I have 3 nodes. As per lab instructions the first two nodes have to be brought down. Now in node 3 i am unable to connect to cqlsh. It keeps throwing error. I have tried providing the explicit ip and port as mentioned in an earlier lab. Please let know how to we connect to db from node 3.
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Erick Ramirez for the following reason: The question is answered, right answer was accepted
Why can't I connect with cqlsh to node 3 in exercise 14 of the Academy DS201 course?
Connection error: ('Unable to connect to any servers', {'127.0.0.3': error(111, "Tried connecting to [('127.0.0.3', 9043)]. Last error: Connection refused")})
I suspect the problem you're encountering is similar to Why can't I connect to nodes in the DS201 Academy VM with cqlsh or nodetool?.
CQL clients configuration
cqlsh by default connects to CQL port 9042 but because all DSE instances are running in the same VM, they have to be configured to listen to different ports. The nodes in the DS201 VM are configured as follows:
$ for _node in node*; do echo "$_node - `grep ^native_transport_port $_node/resources/cassandra/conf/cassandra.yaml`"; done node1 - native_transport_port: 9041 node2 - native_transport_port: 9042 node3 - native_transport_port: 9043
However, all the 3 ports are bound to 127.0.0.1:
$ for _node in node*; do echo "$_node - `grep ^native_transport_address $_node/resources/cassandra/conf/cassandra.yaml`"; done node1 - native_transport_address: localhost node2 - native_transport_address: localhost node3 - native_transport_address: localhost
Sample VM
When I check on my copy of the VM, I can confirm that CQL clients (cqlsh is just another client) can only connect on localhost:
$ sudo lsof -nPi | grep LISTEN | grep 904 java 1544 ubuntu 481u IPv4 19709 0t0 TCP 127.0.0.1:9041 (LISTEN) java 2135 ubuntu 485u IPv4 24848 0t0 TCP 127.0.0.1:9042 (LISTEN) java 18820 ubuntu 480u IPv4 45516 0t0 TCP 127.0.0.1:9043 (LISTEN)
This means that you won't be able to connect to any IP other than 127.0.0.1.
Solution
In order to connect to node 3, run cqlsh with the following parameters:
$ cqlsh 127.0.0.1 9043
Cheers!
In case another user gets into the same situation I just ran into.
Following Exercise 14 step by step, i execute the partition command and see:
ubuntu@ds201-node1:~$ /home/ubuntu/node1/resources/cassandra/bin/nodetool getendpoints killrvideo videos_by_tag 'cassandra' 127.0.0.1 127.0.0.2
I then stop #1 and #2 and try to cqsl to #3. Per document this should be:
where X is the number of the node you are connecting to.
nodeX/bin/cqlsh 127.0.0.X 904X
ubuntu@ds201-node1:~$ /home/ubuntu/node3/resources/cassandra/bin/cqlsh 127.0.0.3 9043
Connection error: ('Unable to connect to any servers', {'127.0.0.3': error(111, "Tried connecting to [('127.0.0.3', 9043)]. Last error: Connection refused")})
Next I try as suggested above 127.0.0.1 w/ 9043 port and still no luck. Then I start investigating the scripts Erick shared and not getting output as above. It turns out that node 3 was not online. I had to start node 3.
ubuntu@ds201-node1:~$ sudo lsof -nPi | grep LISTEN | grep 904 java 9287 ubuntu 598u IPv4 91894 0t0 TCP 127.0.0.1:9043 (LISTEN) ubuntu@ds201-node1:~$ /home/ubuntu/node3/resources/cassandra/bin/cqlsh 127.0.0.1 9043 Connected to Test Cluster at 127.0.0.1:9043. [cqlsh 5.0.1 | Cassandra 4.0.0.2284 | DSE 6.0.0 | CQL spec 3.4.5 | DSE protocol v2] Use HELP for help. cqlsh>
I think the excercise PDF needs to be adjusted to:
nodeX/bin/cqlsh 127.0.0.1 904X
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