scylladb/docs/dev/docker-hub.md

Docker Hub Image

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

ScyllaDB Docker supports x86_64 for all versions, and aarch64 starting from ScyllaDB 4.6. Get it now with ScyllaDB nightly build

Quick start

To startup a ScyllaDB single-node cluster in developer mode, execute:

$ docker run --name some-scylla --hostname some-scylla -d scylladb/scylla --smp 1

This command will start a ScyllaDB single-node cluster in developer mode (see --developer-mode 1) limited by a single CPU core (see --smp). Production grade configuration requires tuning a few kernel parameters such that limiting the number of available cores (with --smp 1) is the simplest way to go.

Using multiple cores requires setting a proper value to the /proc/sys/fs/aio-max-nr. On many non-production systems, it will be equal to 65K. The formula to calculate the proper value is:

Available AIO on the system - (request AIO per-cpu * ncpus) =
aio_max_nr - aio_nr < (reactor::max_aio + detect_aio_poll + reactor_backend_aio::max_polls) * cpu_cores =
aio_max_nr - aio_nr < (1024 + 2 + 10000) * cpu_cores =
aio_max_nr - aio_nr < 11026 * cpu_cores

where

reactor::max_aio = max_aio_per_queue * max_queues,
max_aio_per_queue = 128,
max_queues = 8.

How to use this image

Start a scylla server instance

$ docker run --name some-scylla --hostname some-scylla -d scylladb/scylla

Run nodetool utility

$ 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

$ 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

$ docker run --name some-scylla2  --hostname some-scylla2 -d scylladb/scylla --seeds="$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' some-scylla)"

Make a cluster with Docker Compose

First, create a docker-compose.yml file with the following contents:

version: '3'

services:
  some-scylla:
    image: scylladb/scylla
    container_name: some-scylla

  some-scylla2:
    image: scylladb/scylla
    container_name: some-scylla2
    command: --seeds=some-scylla

  some-scylla3:
    image: scylladb/scylla
    container_name: some-scylla3
    command: --seeds=some-scylla

Then, launch the 3-node cluster as follows:

docker-compose up -d

Check scylla logs

$ 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 the performance of ScyllaDB.

Create a Scylla data directory /var/lib/scylla on the host, which is used by the ScyllaDB container to store all the data:

$ sudo mkdir -p /var/lib/scylla/data /var/lib/scylla/commitlog /var/lib/scylla/hints /var/lib/scylla/view_hints

Launch ScyllaDB using Docker's --volume command line option to mount the created host directory as a data volume in the container and disable ScyllaDB's developer mode to run I/O tuning before starting up the ScyllaDB node.

$ docker run --name some-scylla --volume /var/lib/scylla:/var/lib/scylla -d scylladb/scylla --developer-mode=0

Configuring resource limits

The ScyllaDB docker image defaults to running on overprovisioned mode and won't apply any CPU pinning optimizations, which it normally does in non-containerized environments. For better performance, it is recommended to configure resource limits for your Docker container using the --smp, --memory, and --cpuset command line options, as well as disabling the overprovisioned flag as documented in the section "Command-line options".

Restart ScyllaDB

The Docker image uses supervisord to manage ScyllaDB processes. You can restart ScyllaDB in a Docker container using:

docker exec -it some-scylla supervisorctl restart scylla

Command-line options

The ScyllaDB image supports many command line options that are passed to the docker run command.

--seeds SEEDS

The -seeds command line option configures ScyllaDB's seed nodes. If no --seeds option is specified, ScyllaDB uses its own IP address as the seed.

For example, to configure ScyllaDB to run with two seed nodes 192.168.0.100 and 192.168.0.200:

$ 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 ScyllaDB instance listens on for connections from other ScyllaDB nodes.

For example, to configure ScyllaDB to use listen address 10.0.0.5:

$ docker run --name some-scylla -d scylladb/scylla --listen-address 10.0.0.5

Since: 1.4

--alternator-address ADDR

The --alternator-address command line option configures the Alternator API listen address. The default value is the same as --listen-address.

Since: 3.2

--alternator-port PORT

The --alternator-port command line option configures the Alternator API listen port. The Alternator API is disabled by default. You need to specify the port to enable it.

For example, to configure ScyllaDB to listen to Alternator API at port 8000:

$ docker run --name some-scylla -d scylladb/scylla --alternator-port 8000

Since: 3.2

--alternator-https-port PORT

The --alternator-https-port option is similar to --alternator-port, just enables an encrypted (HTTPS) port. Either the --alternator-https-port or --alternator-http-port, or both, can be used to enable Alternator.

Note that the --alternator-https-port option also requires that files /etc/scylla/scylla.crt and /etc/scylla/scylla.key be inserted into the image. These files contain an SSL certificate and key, respectively.

Since: 4.2

--alternator-write-isolation policy

The --alternator-write-isolation command line option chooses between four allowed write isolation policies described in docs/alternator/alternator.md. This option must be specified if Alternator is enabled - it does not have a default.

Since: 4.1

--broadcast-address ADDR

The --broadcast-address command line option configures the IP address the ScyllaDB instance tells other ScyllaDB nodes in the cluster to connect to.

For example, to configure ScyllaDB to use broadcast address 10.0.0.5:

$ 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 ScyllaDB instance tells clients to connect to.

For example, to configure ScyllaDB to use broadcast RPC address 10.0.0.5:

$ docker run --name some-scylla -d scylladb/scylla --broadcast-rpc-address 10.0.0.5

--smp COUNT

The --smp command line option restricts ScyllaDB 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 ScyllaDB to run on specific CPUs.

For example, to restrict ScyllaDB to 2 CPUs:

$ docker run --name some-scylla -d scylladb/scylla --smp 2

--memory AMOUNT

The --memory command line option restricts ScyllaDB 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 ScyllaDB to 4 GB of memory:

$ docker run --name some-scylla -d scylladb/scylla --memory 4G

--reserve-memory AMOUNT

The --reserve-memory command line option configures ScyllaDB to reserve the AMOUNT of memory to the OS. The AMOUNT value supports both M unit for megabytes and G unit for gigabytes.

For example, to reserve 4 GB of memory to the OS:

$ docker run --name some-scylla -d scylladb/scylla --reserve-memory 4G

--overprovisioned ENABLE

The --overprovisioned command line option enables or disables optimizations for running ScyllaDB in an overprovisioned environment. If no --overprovisioned option is specified, ScyllaDB defaults to running with optimizations enabled. If --overprovisioned is not specified and is left at its default, specifying --cpuset will automatically disable --overprovisioned

For example, to enable optimizations for running in an statically partitioned environment:

$ docker run --name some-scylla -d scylladb/scylla --overprovisioned 0

--io-setup ENABLE

The --io-setup command line option specifies if the scylla_io_setup script is run when the container is started for the first time. This is useful if users want to specify I/O settings themselves in environments such as Kubernetes, where running iotune is problematic. The default of --io-setup is 1, which means I/O setup is run.

For example, to skip running I/O setup:

$ docker run --name some-scylla -d scylladb/scylla --io-setup 0

Since: 4.3

--cpuset CPUSET

The --cpuset command line option restricts ScyllaDB 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 ScyllaDB to run on physical CPUs 0 to 2 and 4:

$ docker run --name some-scylla -d scylladb/scylla --cpuset 0-2,4

--developer-mode ENABLE

The --developer-mode command line option enables ScyllaDB's developer mode, which relaxes checks for things like XFS and enables ScyllaDB to run on unsupported configurations (which usually results in suboptimal performance). If no --developer-mode command line option is defined, ScyllaDB defaults to running with developer mode enabled. It is highly recommended to disable developer mode for production deployments to ensure ScyllaDB is able to run with maximum performance.

For example, to disable developer mode:

$ docker run --name some-scylla -d scylladb/scylla --developer-mode 0

--experimental ENABLE

The --experimental command line option enables ScyllaDB's experimental mode If no --experimental command line option is defined, ScyllaDB defaults to running with experimental mode disabled. It is highly recommended to disable experimental mode for production deployments.

For example, to enable experimental mode:

$ docker run --name some-scylla -d scylladb/scylla --experimental 1

Since: 2.0

--disable-version-check

The --disable-version-check disable the version validation check.

Since: 2.2

--authenticator AUTHENTICATOR

The --authenticator command lines option allows to provide the authenticator class ScyllaDB will use. By default ScyllaDB uses the AllowAllAuthenticator which performs no credentials checks. The second option is using the PasswordAuthenticator parameter, which relies on username/password pairs to authenticate users.

Since: 2.3

--authorizer AUTHORIZER

The --authorizer command lines option allows to provide the authorizer class ScyllaDB will use. By default ScyllaDB uses the AllowAllAuthorizer which allows any action to any user. The second option is using the CassandraAuthorizer parameter, which stores permissions in system.permissions table.

Since: 2.3

JMX parameters

JMX ScyllaDB service is initialized from the /scylla-jmx-service.sh on container startup. By default the script uses /etc/sysconfig/scylla-jmx to read the default configuration. It then can be overridden by setting environmental parameters.

An example:

docker run -d -e "SCYLLA_JMX_ADDR=-ja 0.0.0.0" -e SCYLLA_JMX_REMOTE=-r --publish 7199:7199 scylladb/scylla

SCYLLA_JMX_PORT

Scylla JMX listening port.

Default value:

SCYLLA_JMX_PORT="-jp 7199"

SCYLLA_API_PORT

Scylla API port for JMX to connect to.

Default value:

SCYLLA_API_PORT="-p 10000"

SCYLLA_API_ADDR

Scylla API address for JMX to connect to.

Default value:

SCYLLA_API_ADDR="-a localhost"

SCYLLA_JMX_ADDR

JMX address to bind on.

Default value:

SCYLLA_JMX_ADDR="-ja localhost"

For example, it is possible to make JMX available to the outer world by changing its bind address to 0.0.0.0:

docker run -d -e "SCYLLA_JMX_ADDR=-ja 0.0.0.0" -e SCYLLA_JMX_REMOTE=-r --publish 7199:7199 scylladb/scylla

cassandra-stress requires direct access to the JMX.

SCYLLA_JMX_FILE

A JMX service configuration file path.

Example value:

SCYLLA_JMX_FILE="-cf /etc/scylla.d/scylla-user.cfg"

SCYLLA_JMX_LOCAL

The location of the JMX executable.

Example value:

SCYLLA_JMX_LOCAL="-l /opt/scylladb/jmx

SCYLLA_JMX_REMOTE

Allow JMX to run remotely.

Example value:

SCYLLA_JMX_REMOTE="-r"

SCYLLA_JMX_DEBUG

Enable debugger.

Example value:

SCYLLA_JMX_DEBUG="-d"

Related Links

• Best practices for running ScyllaDB on docker

User Feedback

Issues

For bug reports, please use ScyllaDB's issue tracker on GitHub. Please read the How to report a ScyllaDB problem page before you report bugs.

For general help, see ScyllaDB's documentation.

You can find training material and online courses at ScyllaDB University.

For questions and comments, use ScyllaDB's Community Forum.

Contributing

Want to scratch your own itch and contribute a patch? We are eager to review and merge your code. Please consult the Contributing to ScyllaDB page.