Bash script that checks status for docker swarm services and nodes.

docker-status.sh

#!/bin/bash

#####################################################################################
## docker-status.sh - Bash script that checks status for docker swarm services and nodes.
## Functions: 
# check_replication - Check if all stacks are running in service.
# check_swarm_nodes - Check if all nodes are reacheble and healthy. 
# check_swarm_services - Check if any of the services failed. 
#####################################################################################

set tabstop=8 softtabstop=0 expandtab shiftwidth=4 smarttab

set -o pipefail

STATE_OK=0
STATE_WARNING=1
STATE_CRITICAL=2
STATE_UNKNOWN=3

warning=0
critical=0
unknown=0
state_replicated=0
state_swarm=0

if [ "$(whoami)" != "root" ]; then
    echo "Root privileges are required to run this, try running with sudo..."
    exit $STATE_CRITICAL
fi

if [ "x$(which docker)" == "x" ]; then
    echo "UNKNOWN - Missing docker binary"
    exit $STATE_UNKNOWN
fi

systemctl status docker > /dev/null 2>&1
if [ "${?}" != 0 ]; then 
    echo "Docker daemon is not running"
    exit ${STATE_CRITICAL} 
fi

which json_reformat > /dev/null 2>&1
if [ "${?}" -ne 0 ]; then
    echo "json_reformat is not installed"
    exit ${STATE_CRITICAL} 
fi

usage() {
echo "Usage: 
$0 swarm_check				
$0 check_replication
$0 check_swarm_services"

return $STATE_WARNING
}

function isManager(){
    isManaget=`docker info | grep 'Is Manager'| awk -F' ' '{print $3}'`
    if [ "${isManaget}" == "false" ]; then
            echo "OK - Not a swarm master"
            exit 0
    fi
}

function check_swarm_nodes(){
    isManager
    for NODE in `docker node ls | egrep 'Leader|Reachable|Reachable'| awk '{print $1}'`;do
        ManagerStatus=$(docker node inspect --format="{{.ManagerStatus.Reachability}}" $NODE) > /dev/null 2>&1
        if  [ "$ManagerStatus" == "Unavailable" ]; then
            let "state_swarm=state_swarm+1"
        fi
    done

    if [ "$state_swarm" -gt 0 ]; then
        echo "CRITICAL - Not all swarm nodes are healthy"
    else
        echo "OK - All swarm nodes are healthy" 
    fi 
    return $state_swarm
}

function check_replication(){
    isManager
    for i in `docker service ls -q`; do
    replicated=`docker service inspect --pretty $i | grep -i "Service Mode" | awk '{print $3}'`
    if [ "${replicated}" == "Replicated" ]; then
        replicas=`docker service inspect --pretty $i | grep -i replicas | awk '{print $2}'`
        running_replicas=`docker service ps $i |grep -i running | wc -l`
        if [ ${replicas} -ne "${running_replicas}" ]; then
                let "state_replicated=state_replicated+1"
        fi
    fi
    done 

    if [ "$state_replicated" -gt 0 ]; then
        echo "CRITICAL - Not all services are replicated"
    else
        echo "OK - All services are replicated" 
    fi 
    return $state_replicated
}

function check_swarm_services(){  
    isManager
    for i in `docker service ls -q`; do
	docker service ps $i | grep -E "Failed [0-9]* second" > /dev/null 2&1
	if [ "${?}" -ne 0 ]; then
		echo "CRITICAL - Some services failed to start"
	fi
    done 
}

### Main
case "$1" in
        check_replication)
            check_replication
            ;;
        swarm_check)
            check_swarm_nodes
            ;;
        swarm_service_check)
            check_swarm_services
            ;;
        *)
	    usage
	    exit $?
esac
### END

Can you help on this with mail alert for down one replication in docker swarm and service

@rairaghul with what exactly could I help? Please keep in mind I wrote this script during the first days in Docker Swarm.