Unwanted too many arguments error being printed out - bash

Question

I am writing a bash script that logs into remote nodes and returns the services being run on that node.
#!/bin/bash
declare -a SERVICES=('redis-server' 'kube-controller-manager' 'kubelet' 'postgres' 'mongod' 'elasticsearch');
for svc in "${SERVICES[#]}"
do
RESULT=`ssh 172.29.219.109 "ps -ef | grep -v grep | grep $svc"`
if [ -z ${RESULT} ]
then
echo "Is Empty" > /dev/null
else
echo "$svc is running on this node"
fi
done
Now the output of ssh 172.29.219.109 "ps -ef | grep -v grep | grep $svc" on the node is ::
postgres 2102 1 0 Jan29 ? 00:24:27 /opt/PostgresPlus/pgbouncer/bin/pgbouncer -d /opt/PostgresPlus/pgbouncer/share/pgbouncer.ini
postgres 2394 1 0 Jan29 ? 00:20:10 /opt/PostgresPlus/9.4AS/bin/edb-postgres -D /opt/PostgresPlus/9.4AS/data
postgres 2431 2394 0 Jan29 ? 00:00:01 postgres: logger process
postgres 2434 2394 0 Jan29 ? 00:07:15 postgres: checkpointer process
postgres 2435 2394 0 Jan29 ? 00:01:10 postgres: writer process
postgres 2436 2394 0 Jan29 ? 00:03:27 postgres: wal writer process
postgres 2437 2394 0 Jan29 ? 00:20:03 postgres: autovacuum launcher process
postgres 2438 2394 0 Jan29 ? 00:37:00 postgres: stats collector process
postgres 2494 1 0 Jan29 ? 00:08:12 /opt/PostgresPlus/9.4AS/bin/pgagent -l 1 -s /var/log/ppas-agent-9.4.log hostaddr=localhost port=5432 dbname=postgres user=postgres
postgres 2495 2394 0 Jan29 ? 00:11:25 postgres: postgres postgres 127.0.0.1[59246] idle
When I run the script, I do get the result I want but Im getting an unwanted message which seems to be related to the variable in which I am storing my result.
# ./map_services_to_nodes.sh
./map_services_to_nodes.sh: line 12: [: too many arguments
postgres is found on this node
The Algo that I im using is ::
Search for all services defined in my array.
Store the result in a variable.
If Variable is empty, that means that service is not running.
If its not empty, service is running.

Answer 1

You need to escape $ (to avoid local expansion) and " when using inside ssh command, also avoid using the outdated back-ticks for command-substitution, use $(..), see Why Use $(STATEMENT) instead of legacy STATEMENT
RESULT=$(ssh 172.29.219.109 "ps -ef | grep -v grep | grep \$svc")
and double quote variables inside test operator,
if [ -z "${RESULT}" ]

Answer 2

Changed the below
if [ -z ${RESULT} ]
to
if [ -z "${RESULT}" ]
and it worked.
# ./map_services_to_nodes.sh
postgres is found on this node