diff --git a/content/ja/docs/tutorials/stateful-application/cassandra.md b/content/ja/docs/tutorials/stateful-application/cassandra.md new file mode 100644 index 0000000000..3fa56b26ea --- /dev/null +++ b/content/ja/docs/tutorials/stateful-application/cassandra.md @@ -0,0 +1,276 @@ +--- +title: "Example: Deploying Cassandra with a StatefulSet" +reviewers: +- ahmetb +content_type: tutorial +weight: 30 +--- + + +This tutorial shows you how to run [Apache Cassandra](http://cassandra.apache.org/) on Kubernetes. Cassandra, a database, needs persistent storage to provide data durability (application _state_). In this example, a custom Cassandra seed provider lets the database discover new Cassandra instances as they join the Cassandra cluster. + +*StatefulSets* make it easier to deploy stateful applications into your Kubernetes cluster. For more information on the features used in this tutorial, see [StatefulSet](/docs/concepts/workloads/controllers/statefulset/). + +{{< note >}} +Cassandra and Kubernetes both use the term _node_ to mean a member of a cluster. In this +tutorial, the Pods that belong to the StatefulSet are Cassandra nodes and are members +of the Cassandra cluster (called a _ring_). When those Pods run in your Kubernetes cluster, +the Kubernetes control plane schedules those Pods onto Kubernetes +{{< glossary_tooltip text="Nodes" term_id="node" >}}. + +When a Cassandra node starts, it uses a _seed list_ to bootstrap discovery of other +nodes in the ring. +This tutorial deploys a custom Cassandra seed provider that lets the database discover +new Cassandra Pods as they appear inside your Kubernetes cluster. +{{< /note >}} + + +## {{% heading "objectives" %}} + +* Create and validate a Cassandra headless {{< glossary_tooltip text="Service" term_id="service" >}}. +* Use a {{< glossary_tooltip term_id="StatefulSet" >}} to create a Cassandra ring. +* Validate the StatefulSet. +* Modify the StatefulSet. +* Delete the StatefulSet and its {{< glossary_tooltip text="Pods" term_id="pod" >}}. + + +## {{% heading "prerequisites" %}} + +{{< include "task-tutorial-prereqs.md" >}} + +To complete this tutorial, you should already have a basic familiarity with {{< glossary_tooltip text="Pods" term_id="pod" >}}, {{< glossary_tooltip text="Services" term_id="service" >}}, and {{< glossary_tooltip text="StatefulSets" term_id="StatefulSet" >}}. + +### Additional Minikube setup instructions + +{{< caution >}} +[Minikube](/docs/getting-started-guides/minikube/) defaults to 1024MiB of memory and 1 CPU. Running Minikube with the default resource configuration results in insufficient resource errors during this tutorial. To avoid these errors, start Minikube with the following settings: + +```shell +minikube start --memory 5120 --cpus=4 +``` +{{< /caution >}} + + + + +## Creating a headless Service for Cassandra {#creating-a-cassandra-headless-service} + +In Kubernetes, a {{< glossary_tooltip text="Service" term_id="service" >}} describes a set of {{< glossary_tooltip text="Pods" term_id="pod" >}} that perform the same task. + +The following Service is used for DNS lookups between Cassandra Pods and clients within your cluster: + +{{< codenew file="application/cassandra/cassandra-service.yaml" >}} + +Create a Service to track all Cassandra StatefulSet members from the `cassandra-service.yaml` file: + +```shell +kubectl apply -f https://k8s.io/examples/application/cassandra/cassandra-service.yaml +``` + + +### Validating (optional) {#validating} + +Get the Cassandra Service. + +```shell +kubectl get svc cassandra +``` + +The response is + +``` +NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE +cassandra ClusterIP None 9042/TCP 45s +``` + +If you don't see a Service named `cassandra`, that means creation failed. Read [Debug Services](/docs/tasks/debug-application-cluster/debug-service/) for help troubleshooting common issues. + +## Using a StatefulSet to create a Cassandra ring + +The StatefulSet manifest, included below, creates a Cassandra ring that consists of three Pods. + +{{< note >}} +This example uses the default provisioner for Minikube. Please update the following StatefulSet for the cloud you are working with. +{{< /note >}} + +{{< codenew file="application/cassandra/cassandra-statefulset.yaml" >}} + +Create the Cassandra StatefulSet from the `cassandra-statefulset.yaml` file: + +```shell +# Use this if you are able to apply cassandra-statefulset.yaml unmodified +kubectl apply -f https://k8s.io/examples/application/cassandra/cassandra-statefulset.yaml +``` + +If you need to modify `cassandra-statefulset.yaml` to suit your cluster, download +https://k8s.io/examples/application/cassandra/cassandra-statefulset.yaml and then apply +that manifest, from the folder you saved the modified version into: +```shell +# Use this if you needed to modify cassandra-statefulset.yaml locally +kubectl apply -f cassandra-statefulset.yaml +``` + + +## Validating the Cassandra StatefulSet + +1. Get the Cassandra StatefulSet: + + ```shell + kubectl get statefulset cassandra + ``` + + The response should be similar to: + + ``` + NAME DESIRED CURRENT AGE + cassandra 3 0 13s + ``` + + The `StatefulSet` resource deploys Pods sequentially. + +1. Get the Pods to see the ordered creation status: + + ```shell + kubectl get pods -l="app=cassandra" + ``` + + The response should be similar to: + + ```shell + NAME READY STATUS RESTARTS AGE + cassandra-0 1/1 Running 0 1m + cassandra-1 0/1 ContainerCreating 0 8s + ``` + + It can take several minutes for all three Pods to deploy. Once they are deployed, the same command + returns output similar to: + + ``` + NAME READY STATUS RESTARTS AGE + cassandra-0 1/1 Running 0 10m + cassandra-1 1/1 Running 0 9m + cassandra-2 1/1 Running 0 8m + ``` + +3. Run the Cassandra [nodetool](https://cwiki.apache.org/confluence/display/CASSANDRA2/NodeTool) inside the first Pod, to + display the status of the ring. + + ```shell + kubectl exec -it cassandra-0 -- nodetool status + ``` + + The response should look something like: + + ``` + Datacenter: DC1-K8Demo + ====================== + Status=Up/Down + |/ State=Normal/Leaving/Joining/Moving + -- Address Load Tokens Owns (effective) Host ID Rack + UN 172.17.0.5 83.57 KiB 32 74.0% e2dd09e6-d9d3-477e-96c5-45094c08db0f Rack1-K8Demo + UN 172.17.0.4 101.04 KiB 32 58.8% f89d6835-3a42-4419-92b3-0e62cae1479c Rack1-K8Demo + UN 172.17.0.6 84.74 KiB 32 67.1% a6a1e8c2-3dc5-4417-b1a0-26507af2aaad Rack1-K8Demo + ``` + +## Modifying the Cassandra StatefulSet + +Use `kubectl edit` to modify the size of a Cassandra StatefulSet. + +1. Run the following command: + + ```shell + kubectl edit statefulset cassandra + ``` + + This command opens an editor in your terminal. The line you need to change is the `replicas` field. The following sample is an excerpt of the StatefulSet file: + + ```yaml + # Please edit the object below. Lines beginning with a '#' will be ignored, + # and an empty file will abort the edit. If an error occurs while saving this file will be + # reopened with the relevant failures. + # + apiVersion: apps/v1 + kind: StatefulSet + metadata: + creationTimestamp: 2016-08-13T18:40:58Z + generation: 1 + labels: + app: cassandra + name: cassandra + namespace: default + resourceVersion: "323" + uid: 7a219483-6185-11e6-a910-42010a8a0fc0 + spec: + replicas: 3 + ``` + +1. Change the number of replicas to 4, and then save the manifest. + + The StatefulSet now scales to run with 4 Pods. + +1. Get the Cassandra StatefulSet to verify your change: + + ```shell + kubectl get statefulset cassandra + ``` + + The response should be similar to: + + ``` + NAME DESIRED CURRENT AGE + cassandra 4 4 36m + ``` + + + +## {{% heading "cleanup" %}} + +Deleting or scaling a StatefulSet down does not delete the volumes associated with the StatefulSet. This setting is for your safety because your data is more valuable than automatically purging all related StatefulSet resources. + +{{< warning >}} +Depending on the storage class and reclaim policy, deleting the *PersistentVolumeClaims* may cause the associated volumes to also be deleted. Never assume you’ll be able to access data if its volume claims are deleted. +{{< /warning >}} + +1. Run the following commands (chained together into a single command) to delete everything in the Cassandra StatefulSet: + + ```shell + grace=$(kubectl get pod cassandra-0 -o=jsonpath='{.spec.terminationGracePeriodSeconds}') \ + && kubectl delete statefulset -l app=cassandra \ + && echo "Sleeping ${grace} seconds" 1>&2 \ + && sleep $grace \ + && kubectl delete persistentvolumeclaim -l app=cassandra + ``` + +1. Run the following command to delete the Service you set up for Cassandra: + + ```shell + kubectl delete service -l app=cassandra + ``` + +## Cassandra container environment variables + +The Pods in this tutorial use the [`gcr.io/google-samples/cassandra:v13`](https://github.com/kubernetes/examples/blob/master/cassandra/image/Dockerfile) +image from Google's [container registry](https://cloud.google.com/container-registry/docs/). +The Docker image above is based on [debian-base](https://github.com/kubernetes/kubernetes/tree/master/build/debian-base) +and includes OpenJDK 8. + +This image includes a standard Cassandra installation from the Apache Debian repo. +By using environment variables you can change values that are inserted into `cassandra.yaml`. + +| Environment variable | Default value | +| ------------------------ |:---------------: | +| `CASSANDRA_CLUSTER_NAME` | `'Test Cluster'` | +| `CASSANDRA_NUM_TOKENS` | `32` | +| `CASSANDRA_RPC_ADDRESS` | `0.0.0.0` | + + + +## {{% heading "whatsnext" %}} + + +* Learn how to [Scale a StatefulSet](/docs/tasks/run-application/scale-stateful-set/). +* Learn more about the [*KubernetesSeedProvider*](https://github.com/kubernetes/examples/blob/master/cassandra/java/src/main/java/io/k8s/cassandra/KubernetesSeedProvider.java) +* See more custom [Seed Provider Configurations](https://git.k8s.io/examples/cassandra/java/README.md) + + +