Added script to download and install CNI plugin on Linux

Author: ofiliz

build/install-cni-plugin.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+
+PLUGIN_VERSION=v0.5
+CNI_VERSION=v0.4.0
+
+# Create default CNI directories.
+mkdir -p /etc/cni/net.d
+mkdir -p /opt/cni/bin
+
+# Install ebtables.
+if [ ! -e /sbin/ebtables ]
+then
+    apt-get update
+    apt-get install -y ebtables
+fi
+/sbin/ebtables --list
+
+# Install Azure CNI plugins.
+/usr/bin/curl -sSL https://github.com/Azure/azure-container-networking/releases/download/${PLUGIN_VERSION}/azure-vnet-amd64-${PLUGIN_VERSION}.tgz > /opt/cni/bin/azure.tgz
+tar -xzf /opt/cni/bin/azure.tgz -C /opt/cni/bin
+
+# Install loopback plugin.
+/usr/bin/curl -sSL https://github.com/containernetworking/cni/releases/download/${CNI_VERSION}/cni-amd64-${CNI_VERSION}.tgz > /opt/cni/bin/cni.tgz
+tar -xzf /opt/cni/bin/cni.tgz -C /opt/cni/bin ./loopback
+
+# Cleanup.
+rm /opt/cni/bin/*.tgz
+chown root:root /opt/cni/bin/*