basics.md

ScyllaClusters

Introduction

ScyllaCluster defines a ScyllaDB datacenter and manages the racks within. This section aims to make you familiar with how it looks like and how to perform some of the basic configuration or accessing the APIs. By no means is this a complete description of what it can do. Please consult our generated API reference for a complete list of options.

::::{tip} You can always see the currently supported API fields for a particular version installed in your cluster by running :::{code} kubectl explain --api-version='scylla.scylladb.com/v1' ScyllaCluster.spec ::: ::::

Note that the Kubernetes clusters are only a regional concept, availability-wise they map into a ScyllaDB datacenter. To deploy a ScyllaDB cluster with multiple datacenters, you have to combine multiple Kubernetes clusters, each running a ScyllaCluster. To learn more, please see the dedicated multi-datacenter guide.

Creating a ScyllaCluster

Before we go and create the ScyllaCluster, we'll first create our ScyllaDB config file that we'll reference later in the ScyllaCluster definition.

:::{code-block} bash :linenos: :emphasize-lines: 7

kubectl apply --server-side -f=- <<EOF apiVersion: v1 kind: ConfigMap metadata: name: scylladb-config data: scylla.yaml: | authenticator: PasswordAuthenticator authorizer: CassandraAuthorizer # Other options EOF :::

:::{note} Some of the ScyllaDB config is also generated by the {{productName}} based on your ScyllaCluster definition. While you shall not define conflicting options here ({{productName}} config wins), we still want to give you a reasonable control to fine tune some ScyllaDB knobs. IOW, please stay away from touching networking, listen or published addresses and so on, but feel free to tune buffer sizes and such. :::

Now we can create a simple ScyllaCluster to get ScyllaDB running.

:::{code-block} bash :linenos: :substitutions:

kubectl apply --server-side -f=- <<EOF apiVersion: scylla.scylladb.com/v1 kind: ScyllaCluster metadata: name: scylladb spec: repository: {{imageRepository}} version: {{imageTag}} agentVersion: {{agentVersion}} developerMode: false automaticOrphanedNodeCleanup: true sysctls:

• fs.aio-max-nr=30000000 datacenter: name: us-east-1 racks:
  • name: us-east-1a members: 1 scyllaConfig: scylladb-config storage: capacity: 100Gi storageClassName: scylladb-local-xfs resources: requests: cpu: 1 memory: 8Gi limits: cpu: 1 memory: 8Gi placement: nodeAffinity: requiredDuringSchedulingIgnoredDuringExecution: nodeSelectorTerms: - matchExpressions: - key: scylla.scylladb.com/node-type operator: In values: - scylla tolerations:
    • key: scylla-operator.scylladb.com/dedicated operator: Equal value: scyllaclusters effect: NoSchedule EOF :::

:::{note} Values in these examples are only illustratory. You should always adjust the resources and storage capacity depending on your needs or the size and the type of your Kubernetes nodes. Similarly, the tolerations will differ depending on how and whether you set up dedicated node pools, or the placement if you want to set affinity for your rack to an availability zone or a failure domain. :::

:::{include} ../../.internal/tuning-qos-caution.md :::

(scyllacluster-enterprise)= ::::{note} {{productName}} works with both ScyllaDB Open Source and ScyllaDB Enterprise. You only have to adjust the repository and tag fields for each ScyllaCluster.

In addition to it, if you want to use tuning from the Enterprise repository, you have to adjust scyllaUtilsImage on the global ScyllaOperatorConfig/cluster.

:::{code-block} bash :linenos: :substitutions: :emphasize-lines: 6,7

apiVersion: scylla.scylladb.com/v1 kind: ScyllaCluster metadata: name: scylladb spec: repository: {{enterpriseImageRepository}} version: {{enterpriseImageTag}}

...

EOF :::

::::

:::{code-block} bash

Wait for it to deploy.

kubectl wait --for='condition=Progressing=False' scyllacluster.scylla.scylladb.com/scylladb kubectl wait --for='condition=Degraded=False' scyllacluster.scylla.scylladb.com/scylladb kubectl wait --for='condition=Available=True' scyllacluster.scylla.scylladb.com/scylladb :::

Performance tuning

To get the best performance and latency, you should make sure you have the automatic tuning enabled. Please read our dedicated section about tuning architecture and get familiar with NodeConfig resource.

Forcing a rolling restart

When you change a ScyllaDB config option that's not live reloaded by ScyllaDB, or want to trigger a rolling restart for a different reason, ScyllaCluster allows triggering the rolling restarts declaratively by changing ScyllaCluster.spec.forceRedeploymentReason to any other value. This will trigger a rolling restart of all ScyllaDB nodes in sequence, always respecting the PodDistruptionsBudget and keeping the cluster available.

Spreading racks over availability zones

ScyllaCluster give you the freedom to chose how you want to spread you rack over your Kubernetes nodes with generic placement options. Here is a quick example of how you'd use them to spread your racks across different availability zone:

:::::{tab-set}

::::{tab-item} GKE :::{code} yaml spec: datacenter: name: <dc_name> racks: - name: <rack_name> placement: nodeAffinity: requiredDuringSchedulingIgnoredDuringExecution: nodeSelectorTerms: - matchExpressions: - key: failure-domain.beta.kubernetes.io/zone operator: In values: - <gcp_zone> ::: ::::

::::{tab-item} EKS :::{code} yaml spec: datacenter: name: <dc_name> racks: - name: <rack_name> placement: nodeAffinity: requiredDuringSchedulingIgnoredDuringExecution: nodeSelectorTerms: - matchExpressions: - key: topology.kubernetes.io/zone operator: In values: - <aws_zone> ::: ::::

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Next steps

To follow up with other advanced topics, see the section index for options.