:
Manager: kubectl-create
Operation: Update
Time: 2021-05-20T06:10:39Z
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:spec:
f:parameters:
f:message:
Manager: kubectl-replace
Operation: Update
Time: 2021-05-20T06:14:29Z
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:status:
f:auditTimestamp:
f:byPod:
f:totalViolations:
Manager: gatekeeper
Operation: Update
Time: 2021-05-20T06:21:42Z
Resource Version: 80871
UID: 064073ac-19fd-4eaa-96d3-d97a640c4f57
Spec:
Match:
Kinds:
API Groups:
Kinds:
Pod
Parameters:
Message: NO WAY!
Status:
Audit Timestamp: 2021-05-20T06:21:40Z
By Pod:
Constraint UID: 064073ac-19fd-4eaa-96d3-d97a640c4f57
Enforced: true
Id: gatekeeper-audit-65f658df68-jql6v
Observed Generation: 2
Operations:
audit
status
Constraint UID: 064073ac-19fd-4eaa-96d3-d97a640c4f57
Enforced: true
Id: gatekeeper-controller-manager-5fb6c9ff69-srvg7
Observed Generation: 2
Operations:
webhook
Total Violations: 0
Events: <none>
3. Enforce Namespace Labels
root@master:~/cks/opa# vim template_label.yaml
apiVersion: templates.gatekeeper.sh/v1beta1
kind: ConstraintTemplate
metadata:
name: k8srequiredlabels
spec:
crd:
spec:
names:
kind: K8sRequiredLabels
validation:
# Schema for the `parameters` field
openAPIV3Schema:
properties:
labels:
type: array
items: string
targets:
- target: admission.k8s.gatekeeper.sh
rego: |
package k8srequiredlabels
violation[{"msg": msg, "details": {"missing_labels": missing}}] {
provided := {label | input.review.object.metadata.labels[label]}
required := {label | label := input.parameters.labels[_]}
missing := required - provided
count(missing) > 0
msg := sprintf("you must provide labels: %v", [missing])
}
root@master:~/cks/opa# k -f template_label.yaml create
constrainttemplate.templates.gatekeeper.sh/k8srequiredlabels created
root@master:~/cks/opa# vim all_ns_must_have_cks.yaml
apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sRequiredLabels
metadata:
name: ns-must-have-cks
spec:
match:
kinds:
- apiGroups: [""]
kinds: ["Namespace"]
parameters:
labels: ["cks"]
root@master:~/cks/opa# k -f all_ns_must_have_cks.yaml create
k8srequiredlabels.constraints.gatekeeper.sh/ns-must-have-cks created
root@master:~/cks/opa# k get K8sRequiredLabels
NAME AGE
ns-must-have-cks 2m39s
root@master:~/cks/opa# k describe K8sRequiredLabels ns-must-have-cks
Name: ns-must-have-cks
Namespace:
Labels: <none>
Annotations: <none>
API Version: constraints.gatekeeper.sh/v1beta1
Kind: K8sRequiredLabels
Metadata:
Creation Timestamp: 2021-05-20T06:42:27Z
Generation: 1
Managed Fields:
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:spec:
.:
f:match:
.:
f:kinds:
f:parameters:
.:
f:labels:
Manager: kubectl-create
Operation: Update
Time: 2021-05-20T06:42:27Z
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:auditTimestamp:
f:byPod:
f:totalViolations:
f:violations:
Manager: gatekeeper
Operation: Update
Time: 2021-05-20T06:42:38Z
Resource Version: 85857
UID: 4938d3e2-b926-4e60-ade6-ab957c92a8c2
Spec:
Match:
Kinds:
API Groups:
Kinds:
Namespace
Parameters:
Labels:
cks
Status:
Audit Timestamp: 2021-05-20T07:20:11Z
By Pod:
Constraint UID: 4938d3e2-b926-4e60-ade6-ab957c92a8c2
Enforced: true
Id: gatekeeper-audit-65f658df68-jql6v
Observed Generation: 1
Operations:
audit
status
Constraint UID: 4938d3e2-b926-4e60-ade6-ab957c92a8c2
Enforced: true
Id: gatekeeper-controller-manager-5fb6c9ff69-srvg7
Observed Generation: 1
Operations:
webhook
Total Violations: 5
Violations:
Enforcement Action: deny
Kind: Namespace
Message: you must provide labels: {"cks"}
Name: default
Enforcement Action: deny
Kind: Namespace
Message: you must provide labels: {"cks"}
Name: gatekeeper-system
Enforcement Action: deny
Kind: Namespace
Message: you must provide labels: {"cks"}
Name: kube-node-lease
Enforcement Action: deny
Kind: Namespace
Message: you must provide labels: {"cks"}
Name: kube-public
Enforcement Action: deny
Kind: Namespace
Message: you must provide labels: {"cks"}
Name: kube-system
Events: <none>
root@master:~/cks/opa# k edit ns default
apiVersion: v1
kind: Namespace
metadata:
creationTimestamp: "2021-05-14T08:37:43Z"
labels: # 添加此行
cks: amazing # 添加此行
name: default
resourceVersion: "86550"
uid: 773025bb-2f60-40f9-a10d-924c21e45016
spec:
finalizers:
- kubernetes
status:
phase: Active
root@master:~/cks/opa# k describe K8sRequiredLabels ns-must-have-cks
......................
Total Violations: 4
......................
root@master:~/cks/opa# k create ns test
Error from server ([denied by ns-must-have-cks] you must provide labels: {"cks"}): admission webhook "validation.gatekeeper.sh" denied the request: [denied by ns-must-have-cks] you must provide labels: {"cks"}
root@master:~/cks/opa# vim all_ns_must_have_cks.yaml
apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sRequiredLabels
metadata:
name: ns-must-have-cks
spec:
match:
kinds:
- apiGroups: [""]
kinds: ["Namespace"]
parameters:
labels: ["cks","team"] #修改此行
root@master:~/cks/opa# k -f all_ns_must_have_cks.yaml replace
k8srequiredlabels.constraints.gatekeeper.sh/ns-must-have-cks replaced
root@master:~/cks/opa# k create ns test
Error from server ([denied by ns-must-have-cks] you must provide labels: {"cks", "team"}): admission webhook "validation.gatekeeper.sh" denied the request: [denied by ns-must-have-cks] you must provide labels: {"cks", "team"}
root@master:~/cks/opa# k create ns test -o yaml --dry-run=client
apiVersion: v1
kind: Namespace
metadata:
creationTimestamp: null
name: test
spec: {}
status: {}
root@master:~/cks/opa# k create ns test -o yaml --dry-run=client > ns.yaml
oot@master:~/cks/opa# vim ns.yaml
apiVersion: v1
kind: Namespace
metadata:
creationTimestamp: null
name: test
labels: #添加此行
cks: amazing #添加此行
team: killer-sh #添加此行
spec: {}
status: {}
#创建namespace成功
root@master:~/cks/opa# k create -f ns.yaml
namespace/test created
4. Enforce Deployment replica count
root@master:~/cks/opa# cat template_replicas.yaml
apiVersion: templates.gatekeeper.sh/v1beta1
kind: ConstraintTemplate
metadata:
name: k8sminreplicacount
spec:
crd:
spec:
names:
kind: K8sMinReplicaCount
validation:
# Schema for the `parameters` field
openAPIV3Schema:
properties:
min:
type: integer
targets:
- target: admission.k8s.gatekeeper.sh
rego: |
package k8sminreplicacount
violation[{"msg": msg, "details": {"missing_replicas": missing}}] {
provided := input.review.object.spec.replicas
required := input.parameters.min
missing := required - provided
missing > 0
msg := sprintf("you must provide %v more replicas", [missing])
}
root@master:~/cks/opa# k -f template_replicas.yaml create
constrainttemplate.templates.gatekeeper.sh/k8sminreplicacount created
root@master:~/cks/opa# cat all_deployment_must_have_min_replicacount.yaml
apiVersion: constraints.gatekeeper.sh/v1beta1
kind: K8sMinReplicaCount
metadata:
name: deployment-must-have-min-replicas
spec:
match:
kinds:
- apiGroups: ["apps"]
kinds: ["Deployment"]
parameters:
min: 2
root@master:~/cks/opa# k -f all_deployment_must_have_min_replicacount.yaml create
k8sminreplicacount.constraints.gatekeeper.sh/deployment-must-have-min-replicas created
root@master:~/cks/opa# k get k8sminreplicacount
NAME AGE
deployment-must-have-min-replicas 8s
root@master:~/cks/opa# k describe k8sminreplicacount deployment-must-have-min-replicas
Name: deployment-must-have-min-replicas
Namespace:
Labels: <none>
Annotations: <none>
API Version: constraints.gatekeeper.sh/v1beta1
Kind: K8sMinReplicaCount
Metadata:
Creation Timestamp: 2021-05-20T07:44:35Z
Generation: 1
Managed Fields:
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:spec:
.:
f:match:
.:
f:kinds:
f:parameters:
.:
f:min:
Manager: kubectl-create
Operation: Update
Time: 2021-05-20T07:44:35Z
API Version: constraints.gatekeeper.sh/v1beta1
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:auditTimestamp:
f:byPod:
f:totalViolations:
f:violations:
Manager: gatekeeper
Operation: Update
Time: 2021-05-20T07:45:11Z
Resource Version: 88195
UID: 318fd47c-d885-4cdb-ab87-e827bd7154ae
Spec:
Match:
Kinds:
API Groups:
apps
Kinds:
Deployment
Parameters:
Min: 2
Status:
Audit Timestamp: 2021-05-20T07:47:12Z
By Pod:
Constraint UID: 318fd47c-d885-4cdb-ab87-e827bd7154ae
Enforced: true
Id: gatekeeper-audit-65f658df68-jql6v
Observed Generation: 1
Operations:
audit
status
Constraint UID: 318fd47c-d885-4cdb-ab87-e827bd7154ae
Enforced: true
Id: gatekeeper-controller-manager-5fb6c9ff69-srvg7
Observed Generation: 1
Operations:
webhook
Total Violations: 3
Violations:
Enforcement Action: deny
Kind: Deployment
Message: you must provide 1 more replicas
Name: gatekeeper-audit
Namespace: gatekeeper-system
Enforcement Action: deny
Kind: Deployment
Message: you must provide 1 more replicas
Name: gatekeeper-controller-manager
Namespace: gatekeeper-system
Enforcement Action: deny
Kind: Deployment
Message: you must provide 1 more replicas
Name: calico-kube-controllers
Namespace: kube-system
Events: <none>
#无法创建
root@master:~/cks/opa# k create deploy test --image=nginx
error: failed to create deployment: admission webhook "validation.gatekeeper.sh" denied the request: [denied by deployment-must-have-min-replicas] you must provide 1 more replicas
root@master:~/cks/opa# k create deploy test --image=nginx -oyaml --dry-run=client > deploy.yaml
root@master:~/cks/opa# vim deploy.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: test
name: test
spec:
replicas: 2 #修改为2
selector:
matchLabels:
app: test
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: test
spec:
containers:
- image: nginx
name: nginx
resources: {}
status: {}
#创建成功
root@master:~/cks/opa# k -f deploy.yaml create
deployment.apps/test created
5. The Rego 练习
rego playgroud
