Percona Operator for MySQL based on Percona XtraDB Cluster single-namespace and multi-namespace deployment¶

There are two design patterns that you can choose from when deploying Percona Operator for MySQL based on Percona XtraDB Cluster and database clusters in Kubernetes:

Namespace-scope - one Operator per Kubernetes namespace,
Cluster-wide - one Operator can manage clusters in multiple namespaces.

This how-to explains how to configure Percona Operator for MySQL based on Percona XtraDB Cluster for each scenario.

Namespace-scope¶

By default, Percona Operator for MySQL functions in a specific Kubernetes namespace. You can create one during the installation (like it is shown in the installation instructions) or just use the default namespace. This approach allows several Operators to co-exist in one Kubernetes-based environment, being separated in different namespaces:

Normally this is a recommended approach, as isolation minimizes impact in case of various failure scenarios. This is the default configuration of our Operator.

Let’s say you will use a Kubernetes Namespace called percona-db-1.

Clone percona-xtradb-cluster-operator repository:

$ git clone -b v1.16.0 https://github.com/percona/percona-xtradb-cluster-operator
$ cd percona-xtradb-cluster-operator

Create your percona-db-1 Namespace (if it doesn’t yet exist) as follows:
```
$ kubectl create namespace percona-db-1
```

Deploy the Operator using the following command:

$ kubectl apply --server-side -f deploy/bundle.yaml -n percona-db-1

Once Operator is up and running, deploy the database cluster itself:
```
$ kubectl apply -f deploy/cr.yaml -n percona-db-1
```

You can deploy multiple clusters in this namespace.

Add more namespaces¶

What if there is a need to deploy clusters in another namespace? The solution for namespace-scope deployment is to have more than one Operator. We will use the percona-db-2 namespace as an example.

Create your percona-db-2 namespace (if it doesn’t yet exist) as follows:
```
$ kubectl create namespace percona-db-2
```

Deploy the Operator:

$ kubectl apply --server-side -f deploy/bundle.yaml -n percona-db-2

Once Operator is up and running deploy the database cluster itself:
```
$ kubectl apply -f deploy/cr.yaml -n percona-db-2
```
Note

Cluster names may be the same in different namespaces.

Installing the Operator in cluster-wide mode¶

Sometimes it is more convenient to have one Operator watching for Percona XtraDB Cluster custom resources in several namespaces.

We recommend running Percona Operator for MySQL in a traditional way, limited to a specific namespace, to limit the blast radius. But it is possible to run it in so-called cluster-wide mode, one Operator watching several namespaces, if needed:

Note

Please take into account that if several Operators are configured to watch the same namespace, it is entirely unpredictable which one will get ownership of the Custom Resource in it, so this situation should be avoided.

To use the Operator in such cluster-wide mode, you should install it with a different set of configuration YAML files, which are available in the deploy folder and have filenames with a special cw- prefix: e.g. deploy/cw-bundle.yaml.

While using this cluster-wide versions of configuration files, you should set the following information there:

subjects.namespace option should contain the namespace which will host the Operator,
WATCH_NAMESPACE key-value pair in the env section should have value equal to a comma-separated list of the namespaces to be watched by the Operator (or just a blank string to make the Operator deal with all namespaces in a Kubernetes cluster). Prior to the Operator version 1.12.0 it was necessary to mention the Operator’s own namespace in the list of watched namespaces, but now this limitation has gone.

Note

Installing the Operator cluster-wide on OpenShift via the the Operator Lifecycle Manager (OLM) requires making different selections in the OLM web-based UI instead of patching YAML files.

The following simple example shows how to install Operator cluster-wide on Kubernetes.

First of all, clone the percona-xtradb-cluster-operator repository:

$ git clone -b v1.16.0 https://github.com/percona/percona-xtradb-cluster-operator
$ cd percona-xtradb-cluster-operator

Let’s suppose that Operator’s namespace should be the pxc-operator one. Create it as follows:
```
$ kubectl create namespace pxc-operator
```
Namespaces to be watched by the Operator should be created in the same way if not exist. Let’s say the Operator should watch the pxc namespace:
```
$ kubectl create namespace pxc
```

Edit the deploy/cw-bundle.yaml configuration file to set proper namespaces:

...
subjects:
- kind: ServiceAccount
  name: percona-xtradb-cluster-operator
  namespace: "pxc"
...
env:
         - name: WATCH_NAMESPACE
           value: "pxc"
...

Apply the deploy/cw-bundle.yaml file with the following command:

$ kubectl apply --server-side -f deploy/cw-bundle.yaml -n pxc-operator

After the Operator is started, Percona XtraDB Cluster can be created at any time by applying the deploy/cr.yaml configuration file, like in the case of normal installation:
```
$ kubectl apply -f deploy/cr.yaml -n pxc
```
The creation process will take some time. When the process is over your cluster will obtain the ready status. You can check it with the following command:
```
$ kubectl get pxc
```
Expected output
```
NAME       ENDPOINT                   STATUS   PXC   PROXYSQL   HAPROXY   AGE
cluster1   cluster1-haproxy.default   ready    3                3         5m51s
```

Verifying the cluster operation¶

It may take ten minutes to get the cluster started. When kubectl get pxc command finally shows you the cluster status as ready, you can try to connect to the cluster.

You will need the login and password for the admin user to access the cluster. Use kubectl get secrets command to see the list of Secrets objects (by default the Secrets object you are interested in has cluster1-secrets name). You can use the following command to get the password of the root user:
```
$ kubectl get secrets --namespace=pxc cluster1-secrets --template='{{.data.root | base64decode}}{{"\n"}}'
```
Run a container with mysql client and connect its console output to your terminal. The following command will do this, naming the new Pod percona-client:
```
$ kubectl run -i --rm --tty percona-client --image=percona:5.7 --restart=Never --env="POD_NAMESPACE=pxc" -- bash -il
```
Executing it may require some time to deploy the correspondent Pod.

Now run mysql tool in the percona-client command shell using the password obtained from the secret instead of the <root_password> placeholder. The command will look different depending on whether your cluster provides load balancing with HAProxy (the default choice) or ProxySQL:
with HAProxy (default)with ProxySQL
$ mysql -h cluster1-haproxy -uroot -p'<root_password>'
$ mysql -h cluster1-proxysql -uroot -p'<root_password>'

Note

Some Kubernetes-based environments are specifically configured to have communication across Namespaces is not allowed by default network policies. In this case, you should specifically allow the Operator communication across the needed Namespaces. Following the above example, you would need to allow ingress traffic for the pxc-operator Namespace from the pxc Namespace, and also from the default Namespace. You can do it with the NetworkPolicy resource, specified in the YAML file as follows:

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: percona
  namespace: pxc-operator
spec:
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          kubernetes.io/metadata.name: pxc
    - namespaceSelector:
        matchLabels:
          kubernetes.io/metadata.name: default
  podSelector: {}
  policyTypes:
  - Ingress

Don’t forget to apply the resulting file with the usual kubectl apply command.

You can find more details about Network Policies in the official Kubernetes documentation .

Upgrading the Operator in cluster-wide mode¶

Cluster-wide Operator is upgraded similarly to a single-namespace one. Both deployment variants provide you with the same three upgradable components:

the Operator;
Custom Resource Definition (CRD),
Database Management System (Percona XtraDB Cluster).

To upgrade the cluster-wide Operator you follow the standard upgrade scenario concerning the Operator’s namespace and a different YAML configuration file: the one with a special cw- prefix, deploy/cw-rbac.yaml. The resulting steps will look as follows.

Update the Custom Resource Definition for the Operator, taking it from the official repository on Github, and do the same for the Role-based access control:

$ kubectl apply --server-side -f https://raw.githubusercontent.com/percona/percona-xtradb-cluster-operator/v1.16.0/deploy/crd.yaml
$ kubectl apply --server-side -f https://raw.githubusercontent.com/percona/percona-xtradb-cluster-operator/v1.16.0/deploy/cw-rbac.yaml

Now you should apply a patch to your deployment, supplying the necessary image name with a newer version tag. You can find the proper image name for the current Operator release in the list of certified images (for older releases, please refer to the old releases documentation archive ). For example, updating to the 1.16.0 version in the pxc-operator namespace should look as follows.
```
$ kubectl patch deployment percona-xtradb-cluster-operator \
  -p'{"spec":{"template":{"spec":{"containers":[{"name":"percona-xtradb-cluster-operator","image":"percona/percona-xtradb-cluster-operator:1.16.0"}]}}}}' -n pxc-operator
```
The deployment rollout will be automatically triggered by the applied patch. You can track the rollout process in real time with the kubectl rollout status command with the name of your cluster:
```
$ kubectl rollout status deployments percona-xtradb-cluster-operator -n pxc-operator
```

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Last update: 2024-12-19