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Dockerfile

@@ -1,18 +1,11 @@
-FROM mongo:latest
+FROM alpine:latest
 MAINTAINER Hussein Galal
 
-RUN apt-get update \
-&& apt-get install -yqq python build-essential python-dev python-pip python-setuptools \
-&& pip install pymongo \
-&& pip install netifaces \
-&& pip install pydns
+ENV MONGO_SERVICE_NAME mongo
 
-RUN mkdir -p /mongo
-WORKDIR /mongo
+ADD ./*.sh /opt/rancher/bin/
+RUN chmod u+x /opt/rancher/bin/*.sh
 
-ENV MONGO_SERVICE_NAME mongo
+VOLUME /opt/rancher/bin
 
-COPY docker-entrypoint.sh /entrypoint.sh
-RUN chmod u+x /entrypoint.sh
-ENTRYPOINT ["/entrypoint.sh"]
-CMD ["mongod"]
+ENTRYPOINT ["/bin/true"]

README.md

@@ -1,2 +1,61 @@
-# rancher-mongo
-A Docker container that check for a new mongoDB service container and add it to the Replica set
+# rancher-mongo-config
+A base Docker image to be used as a sidekick for MongoDB container, the scripts in this container will create replica set when you create a service in Rancher environment (at least 3 containers).
+
+## Requirements
+- Docker engine.
+- Rancher server.
+- rancher-compose.
+
+## Usage
+
+After installing rancher-compose, you can create a service that contain the following:
+
+**docker-compose.yml**
+```
+mongo-cluster:
+  restart: always
+  environment:
+    MONGO_SERVICE_NAME: mongo-cluster
+  tty: true
+  entrypoint: /opt/rancher/bin/entrypoint.sh
+  command:
+  - --replSet
+  - "rs0"
+  image: mongo:3.0
+  labels:
+    io.rancher.container.hostname_override: container_name
+    io.rancher.sidekicks: mongo-base, mongo-datavolume
+  volumes_from:
+    - mongo-datavolume
+    - mongo-base
+mongo-base:
+  restart: always
+  tty: true
+  labels:
+    io.rancher.container.hostname_override: container_name
+    io.rancher.container.start_once: true
+  build: ./
+  stdin_open: true
+  entrypoint: /bin/true
+mongo-datavolume:
+  net: none
+  labels:
+    io.rancher.container.hostname_override: container_name
+    io.rancher.container.start_once: true
+  volumes:
+    - /data/db
+  entrypoint: /bin/true
+  image: busybox
+```
+**rancher-compose.yml**
+```
+mongo-cluster:
+  scale: 3
+```
+
+And now to run the service run the following:
+
+```
+# rancher-compose up
+```
+As an added bonus the service can scale up as you go, just change the settings in rancher-compose.yml or use the Web UI to scale the serivce and the container will connect to the replicaset and be attached.

connect.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+DIG=/usr/bin/dig
+
+function cluster_init {
+	sleep 10
+	MYIP=$(ip -o -4 addr list eth0 | awk '{print $4}' | cut -d/ -f1 |  sed -n 2p)
+	$DIG A $MONGO_SERVICE_NAME +short > ips.tmp
+	mongo --eval "printjson(rs.initiate())"
+	for member in $(cat ips.tmp); do
+		if [ $member != $MYIP ]; then
+			mongo --eval "printjson(rs.add('$member:27017'))"
+			sleep 5
+		fi
+	done
+
+}
+
+function find_master {
+	$DIG A $MONGO_SERVICE_NAME +short > ips.tmp
+	for IP in $(cat ips.tmp); do
+		IS_MASTER=`mongo --host $IP --eval "printjson(db.isMaster())" | grep 'ismaster'`
+		if echo $IS_MASTER | grep "true"; then
+			return 0
+		fi
+	done
+	return 1
+}
+# Script starts here
+# wait for mongo to start
+while [ `$DIG A $MONGO_SERVICE_NAME +short | wc -l` -lt 3 ]; do
+	echo 'mongo instances are less than 3.. waiting!'
+	sleep 5
+done
+
+# Wait until all services are up
+sleep 10
+find_master
+if [ $? -eq 0 ]; then
+	echo 'Master is already initated.. nothing to do!'
+else
+	echo 'Initiating the cluster!'
+	cluster_init
+fi

docker-compose.yml

@@ -0,0 +1,34 @@
+mongo-cluster:
+  restart: always
+  environment:
+    MONGO_SERVICE_NAME: mongo-cluster
+  tty: true
+  entrypoint: /opt/rancher/bin/entrypoint.sh
+  command:
+  - --replSet
+  - "rs0"
+  image: mongo:3.0
+  labels:
+    io.rancher.container.hostname_override: container_name
+    io.rancher.sidekicks: mongo-base, mongo-datavolume
+  volumes_from:
+    - mongo-datavolume
+    - mongo-base
+mongo-base:
+  restart: always
+  tty: true
+  labels:
+    io.rancher.container.hostname_override: container_name
+    io.rancher.container.start_once: true
+  build: ./
+  stdin_open: true
+  entrypoint: /bin/true
+mongo-datavolume:
+  net: none
+  labels:
+    io.rancher.container.hostname_override: container_name
+    io.rancher.container.start_once: true
+  volumes:
+    - /data/db
+  entrypoint: /bin/true
+  image: busybox

entrypoint.sh

@@ -0,0 +1,45 @@
+#!/bin/bash
+
+# Installing dnsutils and jq
+echo "deb http://http.debian.net/debian wheezy-backports main" | tee /etc/apt/sources.list.d/wheezy-backports.list > /dev/null
+echo "deb http://security.debian.org/ wheezy/updates main contrib non-free " | tee /etc/apt/sources.list.d/wheezy-security.list > /dev/null
+echo "deb-src http://security.debian.org/ wheezy/updates main contrib non-free" | tee /etc/apt/sources.list.d/wheezy-security.list > /dev/null
+apt-get -q update > /dev/null
+apt-get install -qqy dnsutils jq > /dev/null 2>&1
+
+# Check for lowest ID
+/opt/rancher/bin/lowest_idx.sh
+if [ "$?" -eq "0" ]; then
+    echo "This is the lowest numbered contianer.. Handling the initiation."
+    /opt/rancher/bin/initiate.sh $@
+else
+
+# Run the scaling script
+/opt/rancher/bin/scaling.sh &
+
+# Start mongodb
+if [ $? -ne 0 ]
+then
+echo "Error Occurred.."
+fi
+
+set -e
+
+if [ "${1:0:1}" = '-' ]; then
+	set -- mongod "$@"
+fi
+
+if [ "$1" = 'mongod' ]; then
+	chown -R mongodb /data/db
+
+	numa='numactl --interleave=all'
+	if $numa true &> /dev/null; then
+		set -- $numa "$@"
+	fi
+
+	exec gosu mongodb "$@"
+fi
+
+exec "$@"
+
+fi

initiate.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+
+# Run cluster init script
+/opt/rancher/bin/connect.sh &
+
+# Start mongodb
+if [ $? -ne 0 ]
+then
+echo "Error Occurred.."
+fi
+
+set -e
+
+if [ "${1:0:1}" = '-' ]; then
+       set -- mongod "$@"
+fi
+
+if [ "$1" = 'mongod' ]; then
+       chown -R mongodb /data/db
+
+       numa='numactl --interleave=all'
+       if $numa true &> /dev/null; then
+               set -- $numa "$@"
+       fi
+
+       exec gosu mongodb "$@"
+fi

lowest_idx.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+###
+# Detect if this container has the lowest create ID
+###
+
+META_URL="http://rancher-metadata/2015-07-25"
+
+ALLMETA=$(curl -s -H 'Accept: application/json' ${META_URL})
+MY_CREATE_INDEX="$(echo ${ALLMETA} | jq -r .self.container.create_index)"
+
+get_create_index()
+{
+    echo $(echo ${ALLMETA}| jq -r ".containers[]| select(.name==\"${1}\")| .create_index")
+}
+
+SMALLEST="${MY_CREATE_INDEX}"
+for container in $(echo ${ALLMETA}| jq -r .self.service.containers[]); do
+    IDX=$(get_create_index "${container}")
+    if [ "${IDX}" -lt "${SMALLEST}" ]; then
+        SMALLEST=${IDX}
+    fi
+done
+
+if [ "${MY_CREATE_INDEX}" -eq "${SMALLEST}" ]; then
+  exit 0
+fi
+
+exit 1

rancher-compose.yml

@@ -0,0 +1,2 @@
+mongo-cluster:
+  scale: 3

scaling.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+sleep 5
+DIG=/usr/bin/dig
+
+function scaleup {
+	MYIP=$(ip -o -4 addr list eth0 | awk '{print $4}' | cut -d/ -f1 |  sed -n 2p)
+	$DIG A $MONGO_SERVICE_NAME +short > ips.tmp
+	for IP in $(cat ips.tmp); do
+		IS_MASTER=$(mongo --host $IP --eval "printjson(db.isMaster())" | grep 'ismaster')
+		if echo $IS_MASTER | grep "true"; then
+			mongo --host $IP --eval "printjson(rs.add('$MYIP:27017'))"
+			return 0
+		fi
+	done
+	return 1
+}
+
+# Script starts here
+if [ $($DIG A $MONGO_SERVICE_NAME +short | wc -l) -gt 3 ]; then
+	scaleup
+fi