IEC Reference Foundation Overview

This document provides a general description about the reference foundation of IEC. The Integrated Edge Cloud (IEC) will enable new functionalities and business models on the network edge. The benefits of running applications on the network edge are - Better latencies for end users - Less load on network since more data can be processed locally - Fully utilize the computation power of the edge devices

Currently, the chosen operating system(OS) is Ubuntu 16.04 and/or 18.04. The infrastructure orchestration of IEC is based on Kubernetes, which is a production-grade container orchestration with rich running eco-system. The current container networking mechanism (CNI) choosed for Kubernetes is project Calico, which is a high performance, scalable, policy enabled and widely used container networking solution with rather easy installation and arm64 support. In the future, Contiv/VPP or OVN-Kubernetes would also be candidates for Kubernetes networking.

Kubernetes Install for Ubuntu

Install Docker as Prerequisite

Docker is used for Kuberntes docker images management. The installation script for docker version 18.06 is given below. More docker install information can be found in the install guide:

DOCKER_VERSION=18.06.1
ARCH=arm64
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo apt-key fingerprint 0EBFCD88
sudo add-apt-repository \
 "deb [arch=${ARCH}] https://download.docker.com/linux/ubuntu \
 $(lsb_release -cs) \
 stable"
sudo apt-get update
sudo apt-get install -y docker-ce=${DOCKER_VERSION}~ce~3-0~ubuntu

Disable swap on your machine

Turn off all swap devices and files with:

sudo swapoff -a

Install Kubernetes with Kubeadm

kubeadm helps you bootstrap a minimum viable Kubernetes cluster that conforms to best practices which a preferred installation method for IEC currently. Now we choose v1.13.0 as a current stable version of Kubernetes for arm64. Usually the current host(edge server/gateway)'s management interface is chosen as the Kubeapi-server advertise address which is indicated here as $MGMT_IP.

The common installation steps for both Kubernetes master and slave node are given as Linux shell scripts:

sudo bash
apt-get update && apt-get install -y apt-transport-https curl
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -
cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF
apt-get update
apt-get install -y kubelet=1.13.0-00 kubeadm=1.13.0-00 kubectl=1.13.0-00
apt-mark hold kubelet kubeadm kubectl
sysctl net.bridge.bridge-nf-call-iptables=1

For host setup as Kubernetes master:

sudo kubeadm config images pull
sudo kubeadm init --pod-network-cidr=192.168.0.0/16 --apiserver-advertise-address=$MGMT_IP \
--service-cidr=172.16.1.0/24

To start using your cluster, you need to run (as a regular user):

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

or if you are the root user:

export KUBECONFIG=/etc/kubernetes/admin.conf

For hosts setup as Kubernetes slave:

kubeadm join --token <token> <master-ip>:6443 --discovery-token-ca-cert-hash sha256:<hash>

in which the token is given in the master's kubeadm init.

or using following command which will skip ca-cert verification:

kubeadm join --token <token> <master_ip>:6443 --discovery-token-unsafe-skip-ca-verification

After the slave joining the Kubernetes cluster, in the master node, you could check the cluster node with the command:

kubectl get nodes

Install the Calico CNI Plugin to Kubernetes Cluster

Now we install a Calico network add-on so that Kubernetes pods can communicate with each other. The network must be deployed before any applications. Kubeadm only supports Container Networking Interface(CNI) based networks for which Calico has supported.

Install the Etcd Database

kubectl apply -f https://raw.githubusercontent.com/Jingzhao123/arm64TemporaryCalico/temporay_arm64/
v3.3/getting-started/kubernetes/installation/hosted/etcd-arm64.yaml

Install the RBAC Roles required for Calico

kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/rbac.yaml

Install Calico to system

Firstly, we should get the configuration file from web site and modify the corresponding image from amd64 to arm64 version. Then, by using kubectl, the calico pod will be created.

wget https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/calico.yaml

Since the "quay.io/calico" image repo does not support does not multi-arch, we have to replace the “quay.io/calico” image path to "calico" which supports multi-arch.

sed -i "s/quay.io\/calico/calico/" calico.yaml

Deploy the Calico using following command:

kubectl apply -f calico.yaml

Attention!

In calico.yaml file, there is an option "IP_AUTODETECTION_METHOD" about choosing network interface. The default value is "first-found" which means the first valid IP address (except local interface, docker bridge). So if the number of network-interface is more than 1 on your server, you should configure it depends on your networking environments. If it does not configure it properly, there are some error about calico-node pod: "BGP not established with X.X.X.X".

Remove the taints on master node

kubectl taint nodes --all node-role.kubernetes.io/master-

Verification for the Work of Kubernetes

Now we can verify the work of Kubernetes and Calico with Kubernets pod and service creation and accessing based on Nginx which is a widely used web server.

Firstly, create a file named nginx-app.yaml to describe a Pod and service by:

$ cat <<EOF >~/nginx-app.yaml
apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  type: NodePort
  ports:
  - port: 80
    protocol: TCP
    name: http
  selector:
    app: nginx
---
apiVersion: v1
kind: ReplicationController
metadata:
  name: nginx
spec:
  replicas: 2
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
EOF

then test the Kubernetes working status with the script:

set -ex
kubectl create -f ~/nginx-app.yaml
kubectl get nodes
kubectl get services
kubectl get pods
kubectl get rc
r="0"
while [ $r -ne "2" ]
do
   r=$(kubectl get pods | grep Running | wc -l)
   sleep 60
done
svcip=$(kubectl get services nginx  -o json | grep clusterIP | cut -f4 -d'"')
sleep 10
wget http://$svcip
kubectl delete -f ./examples/nginx-app.yaml
kubectl delete -f ./nginx-app.yaml
kubectl get rc
kubectl get pods
kubectl get services

Helm Install on Arm64

Helm is a tool for managing Kubernetes charts. Charts are packages of pre-configured Kubernetes resources. The installation of Helm on arm64 is as followes:

wget https://storage.googleapis.com/kubernetes-helm/helm-v2.12.3-linux-arm64.tar.gz
xvf helm-v2.12.3-linux-arm64.tar.gz
sudo cp linux-arm64/helm /usr/bin
sudo cp linux-arm64/tiller /usr/bin

Further Information

We would like to provide a walk through shell script to automate the installation of Kubernetes and Calico in the future. But this README is still useful for IEC developers and users.

For issues or anything on the reference foundation stack of IEC, you could contact:

Trevor Tao: trevor.tao@arm.com

Jingzhao Ni: jingzhao.ni@arm.com

Jianlin Lv: jianlin.lv@arm.com