Test client connection

In various scenarios, such as after creating a new cluster or upgrading the cluster, it is highly advisable to verify client connectivity to the database.

To test client connectivity:

1. Create a Redis database and get the database endpoint, which contains the cluster name (FQDN).
2. Try to connect to the database endpoint from your client of choice, and run database commands.
3. If the database does not respond, try to connect to the database endpoint using the IP address rather than the FQDN. If you succeed, then DNS is not properly configured. For additional details, see Configure cluster DNS.

If any issues occur when testing database connections, contact support.

Test database connections

After you create a Redis database, you can connect to your database and store data using one of the following methods:

• redis-cli, the built-in command-line tool

• An application using a Redis client library, such as redis-py for Python

Connect with redis-cli

Connect to your database with redis-cli (located in the /opt/redislabs/bin directory), then store and retrieve a key:

$ redis-cli -h <endpoint> -p <port>
127.0.0.1:16653> set key1 123
OK
127.0.0.1:16653> get key1
"123"

For more redis-cli connection examples, see the redis-cli reference.

Connect with Python

Python applications can connect to the database using the redis-py client library. For installation instructions, see the redis-py README on GitHub.

1. From the command line, create a new file called redis_test.py:

   vi redis_test.py
   

2. Paste the following code in redis_test.py, and replace <host> and <port> with your database’s endpoint details:

   import redis
   
   # Connect to the database
   r = redis.Redis(host='<host>', port=<port>)
   
   # Store a key
   print("set key1 123")
   print(r.set('key1', '123'))
   
   # Retrieve the key
   print("get key1")
   print(r.get('key1'))
   

3. Run the application:

   python redis_test.py
   

4. If the application successfully connects to your database, it outputs:

   set key1 123
   True
   get key1
   123
   

Connect with discovery service

You can also connect a Python application to the database using the discovery service, which complies with the Redis Sentinel API.

In the IP-based connection method, you only need the database name, not the port number. The following example uses the discovery service that listens on port 8001 on all nodes of the cluster to discover the endpoint for the database named “db1”.

from redis.sentinel import Sentinel

# with IP based connections, a list of known node IP addresses is constructed
# to allow connection even if any one of the nodes in the list is unavailable.
sentinel_list = [
('10.0.0.44', 8001),
('10.0.0.45', 8001),
('10.0.0.46', 8001)
]

# change this to the db name you want to connect
db_name = 'db1'

sentinel = Sentinel(sentinel_list, socket_timeout=0.1)
r = sentinel.master_for(db_name, socket_timeout=0.1)

# set key "foo" to value "bar"
print(r.set('foo', 'bar'))
# set value for key "foo"
print(r.get('foo'))

For more redis-py connection examples, see the redis-py developer documentation.