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Network Policy with OVNKubernetes

Info

Work in progress not ready yet!

Nice to know / Basics

  1. Based on labeling or annotations
    • project / namespaces seldom have labels :-/
  2. Empty label selector match all
  3. Rules for allowing
    • Ingress -> who can connect to this POD
    • Egress -> where can this POD connect to
  4. Rules
    • traffic is allowed unless a Network Policy selecting the POD
    • traffic is denied if pod is selected in policie but none of them have any rules allowing it
    • = You can only write rules that allow traffic!
    • Scope: Namespace

Tutorial / Demo - OpenShift v4!

Deploy demo environment

demo overview

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oc new-project bouvier
oc new-app quay.io/openshift-examples/simple-http-server:micro --name patty
oc create route edge patty --service=patty
oc new-app quay.io/openshift-examples/simple-http-server:micro --name selma
oc create route edge selma --service=selma

oc new-project simpson
oc new-app quay.io/openshift-examples/simple-http-server:micro --name homer
oc create route edge homer --service=homer

oc new-app quay.io/openshift-examples/simple-http-server:micro --name marge
oc create route edge marge --service=marge

Download some helper scripts

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git clone https://github.com/openshift-examples/network-policies-tests.git
cd network-policies-tests/

Run connection overview

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./run-tmux.sh apps.<cluster_name>.<base_domain>
Clean

Discover the environment

List POD's

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$ oc get pods -o wide -n simpson
NAME                     READY   STATUS    RESTARTS   AGE    IP             NODE       NOMINATED NODE   READINESS GATES
homer-789b78ddf5-89dqp   1/1     Running   0          142m   10.129.0.113   master-0   <none>           <none>
marge-5887b4985f-td9qx   1/1     Running   0          142m   10.130.0.207   master-1   <none>           <none

$ oc get pods -o wide -n bouvier
NAME                     READY   STATUS    RESTARTS   AGE    IP             NODE       NOMINATED NODE   READINESS GATES
patty-7c674bc58c-tvtnc   1/1     Running   0          142m   10.129.0.111   master-0   <none>           <none>
selma-6787cf669f-bnrj5   1/1     Running   0          142m   10.129.0.112   master-0   <none>           <none>

Let's start with the Network Policy demonstration

Every one can connect to each other

Clean

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$ ./OVNKubernetes/dump-net.sh --all case0
Run dump at
master-1;ovs-node-c97cv
master-0;ovs-node-t84dc
master-2;ovs-node-xs2fm
Write: case0.2020-12-29-12-07-39.1609240059.master-1.OpenFlow13.br-ex
Write: case0.2020-12-29-12-07-39.1609240059.master-1.OpenFlow13.br-int
Write: case0.2020-12-29-12-07-39.1609240059.master-1.OpenFlow13.br-local
Write: case0.2020-12-29-12-07-39.1609240059.master-1.iptables
Write: case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-ex
Write: case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-int
Write: case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-local
Write: case0.2020-12-29-12-07-39.1609240059.master-0.iptables
Write: case0.2020-12-29-12-07-39.1609240059.master-2.OpenFlow13.br-ex
Write: case0.2020-12-29-12-07-39.1609240059.master-2.OpenFlow13.br-int
Write: case0.2020-12-29-12-07-39.1609240059.master-2.OpenFlow13.br-local
Write: case0.2020-12-29-12-07-39.1609240059.master-2.iptables

Case 1 - Simpson - default-deny

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oc create -n simpson  -f - <<EOF
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: default-deny
spec:
  podSelector: {}
EOF

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$ ./OVNKubernetes/dump-net.sh master-0 master-0.case1
Run dump at
master-0;ovs-node-t84dc
Write: master-0.case1.master-0.OpenFlow13.br-ex
Write: master-0.case1.master-0.OpenFlow13.br-int
Write: master-0.case1.master-0.OpenFlow13.br-local
Write: master-0.case1.master-0.iptables

Diff of OpenFlow13 

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$ diff -Nuar case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-ex master-0.case1.master-0.OpenFlow13.br-ex
$ diff -Nuar case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-local master-0.case1.master-0.OpenFlow13.br-local
$ diff -Nuar case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-int master-0.case1.master-0.OpenFlow13.br-int
--- case0.2020-12-29-12-07-39.1609240059.master-0.OpenFlow13.br-int 2020-12-29 12:07:49.000000000 +0100
+++ master-0.case1.master-0.OpenFlow13.br-int   2020-12-29 12:08:58.000000000 +0100
@@ -3327,6 +3327,15 @@
  cookie=0x5ba0d9b7, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0x1/0x1,ip,metadata=0x3,nw_src=10.128.0.2 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
  cookie=0x56194a07, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0x1/0x1,ip,metadata=0x5,nw_src=10.129.0.2 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
  cookie=0xb258993d, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0/0x1,ip,metadata=0x5,nw_src=10.129.0.2 actions=resubmit(,45)
+ cookie=0xa3134bb9, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0x1/0x1,arp,reg15=0x49,metadata=0x5 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
+ cookie=0x8951af69, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0/0x1,arp,reg15=0x49,metadata=0x5 actions=resubmit(,45)
+ cookie=0xa3134bb9, table=44, priority=2001,ct_state=+new-est+trk,arp,reg15=0x49,metadata=0x5 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
+ cookie=0x8951af69, table=44, priority=2001,ct_state=-trk,arp,reg15=0x49,metadata=0x5 actions=resubmit(,45)
+ cookie=0x52df188c, table=44, priority=2000,ct_state=+est+trk,ct_label=0x1/0x1,reg15=0x49,metadata=0x5 actions=drop
+ cookie=0x6ca413a8, table=44, priority=2000,ct_state=+est+trk,ct_label=0/0x1,ipv6,reg15=0x49,metadata=0x5 actions=ct(commit,zone=NXM_NX_REG13[0..15],exec(load:0x1->NXM_NX_CT_LABEL[0]))
+ cookie=0x6ca413a8, table=44, priority=2000,ct_state=+est+trk,ct_label=0/0x1,ip,reg15=0x49,metadata=0x5 actions=ct(commit,zone=NXM_NX_REG13[0..15],exec(load:0x1->NXM_NX_CT_LABEL[0]))
+ cookie=0x52df188c, table=44, priority=2000,ct_state=-trk,reg15=0x49,metadata=0x5 actions=drop
+ cookie=0x52df188c, table=44, priority=2000,ct_state=-est+trk,reg15=0x49,metadata=0x5 actions=drop
  cookie=0x93b0b827, table=44, priority=1,ct_state=-est+trk,ip,metadata=0x4 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
  cookie=0x93b0b827, table=44, priority=1,ct_state=-est+trk,ipv6,metadata=0x4 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
  cookie=0xb723d24c, table=44, priority=1,ct_state=-est+trk,ipv6,metadata=0x3 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)

2) Simpson allow from openshift-ingress namespaces, because of router

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cat << EOF| oc create -f -
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-openshift-ingress
spec:
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          network.openshift.io/policy-group: ingress
  podSelector: {}
  policyTypes:
  - Ingress
EOF

Because of HostNetwork access of the OpenShift Ingress you have to apply a label to the default namespace: 

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oc label namespace default 'network.openshift.io/policy-group=ingress'
Documentation: 2. If the default Ingress Controller configuration has the...

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$ ./OVNKubernetes/dump-net.sh master-0 master-0.case2
Run dump at
master-0;ovs-node-t84dc
Write: master-0.case2.master-0.OpenFlow13.br-ex
Write: master-0.case2.master-0.OpenFlow13.br-int
Write: master-0.case2.master-0.OpenFlow13.br-local
Write: master-0.case2.master-0.iptables

Diff: 

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$ diff -Nuar master-0.case1.master-0.OpenFlow13.br-int master-0.case2.master-0.OpenFlow13.br-int
$ diff -Nuar master-0.case1.master-0.OpenFlow13.br-ex master-0.case2.master-0.OpenFlow13.br-ex
$ diff -Nuar master-0.case1.master-0.OpenFlow13.br-local master-0.case2.master-0.OpenFlow13.br-local

Warning

Problem - did not work! Bug 1909777 - Setting up multitenant netwotk policy does not work with OVN-Kubernetes network plugin.

3) Simpson allow internal communcation

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cat << EOF| oc create -f -
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-same-namespace
spec:
  podSelector:
  ingress:
  - from:
    - podSelector: {}
EOF

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$ ./OVNKubernetes/dump-net.sh master-0 master-0.case3

Diff 

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$ diff -Nuar master-0.case2.master-0.OpenFlow13.br-int master-0.case3.master-0.OpenFlow13.br-int
--- master-0.case2.master-0.OpenFlow13.br-int   2020-12-29 13:22:34.000000000 +0100
+++ master-0.case3.master-0.OpenFlow13.br-int   2020-12-29 13:27:13.000000000 +0100
@@ -3331,6 +3331,14 @@
  cookie=0x8951af69, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0/0x1,arp,reg15=0x49,metadata=0x5 actions=resubmit(,45)
  cookie=0xa3134bb9, table=44, priority=2001,ct_state=+new-est+trk,arp,reg15=0x49,metadata=0x5 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
  cookie=0x8951af69, table=44, priority=2001,ct_state=-trk,arp,reg15=0x49,metadata=0x5 actions=resubmit(,45)
+ cookie=0x25d2c138, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0/0x1,ip,reg15=0x49,metadata=0x5,nw_src=10.129.0.113 actions=resubmit(,45)
+ cookie=0x4b57e23f, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0x1/0x1,ip,reg15=0x49,metadata=0x5,nw_src=10.129.0.113 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
+ cookie=0x4b57e23f, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0x1/0x1,ip,reg15=0x49,metadata=0x5,nw_src=10.130.0.207 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
+ cookie=0x25d2c138, table=44, priority=2001,ct_state=-new+est-rpl+trk,ct_label=0/0x1,ip,reg15=0x49,metadata=0x5,nw_src=10.130.0.207 actions=resubmit(,45)
+ cookie=0x25d2c138, table=44, priority=2001,ct_state=-trk,ip,reg15=0x49,metadata=0x5,nw_src=10.129.0.113 actions=resubmit(,45)
+ cookie=0x25d2c138, table=44, priority=2001,ct_state=-trk,ip,reg15=0x49,metadata=0x5,nw_src=10.130.0.207 actions=resubmit(,45)
+ cookie=0x4b57e23f, table=44, priority=2001,ct_state=+new-est+trk,ip,reg15=0x49,metadata=0x5,nw_src=10.129.0.113 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
+ cookie=0x4b57e23f, table=44, priority=2001,ct_state=+new-est+trk,ip,reg15=0x49,metadata=0x5,nw_src=10.130.0.207 actions=load:0x1->NXM_NX_XXREG0[97],resubmit(,45)
  cookie=0x52df188c, table=44, priority=2000,ct_state=+est+trk,ct_label=0x1/0x1,reg15=0x49,metadata=0x5 actions=drop
  cookie=0x6ca413a8, table=44, priority=2000,ct_state=+est+trk,ct_label=0/0x1,ipv6,reg15=0x49,metadata=0x5 actions=ct(commit,zone=NXM_NX_REG13[0..15],exec(load:0x1->NXM_NX_CT_LABEL[0]))
  cookie=0x6ca413a8, table=44, priority=2000,ct_state=+est+trk,ct_label=0/0x1,ip,reg15=0x49,metadata=0x5 actions=ct(commit,zone=NXM_NX_REG13[0..15],exec(load:0x1->NXM_NX_CT_LABEL[0]))
$ diff -Nuar master-0.case2.master-0.OpenFlow13.br-ex master-0.case3.master-0.OpenFlow13.br-ex
$ diff -Nuar master-0.case3.master-0.OpenFlow13.br-local master-0.case3.master-0.OpenFlow13.br-local

4) Selma and Patty want's to talk with Marge!

1) First label the namespace bouvier: 

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oc label namespace/bouvier name=bouvier

2) Apply Network Policy 

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oc create -n simpson -f - <<EOF
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-bouviers-to-marge
spec:
  podSelector:
    matchLabels:
      deployment: marge
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          name: bouvier
EOF


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$ ./OVNKubernetes/dump-net.sh master-0 master-0.case4

Diff 

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$ diff -Nuar master-0.case3.master-0.OpenFlow13.br-int master-0.case4.master-0.OpenFlow13.br-int
$ diff -Nuar master-0.case3.master-0.OpenFlow13.br-ex master-0.case4.master-0.OpenFlow13.br-ex
$ diff -Nuar master-0.case3.master-0.OpenFlow13.br-local master-0.case4.master-0.OpenFlow13.br-local

Nothing??

Destroy demo env

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oc delete project simpson bouvier

Useful commands

Info Command
Dump northbound db oc rsh -n openshift-ovn-kubernetes -c northd ovnkube-master-6s6bw ovn-nbctl -C /ovn-ca/ca-bundle.crt -p /ovn-cert/tls.key -c /ovn-cert/tls.crt --db=ssl:192.168.51.10:9641 --pretty show
Last update: October 12, 2021