Newest Multus Version v2.1(Kubernetes Network Plumbing working group- reference meta plugin) will be merged to master from dev branch(network-plumbing-working-group-crd-change). For more info - refer : Multus v2.1 readme.md
- MULTUS CNI plugin
- Multi-Homed pod
- Build
- Work flow
- Usage with Kubernetes CRD/TPR based network objects
- Using with Multus conf file
- Testing Multus CNI
- Multus additional plugins
- NFV based networking in Kubernetes
- Need help
- Contacts
- Multus is a latin word for "Multi"
- As the name suggests, it acts as a Multi plugin in Kubernetes and provides the multiple network interface support in a pod
- Multus supports all reference plugins (eg. Flannel, DHCP, Macvlan) that implement the CNI specification and all 3rd party plugins (eg. Calico, Weave, Cilium, Contiv). In addition to it, Multus supports SRIOV, SRIOV-DPDK, OVS-DPDK & VPP workloads in Kubernetes with both cloud native and NFV based applications in Kubernetes
- It is a contact between the container runtime and other plugins, and it doesn't have any of its own net configuration, it calls other plugins like flannel/calico to do the real net conf job.
- Multus reuses the concept of invoking delegates as used in flannel by grouping multiple plugins into delegates and invoking them in the sequential order of the CNI configuration file provided in json format
- Number of plugins supported is depends on the number of delegates in the configuration file.
- The "masterplugin" is the only net conf option of multus cni, it identifies the primary network. The default route will point to the primary network
- One of the plugin acts as a “Master” plugin and responsible for configuring k8s network with Pod interface “eth0”
- The “Master” plugin also responsible to set the default route for the Pod
- Any subsequent plugin gets Pod interface name as “net0”, “net1”,… “netX and so on
- Multus is one of the projects in the Baremetal Container Experience kit.
Please check the CNI documentation for more information on container networking.
This plugin requires Go 1.8 to build.
Go 1.5 users will need to set GO15VENDOREXPERIMENT=1 to get vendored dependencies. This flag is set by default in 1.6.
#./build
- name (string, required): the name of the network
- type (string, required): "multus"
- kubeconfig (string, optional): kubeconfig file for the out of cluster communication with kube-apiserver. See the example kubeconfig
- delegates (([]map,required): number of delegate details in the Multus, ignored in case kubeconfig is added.
- masterplugin (bool,required): master plugin to report back the IP address and DNS to the container
Kubelet is responsible for establishing network interfaces for pods; it does this by invoking its configured CNI plugin. When Multus is invoked it retrieves network references from Pod annotation. Multus then uses these network references to get network configurations. Network configurations are defined as Kubernetes Custom Resource Object (CRD). These configurations describe which CNI plugins to invoke and what their configurations are. The order of plugin invocation is important as it identifies the primary plugin. This order is taken from network object references given in a Pod spec.
Multus is compatible to work with both CRD/TPR. Both CRD/TPR based network object api self link is same.
- Create a Custom Resource Definition "crdnetwork.yaml" for the network object as shown below:
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
# name must match the spec fields below, and be in the form: <plural>.<group>
name: networks.kubernetes.com
spec:
# group name to use for REST API: /apis/<group>/<version>
group: kubernetes.com
# version name to use for REST API: /apis/<group>/<version>
version: v1
# either Namespaced or Cluster
scope: Namespaced
names:
# plural name to be used in the URL: /apis/<group>/<version>/<plural>
plural: networks
# singular name to be used as an alias on the CLI and for display
singular: network
# kind is normally the CamelCased singular type. Your resource manifests use this.
kind: Network
# shortNames allow shorter string to match your resource on the CLI
shortNames:
- net
- Run kubectl create command for the Custom Resource Definition
# kubectl create -f ./crdnetwork.yaml
customresourcedefinition "network.kubernetes.com" created
- Run kubectl get command to check the Network CRD creation
# kubectl get CustomResourceDefinition
NAME KIND
networks.kubernetes.com CustomResourceDefinition.v1beta1.apiextensions.k8s.io
- Save the following YAML to flannel-network.yaml
apiVersion: "kubernetes.com/v1"
kind: Network
metadata:
name: flannel-networkobj
plugin: flannel
args: '[
{
"delegate": {
"isDefaultGateway": true
}
}
]'
- Create the custom resource definition
# kubectl create -f customCRD/flannel-network.yaml
network "flannel-networkobj" created
# kubectl get network
NAME KIND ARGS PLUGIN
flannel-networkobj Network.v1.kubernetes.com [ { "delegate": { "isDefaultGateway": true } } ] flannel
- Get the custom network object details
# kubectl get network flannel-networkobj -o yaml
apiVersion: kubernetes.com/v1
args: '[ { "delegate": { "isDefaultGateway": true } } ]'
kind: Network
metadata:
clusterName: ""
creationTimestamp: 2017-07-11T21:46:52Z
deletionGracePeriodSeconds: null
deletionTimestamp: null
name: flannel-networkobj
namespace: default
resourceVersion: "6848829"
selfLink: /apis/kubernetes.com/v1/namespaces/default/networks/flannel-networkobj
uid: 7311c965-6682-11e7-b0b9-408d5c537d27
plugin: flannel
For Kubernetes v1.7 and above use CRD to create network object. For version older than 1.7 use TPR based objects as shown below:
Note: Both TPR and CRD will have same selfLink :
/apis/kubernetes.com/v1/namespaces/default/networks/
- Create a Third Party Resource "tprnetwork.yaml" for the network object as shown below:
apiVersion: extensions/v1beta1
kind: ThirdPartyResource
metadata:
name: network.kubernetes.com
description: "A specification of a Network obj in the kubernetes"
versions:
- name: v1
- Run kubectl create command for the Third Party Resource
# kubectl create -f ./tprnetwork.yaml
thirdpartyresource "network.kubernetes.com" created
- Run kubectl get command to check the Network TPR creation
# kubectl get thirdpartyresource
NAME DESCRIPTION VERSION(S)
network.kubernetes.com A specification of a Network obj in the kubernetes v1
-
After creating CRD/TPR network object you can create network resources in Kubernetes. These network resources may contain additional underlying CNI plugin parameters given in JSON format. In the following example shown below the args field contains parameters that will be passed into “flannel” plugin.
-
Save the following YAML to flannel-network.yaml
apiVersion: "kubernetes.com/v1"
kind: Network
metadata:
name: flannel-conf
plugin: flannel
args: '[
{
"delegate": {
"isDefaultGateway": true
}
}
]'
- Run kubectl create command to create network object
# kubectl create -f ./flannel-network.yaml
network "flannel-conf" created
- Show network objects using kubectl:
# kubectl get network
NAME KIND
flannel-conf Network.v1.kubernetes.com
- Show details of the network object:
# kubectl get network flannel-conf -o yaml
apiVersion: kubernetes.com/v1
args: '[ { "delegate": { "isDefaultGateway": true } } ]'
kind: Network
metadata:
creationTimestamp: 2017-06-28T14:20:52Z
name: flannel-conf
namespace: default
resourceVersion: "5422876"
selfLink: /apis/kubernetes.com/v1/namespaces/default/networks/flannel-conf
uid: fdcb94a2-5c0c-11e7-bbeb-408d5c537d27
plugin: flannel
- Save the following YAML to sriov-network.yaml to creating sriov network object. ( Refer to Intel - SR-IOV CNI or contact @kural in Intel-Corp Slack for running the DPDK based workloads in Kubernetes)
apiVersion: "kubernetes.com/v1"
kind: Network
metadata:
name: sriov-conf
plugin: sriov
args: '[
{
"if0": "enp12s0f1",
"ipam": {
"type": "host-local",
"subnet": "10.56.217.0/24",
"rangeStart": "10.56.217.171",
"rangeEnd": "10.56.217.181",
"routes": [
{ "dst": "0.0.0.0/0" }
],
"gateway": "10.56.217.1"
}
}
]'
- Likewise save the following YAML to sriov-vlanid-l2enable-network.yaml to create another sriov based network object:
apiVersion: "kubernetes.com/v1"
kind: Network
metadata:
name: sriov-vlanid-l2enable-conf
plugin: sriov
args: '[
{
"if0": "enp2s0",
"vlan": 210,
"if0name": "north",
"l2enable": true
}
]'
- Follow step 3 above to create "sriov-vlanid-l2enable-conf" and "sriov-conf" network objects
- View network objects using kubectl
# kubectl get network
NAME KIND
flannel-conf Network.v1.kubernetes.com
sriov-vlanid-l2enable-conf Network.v1.kubernetes.com
sriov-conf Network.v1.kubernetes.com
- Create a Mutlus CNI configuration file on each Kubernetes node. This file should be created in: /etc/cni/net.d/multus-cni.conf with the content shown below. Use only the absolute path to point to the kubeconfig file (as it may change depending upon your cluster env). We are assuming all CNI plugin binaries are default location (
\opt\cni\bin dir)
{
"name": "node-cni-network",
"type": "multus",
"kubeconfig": "/etc/kubernetes/node-kubeconfig.yaml"
}
- Restart kubelet service
# systemctl restart kubelet
- Many users want Kubernetes default networking feature along with network objects. Refer to issues #14 & #17 for more information. In the following Multus configuration, Weave act as the default network in the absence of network field in the pod metadata annotation.
{
"name": "node-cni-network",
"type": "multus",
"kubeconfig": "/etc/kubernetes/node-kubeconfig.yaml",
"delegates": [{
"type": "weave-net",
"hairpinMode": true,
"masterplugin": true
}]
}
- Restart kubelet service
# systemctl restart kubelet
- Save the following YAML to pod-multi-network.yaml. In this case flannel-conf network object acts as the primary network.
# cat pod-multi-network.yaml
apiVersion: v1
kind: Pod
metadata:
name: multus-multi-net-poc
annotations:
networks: '[
{ "name": "flannel-conf" },
{ "name": "sriov-conf"},
{ "name": "sriov-vlanid-l2enable-conf" }
]'
spec: # specification of the pod's contents
containers:
- name: multus-multi-net-poc
image: "busybox"
command: ["top"]
stdin: true
tty: true
- Create Multiple network based pod from the master node
# kubectl create -f ./pod-multi-network.yaml
pod "multus-multi-net-poc" created
- Get the details of the running pod from the master
# kubectl get pods
NAME READY STATUS RESTARTS AGE
multus-multi-net-poc 1/1 Running 0 30s
- Run "ifconfig" command in Pod:
# kubectl exec -it multus-multi-net-poc -- ifconfig
eth0 Link encap:Ethernet HWaddr 06:21:91:2D:74:B9
inet addr:192.168.42.3 Bcast:0.0.0.0 Mask:255.255.255.0
inet6 addr: fe80::421:91ff:fe2d:74b9/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:648 (648.0 B)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
net0 Link encap:Ethernet HWaddr D2:94:98:82:00:00
inet addr:10.56.217.171 Bcast:0.0.0.0 Mask:255.255.255.0
inet6 addr: fe80::d094:98ff:fe82:0/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:120 (120.0 B) TX bytes:648 (648.0 B)
north Link encap:Ethernet HWaddr BE:F2:48:42:83:12
inet6 addr: fe80::bcf2:48ff:fe42:8312/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1420 errors:0 dropped:0 overruns:0 frame:0
TX packets:1276 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:95956 (93.7 KiB) TX bytes:82200 (80.2 KiB)
| Interface name | Description |
|---|---|
| lo | loopback |
| eth0@if41 | Flannel network tap interface |
| net0 | VF0 of NIC 1 assigned to the container by Intel - SR-IOV CNI plugin |
| north | VF0 of NIC 2 assigned with VLAN ID 210 to the container by SR-IOV CNI plugin |
- Check the vlan ID of the NIC 2 VFs
# ip link show enp2s0
20: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
link/ether 24:8a:07:e8:7d:40 brd ff:ff:ff:ff:ff:ff
vf 0 MAC 00:00:00:00:00:00, vlan 210, spoof checking off, link-state auto
vf 1 MAC 00:00:00:00:00:00, vlan 4095, spoof checking off, link-state auto
vf 2 MAC 00:00:00:00:00:00, vlan 4095, spoof checking off, link-state auto
vf 3 MAC 00:00:00:00:00:00, vlan 4095, spoof checking off, link-state auto
Given the following network configuration:
# tee /etc/cni/net.d/multus-cni.conf <<-'EOF'
{
"name": "multus-demo-network",
"type": "multus",
"delegates": [
{
"type": "sriov",
#part of sriov plugin conf
"if0": "enp12s0f0",
"ipam": {
"type": "host-local",
"subnet": "10.56.217.0/24",
"rangeStart": "10.56.217.131",
"rangeEnd": "10.56.217.190",
"routes": [
{ "dst": "0.0.0.0/0" }
],
"gateway": "10.56.217.1"
}
},
{
"type": "ptp",
"ipam": {
"type": "host-local",
"subnet": "10.168.1.0/24",
"rangeStart": "10.168.1.11",
"rangeEnd": "10.168.1.20",
"routes": [
{ "dst": "0.0.0.0/0" }
],
"gateway": "10.168.1.1"
}
},
{
"type": "flannel",
"masterplugin": true,
"delegate": {
"isDefaultGateway": true
}
}
]
}
EOF
Github user YYGCui has used multiple flannel network to work with Multus CNI plugin. Please refer to this closed issue for ,multiple overlay network support with Multus CNI.
Make sure that the multus, sriov, flannel, and ptp binaries are in the /opt/cni/bin directories and follow the steps as mentioned in the CNI
Kubelet must be configured to run with the CNI network plugin. Edit /etc/kubernetes/kubelet file and add "--network-plugin=cni" flags in KUBELET_OPTS as shown below:
KUBELET_OPTS="...
--network-plugin-dir=/etc/cni/net.d
--network-plugin=cni
"
Refer to the Kubernetes User Guide and network plugin for more information.
Restart kubelet:
# systemctl restart kubelet.service
With Multus CNI configured as described in sections above each workload launched via a Kubernetes Pod will have multiple network interfacesLaunch the workload using yaml file in the kubernetes master, with above configuration in the multus CNI, each pod should have multiple interfaces.
Note: To verify whether Multus CNI plugin is working correctly, create a pod containing one "busybox" container and execute "ip link" command to check if interfaces management follows configuration.
- Create "multus-test.yaml" file containing below configuration. Created pod will consist of one "busybox" container running "top" command.
apiVersion: v1
kind: Pod
metadata:
name: multus-test
spec: # specification of the pod's contents
restartPolicy: Never
containers:
- name: test1
image: "busybox"
command: ["top"]
stdin: true
tty: true
- Create pod using command:
# kubectl create -f multus-test.yaml
pod "multus-test" created
- Run "ip link" command inside the container:
# 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue qlen 1
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
3: eth0@if41: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue
link/ether 26:52:6b:d8:44:2d brd ff:ff:ff:ff:ff:ff
20: net0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq qlen 1000
link/ether f6:fb:21:4f:1d:63 brd ff:ff:ff:ff:ff:ff
21: net1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq qlen 1000
link/ether 76:13:b1:60:00:00 brd ff:ff:ff:ff:ff:ff
| Interface name | Description |
|---|---|
| lo | loopback |
| eth0@if41 | Flannel network tap interface |
| net0 | VF assigned to the container by SR-IOV CNI plugin |
| net1 | ptp localhost interface |
- DPDK-SRIOV CNI
- Vhostuser CNI - a Dataplane network plugin - Supports OVS-DPDK & VPP
- Bond CNI - For fail-over and high availability of networking
- KubeCon workshop on "Enabling NFV features in Kubernetes" presentation slide deck
- Feature brief
- Application note
- White paper
- Multus's related project github pages
- Read Containers Experience Kits
- Try our container exp kit demo - KubeCon workshop on Enabling NFV Features in Kubernetes
- Join us on #intel-sddsg-slack slack channel and ask question in #general-discussion
- You can also email us
- Feel free to submit an issue
Please fill in the Questions/feedback - google-form!
For any questions about Multus CNI, please reach out on github issue or feel free to contact the developer @kural in our Intel-Corp Slack