Bridge CNI + Static IPAM in OpenShift 4.2 demo

README.md

This is a demonstration of the Bridge CNI plugin, plus the static IPAM CNI plugin.

Requirements

• A recently installed OpenShift (4.2/4.3) installed cluster.

Demo!

Firstly, we'll label a node so that we have two pods going to the same node.

oc get nodes | grep worker | awk '{print $1}'
oc label node ip-10-0-140-29.us-west-2.compute.internal bridgedemo=true
oc get nodes --show-labels | grep bridgedemo

Custom resource setup

Next, we're going to create two net-attach-defs

"Bridge A"

cat <<EOF | oc create -f -
apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
  name: static-bridge-a
spec:
  config: '{
      "name": "static-bridge-a",
      "cniVersion": "0.3.1",
      "type": "bridge",
      "bridge": "demo0",
      "vlan": 200,
      "ipam": {
        "type": "static",
        "addresses": [
            {
                "address": "10.200.0.2/24"
            }
        ]
      }
    }'
EOF

"Bridge B"

cat <<EOF | oc create -f -
apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
  name: static-bridge-b
spec:
  config: '{
      "name": "static-bridge-b",
      "cniVersion": "0.3.1",
      "type": "bridge",
      "bridge": "demo0",
      "vlan": 200,
      "ipam": {
        "type": "static",
        "addresses": [
            {
                "address": "10.200.0.3/24"
            }
        ]
      }
    }'
EOF

Pod Setup

cat <<EOF | oc create -f -
apiVersion: v1
kind: Pod
metadata:
  name: demo-bridge-a
  annotations:
    k8s.v1.cni.cncf.io/networks: static-bridge-a
spec:
  containers:
  - name: demo-bridge-a
    command: ["/bin/bash", "-c", "trap : TERM INT; sleep infinity & wait"]
    image: centos/tools
  nodeSelector:
    bridgedemo: "true"
EOF

cat <<EOF | oc create -f -
apiVersion: v1
kind: Pod
metadata:
  name: demo-bridge-b
  annotations:
    k8s.v1.cni.cncf.io/networks: static-bridge-b
spec:
  containers:
  - name: demo-bridge-b
    command: ["/bin/bash", "-c", "trap : TERM INT; sleep infinity & wait"]
    image: centos/tools
  nodeSelector:
    bridgedemo: "true"
EOF

Check out the results and ping!

Let's list the interfaces

oc exec -it demo-bridge-a -- ip a
oc exec -it demo-bridge-b -- ip a

Note that we have a statically assigned IP address for each of those.

Now we can make a ping from one to the other...

oc exec -it demo-bridge-b -- ping -c5 10.200.0.2