Connecting to cassandra running in Docker

Question

I'm trying to run Cassandra in a docker container and connect to it from my Mac (the host) but I keep getting Connection refused errors.

The docker command:

=> docker run --rm --name cassandra -d cassandra:3.11 -p 9042:9042

=> docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                                    NAMES
4ecc9dcd8647        cassandra:3.11      "/docker-entrypoin..."   33 minutes ago      Up 33 minutes       7000-7001/tcp, 7199/tcp, 9042/tcp, 9160/tcp   cassandra

=> cqlsh
Connection error: ('Unable to connect to any servers', {'127.0.0.1': 
error(61, "Tried connecting to [('127.0.0.1', 9042)]. Last error: 
Connection refused")})

If I'm executing bash shell in the instance:

=> docker exec -it cassandra bash

I can run the cqlsh and connect to cassandra locally.

What am I missing?

Answer 1

Port is still not exposed outside Try this

• docker run -p 9042:9042 --rm --name cassandra -d cassandra:3.11

Do docker ps you should see something like this

• 0.0.0.0:9042->9042/tcp

For more info : https://docs.docker.com/engine/reference/commandline/run/

Answer 2

Anything passed after docker image name it considers argument to the container entrypoint.

cassandra:3.11 -p 9042:9042

so actually docker pass -p 9042:9042 this as an argument to the entrypoint, you can very this by inspecting docker container.

To run and publish port

docker run -it  - - name cassandra -e CASSANDRA_PASSWORD=cassandra --rm docker.io/bitnami/cassandra:3-debian-10

Once container up then verify connection

docker exec -it cassandra bash -c "cqlsh -u cassandra -p cassandra"