use 'swarmctl' for 17.06 and estimate peers when we don't get ipam info

merge fcrisciani/ip-util-check:fix-peers-list and adamancini/ip-util-check:swarmctl

Author: adamancini

Dockerfile

@@ -1,4 +1,33 @@
-FROM ctelfer/swarmctl:latest
-RUN apk add --update bash docker jq
+FROM golang:1.11-alpine as build-swarmctl
+WORKDIR /go/src/github.com/docker
+
+RUN apk add --no-cache --update bash ca-certificates curl make git openssh-client
+RUN git clone https://github.com/docker/swarmkit.git swarmkit && cd swarmkit && make bin/swarmctl && cp bin/swarmctl /usr/bin/swarmctl && rm -rf /go/src/github.com/docker/swarmkit
+
+FROM alpine:3.9 as build-protoc
+ARG PROTOC_VERSION=3.6.1
+RUN apk add --update --no-cache unzip curl
+# download and install protoc binary and .proto files
+RUN curl --silent --show-error --location --output protoc.zip \
+  https://github.com/google/protobuf/releases/download/v$PROTOC_VERSION/protoc-$PROTOC_VERSION-linux-x86_64.zip \
+  && unzip -d /usr/local protoc.zip include/\* bin/\* \
+  && rm -f protoc.zip
+
+FROM alpine:3.9 as build-docker
+ARG DOCKER_CLIENT_VERSION=18.09.1
+RUN apk add --update --no-cache curl
+RUN curl -SsL --output docker.tgz \
+  https://download.docker.com/linux/static/stable/x86_64/docker-$DOCKER_CLIENT_VERSION.tgz \
+  && tar xvzf docker.tgz \
+  && cp docker/docker /usr/bin/docker \
+  && rm -f docker.tgz
+
+FROM alpine:3.9
+RUN apk add --no-cache --update bash jq
+# WORKDIR /go/src/github.com/docker
+# RUN git clone https://github.com/docker/swarmkit.git swarmkit && cd swarmkit && make bin/swarmctl && cp bin/swarmctl /usr/bin/swarmctl && rm -rf /go/src/github.com/docker/swarmkit
+COPY --from=build-swarmctl /usr/bin/swarmctl /usr/bin
+COPY --from=build-protoc /usr/local/. /usr/local
+COPY --from=build-docker /usr/bin/docker /usr/bin
 COPY ip-util-check /usr/bin
-ENTRYPOINT [ "/usr/bin/ip-util-check" ]
+CMD [ "/usr/bin/ip-util-check" ]

README.md

@@ -20,16 +20,29 @@ The script flags several potential conditions for each overlay:
     cluster size scales up to a certain number of nodes
   * IP address space is allocated to > 80% capacity
 
+####  Note: 
+Under certain conditions, it may not be possible to accurately
+count the number of IP addresses on a network due to Docker's
+networking state distribution architecture.
+
+Gossip protocol only distributes network programming to nodes that 
+participate in an overlay network.  A node must have a container or 
+service task scheduled on it attached to an overlay network to be 
+considered an overlay network peer.  Manager nodes that are not running
+workloads may not be able to accurately count the number of IP addresses
+on overlay networks scheduled on worker nodes.  In this case, we approximate.
 
 Building the Container
 ======================
-docker image build -t docker/ip-util-check .
-
+```
+docker build -t docker/ip-util-check .
+```
 
 Running the Container
 =====================
-
-    docker run -it --rm \
-    -v /var/run/docker.sock:/var/run/docker.sock \
-    -v /var/run/docker/swarm/control.sock:/var/run/swarmd.sock \
-            docker/ip-util-check
+```
+docker run -it --rm \
+ -v /var/run/docker.sock:/var/run/docker.sock \
+ -v /var/run/docker/swarm/control.sock:/var/run/swarmd.sock \
+ docker/ip-util-check
+```

ip-util-check

@@ -68,10 +68,11 @@ for net in $NETS ; do
         NET2NAME[$net]=$(echo $networkInspect | jq -r '.[].Name')
   set +e
         NET2SUB[$net]=$(echo $networkInspect | jq -r '.[].IPAM.Config[].Subnet' 2>/dev/null)
-  if [ -z "${NET2SUB[$net]}" ] ; then
-    NET2SUB[$net]=$(docker network inspect ${NET2NAME[$net]} | jq -r '.[].IPAM.Config[].Subnet' 2>/dev/null)
-  fi
-  set -e
+
+	if [ -z "${NET2SUB[$net]}" ] ; then
+		NET2SUB[$net]=$(/usr/bin/swarmctl network inspect ${NET2NAME[$net]} | grep Subnet | awk -F ": " '{print $2}' 2>/dev/null)
+	fi
+	set -e
         NET2CAP[$net]=0
         NET2NCIP[$net]=0
         NET2NVIP[$net]=0