Implement multi-node networking support in the Flannel script

Signed-off-by: Dennis Marttinen <dennis@weave.works>

tools/ignite-flannel.sh

@@ -32,16 +32,45 @@ FLANNEL_CONFLIST='{
 	]
 }'
 
+FLANNEL_NETWORK_CONFIG='{
+	"Network": "10.50.0.0/16",
+	"SubnetLen": 24,
+	"SubnetMin": "10.50.10.0",
+	"SubnetMax": "10.50.99.0",
+	"Backend": {
+		"Type": "udp",
+		"Port": 8285
+	}
+}'
+
 ARGS=("$@") # Save the args before shifting them away
-ACTIONS="init|cleanup"
+ACTION_ARGS=() # Arguments passed to the action
+ACTIONS="init|join|cleanup"
 
 usage() {
 	cat <<- EOF
 	Usage:
-	    $0 [-h|--help] ($ACTIONS)
+	    $0 [-h|--help] ($ACTIONS) [parameter]...
+
+	Available Actions:
+	    init             Start etcd and Flannel on this machine. For standalone and multi-node host use cases.
+	    join <host>      Start Flannel on this machine and join the multi-node overlay initialized by <host>.
+	    cleanup          Remove all persistent data created by this script. Does not remove interfaces, iptables etc.
 
 	Available Options:
-	    -h, --help        Show this help text
+	    -h, --help       Show this help text.
+	EOF
+
+	exit "$1"
+}
+
+join_usage() {
+	cat <<- EOF
+	Usage:
+	    $0 join <host>
+
+	where <host> is the IP address or FQDN of a host
+	machine initialized with '$0 init'.
 	EOF
 
 	exit "$1"
@@ -62,12 +91,11 @@ while test "$#" -gt 0; do
 		-h|--help)
 			usage 0
 			;;
-		*)
-			usage 1
-			;;
 	esac
 
 	shift
+
+	[ -n "$ACTION" ] && ACTION_ARGS+=("$1")
 done
 
 [ -z "$ACTION" ] && usage 1
@@ -85,7 +113,7 @@ log() {
 # Stops the given containers
 stop_container() {
 	mapfile -t ID <<< "$(docker ps -q --filter "name=$1")"
-	{ (( ${#ID[@]} )) && docker stop "${ID[@]}" 1> /dev/null; } || true
+	{ [ -n "${ID[0]}" ] && docker stop "${ID[@]}" 1> /dev/null; } || true
 }
 
 # Forwards the passed parameters to 'etcdctl set'
@@ -94,9 +122,6 @@ set_config() {
 }
 
 run_init() {
-	# Stop etcd and/or Flannel if they're already running
-	stop_container "$ETCD_NAME|$FLANNEL_NAME"
-
 	log "Starting $ETCD_NAME container... "
 	docker run -d --rm \
 		-p 2379:2379 \
@@ -115,7 +140,7 @@ run_init() {
 		--initial-cluster-state new
 
 	log "Setting Flannel config:"
-	set_config /coreos.com/network/config '{ "Network": "10.1.0.0/16" }'
+	set_config /coreos.com/network/config "$FLANNEL_NETWORK_CONFIG"
 
 	log "Starting $FLANNEL_NAME container... "
 	docker run -d --rm \
@@ -136,27 +161,58 @@ run_init() {
 	echo "$FLANNEL_CONFLIST" > /etc/cni/net.d/10-flannel.conflist
 }
 
+run_join() {
+	# Get the passed etcd endpoint
+	[ -z "${ACTION_ARGS[0]}" ] && join_usage 1
+	ETCD_ENDPOINT="http://${ACTION_ARGS[0]}:2379"
+
+	log "Starting $FLANNEL_NAME container... "
+	docker run -d --rm \
+		--net host \
+		--name "$FLANNEL_NAME" \
+		--cap-add NET_ADMIN \
+		--device /dev/net/tun \
+		-v /etc/cni:/etc/cni \
+		-v /run/flannel:/run/flannel \
+		quay.io/coreos/flannel:${FLANNEL_VERSION} \
+		-ip-masq \
+		-etcd-endpoints "$ETCD_ENDPOINT"
+
+	log "Setting CNI config..."
+	# Remove Ignite's conflist if it exists
+	rm -f /etc/cni/net.d/10-ignite.conflist
+
+	# Write the Flannel conflist
+	echo "$FLANNEL_CONFLIST" > /etc/cni/net.d/10-flannel.conflist
+}
+
 run_cleanup() {
 	# Remove Flannel's conflist
 	rm -f /etc/cni/net.d/10-flannel.conflist
-
-	# Stop etcd and/or Flannel if they're running
-	stop_container "$ETCD_NAME|$FLANNEL_NAME"
 }
 
+# Stop etcd and/or Flannel if they're already running
+stop_container "$ETCD_NAME|$FLANNEL_NAME"
+
 # Run the specified action
 case "$ACTION" in
 	init)
 		run_init
 		log "Initialized, now start your Ignite VMs with the CNI network plugin."
 		;;
+	join)
+		run_join
+		log "Complete, now check if joining was successful using 'docker logs $FLANNEL_NAME'."
+		log "If so, go ahead and start your Ignite VMs with the CNI network plugin."
+		;;
 	cleanup)
 		run_cleanup
-		log "Cleanup complete."
+		log "Cleanup complete. To finish removal of non-persistent resources such as generated"
+		log "network interfaces and iptables rules, reboot your system (or remove them by hand)."
 		;;
 	*)
 		# Should never happen
-		log "Configuration error: invalid action $ACTION"
+		log "Internal error: invalid action $ACTION"
 		exit 1
 		;;
 esac