How to verify a cassandra running on linux? - cassandra

Question

Now I have a VM on google cloud platform which was created by someone else
and he configured a cassandra on the VM.I'd like to access this cassandra node.
I used the IP to access it, but I failed.I don't know whether the cassandra is running on the VM.
How can I verify that?

Answer 1

If you can access over ssh then ps aux | grep cassandra or try to telnet 9042 port.

Answer 2

At first, ssh to the server by using your username , password and ip:
For Example:
$ ssh jack#11.1.41.1
Use jps to find the cassandra process:
[jack#11.1.41.1 ~]$ jps
1136 CassandraDaemon
15314 Jps
If you see, CassandraDaemon is running with a process id, then you can be assured that cassandra is running on this server.
You can try Nodetool to check the status too. If Nodetool command worked, then it's confirmed that cassandra is running.
[jack#11.1.41.1 ~]$ nodetool status

Answer 3

By default, Google Compute Engine VMs only expose port 22 (SSH), not any application ports, because that would be insecure.
If you want to connect to a Cassandra server running on a GCE VM, you should create an SSH tunnel with port forwarding, and then access the Cassandra server via that SSH tunnel.
Specifically, follow the tutorial by running this command (adjusted from the original to use the Cassandra port 9042 for native clients):
gcloud compute ssh example-instance \
--project my-project \
--zone us-central1-a \
--ssh-flag="-L" \
--ssh-flag="2222:localhost:9042"
In the above command, the parameters are defined as follows:
example-instance is the name of the instance to which you'd like to
connect.
my-project is your Google Cloud Platform project ID.
us-central1-a is the zone in which your instance is running.
2222 is the local port you're listening on.
9042 is the remote port you're connecting to.
[...]
The gcloud command creates and maintains an SSH connection, and this approach only works while the SSH session is active. As soon as you exit the SSH session that gcloud creates, port forwarding via localhost:2222 will stop working.
If you want to create more than one port forwarding rule, you can specify multiple rules on a single command line by repeating the flags:
gcloud compute ssh example-instance \
--project my-project \
--zone us-central1-a \
--ssh-flag="-L" \
--ssh-flag="2222:localhost:9042" \
--ssh-flag="-L" \
--ssh-flag="2299:localhost:8000"
Alternatively, you can run a new gcloud command each time to create a separate tunnel. Note that you cannot add or remove port forwarding from an existing connection without exiting and re-establishing the connection from scratch.
Make appropriate substitutions as necessary; for example, according to the Cassandra docs on port usage:
By default, Cassandra uses 7000 for cluster communication (7001 if SSL is enabled), 9042 for native protocol clients, and 7199 for JMX (and 9160 for the deprecated Thrift interface). The internode communication and native protocol ports are configurable in the Cassandra Configuration File. The JMX port is configurable in cassandra-env.sh (through JVM options). All ports are TCP.
If you have a custom configuration for Cassandra ports, you will need to take that into account, of course.