# What is ScyllaDB ? ScyllaDB is a high-performance NoSQL database system, fully compatible with Apache Cassandra. ScyllaDB is released under the GNU Affero General Public License version 3 and the Apache License, ScyllaDB is free and open-source software. > [ScyllaDB](http://www.scylladb.com/) ![logo](http://www.scylladb.com/img/mascot_1.png) # How to use this image ## Start a `scylla` server instance ```console $ docker run --name some-scylla -d scylladb/scylla ``` ## Run `nodetool` utility ```console $ docker exec -it some-scylla nodetool status Datacenter: datacenter1 ======================= Status=Up/Down |/ State=Normal/Leaving/Joining/Moving -- Address Load Tokens Owns (effective) Host ID Rack UN 172.17.0.2 125.51 KB 256 100.0% c9155121-786d-44f8-8667-a8b915b95665 rack1 ``` ## Run `cqlsh` utility ```console $ docker exec -it some-scylla cqlsh Connected to Test Cluster at 172.17.0.2:9042. [cqlsh 5.0.1 | Cassandra 2.1.8 | CQL spec 3.2.1 | Native protocol v3] Use HELP for help. cqlsh> ``` ## Make a cluster ```console $ docker run --name some-scylla2 -d scylladb/scylla --seeds="$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' some-scylla)" ``` ## Check `scylla` logs ```console $ docker logs some-scylla | tail INFO 2016-08-04 06:57:40,836 [shard 5] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,836 [shard 3] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,836 [shard 1] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,836 [shard 2] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,836 [shard 4] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,836 [shard 7] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,837 [shard 6] database - Setting compaction strategy of system_traces.events to SizeTieredCompactionStrategy INFO 2016-08-04 06:57:40,839 [shard 0] database - Schema version changed to fea14d93-9c5a-34f5-9d0e-2e49dcfa747e INFO 2016-08-04 06:57:40,839 [shard 0] storage_service - Starting listening for CQL clients on 172.17.0.2:9042... INFO 2016-08-04 06:57:40,840 [shard 0] storage_service - Thrift server listening on 172.17.0.2:9160 ... ``` ## Configuring data volume for storage You can use Docker volumes to improve performance of Scylla. Create a Scylla data directory ``/var/lib/scylla`` on the host, which is used by Scylla container to store all data: ```console $ sudo mkdir -p /var/lib/scylla/data /var/lib/scylla/commitlog ``` Launch Scylla using Docker's ``--volume`` command line option to mount the created host directory as a data volume in the container and disable Scylla's developer mode to run I/O tuning before starting up the Scylla node. ```console $ docker run --name some-scylla --volume /var/lib/scylla:/var/lib/scylla -d scylladb/scylla --developer-mode=0 ``` ## Configuring resource limits Scylla utilizes all CPUs and all memory by default. To configure resource limits for your Docker container, you can use the `--smp`, `--memory`, and `--cpuset` command line options documented in the section "Command-line options". If you run multiple Scylla instances on the same machine, it is highly recommended that you enable the `--overprovisioned` command line option, which enables certain optimizations for Scylla to run efficiently in an overprovisioned environment. ## Command-line options The Scylla image supports many command line options that are passed to the `docker run` command. ### `--seeds SEEDS` The `-seeds` command line option configures Scylla's seed nodes. If no `--seeds` option is specified, Scylla uses its own IP address as the seed. For example, to configure Scylla to run with two seed nodes `192.168.0.100` and `192.168.0.200`. ```console $ docker run --name some-scylla -d scylladb/scylla --seeds 192.168.0.100,192.168.0.200 ``` ### `--listen-address ADDR` The `--listen-address` command line option configures the IP address the Scylla instance listens for client connections. For example, to configure Scylla to use listen address `10.0.0.5`: ```console $ docker run --name some-scylla -d scylladb/scylla --listen-address 10.0.0.5 ``` **Since: 1.4** ### `--broadcast-address ADDR` The `--broadcast-address` command line option configures the IP address the Scylla instance tells other Scylla nodes in the cluster to connect to. For example, to configure Scylla to use broadcast address `10.0.0.5`: ```console $ docker run --name some-scylla -d scylladb/scylla --broadcast-address 10.0.0.5 ``` ### `--broadcast-rpc-address ADDR` The `--broadcast-rpc-address` command line option configures the IP address the Scylla instance tells clients to connect to. For example, to configure Scylla to use broadcast RPC address `10.0.0.5`: ```console $ docker run --name some-scylla -d scylladb/scylla --broadcast-rpc-address 10.0.0.5 ``` ### `--smp COUNT` The `--smp` command line option restricts Scylla to `COUNT` number of CPUs. The option does not, however, mandate a specific placement of CPUs. See the `--cpuset` command line option if you need Scylla to run on specific CPUs. For example, to restrict Scylla to 2 CPUs: ```console $ docker run --name some-scylla -d scylladb/scylla --smp 2 ``` ### `--memory AMOUNT` The `--memory` command line options restricts Scylla to use up to `AMOUNT` of memory. The `AMOUNT` value supports both `M` unit for megabytes and `G` unit for gigabytes. For example, to restrict Scylla to 4 GB of memory: ```console $ docker run --name some-scylla -d scylladb/scylla --memory 4G ``` ### `--overprovisioned ENABLE` The `--overprovisioned` command line option enables or disables optimizations for running Scylla in an overprovisioned environment. If no `--overprovisioned` option is specified, Scylla defaults to running with optimizations *disabled*. For example, to enable optimizations for running in an overprovisioned environment: ```console $ docker run --name some-scylla -d scylladb/scylla --overprovisioned 1 ``` ### `--cpuset CPUSET` The `--cpuset` command line option restricts Scylla to run on only on CPUs specified by `CPUSET`. The `CPUSET` value is either a single CPU (e.g. `--cpuset 1`), a range (e.g. `--cpuset 2-3`), or a list (e.g. `--cpuset 1,2,5`), or a combination of the last two options (e.g. `--cpuset 1-2,5`). For example, to restrict Scylla to run on physical CPUs 0 to 2 and 4: ```console $ docker run --name some-scylla -d scylladb/scylla --cpuset 0-2,4 ``` ### `--developer-mode ENABLE` The `--developer-mode` command line option enables Scylla's developer mode, which relaxes checks for things like XFS and enables Scylla to run on unsupported configurations (which usually results in suboptimal performance). If no `--developer-mode` command line option is defined, Scylla defaults to running with developer mode *enabled*. It is highly recommended to disable developer mode for production deployments to ensure Scylla is able to run with maximum performance. For example, to disable developer mode: ```console $ docker run --name some-scylla -d scylladb/scylla --developer-mode 0 ``` # User Feedback ## Issues For bug reports, please use Scylla's [issue tracker](https://github.com/scylladb/scylla/issues) on GitHub. Please read the [How to report a Scylla problem](https://github.com/scylladb/scylla/wiki/How-to-report-a-Scylla-problem) page before you report bugs. For general help, see Scylla's [documentation](http://www.scylladb.com/doc/). For questions and comments, use Scylla's [mailing lists](http://www.scylladb.com/community/). ## Contributing Want to scratch your own itch and contribute a patch. We are eager to review and merge your code. Please consult the [Contributing on Scylla page](http://www.scylladb.com/kb/contributing/)