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