Add IT case for proper /etc/hosts handling

Added an IT case for checking proper /etc/hosts
handling in the overlay network. This also to see
if there are any stale entries in the /etc/hosts

Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>

libnetwork/test/integration/dnet/helpers.bash

@@ -292,6 +292,110 @@ function test_overlay() {
     dnet_cmd $(inst_id2port 2) network rm multihost
 }
 
+function check_etchosts() {
+    local dnet sbid retval
+    dnet=${1}
+    shift
+    sbid=${1}
+    shift
+
+    retval="true"
+
+    for i in $*;
+    do
+	run runc ${dnet} ${sbid} "cat /etc/hosts"
+	if [ "$status" -ne 0 ]; then
+	    retval="${output}"
+	    break
+	fi
+
+	line=$(echo ${output} | grep ${i})
+	if [ "${line}" == "" ]; then
+	    retval="false"
+	fi
+    done
+
+    echo ${retval}
+}
+
+function test_overlay_etchosts() {
+    local clist dnet_suffix
+
+    dnet_suffix=$1
+    shift
+
+    echo $(docker ps)
+
+    start=1
+    end=3
+    # Setup overlay network and connect containers ot it
+    dnet_cmd $(inst_id2port 1) network create -d overlay multihost
+
+    for iter in `seq 1 2`;
+    do
+	for i in `seq ${start} ${end}`;
+	do
+	    dnet_cmd $(inst_id2port $i) container create container_${iter}_${i}
+	    net_connect ${i} container_${iter}_${i} multihost
+	done
+
+	# Now test the /etc/hosts content of all the containers
+	for i in `seq ${start} ${end}`;
+	do
+	    clist=""
+	    oldclist=""
+	    for j in `seq ${start} ${end}`;
+	    do
+		if [ "$i" -eq "$j" ]; then
+		    continue
+		fi
+		clist="$clist container_${iter}_$j"
+		oldclist="$oldclist container_1_$j"
+	    done
+	    rv=$(check_etchosts $(dnet_container_name $i $dnet_suffix) \
+				$(get_sbox_id ${i} container_${iter}_${i}) \
+				${clist})
+	    [ "$rv" = "true" ]
+
+	    # check to see the containers don't have stale entries from previous iteration
+	    if [ "$iter" -eq 2 ]; then
+		rv=$(check_etchosts $(dnet_container_name $i $dnet_suffix) \
+				    $(get_sbox_id ${i} container_${iter}_${i}) \
+				    ${oldclist})
+		[ "$rv" = "false" ]
+	    fi
+	done
+
+	# Teardown the container connections and the network
+	clist=""
+	for i in `seq ${start} ${end}`;
+	do
+	    net_disconnect ${i} container_${iter}_${i} multihost
+	    dnet_cmd $(inst_id2port $i) container rm container_${iter}_${i}
+
+	    #check if the /etc/hosts of other containers does not contain this container
+	    for j in `seq ${start} ${end}`;
+	    do
+		if [ "$i" -eq "$j" ]; then
+		    continue
+		fi
+
+		if [[ "${clist}" =~ .*container_${iter}_${j}.* ]]; then
+		    continue
+		fi
+
+		rv=$(check_etchosts $(dnet_container_name $j $dnet_suffix) \
+				    $(get_sbox_id ${j} container_${iter}_${j}) \
+				    container_${iter}_${i})
+		[ "$rv" = "false" ]
+	    done
+	    clist="${clist} container_${iter}_${i}"
+	done
+    done
+
+    dnet_cmd $(inst_id2port 2) network rm multihost
+}
+
 function test_overlay_singlehost() {
     dnet_suffix=$1
     shift

libnetwork/test/integration/dnet/overlay-consul.bats

@@ -12,3 +12,8 @@ load helpers
     skip_for_circleci
     test_overlay_singlehost consul
 }
+
+@test "test overlay network etc hosts with consul" {
+    skip_for_circleci
+    test_overlay_etchosts consul
+}