Aim: to configure a multi node Cassandra cluster on Centos7
Method
This documentation is used to configure a multi node Cassandra cluster.
[user@cassandra01 ~]$ cat /etc/cassandra/conf/cassandra.yaml
cluster_name: 'MyCassandraCluster'
num_tokens: 256
seed_provider:
- class_name: org.apache.cassandra.locator.SimpleSeedProvider
parameters:
- seeds: "<ipaddress_cassandra01>,<ipaddress_cassandra02>"
listen_address:
rpc_address: 0.0.0.0
endpoint_snitch: GossipingPropertyFileSnitch
Problem
When the first Cassandra node has been started by issuing:
sudo systemctl start cassandra
the node does not seem to start and the /var/log/cassandra/cassandra.log
indicates that:
INFO 12:56:38,057 Loading settings from file:/etc/cassandra/default.conf/cassandra.yaml
INFO 12:56:40,073 Data files directories: null
INFO 12:56:40,089 Commit log directory: null
ERROR 12:56:40,097 Fatal configuration error
org.apache.cassandra.exceptions.ConfigurationException: Missing required directive CommitLogSync
at org.apache.cassandra.config.DatabaseDescriptor.applyConfig(DatabaseDescriptor.java:148)
at org.apache.cassandra.config.DatabaseDescriptor.<clinit>(DatabaseDescriptor.java:112)
at org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:213)
at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:554)
at org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:643)
Missing required directive CommitLogSync
Fatal configuration error; unable to start. See log for stacktrace.
Attempt to solve the issue
According the error message it looks like that there is a configuration issue or certain directories do not exist.
1) Missing required directive CommitLogSync
:
According this documentation there is a default commitlog_sync
, i.e.:
commitlog_sync (Default: periodic ) The method that Cassandra uses to acknowledge writes in milliseconds:
periodic : Used with commitlog_sync_period_in_ms (Default: 10000 - 10 seconds ) to control how often the commit log is
synchronized to disk. Periodic syncs are acknowledged immediately. batch : Used with commitlog_sync_batch_window_in_ms (Default: disabled **) to control how long Cassandra waits for other writes before performing a sync. When using this method, writes are not acknowledged until fsynced to disk.
2) Data files directories: null
:
data_file_directories (Default: /var/lib/cassandra/data ) The directory location where table data (SSTables) is stored.
Issuing ls /var/lib/cassandra/data
returns a 0
and indicates that the directory exists.
3) Commit log directory: null
:
commitlog_directory (Default: /var/lib/cassandra/commitlog ) The directory where the commit log is stored. For optimal write performance, it is recommended the commit log be on a separate disk partition (ideally, a separate physical device) from the data file directories.
Confirmed that the /var/lib/cassandra/commitlog
directory exists as well.
Question
What is causing this issue and how to solve it?