Make sure you have met the System Requirements before you install and configure Scylla.
See System Configuration Guide for details on optimum OS settings for Scylla. (These settings are performed automatically in the Scylla packages, Docker containers, and Amazon AMIs.)
Scylla configuration files are:
||Server startup options|
||Main Scylla configuration file|
||Rack & dc configuration file|
Address Configuration in Scylla¶
The following addresses can be configured in scylla.yaml:
|listen_address||Address Scylla listens for connections from other nodes. See storage_port and ssl_storage_ports.|
|rpc_address||Address on which Scylla is going to expect Thrift and CQL clients connections. See rpc_port, native_transport_port and native_transport_port_ssl in the Networking parameters.|
|broadcast_address||Address that is broadcasted to tell other Scylla nodes to connect to. Related to listen_address above.|
|broadcast_rpc_address||Address that is broadcasted to tell the clients to connect to. Related to rpc_address.|
|seeds||These are broadcast_addresses of seeder nodes.|
|endpoint_snitch||Node’s address resolution helper.|
|api_address||Address for REST API requests. See api_port in the Networking parameters.|
|prometheus_address||Address for Prometheus queries. See prometheus_port in the Networking parameters and Scylla Monitoring for more details.|
|replace_address||Address of the node this Scylla instance is meant to replace. Refer to Replace a Dead Node in a Scylla Cluster for more details.|
When the listen_address, rpc_address, broadcast_address and broadcast_rpc_address parameters are not set correctly, Scylla does not to work as expected.
scylla-server file contains configuration related to starting up the Scylla server.
scylla.yaml is equivalent to the Apache Cassandra cassandra.yaml configuration file, and it is compatible for relevant parameters. Below is a subset of scylla.yaml with parameters you are likely to update. For full list of parameters, look at the file itself.
# The name of the cluster. This is mainly used to prevent machines in # one logical cluster from joining another. cluster_name: 'Test Cluster' # This defines the number of tokens randomly assigned to this node on the ring # The more tokens, relative to other nodes, the larger the proportion of data # that this node will store. You probably want all nodes to have the same number # of tokens assuming they have equal hardware capability. # # If you already have a cluster with 1 token per node, and wish to migrate to # multiple tokens per node, see http://wiki.apache.org/cassandra/Operations num_tokens: 256 # Directory where Scylla should store data on disk. data_file_directories: - /var/lib/scylla/data # commit log. when running on magnetic HDD, this should be a # separate spindle than the data directories. commitlog_directory: /var/lib/scylla/commitlog # seed_provider class_name is saved for future use. # seeds address are mandatory! seed_provider: # Addresses of hosts that are deemed contact points. # Scylla nodes use this list of hosts to find each other and learn # the topology of the ring. You must change this if you are running # multiple nodes! - class_name: org.apache.cassandra.locator.SimpleSeedProvider parameters: # seeds is actually a comma-delimited list of addresses. # Ex: "<ip1>,<ip2>,<ip3>" - seeds: "127.0.0.1" # Address or interface to bind to and tell other Scylla nodes to connect to. # You _must_ change this if you want multiple nodes to be able to communicate! # # Setting listen_address to 0.0.0.0 is always wrong. listen_address: localhost # Address to broadcast to other Scylla nodes # Leaving this blank will set it to the same value as listen_address # broadcast_address: 184.108.40.206 # port for the CQL native transport to listen for clients on # For security reasons, you should not expose this port to the internet. Firewall it if needed. native_transport_port: 9042 # Uncomment to enable experimental features # experimental: true
By default scylla.yaml is located at
/etc/scylla/scylla.yaml. Note that the file will open as read only unless you edit it as the root user or by using sudo.
scylla.yaml required settings¶
The following configuration items must be set
|cluster_name||Name of the cluster, all the nodes in the cluster must have the same name|
|seeds||Seed nodes are used during startup to bootstrap the gossip process and join the cluster|
|listen_address||IP address that the Scylla use to connect to other Scylla nodes in the cluster|
|rpc_address||IP address of interface for client connections (Thrift, CQL)|
internode_compression controls whether traffic between nodes is compressed.
- all - all traffic is compressed.
- dc - traffic between different datacenters is compressed.
- none - nothing is compressed (default).
Configuring TLS/SSL in scylla.yaml¶
Scylla versions 1.1 and greater support encryption between nodes and between client and node. See the Scylla Scylla TLS/SSL guide: for configuration settings.
Scylla uses the following ports:
|7000||Inter-node communication (RPC)||TCP|
|7001||SSL inter-node communication (RPC)||TCP|
|10000||Scylla REST API||TCP|
|9160||Scylla client port (Thrift)||TCP|
All ports above need to be open to external clients (CQL), external admin systems (JMX), and other nodes (RPC). REST API port can be kept closed for external incoming connections.
The JMX service,
scylla-jmx, runs on port 7199. It is required in order to manage Scylla using
nodetool and other Apache Cassandra-compatible utilities. The
scylla-jmx process must be able to connect to port 10000 on localhost. The JMX service listens for incoming JMX connections on all network interfaces on the system.
It is possible that a client, or another node, may need to use a different IP address to connect to a Scylla node from the address that the node is listening on. This is the case when a node is behind port forwarding. Scylla allows for setting alternate IP addresses.
Do not set any IP address to
|listen_address (required)||Address Scylla listens for connections from other nodes. See storage_port and ssl_storage_ports.||No default|
|rpc_address (required)||Address on which Scylla is going to expect Thrift and CQL clients connections. See rpc_port, native_transport_port and native_transport_port_ssl in the Networking parameters.||No default|
|broadcast_address||Address that is broadcasted to tell other Scylla nodes to connect to. Related to listen_address above.||listen_address|
|broadcast_rpc_address||Address that is broadcasted to tell the clients to connect to. Related to rpc_address.||rpc_address|
If other nodes can connect directly to
broadcast_address does not need to be set.
If clients can connect directly to
broadcast_rpc_address does not need to be set.
For tips and examples on how to configure these addresses, refer to How to Properly Set Address Values in scylla.yaml
On RHEL and CentOS, the Automatic Bug Reporting Tool (ABRT) conflict with Scylla coredump configuration. Remove it before installing Scylla:
sudo yum remove -y abrt
Scylla places any core dumps in
var/lib/scylla/coredump. They are not visible with the
coredumpctl command. See the System Configuration Guide for details on core dump configuration scripts. Check with Scylla support before sharing any core dump, as they may contain sensitive data.
Scylla sets up daily fstrim on the filesystem(s). Containing your Scylla commitlog and data directory. This utility will discard, or trim, any blocks no longer in use by the filesystem.
Scylla exposes interfaces for online monitoring, as described below.
Scylla JMX is compatible with Apache Cassandra, exposing the relevant subset of MBeans.
For each JMX operation, attribute get and set, Scylla exposes a matching REST API. You can interact with the REST API using
curl or using the Swagger UI available at
Scylla is designed for high performance before tuning, for fewer layers that interact in unpredictable ways, and to use better algorithms that do not require manual tuning. The following items are found in the manuals for other data stores, but do not need to appear here.
- Generating tokens
- Configuring virtual nodes
- Tuning Bloom filters
- Data caching
- Configuring memtable throughput
- Configuring compaction
Testing compaction and compression¶
- Tuning Java resources
- Purging gossip state on a node
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