Sample airflow dag for ssh tunnel + postgres (assuming both SERVER_ssh_connector and SERVER_ssh_postresql_tunnel_connector are available)

ssh_tunnel_postgres.py

from datetime import timedelta, datetime
import airflow
from airflow import DAG
from airflow.models import Variable
from airflow.contrib.operators.ssh_operator import SSHOperator
from airflow.contrib.hooks.ssh_hook import SSHHook
from airflow.operators.postgres_operator import PostgresOperator

default_args = {
    'owner': 'airflow',
    'depends_on_past': False,
    'retries': 5,
    'retry_delay': timedelta(minutes=5),
}

dag = DAG(
    dag_id='testing_postgres_tunnel_ssh',
    default_args=default_args,
    start_date=datetime(2019, 12, 1),
    end_date=datetime(2019, 12, 30),
    schedule_interval= timedelta(minutes=10) #'@daily'
)

REMOTE_BIND_IP = Variable.get('SERVER_REMOTE_BIND_IP')
REMOTE_BIND_PORT = Variable.get('SERVER_REMOTE_BIND_PORT')
LOCAL_BIND_PORT = Variable.get('SERVER_LOCAL_BIND_PORT')

ssh_hook = SSHHook(ssh_conn_id='SERVER_ssh_connector', keepalive_interval=60).get_tunnel(
    int(REMOTE_BIND_PORT),
    remote_host=REMOTE_BIND_IP,
    local_port=int(LOCAL_BIND_PORT)
).start()

ssh_operator = SSHOperator(
    ssh_hook=ssh_hook,
    task_id='open_tunnel_to_SERVER',
    command='ls -al',
    dag=dag
)

postgres_operator = PostgresOperator(
    postgres_conn_id='SERVER_ssh_postresql_tunnel_connector',
    sql="select * from users limit 100",
    task_id='get_users_from_SERVER_postgres_table',
    dag=dag
)

ssh_operator >> postgres_operator

Hey guys, I made an Kubernetes SSH Tunnel operator and dashboard , check it out may help
https://github.com/ngn-au/whiplash

There are couple of things to tweek in here to make this work!
hook part should be something like the following:

ssh_hook = SSHHook(ssh_conn_id='SERVER_ssh_connector', keepalive_interval=60)
ssh_hook.get_tunnel(
    int(REMOTE_BIND_PORT),
    remote_host=REMOTE_BIND_IP,
    local_port=int(LOCAL_BIND_PORT)
).start()

# and then pass it to operator
ssh_operator = SSHOperator(
    ssh_hook=ssh_hook,
    task_id='open_tunnel_to_SERVER',
    command='ls -al',
    dag=dag
)

!! IMPORTANT thing to remember is the mapping of remote host and port to your local
when opening the tunnel you should specify remote_host as your postgres host and port to the port your postgres communicate with.
Then when creating connection in your postgres operator the connection should be to your locahost and the port.

So, what this setup does, it will create a tunnel to access the postgres_host:port from your localhost:port