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/lgtm OSDOCS-10472:nodes peer ANP
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‎_topic_maps/_topic_map.yml

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File: ovn-k-banp
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- Name: Metrics for AdminNetworkPolicy
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File: ovn-k-anp-banp-metrics
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- Name: Northbound Traffic Controls for AdminNetworkPolicy
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File: ovn-k-egress-nodes-networks-peer
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- Name: Network policy
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Dir: network_policy
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Distros: openshift-enterprise, openshift-origin

‎modules/nw-anp-nodes-peer-concept.adoc

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// Module included in the following assemblies:
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//
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// * networking/network_security/AdminNetworkPolicy/ovn-k-egress-nodes-networks-peer.adoc
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:_mod-docs-content-type: CONCEPT
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[id="nw-anp-egress_{context}"]
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= Northbound traffic controls for AdminNetworkPolicy and BaselineAdminNetworkPolicy
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In addition to supporting east-west traffic controls, ANP and BANP also allow administrators to control their northbound traffic leaving the cluster or traffic leaving the node to other nodes in the cluster. End-users can do the following:
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* Implement egress traffic control towards cluster nodes using `nodes` egress peer
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* Implement egress traffic control towards Kubernetes API servers using `nodes` or `networks` egress peers
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* Implement egress traffic control towards external destinations outside the cluster using `networks` peer
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[NOTE]
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====
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For ANP and BANP, `nodes` and `networks` peers can be specified for egress rules only.
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====
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[id="egress-traffic-control-towards-cluster-nodes_{context}"]
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== Using nodes peer to control egress traffic to cluster nodes
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Using the `nodes` peer administrators can control egress traffic from pods to nodes in the cluster. A benefit of this is that you do not have to change the policy when nodes are added to or deleted from the cluster.
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The following example allows egress traffic to the Kubernetes API server on port `6443` by any of the namespaces with a `restricted`, `confidential`, or `internal` level of security using the node selector peer. It also denies traffic to all worker nodes in your cluster from any of the namespaces with a `restricted`, `confidential`, or `internal` level of security.
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.Example of ANP `Allow` egress using `nodes` peer
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[%collapsible]
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====
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[source,yaml]
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----
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apiVersion: policy.networking.k8s.io/v1alpha1
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kind: AdminNetworkPolicy
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metadata:
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name: egress-security-allow
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spec:
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egress:
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- action: Deny
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to:
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- nodes:
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matchExpressions:
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- key: node-role.kubernetes.io/worker
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operator: Exists
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- action: Allow
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name: allow-to-kubernetes-api-server-and-engr-dept-pods
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ports:
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- portNumber:
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port: 6443
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protocol: TCP
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to:
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- nodes: <1>
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matchExpressions:
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- key: node-role.kubernetes.io/control-plane
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operator: Exists
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- pods: <2>
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namespaceSelector:
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matchLabels:
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dept: engr
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podSelector: {}
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priority: 55
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subject: <3>
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namespaces:
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matchExpressions:
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- key: security <4>
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operator: In
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values:
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- restricted
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- confidential
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- internal
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----
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<1> Specifies a node or set of nodes in the cluster using the `matchExpressions` field.
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<2> Specifies all the pods labeled with `dept: engr`.
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<3> Specifies the subject of the ANP which includes any namespaces that match the labels used by the network policy. The example matches any of the namespaces with `restricted`, `confidential`, or `internal` level of `security`.
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<4> Specifies key/value pairs for `matchExpressions` field.
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====
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[id="egress-traffic-control-networks-peer-external-destinations_{context}"]
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== Using networks peer to control egress traffic towards external destinations
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Cluster administrators can use CIDR ranges in `networks` peer and apply a policy to control egress traffic leaving from pods and going to a destination configured at the IP address that is within the CIDR range specified with `networks` field.
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The following example uses `networks` peer and combines ANP and BANP policies to restrict egress traffic.
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[IMPORTANT]
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====
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Use the empty selector ({}) in the `namespace` field for ANP and BANP with caution. When using an empty selector, it also selects OpenShift namespaces.
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If you use values of `0.0.0.0/0` in a ANP or BANP `Deny` rule, you must set a higher priority ANP `Allow` rule to necessary destinations before setting the `Deny` to `0.0.0.0/0`.
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====
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.Example of ANP and BANP using `networks` peers
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[%collapsible]
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====
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[source,yaml]
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----
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apiVersion: policy.networking.k8s.io/v1alpha1
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kind: AdminNetworkPolicy
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metadata:
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name: network-as-egress-peer
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spec:
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priority: 70
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subject:
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namespaces: {} # Use the empty selector with caution because it also selects OpenShift namespaces as well.
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egress:
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- name: "deny-egress-to-external-dns-servers"
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action: "Deny"
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to:
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- networks:<1>
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- 8.8.8.8/32
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- 8.8.4.4/32
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- 208.67.222.222/32
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ports:
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- portNumber:
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protocol: UDP
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port: 53
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- name: "allow-all-egress-to-intranet"
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action: "Allow"
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to:
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- networks: <2>
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- 89.246.180.0/22
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- 60.45.72.0/22
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- name: "allow-all-intra-cluster-traffic"
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action: "Allow"
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to:
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- namespaces: {} # Use the empty selector with caution because it also selects OpenShift namespaces as well.
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- name: "pass-all-egress-to-internet"
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action: "Pass"
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to:
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- networks:
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- 0.0.0.0/0 <3>
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---
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apiVersion: policy.networking.k8s.io/v1alpha1
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kind: BaselineAdminNetworkPolicy
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metadata:
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name: default
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spec:
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subject:
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namespaces: {} # Use the empty selector with caution because it also selects OpenShift namespaces as well.
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egress:
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- name: "deny-all-egress-to-internet"
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action: "Deny"
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to:
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- networks:
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- 0.0.0.0/0 <3>
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---
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----
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<1> Use `networks` to specify a range of CIDR networks outside of the cluster.
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<2> Specifies the CIDR ranges for the intra-cluster traffic from your resources.
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<3> Specifies a `Deny` egress to everything by setting `networks` values to `0.0.0.0/0`. Make sure you have a higher priority `Allow` rule to necessary destinations before setting a `Deny` to `0.0.0.0/0` because this will deny all traffic including to Kubernetes API and DNS servers.
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====
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Collectively the `network-as-egress-peer` ANP and `default` BANP using `networks` peers enforces the following egress policy:
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* All pods cannot talk to external DNS servers at the listed IP addresses.
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* All pods can talk to rest of the company's intranet.
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* All pods can talk to other pods, nodes, and services.
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* All pods cannot talk to the internet. Combining the last ANP `Pass` rule and the strong BANP `Deny` rule a guardrail policy is created that secures traffic in the cluster.
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[id="combined-nodes-peer-networks-peer-anp"]
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== Using nodes peer and networks peer together
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Cluster administrators can combine `nodes` and `networks` peer in your ANP and BANP policies.
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.Example of `nodes` and `networks` peer
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[%collapsible]
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====
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[source,yaml]
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----
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apiVersion: policy.networking.k8s.io/v1alpha1
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kind: AdminNetworkPolicy
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metadata:
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name: egress-peer-1 <1>
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spec:
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egress: <2>
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- action: "Allow"
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name: "allow-egress"
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to:
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- nodes:
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matchExpressions:
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- key: worker-group
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operator: In
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values:
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- workloads # Egress traffic from nodes with label worker-group: workloads is allowed.
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- networks:
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- 104.154.164.170/32
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- pods:
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namespaceSelector:
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matchLabels:
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apps: external-apps
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podSelector:
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matchLabels:
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app: web # This rule in the policy allows the traffic directed to pods labeled apps: web in projects with apps: external-apps to leave the cluster.
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- action: "Deny"
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name: "deny-egress"
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to:
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- nodes:
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matchExpressions:
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- key: worker-group
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operator: In
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values:
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- infra # Egress traffic from nodes with label worker-group: infra is denied.
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- networks:
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- 104.154.164.160/32 # Egress traffic to this IP address from cluster is denied.
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- pods:
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namespaceSelector:
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matchLabels:
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apps: internal-apps
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podSelector: {}
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- action: "Pass"
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name: "pass-egress"
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to:
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- nodes:
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matchExpressions:
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- key: node-role.kubernetes.io/worker
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operator: Exists # All other egress traffic is passed to NetworkPolicy or BANP for evaluation.
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priority: 30 <3>
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subject: <4>
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namespaces:
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matchLabels:
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apps: all-apps
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----
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<1> Specifies the name of the policy.
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<2> For `nodes` and `networks` peers, you can only use northbound traffic controls in ANP as `egress`.
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<3> Specifies the priority of the ANP, determining the order in which they should be evaluated. Lower priority rules have higher precedence. ANP accepts values of 0-99 with 0 being the highest priority and 99 being the lowest.
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<4> Specifies the set of pods in the cluster on which the rules of the policy are to be applied. In the example, any pods with the `apps: all-apps` label across all namespaces are the `subject` of the policy.
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====

‎modules/nw-banp-audit-logging-concept.adoc

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- name: "default-deny-dns" # This rule denies all ingress from all pods to workloads.
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action: "Deny"
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from:
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- namespaces: {}
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- namespaces: {} # Use the empty selector with caution because it also selects OpenShift namespaces as well.
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egress:
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- name: "default-deny-dns" # This rule denies all egress from workloads. It will be applied when no ANP or network policy matches.
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action: "Deny"
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to:
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- namespaces: {}
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- namespaces: {} # Use the empty selector with caution because it also selects OpenShift namespaces as well.
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----
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====
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‎modules/nw-ovn-k-adminnetwork-policy-action-rules.adoc

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spec:
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priority: 9
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subject:
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namespaces: {}
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namespaces: {} # Use the empty selector with caution because it also selects OpenShift namespaces as well.
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ingress:
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- name: "allow-ingress-from-monitoring"
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action: "Allow"

‎networking/network_security/AdminNetworkPolicy/ovn-k-egress-nodes-networks-peer.adoc

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:_mod-docs-content-type: ASSEMBLY
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[id="ovn-k-egress-nodes-networks-peer"]
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= Egress nodes and networks peer for AdminNetworkPolicy
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include::_attributes/common-attributes.adoc[]
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:context: ovn-k-egress-nodes-networks-peer
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toc::[]
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This section explains `nodes` and `networks` peers. Administrators can use the examples in this section to design `AdminNetworkPolicy` and `BaselineAdminNetworkPolicy` to control northbound traffic in their cluster.
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include::modules/nw-anp-nodes-peer-concept.adoc[leveloffset=+1]

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