When using the IPv6 address of nodes in a cluster, connections to the native port (9042 by default) are refused
The user is unable to connect applications using the driver or any other clients using the native port into the cluster. Thrift connections seem to be allowed via IPv6. A simple test with netcat or telnet shows the following:
# nc -v -w1 2001::300 9042
Ncat: Connection refused.
The default DSE settings are configured for IPv4. Also IPv6 is generally disabled in /etc/sysctl.conf
1. Change the /etc/sysctl.conf file to allow IPv6
net.ipv6.conf.all.disable_ipv6 = 0
net.ipv6.conf.default.disable_ipv6 = 0
2 - Reload sysctl
# sysctl -p
3. Enable IPv6 in the /etc/dse/cassandra/cassandra-env.sh by commenting out the following line
# JVM_OPTS="$JVM_OPTS -Djava.net.preferIPv4Stack=true"
4. Add a IPv6 address (optional as one might already be configured)
ip -6 addr add dev eth0 2001::1002/64
5. Change the cassandra.yaml to use interface or address as you prefer.
# rpc_address: 0.0.0.0 rpc_interface: eth0 rpc_interface_prefer_ipv6: true
6. Check netcat / netstat
# nc -v -w1 -6 2001::1002 9042 Connection to 2001::1002 9042 port [tcp/*] succeeded!# netstat -ant | awk 'NR==2;/9160/;/9042/' Proto Recv-Q Send-Q Local Address Foreign Address State tcp6 0 0 2001::1002:9160 :::* LISTEN tcp6 0 0 2001::1002:9042 :::* LISTEN
7. Check cqlsh
# cqlsh 2001::1002 -u cassandra -p cassandra Connected to DRWP at 2001::1002:9042. [cqlsh 5.0.1 | Cassandra 126.96.36.1999 | DSE 4.7.3 | CQL spec 3.2.0 | Native protocol v3] Use HELP for help. cassandra@cqlsh>
The following issue also addresses issues with native port binding in Cassandra
Related tech notes
Clients of DSE also include OpsCenter so check that your OpsCenter version has IPv6 support