Redirect tutorials to the docs site (#85)
Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>
This commit is contained in:
Ahmet Alp Balkan
GitHub
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<!-- EXCLUDE_FROM_DOCS BEGIN -->
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# Example: Cassandra with StatefulSets on Kubernetes
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> :warning: :warning: Follow this tutorial on the Kubernetes website:
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> https://kubernetes.io/docs/tutorials/stateful-application/cassandra/.
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> Otherwise some of the URLs will not work properly.
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# Cloud Native Deployments of Cassandra using Kubernetes
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<!-- EXCLUDE_FROM_DOCS END -->
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This directory contains the source code and Kubernetes manifests for Cassandra
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deployment with StatefulSets tutorial.
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{% capture overview %}
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This tutorial shows you how to develop a native cloud [Cassandra](http://cassandra.apache.org/) deployment on Kubernetes. In this instance, a custom Cassandra `SeedProvider` enables Cassandra to discover new Cassandra nodes as they join the cluster.
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Deploying stateful distributed applications, like Cassandra, within a clustered environment can be challenging. StatefulSets greatly simplify this process. Please read about [StatefulSets](https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/) for more information about the features used in this tutorial.
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**Cassandra Docker**
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The Pods use the [`gcr.io/google-samples/cassandra:v12`](https://github.com/kubernetes/examples/blob/master/cassandra/image/Dockerfile)
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image from Google's [container registry](https://cloud.google.com/container-registry/docs/).
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The docker is based on `debian:jessie` 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`.
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| ENV VAR | DEFAULT VALUE |
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| ------------- |:-------------: |
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| CASSANDRA_CLUSTER_NAME | 'Test Cluster' |
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| CASSANDRA_NUM_TOKENS | 32 |
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| CASSANDRA_RPC_ADDRESS | 0.0.0.0 |
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{% endcapture %}
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{% capture objectives %}
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* Create and Validate a Cassandra headless `Service`.
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* Use a `StatefulSet` to create a Cassandra ring.
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* Validate the `StatefulSet`.
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* Modify the `StatefulSet`.
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* Delete the `StatefulSet` and its `Pods`.
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{% endcapture %}
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{% capture prerequisites %}
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To complete this tutorial, you should already have a basic familiarity with [Pods](https://kubernetes.io/docs/concepts/workloads/pods/pod/), [Services](https://kubernetes.io/docs/concepts/services-networking/service/), and [StatefulSets](https://kubernetes.io/docs/concepts/workloads/controllers/statefulset/). In addition, you should:
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* [Install and Configure](https://kubernetes.io/docs/tasks/tools/install-kubectl/) the `kubectl` command line
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* Download [cassandra-service.yaml](https://kubernetes.io/docs/tutorials/stateful-application/cassandra-service.yaml) and [cassandra-statefulset.yaml](https://kubernetes.io/docs/tutorials/stateful-application/cassandra-statefulset.yaml)
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* Have a supported Kubernetes Cluster running
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**Note:** Please read the [getting started guides](https://kubernetes.io/docs/setup/pick-right-solution/) if you do not already have a cluster.
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{: .note}
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### Additional Minikube Setup Instructions
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**Caution:** [Minikube](https://kubernetes.io/docs/getting-started-guides/minikube/) defaults to 1024MB of memory and 1 CPU which results in an insufficient resource errors during this tutorial.
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{: .caution}
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To avoid these errors, run minikube with:
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minikube start --memory 5120 --cpus=4
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{% endcapture %}
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{% capture lessoncontent %}
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## Creating a Cassandra Headless Service
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A Kubernetes [Service](https://kubernetes.io/docs/concepts/services-networking/service/) describes a set of [Pods](https://kubernetes.io/docs/concepts/workloads/pods/pod/) that perform the same task.
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The following `Service` is used for DNS lookups between Cassandra Pods and clients within the Kubernetes Cluster.
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1. Launch a terminal window in the directory you downloaded the manifest files.
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2. Create a `Service` to track all Cassandra StatefulSet Nodes from the `cassandra-service.yaml` file:
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kubectl create -f cassandra-service.yaml
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{% include code.html language="yaml" file="cassandra-service.yaml" ghlink="/docs/tutorials/stateful-application/cassandra-service.yaml" %}
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### Validating (optional)
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Get the Cassandra `Service`.
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kubectl get svc cassandra
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The response should be
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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cassandra None <none> 9042/TCP 45s
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If anything else returns, the service was not successfully created. Read [Debug Services](https://kubernetes.io/docs/tasks/debug-application-cluster/debug-service/) for common issues.
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## Using a StatefulSet to Create a Cassandra Ring
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The StatefulSet manifest, included below, creates a Cassandra ring that consists of three Pods.
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**Note:** This example uses the default provisioner for Minikube. Please update the following StatefulSet for the cloud you are working with.
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{: .note}
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1. Update the StatefulSet if necessary.
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2. Create the Cassandra StatefulSet from the `cassandra-statefulset.yaml` file:
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kubectl create -f cassandra-statefulset.yaml
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{% include code.html language="yaml" file="cassandra-statefulset.yaml" ghlink="/docs/tutorials/stateful-application/cassandra-statefulset.yaml" %}
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## Validating The Cassandra StatefulSet
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1. Get the Cassandra StatefulSet:
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kubectl get statefulset cassandra
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The response should be
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NAME DESIRED CURRENT AGE
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cassandra 3 0 13s
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The StatefulSet resource deploys Pods sequentially.
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2. Get the Pods to see the ordered creation status:
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kubectl get pods -l="app=cassandra"
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The response should be
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NAME READY STATUS RESTARTS AGE
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cassandra-0 1/1 Running 0 1m
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cassandra-1 0/1 ContainerCreating 0 8s
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**Note:** It can take up to ten minutes for all three Pods to deploy.
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{: .note}
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Once all Pods are deployed, the same command returns:
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NAME READY STATUS RESTARTS AGE
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cassandra-0 1/1 Running 0 10m
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cassandra-1 1/1 Running 0 9m
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cassandra-2 1/1 Running 0 8m
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3. Run the Cassandra utility nodetool to display the status of the ring.
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kubectl exec cassandra-0 -- nodetool status
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The response is:
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Datacenter: DC1-K8Demo
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======================
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Status=Up/Down
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|/ State=Normal/Leaving/Joining/Moving
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-- Address Load Tokens Owns (effective) Host ID Rack
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UN 172.17.0.5 83.57 KiB 32 74.0% e2dd09e6-d9d3-477e-96c5-45094c08db0f Rack1-K8Demo
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UN 172.17.0.4 101.04 KiB 32 58.8% f89d6835-3a42-4419-92b3-0e62cae1479c Rack1-K8Demo
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UN 172.17.0.6 84.74 KiB 32 67.1% a6a1e8c2-3dc5-4417-b1a0-26507af2aaad Rack1-K8Demo
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## Modifying the Cassandra StatefulSet
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Use `kubectl edit` to modify the size of a Cassandra StatefulSet.
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1. Run the following command:
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kubectl edit statefulset cassandra
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This command opens an editor in your terminal. The line you need to change is the `replicas` field.
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**Note:** The following sample is an excerpt of the StatefulSet file.
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{: .note}
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```yaml
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# Please edit the object below. Lines beginning with a '#' will be ignored,
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# and an empty file will abort the edit. If an error occurs while saving this file will be
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# reopened with the relevant failures.
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#
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apiVersion: apps/v1beta1
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kind: StatefulSet
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metadata:
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creationTimestamp: 2016-08-13T18:40:58Z
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generation: 1
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labels:
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app: cassandra
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name: cassandra
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namespace: default
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resourceVersion: "323"
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selfLink: /apis/apps/v1beta1/namespaces/default/statefulsets/cassandra
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uid: 7a219483-6185-11e6-a910-42010a8a0fc0
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spec:
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replicas: 3
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```
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2. Change the number of replicas to 4, and then save the manifest.
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The StatefulSet now contains 4 Pods.
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3. Get the Cassandra StatefulSet to verify:
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kubectl get statefulset cassandra
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The response should be
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NAME DESIRED CURRENT AGE
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cassandra 4 4 36m
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{% endcapture %}
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{% capture cleanup %}
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Deleting or scaling a StatefulSet down does not delete the volumes associated with the StatefulSet. This ensures safety first: your data is more valuable than an auto purge of all related StatefulSet resources.
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**Warning:** Depending on the storage class and reclaim policy, deleting the Persistent Volume Claims may cause the associated volumes to also be deleted. Never assume you’ll be able to access data if its volume claims are deleted.
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{: .warning}
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1. Run the following commands to delete everything in a `StatefulSet`:
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grace=$(kubectl get po cassandra-0 -o=jsonpath='{.spec.terminationGracePeriodSeconds}') \
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&& kubectl delete statefulset -l app=cassandra \
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&& echo "Sleeping $grace" \
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&& sleep $grace \
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&& kubectl delete pvc -l app=cassandra
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2. Run the following command to delete the Cassandra `Service`.
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kubectl delete service -l app=cassandra
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{% endcapture %}
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{% capture whatsnext %}
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* Learn how to [Scale a StatefulSet](https://kubernetes.io/docs/tasks/run-application/scale-stateful-set/).
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* Learn more about the [KubernetesSeedProvider](https://github.com/kubernetes/examples/blob/master/cassandra/java/src/main/java/io/k8s/cassandra/KubernetesSeedProvider.java)
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* See more custom [Seed Provider Configurations](https://git.k8s.io/examples/cassandra/java/README.md)
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{% endcapture %}
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{% include templates/tutorial.md %}
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<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
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[]()
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<!-- END MUNGE: GENERATED_ANALYTICS -->
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Follow this tutorial at https://kubernetes.io/docs/tutorials/stateful-application/cassandra/.
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@ -1,306 +1,6 @@
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<!-- EXCLUDE_FROM_DOCS BEGIN -->
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# Example: Guestbook application on Kubernetes
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> :warning: :warning: Follow this tutorial on the Kubernetes website:
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> https://kubernetes.io/docs/tutorials/stateless-application/guestbook/.
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> Otherwise some of the URLs will not work properly.
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This directory contains the source code and Kubernetes manifests for PHP
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Guestbook application.
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## Creating a Guestbook
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<!-- EXCLUDE_FROM_DOCS END -->
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{% capture overview %}
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This tutorial shows you how to build and deploy a simple, multi-tier web application using Kubernetes and [Docker](https://www.docker.com/). This example consists of the following components:
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* A single-instance [Redis](https://redis.io/) master to store guestbook entries
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* Multiple replicated Redis instances to serve reads
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* Multiple web frontend instances
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{% endcapture %}
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{% capture objectives %}
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* Start up a Redis master.
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* Start up Redis slaves.
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* Start up the guestbook frontend.
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* Expose and view the Frontend Service.
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* Clean up.
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{% endcapture %}
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{% capture prerequisites %}
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{% include task-tutorial-prereqs.md %}
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Download the following configuration files:
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1. [redis-master-deployment.yaml](https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-master-deployment.yaml)
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1. [redis-master-service.yaml](https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-master-service.yaml)
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1. [redis-slave-deployment.yaml](https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-slave-deployment.yaml)
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1. [redis-slave-service.yaml](https://kubernetes.io/docs/tutorials/stateless-application/guestbook/redis-slave-service.yaml)
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1. [frontend-deployment.yaml](https://kubernetes.io/docs/tutorials/stateless-application/guestbook/frontend-deployment.yaml)
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1. [frontend-service.yaml](https://kubernetes.io/docs/tutorials/stateless-application/guestbook/frontend-service.yaml)
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{% endcapture %}
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{% capture lessoncontent %}
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## Start up the Redis Master
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The guestbook application uses Redis to store its data. It writes its data to a Redis master instance and reads data from multiple Redis slave instances.
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### Creating the Redis Master Deployment
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The manifest file, included below, specifies a Deployment controller that runs a single replica Redis master Pod.
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1. Launch a terminal window in the directory you downloaded the manifest files.
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2. Apply the Redis Master Deployment from the `redis-master-deployment.yaml` file:
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kubectl apply -f redis-master-deployment.yaml
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{% include code.html language="yaml" file="guestbook/redis-master-deployment.yaml" ghlink="/docs/tutorials/stateless-application/guestbook/redis-master-deployment.yaml" %}
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3. Query the list of Pods to verify that the Redis Master Pod is running:
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kubectl get pods
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The response should be similar to this:
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NAME READY STATUS RESTARTS AGE
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redis-master-1068406935-3lswp 1/1 Running 0 28s
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4. Run the following command to view the logs from the Redis Master Pod:
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kubectl logs -f POD-NAME
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**Note:** Replace POD-NAME with the name of your Pod.
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{: .note}
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### Creating the Redis Master Service
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The guestbook applications needs to communicate to the Redis master to write its data. You need to apply a [Service](https://kubernetes.io/docs/concepts/services-networking/service/) to proxy the traffic to the Redis master Pod. A Service defines a policy to access the Pods.
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1. Apply the Redis Master Service from the following `redis-master-service.yaml` file:
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kubectl apply -f redis-master-service.yaml
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{% include code.html language="yaml" file="guestbook/redis-master-service.yaml" ghlink="/docs/tutorials/stateless-application/guestbook/redis-master-service.yaml" %}
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**Note:** This manifest file creates a Service named `redis-master` with a set of labels that match the labels previously defined, so the Service routes network traffic to the Redis master Pod.
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{: .note}
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2. Query the list of Services to verify that the Redis Master Service is running:
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kubectl get service
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The response should be similar to this:
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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kubernetes 10.0.0.1 <none> 443/TCP 1m
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redis-master 10.0.0.151 <none> 6379/TCP 8s
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## Start up the Redis Slaves
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Although the Redis master is a single pod, you can make it highly available to meet traffic demands by adding replica Redis slaves.
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### Creating the Redis Slave Deployment
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Deployments scale based off of the configurations set in the manifest file. In this case, the Deployment object specifies two replicas.
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If there are not any replicas running, this Deployment would start the two replicas on your container cluster. Conversely, if there are more than two replicas are running, it would scale down until two replicas are running.
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1. Apply the Redis Slave Deployment from the `redis-slave-deployment.yaml` file:
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kubectl apply -f redis-slave-deployment.yaml
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{% include code.html language="yaml" file="guestbook/redis-slave-deployment.yaml" ghlink="/docs/tutorials/stateless-application/guestbook/redis-slave-deployment.yaml" %}
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2. Query the list of Pods to verify that the Redis Slave Pods are running:
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kubectl get pods
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The response should be similar to this:
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NAME READY STATUS RESTARTS AGE
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redis-master-1068406935-3lswp 1/1 Running 0 1m
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redis-slave-2005841000-fpvqc 0/1 ContainerCreating 0 6s
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redis-slave-2005841000-phfv9 0/1 ContainerCreating 0 6s
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### Creating the Redis Slave Service
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The guestbook application needs to communicate to Redis slaves to read data. To make the Redis slaves discoverable, you need to set up a Service. A Service provides transparent load balancing to a set of Pods.
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1. Apply the Redis Slave Service from the following `redis-slave-service.yaml` file:
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kubectl apply -f redis-slave-service.yaml
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{% include code.html language="yaml" file="guestbook/redis-slave-service.yaml" ghlink="/docs/tutorials/stateless-application/guestbook/redis-slave-service.yaml" %}
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2. Query the list of Services to verify that the Redis Slave Service is running:
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kubectl get services
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The response should be similar to this:
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NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
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kubernetes 10.0.0.1 <none> 443/TCP 2m
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redis-master 10.0.0.151 <none> 6379/TCP 1m
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redis-slave 10.0.0.223 <none> 6379/TCP 6s
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## Set up and Expose the Guestbook Frontend
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The guestbook application has a web frontend serving the HTTP requests written in PHP. It is configured to connect to the `redis-master` Service for write requests and the `redis-slave` service for Read requests.
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### Creating the Guestbook Frontend Deployment
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1. Apply the frontend Deployment from the following `frontend-deployment.yaml` file:
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kubectl apply -f frontend-deployment.yaml
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{% include code.html language="yaml" file="guestbook/frontend-deployment.yaml" ghlink="/docs/tutorials/stateless-application/guestbook/frontend-deployment.yaml" %}
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2. Query the list of Pods to verify that the three frontend replicas are running:
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kubectl get pods -l app=guestbook -l tier=frontend
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The response should be similar to this:
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NAME READY STATUS RESTARTS AGE
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frontend-3823415956-dsvc5 1/1 Running 0 54s
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frontend-3823415956-k22zn 1/1 Running 0 54s
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frontend-3823415956-w9gbt 1/1 Running 0 54s
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### Creating the Frontend Service
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The `redis-slave` and `redis-master` Services you applied are only accessible within the container cluster because the default type for a Service is [ClusterIP](https://kubernetes.io/docs/concepts/services-networking/service/#publishing-services---service-types). `ClusterIP` provides a single IP address for the set of Pods the Service is pointing to. This IP address is accessible only within the cluster.
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If you want guests to be able to access your guestbook, you must configure the frontend Service to be externally visible, so a client can request the Service from outside the container cluster. Minikube can only expose Services through `NodePort`.
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**Note:** Some cloud providers, like Google Compute Engine or Google Container Engine, support external load balancers. If your cloud provider supports load balancers and you want to use it, simply delete or comment out `type: NodePort`, and uncomment `type: LoadBalancer`.
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{: .note}
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||||
1. Apply the frontend Service from the following `frontend-service.yaml` file:
|
||||
|
||||
kubectl apply -f frontend-service.yaml
|
||||
|
||||
{% include code.html language="yaml" file="guestbook/frontend-service.yaml" ghlink="/docs/tutorials/stateless-application/guestbook/frontend-service.yaml" %}
|
||||
|
||||
2. Query the list of Services to verify that the frontend Service is running:
|
||||
|
||||
kubectl get services
|
||||
|
||||
The response should be similar to this:
|
||||
|
||||
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
|
||||
frontend 10.0.0.112 <nodes> 80:31323/TCP 6s
|
||||
kubernetes 10.0.0.1 <none> 443/TCP 4m
|
||||
redis-master 10.0.0.151 <none> 6379/TCP 2m
|
||||
redis-slave 10.0.0.223 <none> 6379/TCP 1m
|
||||
|
||||
### Viewing the Frontend Service via `NodePort`
|
||||
|
||||
If you deployed this application to Minikube or a local cluster, you need to find the IP address to view your Guestbook.
|
||||
|
||||
1. Run the following command to get the IP address for the frontend Service.
|
||||
|
||||
minikube service frontend --url
|
||||
|
||||
The response should be similar to this:
|
||||
|
||||
http://192.168.99.100:31323
|
||||
|
||||
2. Copy the IP address, and load the page in your browser to view your guestbook.
|
||||
|
||||
### Viewing the Frontend Service via `LoadBalancer`
|
||||
|
||||
If you deployed the `frontend-service.yaml` manifest with type: `LoadBalancer` you need to find the IP address to view your Guestbook.
|
||||
|
||||
1. Run the following command to get the IP address for the frontend Service.
|
||||
|
||||
kubectl get service frontend
|
||||
|
||||
The response should be similar to this:
|
||||
|
||||
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
|
||||
frontend 10.51.242.136 109.197.92.229 80:32372/TCP 1m
|
||||
|
||||
2. Copy the External IP address, and load the page in your browser to view your guestbook.
|
||||
|
||||
## Scale the Web Frontend
|
||||
|
||||
Scaling up or down is easy because your servers are defined as a Service that uses a Deployment controller.
|
||||
|
||||
1. Run the following command to scale up the number of frontend Pods:
|
||||
|
||||
kubectl scale deployment frontend --replicas=5
|
||||
|
||||
2. Query the list of Pods to verify the number of frontend Pods running:
|
||||
|
||||
kubectl get pods
|
||||
|
||||
The response should look similar to this:
|
||||
|
||||
NAME READY STATUS RESTARTS AGE
|
||||
frontend-3823415956-70qj5 1/1 Running 0 5s
|
||||
frontend-3823415956-dsvc5 1/1 Running 0 54m
|
||||
frontend-3823415956-k22zn 1/1 Running 0 54m
|
||||
frontend-3823415956-w9gbt 1/1 Running 0 54m
|
||||
frontend-3823415956-x2pld 1/1 Running 0 5s
|
||||
redis-master-1068406935-3lswp 1/1 Running 0 56m
|
||||
redis-slave-2005841000-fpvqc 1/1 Running 0 55m
|
||||
redis-slave-2005841000-phfv9 1/1 Running 0 55m
|
||||
|
||||
3. Run the following command to scale down the number of frontend Pods:
|
||||
|
||||
kubectl scale deployment frontend --replicas=2
|
||||
|
||||
4. Query the list of Pods to verify the number of frontend Pods running:
|
||||
|
||||
kubectl get pods
|
||||
|
||||
The response should look similar to this:
|
||||
|
||||
NAME READY STATUS RESTARTS AGE
|
||||
frontend-3823415956-k22zn 1/1 Running 0 1h
|
||||
frontend-3823415956-w9gbt 1/1 Running 0 1h
|
||||
redis-master-1068406935-3lswp 1/1 Running 0 1h
|
||||
redis-slave-2005841000-fpvqc 1/1 Running 0 1h
|
||||
redis-slave-2005841000-phfv9 1/1 Running 0 1h
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture cleanup %}
|
||||
Deleting the Deployments and Services also deletes any running Pods. Use labels to delete multiple resources with one command.
|
||||
|
||||
1. Run the following commands to delete all Pods, Deployments, and Services.
|
||||
|
||||
kubectl delete deployment -l app=redis
|
||||
kubectl delete service -l app=redis
|
||||
kubectl delete deployment -l app=guestbook
|
||||
kubectl delete service -l app=guestbook
|
||||
|
||||
The responses should be:
|
||||
|
||||
deployment "redis-master" deleted
|
||||
deployment "redis-slave" deleted
|
||||
service "redis-master" deleted
|
||||
service "redis-slave" deleted
|
||||
deployment "frontend" deleted
|
||||
service "frontend" deleted
|
||||
|
||||
2. Query the list of Pods to verify that no Pods are running:
|
||||
|
||||
kubectl get pods
|
||||
|
||||
The response should be this:
|
||||
|
||||
No resources found.
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture whatsnext %}
|
||||
* Complete the [Kubernetes Basics](https://kubernetes.io//docs/tutorials/kubernetes-basics/) Interactive Tutorials
|
||||
* Use Kubernetes to create a blog using [Persistant Volumes for MySQL and Wordpress](https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/#visit-your-new-wordpress-blog)
|
||||
* Read more about [connecting applications](https://kubernetes.io/docs/concepts/services-networking/connect-applications-service/)
|
||||
* Read more about [Managing Resources](https://kubernetes.io/docs/concepts/cluster-administration/manage-deployment/#using-labels-effectively)
|
||||
{% endcapture %}
|
||||
{% include templates/tutorial.md %}
|
||||
|
||||
<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
|
||||
[]()
|
||||
<!-- END MUNGE: GENERATED_ANALYTICS -->
|
||||
Follow the tutorial at https://kubernetes.io/docs/tutorials/stateless-application/guestbook/.
|
||||
|
|
|
|||
|
|
@ -1,198 +1,6 @@
|
|||
<!-- EXCLUDE_FROM_DOCS BEGIN -->
|
||||
# Example: WordPress and MySQL on Kubernetes
|
||||
|
||||
> :warning: :warning: Follow this tutorial on the Kubernetes website:
|
||||
> https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/.
|
||||
> Otherwise some of the URLs will not work properly.
|
||||
This directory contains the Kubernetes manifest files of the WordPress and
|
||||
MySQL tutorial for Kubernetes.
|
||||
|
||||
# Using Persistent Volumes with MySQL and WordPress
|
||||
<!-- EXCLUDE_FROM_DOCS END -->
|
||||
|
||||
{% capture overview %}
|
||||
This tutorial shows you how to deploy a WordPress site and a MySQL database using Minikube. Both applications use PersistentVolumes and PersistentVolumeClaims to store data.
|
||||
|
||||
A [PersistentVolume](https://kubernetes.io/docs/concepts/storage/persistent-volumes/) (PV) is a piece of storage in the cluster that has been provisioned by an administrator, and a [PeristentVolumeClaim](https://kubernetes.io/docs/concepts/storage/persistent-volumes/#persistentvolumeclaims) (PVC) is a set amout of storage in a PV. PersistentVolumes and PeristentVolumeClaims are independent from Pod lifecycles and preserve data through restarting, rescheduling, and even deleting Pods.
|
||||
|
||||
**Warning:** This deployment is not suitable for production use cases, as it uses single instance WordPress and MySQL Pods. Consider using [WordPress Helm Chart](https://github.com/kubernetes/charts/tree/master/stable/wordpress) to deploy WordPress in production.
|
||||
{: .warning}
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture objectives %}
|
||||
* Create a PersistentVolume
|
||||
* Create a Secret
|
||||
* Deploy MySQL
|
||||
* Deploy WordPress
|
||||
* Clean up
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture prerequisites %}
|
||||
|
||||
{% include task-tutorial-prereqs.md %}
|
||||
|
||||
Download the following configuration files:
|
||||
|
||||
1. [local-volumes.yaml](https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/local-volumes.yaml)
|
||||
|
||||
1. [mysql-deployment.yaml](https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/mysql-deployment.yaml)
|
||||
|
||||
1. [wordpress-deployment.yaml](https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume//wordpress-deployment.yaml)
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture lessoncontent %}
|
||||
|
||||
## Create a PersistentVolume
|
||||
|
||||
MySQL and Wordpress each use a PersistentVolume to store data. While Kubernetes supports many different [types of PersistentVolumes](https://kubernetes.io/docs/concepts/storage/persistent-volumes/#types-of-persistent-volumes), this tutorial covers [hostPath](https://kubernetes.io/docs/concepts/storage/volumes/#hostpath).
|
||||
|
||||
**Note:** If you have a Kubernetes cluster running on Google Container Engine, please follow [this guide](https://cloud.google.com/container-engine/docs/tutorials/persistent-disk).
|
||||
{: .note}
|
||||
|
||||
### Setting up a hostPath Volume
|
||||
|
||||
A `hostPath` mounts a file or directory from the host node’s filesystem into your Pod.
|
||||
|
||||
**Warning:** Only use `hostPath` for developing and testing. With hostPath, your data lives on the node the Pod is scheduled onto and does not move between nodes. If a Pod dies and gets scheduled to another node in the cluster, the data is lost.
|
||||
{: .warning}
|
||||
|
||||
1. Launch a terminal window in the directory you downloaded the manifest files.
|
||||
|
||||
2. Create two PersistentVolumes from the `local-volumes.yaml` file:
|
||||
|
||||
kubectl create -f local-volumes.yaml
|
||||
|
||||
{% include code.html language="yaml" file="mysql-wordpress-persistent-volume/local-volumes.yaml" ghlink="/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/local-volumes.yaml" %}
|
||||
|
||||
{:start="3"}
|
||||
3. Run the following command to verify that two 20GiB PersistentVolumes are available:
|
||||
|
||||
kubectl get pv
|
||||
|
||||
The response should be like this:
|
||||
|
||||
NAME CAPACITY ACCESSMODES RECLAIMPOLICY STATUS CLAIM STORAGECLASS REASON AGE
|
||||
local-pv-1 20Gi RWO Retain Available 1m
|
||||
local-pv-2 20Gi RWO Retain Available 1m
|
||||
|
||||
## Create a Secret for MySQL Password
|
||||
|
||||
A [Secret](https://kubernetes.io/docs/concepts/configuration/secret/) is an object that stores a piece of sensitive data like a password or key. The manifest files are already configured to use a Secret, but you have to create your own Secret.
|
||||
|
||||
1. Create the Secret object from the following command:
|
||||
|
||||
kubectl create secret generic mysql-pass --from-literal=password=YOUR_PASSWORD
|
||||
|
||||
**Note:** Replace `YOUR_PASSWORD` with the password you want to apply.
|
||||
{: .note}
|
||||
|
||||
2. Verify that the Secret exists by running the following command:
|
||||
|
||||
kubectl get secrets
|
||||
|
||||
The response should be like this:
|
||||
|
||||
NAME TYPE DATA AGE
|
||||
mysql-pass Opaque 1 42s
|
||||
|
||||
**Note:** To protect the Secret from exposure, neither `get` nor `describe` show its contents.
|
||||
{: .note}
|
||||
|
||||
## Deploy MySQL
|
||||
|
||||
The following manifest describes a single-instance MySQL Deployment. The MySQL container mounts the PersistentVolume at /var/lib/mysql. The `MYSQL_ROOT_PASSWORD` environment variable sets the database password from the Secret.
|
||||
|
||||
{% include code.html language="yaml" file="mysql-wordpress-persistent-volume/mysql-deployment.yaml" ghlink="/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/mysql-deployment.yaml" %}
|
||||
|
||||
1. Deploy MySQL from the `mysql-deployment.yaml` file:
|
||||
|
||||
kubectl create -f mysql-deployment.yaml
|
||||
|
||||
2. Verify that the Pod is running by running the following command:
|
||||
|
||||
kubectl get pods
|
||||
|
||||
**Note:** It can take up to a few minutes for the Pod's Status to be `RUNNING`.
|
||||
{: .note}
|
||||
|
||||
The response should be like this:
|
||||
|
||||
NAME READY STATUS RESTARTS AGE
|
||||
wordpress-mysql-1894417608-x5dzt 1/1 Running 0 40s
|
||||
|
||||
## Deploy WordPress
|
||||
|
||||
The following manifest describes a single-instance WordPress Deployment and Service. It uses many of the same features like a PVC for persistent storage and a Secret for the password. But it also uses a different setting: `type: NodePort`. This setting exposes WordPress to traffic from outside of the cluster.
|
||||
|
||||
{% include code.html language="yaml" file="mysql-wordpress-persistent-volume/mysql-deployment.yaml" ghlink="/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/wordpress-deployment.yaml" %}
|
||||
|
||||
1. Create a WordPress Service and Deployment from the `wordpress-deployment.yaml` file:
|
||||
|
||||
kubectl create -f wordpress-deployment.yaml
|
||||
|
||||
2. Verify that the Service is running by running the following command:
|
||||
|
||||
kubectl get services wordpress
|
||||
|
||||
The response should be like this:
|
||||
|
||||
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
|
||||
wordpress 10.0.0.89 <pending> 80:32406/TCP 4m
|
||||
|
||||
**Note:** Minikube can only expose Services through `NodePort`. <br/><br/>The `EXTERNAL-IP` is always `<pending>`.
|
||||
{: .note}
|
||||
|
||||
3. Run the following command to get the IP Address for the WordPress Service:
|
||||
|
||||
minikube service wordpress --url
|
||||
|
||||
The response should be like this:
|
||||
|
||||
http://1.2.3.4:32406
|
||||
|
||||
4. Copy the IP address, and load the page in your browser to view your site.
|
||||
|
||||
You should see the WordPress set up page similar to the following screenshot.
|
||||
|
||||
|
||||
|
||||
**Warning:** Do not leave your WordPress installation on this page. If another user finds it, they can set up a website on your instance and use it to serve malicious content. <br/><br/>Either install WordPress by creating a username and password or delete your instance.
|
||||
{: .warning}
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture cleanup %}
|
||||
|
||||
1. Run the following command to delete your Secret:
|
||||
|
||||
kubectl delete secret mysql-pass
|
||||
|
||||
2. Run the following commands to delete all Deployments and Services:
|
||||
|
||||
kubectl delete deployment -l app=wordpress
|
||||
kubectl delete service -l app=wordpress
|
||||
|
||||
3. Run the following commands to delete the PersistentVolumeClaims and the PersistentVolumes:
|
||||
|
||||
kubectl delete pvc -l app=wordpress
|
||||
kubectl delete pv local-pv-1 local-pv-2
|
||||
|
||||
**Note:** Any other Type of PersistentVolume would allow you to recreate the Deployments and Services at this point without losing data, but `hostPath` loses the data as soon as the Pod stops running.
|
||||
{: .note}
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% capture whatsnext %}
|
||||
|
||||
* Learn more about [Introspection and Debugging](https://kubernetes.io/docs/tasks/debug-application-cluster/debug-application-introspection/)
|
||||
* Learn more about [Jobs](https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/)
|
||||
* Learn more about [Port Forwarding](https://kubernetes.io/docs/tasks/access-application-cluster/port-forward-access-application-cluster/)
|
||||
* Learn how to [Get a Shell to a Container](https://kubernetes.io/docs/tasks/debug-application-cluster/get-shell-running-container/)
|
||||
|
||||
{% endcapture %}
|
||||
|
||||
{% include templates/tutorial.md %}
|
||||
|
||||
<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
|
||||
[]()
|
||||
<!-- END MUNGE: GENERATED_ANALYTICS -->
|
||||
Follow this tutorial at https://kubernetes.io/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/.
|
||||
|
|
|
|||
Loading…
Reference in New Issue