114 lines
4.3 KiB
Markdown
114 lines
4.3 KiB
Markdown
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## Vitess Example
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This example shows how to run a [Vitess](http://vitess.io) cluster in Kubernetes.
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Vitess is a MySQL clustering system developed at YouTube that makes sharding
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transparent to the application layer. It also makes scaling MySQL within
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Kubernetes as simple as launching more pods.
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The example brings up a database with 2 shards, and then runs a pool of
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[sharded guestbook](https://github.com/youtube/vitess/tree/master/examples/kubernetes/guestbook)
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pods. The guestbook app was ported from the original
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[guestbook](../../../examples/guestbook-go/)
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example found elsewhere in this tree, modified to use Vitess as the backend.
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For a more detailed, step-by-step explanation of this example setup, see the
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[Vitess on Kubernetes](http://vitess.io/getting-started/) guide.
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### Prerequisites
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You'll need to install [Go 1.4+](https://golang.org/doc/install) to build
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`vtctlclient`, the command-line admin tool for Vitess.
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We also assume you have a running Kubernetes cluster with `kubectl` pointing to
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it by default. See the [Getting Started guides](../../../docs/getting-started-guides/)
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for how to get to that point. Note that your Kubernetes cluster needs to have
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enough resources (CPU+RAM) to schedule all the pods. By default, this example
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requires a cluster-wide total of at least 6 virtual CPUs and 10GiB RAM. You can
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tune these requirements in the
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[resource limits](../../../docs/user-guide/compute-resources.md)
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section of each YAML file.
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Lastly, you need to open ports 30000-30001 (for the Vitess admin daemon) and 80 (for
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the guestbook app) in your firewall. See the
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[Services and Firewalls](../../../docs/user-guide/services-firewalls.md)
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guide for examples of how to do that.
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### Configure site-local settings
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Run the `configure.sh` script to generate a `config.sh` file, which will be used
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to customize your cluster settings.
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``` console
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./configure.sh
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```
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Currently, we have out-of-the-box support for storing
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[backups](http://vitess.io/user-guide/backup-and-restore.html) in
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[Google Cloud Storage](https://cloud.google.com/storage/).
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If you're using GCS, fill in the fields requested by the configure script.
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Note that your Kubernetes cluster must be running on instances with the
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`storage-rw` scope for this to work. With Container Engine, you can do this by
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passing `--scopes storage-rw` to the `glcoud container clusters create` command.
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For other platforms, you'll need to choose the `file` backup storage plugin,
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and mount a read-write network volume into the `vttablet` and `vtctld` pods.
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For example, you can mount any storage service accessible through NFS into a
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Kubernetes volume. Then provide the mount path to the configure script here.
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If you prefer to skip setting up a backup volume for the purpose of this example,
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you can choose `file` mode and set the path to `/tmp`.
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### Start Vitess
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``` console
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./vitess-up.sh
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```
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This will run through the steps to bring up Vitess. At the end, you should see
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something like this:
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``` console
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****************************
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* Complete!
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* Use the following line to make an alias to kvtctl:
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* alias kvtctl='$GOPATH/bin/vtctlclient -server 104.197.47.173:30001'
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* See the vtctld UI at: http://104.197.47.173:30000
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****************************
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```
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### Start the Guestbook app
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``` console
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./guestbook-up.sh
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```
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The guestbook service is configured with `type: LoadBalancer` to tell Kubernetes
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to expose it on an external IP. It may take a minute to set up, but you should
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soon see the external IP show up under the internal one like this:
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``` console
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$ kubectl get service guestbook
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NAME LABELS SELECTOR IP(S) PORT(S)
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guestbook <none> name=guestbook 10.67.253.173 80/TCP
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104.197.151.132
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```
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Visit the external IP in your browser to view the guestbook. Note that in this
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modified guestbook, there are multiple pages to demonstrate range-based sharding
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in Vitess. Each page number is assigned to one of the shards using a
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[consistent hashing](https://en.wikipedia.org/wiki/Consistent_hashing) scheme.
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### Tear down
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``` console
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./guestbook-down.sh
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./vitess-down.sh
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```
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You may also want to remove any firewall rules you created.
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<!-- BEGIN MUNGE: GENERATED_ANALYTICS -->
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[]()
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<!-- END MUNGE: GENERATED_ANALYTICS -->
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