CODEWITHSUNDEEP
ubuntucassandra
Payal
Payal

Reputation: 564

Cassandra nodes can not talk to each other

I've installed cassandra on 3 AWS EC2 instances but none of them can ping each other neither do telnet on 7000.

telnet tm1 7000 Trying 172.31.30.37... telnet: Unable to connect to remote host: Connection timed out

Below is the output for netstat

netstat -na|grep LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp6 0 0 :::22 :::* LISTEN

I understand for cassandra inter node communication i need to have 7000 port open but wondering how can i make it listen on ubuntu.

Any help would be appreciated !

Upvotes: 0

Views: 673

Answers (1)

markc
markc

Reputation: 2158

Ok so you're testing TCP communication for port 7000 here, but this could be any port really. The first thing you need to do is setup a process to listen on a port and then test the connection (a TCP socket must first be opened before you can test connectivity to it).

You can use netcat (nc) which is an ideal tool to check this. Ensure you have it installed first then you can run up a "server" to bind to a port like so:

nc -l 0.0.0.0 7000

Then you can check to make sure its listening

$ netstat -lnt | awk '/7000/;NR==2'
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:7000            0.0.0.0:*               LISTEN

Finally check connectivity from your other node like so:

$ nc -v -w2 10.1.2.3 7000
Connection to 10.1.2.3 7000 port [tcp/afs3-bos] succeeded!

The -vis for verbose and the -w is a timeout

Note outside of testing ports, ping is not going to be a good test for general connectivity because in a lot of cases ICMP packets are dropped (security). So if it doesn't ping, it doesn't mean you have a connection issue.

Upvotes: 3

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