Orchestrate CockroachDB in a Single Kubernetes Cluster

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Warning:

As of November 12, 2021, CockroachDB v20.1 is no longer supported. For more details, refer to the Release Support Policy.

This page shows you how to orchestrate the deployment, management, and monitoring of a secure 3-node CockroachDB cluster in a single Kubernetes cluster, using the StatefulSet feature directly or via the Helm package manager for Kubernetes.

To deploy across multiple Kubernetes clusters in different geographic regions instead, see Kubernetes Multi-Cluster Deployment. Also, for details about potential performance bottlenecks to be aware of when running CockroachDB in Kubernetes and guidance on how to optimize your deployment for better performance, see CockroachDB Performance on Kubernetes.

Tip:

To deploy a free CockroachDB Cloud cluster instead of running CockroachDB yourself, see the Quickstart.

Before you begin

Before getting started, it's helpful to review some Kubernetes-specific terminology and current limitations.

Kubernetes terminology
Limitations

Kubernetes terminology

Feature	Description
node	A physical or virtual machine. In this tutorial, you'll create GCE or AWS instances and join them as worker nodes into a single Kubernetes cluster from your local workstation.
pod	A pod is a group of one of more Docker containers. In this tutorial, each pod will run on a separate Kubernetes node and include one Docker container running a single CockroachDB node. You'll start with 3 pods and grow to 4.
StatefulSet	A StatefulSet is a group of pods treated as stateful units, where each pod has distinguishable network identity and always binds back to the same persistent storage on restart. StatefulSets are considered stable as of Kubernetes version 1.9 after reaching beta in version 1.5.
persistent volume	A persistent volume is a piece of networked storage (Persistent Disk on GCE, Elastic Block Store on AWS) mounted into a pod. The lifetime of a persistent volume is decoupled from the lifetime of the pod that's using it, ensuring that each CockroachDB node binds back to the same storage on restart. This tutorial assumes that dynamic volume provisioning is available. When that is not the case, persistent volume claims need to be created manually.
RBAC	RBAC, or Role-Based Access Control, is the system Kubernetes uses to manage permissions within the cluster. In order to take an action (e.g., `get` or `create`) on an API resource (e.g., a `pod`), the client must have a `Role` that allows it to do so. This tutorial creates the RBAC resources necessary for CockroachDB to create and access certificates.

Limitations

Kubernetes version

To deploy CockroachDB v20.1, Kubernetes 1.18 or higher is required. Cockroach Labs strongly recommends that you use a Kubernetes version that is eligible for patch support by the Kubernetes project.

Helm version

Helm 3.0 or higher is required when using our instructions to deploy via Helm.

Resources

When starting Kubernetes, select machines with at least 4 vCPUs and 16 GiB of memory, and provision at least 2 vCPUs and 8 Gi of memory to CockroachDB per pod. These minimum settings are used by default in this deployment guide, and are appropriate for testing purposes only. On a production deployment, you should adjust the resource settings for your workload.

Storage

At this time, orchestrations of CockroachDB with Kubernetes use external persistent volumes that are often replicated by the provider. Because CockroachDB already replicates data automatically, this additional layer of replication is unnecessary and can negatively impact performance. High-performance use cases on a private Kubernetes cluster may want to consider using local volumes.

CSR names

When Kubernetes issues a CSR (Certificate Signing Request) to have a node or client certificate signed by the Kubernetes CA, Kubernetes requires the CSR name to start and end with an alphanumeric character and otherwise consist of lowercase alphanumeric characters, -, or .

CSR names contain the StatefulSet or Helm chart name, so if you customize that value, be sure to conform to these naming requirements. For client certificates, CSR names also contain the username of the SQL user for which the certificate is being generated, so be sure SQL usernames also conform to these naming requirements. For example, avoid using the underscore character (_) in these names.

Step 1. Start Kubernetes

You can use the hosted Google Kubernetes Engine (GKE) service or the hosted Amazon Elastic Kubernetes Service (EKS) to quickly start Kubernetes.

Hosted GKE
Hosted EKS

Note:

The CockroachDB Kubernetes Operator is currently supported for GKE. You can also use the Operator on platforms such as Red Hat OpenShift and IBM Cloud Pak for Data.

Hosted GKE

Complete the Before You Begin steps described in the Google Kubernetes Engine Quickstart documentation.

This includes installing gcloud, which is used to create and delete Kubernetes Engine clusters, and kubectl, which is the command-line tool used to manage Kubernetes from your workstation.

Tip:

The documentation offers the choice of using Google's Cloud Shell product or using a local shell on your machine. Choose to use a local shell if you want to be able to view the CockroachDB Admin UI using the steps in this guide.
From your local workstation, start the Kubernetes cluster, specifying one of the available regions (e.g., us-east1):

Tip:

Since this region can differ from your default gcloud region, be sure to include the --region flag to run gcloud commands against this cluster.
```
$ gcloud container clusters create cockroachdb --machine-type n2-standard-4 --region {region-name} --num-nodes 1
```
```
Creating cluster cockroachdb...done.
```
This creates GKE instances and joins them into a single Kubernetes cluster named cockroachdb. The --region flag specifies a regional three-zone cluster, and --num-nodes specifies one node in each zone.

The --machine-type flag tells the node pool to use the n2-standard-4 machine type (4 vCPUs, 16 GB memory), which meets our recommended CPU and memory configuration.

The process can take a few minutes, so do not move on to the next step until you see a Creating cluster cockroachdb...done message and details about your cluster.
Get the email address associated with your Google Cloud account:
```
$ gcloud info | grep Account
```
```
Account: [your.google.cloud.email@example.org]
```
Warning:

This command returns your email address in all lowercase. However, in the next step, you must enter the address using the accurate capitalization. For example, if your address is YourName@example.com, you must use YourName@example.com and not yourname@example.com.

Create the RBAC roles CockroachDB needs for running on GKE, using the address from the previous step:

$ kubectl create clusterrolebinding $USER-cluster-admin-binding \
--clusterrole=cluster-admin \
--user=<your.google.cloud.email@example.org>

clusterrolebinding.rbac.authorization.k8s.io/your.username-cluster-admin-binding created

Hosted EKS

Complete the steps described in the EKS Getting Started documentation.

This includes installing and configuring the AWS CLI and eksctl, which is the command-line tool used to create and delete Kubernetes clusters on EKS, and kubectl, which is the command-line tool used to manage Kubernetes from your workstation.
From your local workstation, start the Kubernetes cluster:

Tip:

To ensure that all 3 nodes can be placed into a different availability zone, you may want to first confirm that at least 3 zones are available in the region for your account.
```
$ eksctl create cluster \
--name cockroachdb \
--nodegroup-name standard-workers \
--node-type m5.xlarge \
--nodes 3 \
--nodes-min 1 \
--nodes-max 4 \
--node-ami auto
```
This creates EKS instances and joins them into a single Kubernetes cluster named cockroachdb. The --node-type flag tells the node pool to use the m5.xlarge instance type (4 vCPUs, 16 GB memory), which meets our recommended CPU and memory configuration.

Cluster provisioning usually takes between 10 and 15 minutes. Do not move on to the next step until you see a message like [✔] EKS cluster "cockroachdb" in "us-east-1" region is ready and details about your cluster.
Open the AWS CloudFormation console to verify that the stacks eksctl-cockroachdb-cluster and eksctl-cockroachdb-nodegroup-standard-workers were successfully created. Be sure that your region is selected in the console.

Step 2. Start CockroachDB

To start your CockroachDB cluster, you can either use our StatefulSet configuration and related files directly, or you can use the Helm package manager for Kubernetes to simplify the process.

Note:

Secure CockroachDB deployments on Amazon EKS via Helm are not yet supported. In the meantime, use a StatefulSet configuration to deploy on EKS.

Set up configuration file

Download and modify our StatefulSet configuration:

$ curl -O https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/bring-your-own-certs/cockroachdb-statefulset.yaml

Allocate CPU and memory resources to CockroachDB on each pod. These settings should be appropriate for your workload. For more context on provisioning CPU and memory, see the Production Checklist.

Tip:

Resource requests and limits should have identical values.
```
resources:
  requests:
    cpu: "2"
    memory: "8Gi"
  limits:
    cpu: "2"
    memory: "8Gi"
```
Note:

If no resource limits are specified, the pods will be able to consume the maximum available CPUs and memory. However, to avoid overallocating resources when another memory-intensive workload is on the same instance, always set resource requests and limits explicitly.
In the volumeClaimTemplates specification, you may want to modify resources.requests.storage for your use case. This configuration defaults to 100Gi of disk space per pod. For more details on customizing disks for performance, see these instructions.
```
resources:
  requests:
    storage: "100Gi"
```

Initialize the cluster

Note:

The below steps use cockroach cert commands to quickly generate and sign the CockroachDB node and client certificates. If you use a different method of generating certificates, make sure to update secret.secretName in the StatefulSet configuration with the name of your node secret.

Create two directories:

$ mkdir certs my-safe-directory

Directory	Description
`certs`	You'll generate your CA certificate and all node and client certificates and keys in this directory.
`my-safe-directory`	You'll generate your CA key in this directory and then reference the key when generating node and client certificates.

Create the CA certificate and key pair:
```
$ cockroach cert create-ca \
--certs-dir=certs \
--ca-key=my-safe-directory/ca.key
```
Create a client certificate and key pair for the root user:
```
$ cockroach cert create-client \
root \
--certs-dir=certs \
--ca-key=my-safe-directory/ca.key
```
Upload the client certificate and key to the Kubernetes cluster as a secret:
```
$ kubectl create secret \
generic cockroachdb.client.root \
--from-file=certs
```
```
secret/cockroachdb.client.root created
```

Create the certificate and key pair for your CockroachDB nodes:

$ cockroach cert create-node \
localhost 127.0.0.1 \
cockroachdb-public \
cockroachdb-public.default \
cockroachdb-public.default.svc.cluster.local \
*.cockroachdb \
*.cockroachdb.default \
*.cockroachdb.default.svc.cluster.local \
--certs-dir=certs \
--ca-key=my-safe-directory/ca.key

Upload the node certificate and key to the Kubernetes cluster as a secret:
```
$ kubectl create secret \
generic cockroachdb.node \
--from-file=certs
```
```
secret/cockroachdb.node created
```

Check that the secrets were created on the cluster:

$ kubectl get secrets

NAME                      TYPE                                  DATA   AGE
cockroachdb.client.root   Opaque                                3      41m
cockroachdb.node          Opaque                                5      14s
default-token-6qjdb       kubernetes.io/service-account-token   3      4m

Use the config file you downloaded to create the StatefulSet that automatically creates 3 pods, each running a CockroachDB node:

$ kubectl create -f cockroachdb-statefulset.yaml

serviceaccount/cockroachdb created
role.rbac.authorization.k8s.io/cockroachdb created
rolebinding.rbac.authorization.k8s.io/cockroachdb created
service/cockroachdb-public created
service/cockroachdb created
poddisruptionbudget.policy/cockroachdb-budget created
statefulset.apps/cockroachdb created

Initialize the CockroachDB cluster:

Confirm that three pods are Running successfully. Note that they will not be considered Ready until after the cluster has been initialized:

$ kubectl get pods

NAME            READY     STATUS    RESTARTS   AGE
cockroachdb-0   0/1       Running   0          2m
cockroachdb-1   0/1       Running   0          2m
cockroachdb-2   0/1       Running   0          2m

Confirm that the persistent volumes and corresponding claims were created successfully for all three pods:

$ kubectl get pv

NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                           STORAGECLASS   REASON   AGE
pvc-9e435563-fb2e-11e9-a65c-42010a8e0fca   100Gi      RWO            Delete           Bound    default/datadir-cockroachdb-0   standard                51m
pvc-9e47d820-fb2e-11e9-a65c-42010a8e0fca   100Gi      RWO            Delete           Bound    default/datadir-cockroachdb-1   standard                51m
pvc-9e4f57f0-fb2e-11e9-a65c-42010a8e0fca   100Gi      RWO            Delete           Bound    default/datadir-cockroachdb-2   standard                51m

Run cockroach init on one of the pods to complete the node startup process and have them join together as a cluster:
```
$ kubectl exec -it cockroachdb-0 \
-- /cockroach/cockroach init \
--certs-dir=/cockroach/cockroach-certs
```
```
Cluster successfully initialized
```

Confirm that cluster initialization has completed successfully. The job should be considered successful and the Kubernetes pods should soon be considered Ready:

$ kubectl get pods

NAME            READY     STATUS    RESTARTS   AGE
cockroachdb-0   1/1       Running   0          3m
cockroachdb-1   1/1       Running   0          3m
cockroachdb-2   1/1       Running   0          3m

Install the Helm client (version 3.0 or higher) and add the cockroachdb chart repository:
```
$ helm repo add cockroachdb https://charts.cockroachdb.com/
```
```
"cockroachdb" has been added to your repositories
```
Update your Helm chart repositories to ensure that you're using the latest CockroachDB chart:
```
$ helm repo update
```
Modify our Helm chart's values.yaml parameters for your deployment scenario.

Create a my-values.yaml file to override the defaults in values.yaml, substituting your own values in this example based on the guidelines below.
```
statefulset:
  resources:
    limits:
      memory: "8Gi"
    requests:
      memory: "8Gi"
conf:
  cache: "2Gi"
  max-sql-memory: "2Gi"
tls:
  enabled: true
```
1. To avoid running out of memory when CockroachDB is not the only pod on a Kubernetes node, you must set memory limits explicitly. This is because CockroachDB does not detect the amount of memory allocated to its pod when run in Kubernetes. We recommend setting conf.cache and conf.max-sql-memory each to 1/4 of the memory allocation specified in statefulset.resources.requests and statefulset.resources.limits.
  
  Tip:
  
  For example, if you are allocating 8Gi of memory to each CockroachDB node, allocate 2Gi to cache and 2Gi to max-sql-memory.
2. You may want to modify storage.persistentVolume.size and storage.persistentVolume.storageClass for your use case. This chart defaults to 100Gi of disk space per pod. For more details on customizing disks for performance, see these instructions.
  
  Note:
  
  If necessary, you can expand disk size after the cluster is live.
3. For a secure deployment, set tls.enabled to true.
Install the CockroachDB Helm chart.

Provide a "release" name to identify and track this particular deployment of the chart, and override the default values with those in my-values.yaml.

Note:

This tutorial uses my-release as the release name. If you use a different value, be sure to adjust the release name in subsequent commands. Also be sure to start and end the name with an alphanumeric character and otherwise use lowercase alphanumeric characters, -, or . so as to comply with CSR naming requirements.
```
$ helm install my-release --values my-values.yaml cockroachdb/cockroachdb
```
Behind the scenes, this command uses our cockroachdb-statefulset.yaml file to create the StatefulSet that automatically creates 3 pods, each with a CockroachDB node running inside it, where each pod has distinguishable network identity and always binds back to the same persistent storage on restart.

As each pod is created, it issues a Certificate Signing Request, or CSR, to have the CockroachDB node's certificate signed by the Kubernetes CA. You must manually check and approve each node's certificate, at which point the CockroachDB node is started in the pod.

Get the names of the Pending CSRs:

$ kubectl get csr

NAME                                    AGE       REQUESTOR                                              CONDITION
default.client.root                     21s       system:serviceaccount:default:my-release-cockroachdb   Pending
default.node.my-release-cockroachdb-0   15s       system:serviceaccount:default:my-release-cockroachdb   Pending
default.node.my-release-cockroachdb-1   16s       system:serviceaccount:default:my-release-cockroachdb   Pending
default.node.my-release-cockroachdb-2   15s       system:serviceaccount:default:my-release-cockroachdb   Pending
...

If you do not see a Pending CSR, wait a minute and try again.

Examine the CSR for the first pod:

$ kubectl describe csr default.node.my-release-cockroachdb-0

Name:               default.node.my-release-cockroachdb-0
Labels:             <none>
Annotations:        <none>
CreationTimestamp:  Mon, 10 Dec 2018 05:36:35 -0500
Requesting User:    system:serviceaccount:default:my-release-cockroachdb
Status:             Pending
Subject:
  Common Name:    node
  Serial Number:
  Organization:   Cockroach
Subject Alternative Names:
         DNS Names:     localhost
                        my-release-cockroachdb-0.my-release-cockroachdb.default.svc.cluster.local
                        my-release-cockroachdb-0.my-release-cockroachdb
                        my-release-cockroachdb-public
                        my-release-cockroachdb-public.default.svc.cluster.local
         IP Addresses:  127.0.0.1
Events:  <none>

If everything looks correct, approve the CSR for the first pod:

$ kubectl certificate approve default.node.my-release-cockroachdb-0

certificatesigningrequest.certificates.k8s.io/default.node.my-release-cockroachdb-0 approved

Repeat steps 2 and 3 for the other 2 pods.

Confirm that three pods are Running successfully:

$ kubectl get pods

NAME                                READY     STATUS     RESTARTS   AGE
my-release-cockroachdb-0            0/1       Running    0          6m
my-release-cockroachdb-1            0/1       Running    0          6m
my-release-cockroachdb-2            0/1       Running    0          6m
my-release-cockroachdb-init-hxzsc   0/1       Init:0/1   0          6m

Approve the CSR for the one-off pod from which cluster initialization happens:
```
$ kubectl certificate approve default.client.root
```
```
certificatesigningrequest.certificates.k8s.io/default.client.root approved
```

Confirm that CockroachDB cluster initialization has completed successfully, with the pods for CockroachDB showing 1/1 under READY and the pod for initialization showing COMPLETED under STATUS:

$ kubectl get pods

NAME                                READY     STATUS      RESTARTS   AGE
my-release-cockroachdb-0            1/1       Running     0          8m
my-release-cockroachdb-1            1/1       Running     0          8m
my-release-cockroachdb-2            1/1       Running     0          8m
my-release-cockroachdb-init-hxzsc   0/1       Completed   0          1h

Confirm that the persistent volumes and corresponding claims were created successfully for all three pods:

$ kubectl get pv

NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS    CLAIM                                      STORAGECLASS   REASON    AGE
pvc-71019b3a-fc67-11e8-a606-080027ba45e5   100Gi      RWO            Delete           Bound     default/datadir-my-release-cockroachdb-0   standard                 11m
pvc-7108e172-fc67-11e8-a606-080027ba45e5   100Gi      RWO            Delete           Bound     default/datadir-my-release-cockroachdb-1   standard                 11m
pvc-710dcb66-fc67-11e8-a606-080027ba45e5   100Gi      RWO            Delete           Bound     default/datadir-my-release-cockroachdb-2   standard                 11m

Tip:

The StatefulSet configuration sets all CockroachDB nodes to log to stderr, so if you ever need access to a pod/node's logs to troubleshoot, use kubectl logs <podname> rather than checking the log on the persistent volume.

Step 3. Use the built-in SQL client

To use the built-in SQL client, you need to launch a pod that runs indefinitely with the cockroach binary inside it, get a shell into the pod, and then start the built-in SQL client.

~~~ shell $ kubectl create \ -f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/bring-your-own-certs/client.yaml ~~~

Note:

The pod uses the root client certificate created earlier to initialize the cluster, so there's no CSR approval required. If you issue client certificates for other users, however, be sure your SQL usernames contain only lowercase alphanumeric characters, -, or . so as to comply with CSR naming requirements.

~~~ pod/cockroachdb-client-secure created ~~~

Get a shell into the pod and start the CockroachDB built-in SQL client:

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public

# Welcome to the CockroachDB SQL shell.
# All statements must be terminated by a semicolon.
# To exit, type: \q.
#
# Server version: CockroachDB CCL v20.1.0 (x86_64-unknown-linux-gnu, built 2020/07/29 22:56:36, go1.13.9) (same version as client)
# Cluster ID: f82abd88-5d44-4493-9558-d6c75a3b80cc
#
# Enter \? for a brief introduction.
#
root@:26257/defaultdb>

Run some basic CockroachDB SQL statements:
```
> CREATE DATABASE bank;
```
```
> CREATE TABLE bank.accounts (id INT PRIMARY KEY, balance DECIMAL);
```
```
> INSERT INTO bank.accounts VALUES (1, 1000.50);
```
```
> SELECT * FROM bank.accounts;
```
```
  id | balance
+----+---------+
   1 | 1000.50
(1 row)
```
Create a user with a password:
```
> CREATE USER roach WITH PASSWORD 'Q7gc8rEdS';
```
You will need this username and password to access the Admin UI later.
Exit the SQL shell and pod:
```
> \q
```

From your local workstation, use our client-secure.yaml file to launch a pod and keep it running indefinitely.
1. Download the file:
```
$ curl -OOOOOOOOO \
https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/client-secure.yaml
```
2. In the file, change serviceAccountName: cockroachdb to serviceAccountName: my-release-cockroachdb.
3. Use the file to launch a pod and keep it running indefinitely:
```
$ kubectl create -f client-secure.yaml
```
```
pod "cockroachdb-client-secure" created
```
  Note:
  
  The pod uses the root client certificate created earlier to initialize the cluster, so there's no CSR approval required. If you issue client certificates for other users, however, be sure your SQL usernames contain only lowercase alphanumeric characters, -, or . so as to comply with CSR naming requirements.

Get a shell into the pod and start the CockroachDB built-in SQL client:

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=my-release-cockroachdb-public

# Welcome to the CockroachDB SQL shell.
# All statements must be terminated by a semicolon.
# To exit, type: \q.
#
# Server version: CockroachDB CCL v20.1.0 (x86_64-unknown-linux-gnu, built 2020/07/29 22:56:36, go1.13.9) (same version as client)
# Cluster ID: f82abd88-5d44-4493-9558-d6c75a3b80cc
#
# Enter \? for a brief introduction.
#
root@:26257/defaultdb>

Run some basic CockroachDB SQL statements:
```
> CREATE DATABASE bank;
```
```
> CREATE TABLE bank.accounts (id INT PRIMARY KEY, balance DECIMAL);
```
```
> INSERT INTO bank.accounts VALUES (1, 1000.50);
```
```
> SELECT * FROM bank.accounts;
```
```
  id | balance
+----+---------+
   1 | 1000.50
(1 row)
```
Create a user with a password:
```
> CREATE USER roach WITH PASSWORD 'Q7gc8rEdS';
```
You will need this username and password to access the Admin UI later.
Exit the SQL shell and pod:
```
> \q
```

Tip:

This pod will continue running indefinitely, so any time you need to reopen the built-in SQL client or run any other cockroach client commands (e.g., cockroach node), repeat step 2 using the appropriate cockroach command.

If you'd prefer to delete the pod and recreate it when needed, run kubectl delete pod cockroachdb-client-secure.

Step 4. Access the Admin UI

To access the cluster's Admin UI:

On secure clusters, certain pages of the Admin UI can only be accessed by admin users.

Get a shell into the pod and start the CockroachDB built-in SQL client:
```
$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public
```
Assign roach to the admin role (you only need to do this once):
```
> GRANT admin TO roach;
```
Exit the SQL shell and pod:
```
> \q
```
In a new terminal window, port-forward from your local machine to the cockroachdb-public service:
```
$ kubectl port-forward service/cockroachdb-public 8080
```
```
$ kubectl port-forward service/my-release-cockroachdb-public 8080
```
```
Forwarding from 127.0.0.1:8080 -> 8080
```
Note:
The port-forward command must be run on the same machine as the web browser in which you want to view the Admin UI. If you have been running these commands from a cloud instance or other non-local shell, you will not be able to view the UI without configuring kubectl locally and running the above port-forward command on your local machine.
Go to https://localhost:8080 and log in with the username and password you created earlier.

Note:

If you are using Google Chrome, and you are getting an error about not being able to reach localhost because its certificate has been revoked, go to chrome://flags/#allow-insecure-localhost, enable "Allow invalid certificates for resources loaded from localhost", and then restart the browser. Enabling this Chrome feature degrades security for all sites running on localhost, not just CockroachDB's Admin UI, so be sure to enable the feature only temporarily.
In the UI, verify that the cluster is running as expected:
- Click View nodes list on the right to ensure that all nodes successfully joined the cluster.
- Click the Databases tab on the left to verify that bank is listed.

Step 5. Simulate node failure

Based on the replicas: 3 line in the StatefulSet configuration, Kubernetes ensures that three pods/nodes are running at all times. When a pod/node fails, Kubernetes automatically creates another pod/node with the same network identity and persistent storage.

To see this in action:

Terminate one of the CockroachDB nodes:

$ kubectl delete pod cockroachdb-2

pod "cockroachdb-2" deleted

$ kubectl delete pod my-release-cockroachdb-2

pod "my-release-cockroachdb-2" deleted

In the Admin UI, the Cluster Overview will soon show one node as Suspect. As Kubernetes auto-restarts the node, watch how the node once again becomes healthy.

Back in the terminal, verify that the pod was automatically restarted:

$ kubectl get pod cockroachdb-2

NAME            READY     STATUS    RESTARTS   AGE
cockroachdb-2   1/1       Running   0          12s

$ kubectl get pod my-release-cockroachdb-2

NAME                       READY     STATUS    RESTARTS   AGE
my-release-cockroachdb-2   1/1       Running   0          44s

Step 6. Monitor the cluster

Despite CockroachDB's various built-in safeguards against failure, it is critical to actively monitor the overall health and performance of a cluster running in production and to create alerting rules that promptly send notifications when there are events that require investigation or intervention.

Configure Prometheus

Every node of a CockroachDB cluster exports granular timeseries metrics formatted for easy integration with Prometheus, an open source tool for storing, aggregating, and querying timeseries data. This section shows you how to orchestrate Prometheus as part of your Kubernetes cluster and pull these metrics into Prometheus for external monitoring.

This guidance is based on CoreOS's Prometheus Operator, which allows a Prometheus instance to be managed using built-in Kubernetes concepts.

Note:

If you're on Hosted GKE, before starting, make sure the email address associated with your Google Cloud account is part of the cluster-admin RBAC group, as shown in Step 1. Start Kubernetes.

From your local workstation, edit the cockroachdb service to add the prometheus: cockroachdb label:
```
$ kubectl label svc cockroachdb prometheus=cockroachdb
```
```
service/cockroachdb labeled
```
This ensures that only the cockroachdb (not the cockroach-public service) is being monitored by a Prometheus job.
```
$ kubectl label svc cockroachdb prometheus=cockroachdb
```
```
service/cockroachdb labeled
```
This ensures that only the cockroachdb (not the cockroach-public service) is being monitored by a Prometheus job.
```
$ kubectl label svc my-release-cockroachdb prometheus=cockroachdb
```
```
service/my-release-cockroachdb labeled
```
This ensures that there is a Prometheus job and monitoring data only for the my-release-cockroachdb service, not for the my-release-cockroach-public service.

Install CoreOS's Prometheus Operator:

Note:

If you run into an error when installing the Prometheus Operator, first try updating the release version specified in the below command and reapplying the manifest. If this doesn't work, please file an issue.

$ kubectl apply \
-f https://raw.githubusercontent.com/prometheus-operator/prometheus-operator/release-0.43/bundle.yaml

customresourcedefinition.apiextensions.k8s.io/alertmanagers.monitoring.coreos.com created
customresourcedefinition.apiextensions.k8s.io/podmonitors.monitoring.coreos.com created
customresourcedefinition.apiextensions.k8s.io/probes.monitoring.coreos.com created
customresourcedefinition.apiextensions.k8s.io/prometheuses.monitoring.coreos.com created
customresourcedefinition.apiextensions.k8s.io/prometheusrules.monitoring.coreos.com created
customresourcedefinition.apiextensions.k8s.io/servicemonitors.monitoring.coreos.com created
customresourcedefinition.apiextensions.k8s.io/thanosrulers.monitoring.coreos.com created
clusterrolebinding.rbac.authorization.k8s.io/prometheus-operator configured
clusterrole.rbac.authorization.k8s.io/prometheus-operator configured
deployment.apps/prometheus-operator created
serviceaccount/prometheus-operator configured
service/prometheus-operator created

Confirm that the prometheus-operator has started:

$ kubectl get deploy prometheus-operator

NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
prometheus-operator   1/1     1            1           27s

Use our prometheus.yaml file to create the various objects necessary to run a Prometheus instance:

Note:

By default, this manifest uses the secret name generated by the CockroachDB Kubernetes Operator. If you generated your own certificates and keys when starting CockroachDB, be sure that ca.secret.name matches the name of the node secret you created.
```
$ kubectl apply \
-f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/prometheus.yaml
```
```
serviceaccount/prometheus created
clusterrole.rbac.authorization.k8s.io/prometheus created
clusterrolebinding.rbac.authorization.k8s.io/prometheus created
servicemonitor.monitoring.coreos.com/cockroachdb created
prometheus.monitoring.coreos.com/cockroachdb created
```
Access the Prometheus UI locally and verify that CockroachDB is feeding data into Prometheus:
1. Port-forward from your local machine to the pod running Prometheus:
```
$ kubectl port-forward prometheus-cockroachdb-0 9090
```
2. Go to http://localhost:9090 in your browser.
3. To verify that each CockroachDB node is connected to Prometheus, go to Status > Targets. The screen should look like this:
4. To verify that data is being collected, go to Graph, enter the sys_uptime variable in the field, click Execute, and then click the Graph tab. The screen should like this:
Tip:

Prometheus auto-completes CockroachDB time series metrics for you, but if you want to see a full listing, with descriptions, port-forward as described in Access the Admin UI and then point your browser to http://localhost:8080/_status/vars.

For more details on using the Prometheus UI, see their official documentation.

Configure Alertmanager

Active monitoring helps you spot problems early, but it is also essential to send notifications when there are events that require investigation or intervention. This section shows you how to use Alertmanager and CockroachDB's starter alerting rules to do this.

Download our alertmanager-config.yaml configuration file:

$ curl -OOOOOOOOO \
https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/alertmanager-config.yaml

Edit the alertmanager-config.yaml file to specify the desired receivers for notifications. Initially, the file contains a placeholder web hook.
Add this configuration to the Kubernetes cluster as a secret, renaming it to alertmanager.yaml and labelling it to make it easier to find:
```
$ kubectl create secret generic alertmanager-cockroachdb \
--from-file=alertmanager.yaml=alertmanager-config.yaml
```
```
secret/alertmanager-cockroachdb created
```
```
$ kubectl label secret alertmanager-cockroachdb app=cockroachdb
```
```
secret/alertmanager-cockroachdb labeled
```
Warning:

The name of the secret, alertmanager-cockroachdb, must match the name used in the alertmanager.yaml file. If they differ, the Alertmanager instance will start without configuration, and nothing will happen.

Use our alertmanager.yaml file to create the various objects necessary to run an Alertmanager instance, including a ClusterIP service so that Prometheus can forward alerts:

$ kubectl apply \
-f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/alertmanager.yaml

alertmanager.monitoring.coreos.com/cockroachdb created
service/alertmanager-cockroachdb created

Verify that Alertmanager is running:
1. Port-forward from your local machine to the pod running Alertmanager:
```
$ kubectl port-forward alertmanager-cockroachdb-0 9093
```
2. Go to http://localhost:9093 in your browser. The screen should look like this:
Ensure that the Alertmanagers are visible to Prometheus by opening http://localhost:9090/status. The screen should look like this:

Add CockroachDB's starter alerting rules:

$ kubectl apply \
-f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/prometheus/alert-rules.yaml

prometheusrule.monitoring.coreos.com/prometheus-cockroachdb-rules created

Ensure that the rules are visible to Prometheus by opening http://localhost:9090/rules. The screen should look like this:
Verify that the TestAlertManager example alert is firing by opening http://localhost:9090/alerts. The screen should look like this:
To remove the example alert:
1. Use the kubectl edit command to open the rules for editing:
```
$ kubectl edit prometheusrules prometheus-cockroachdb-rules
```
2. Remove the dummy.rules block and save the file:
```
- name: rules/dummy.rules
  rules:
  - alert: TestAlertManager
    expr: vector(1)
```

Add nodes

Your Kubernetes cluster includes 3 worker nodes, or instances, that can run pods. A CockroachDB node runs in each pod. As recommended in our production best practices, you should ensure that two pods are not placed on the same worker node.

On a production deployment, first add a worker node, bringing the total from 3 to 4:
- On GKE, resize your cluster.
- On EKS, resize your Worker Node Group.
- On GCE, resize your Managed Instance Group.
- On AWS, resize your Auto Scaling Group.
Edit your StatefulSet configuration to add another pod for the new CockroachDB node:
```
$ kubectl scale statefulset cockroachdb --replicas=4
```
```
statefulset.apps/cockroachdb scaled
```

Verify that the new pod started successfully:

$ kubectl get pods

NAME                        READY     STATUS    RESTARTS   AGE
cockroachdb-0               1/1       Running   0          51m
cockroachdb-1               1/1       Running   0          47m
cockroachdb-2               1/1       Running   0          3m
cockroachdb-3               1/1       Running   0          1m
cockroachdb-client-secure   1/1       Running   0          15m
...

Back in the Admin UI, view the Node List to ensure that the fourth node successfully joined the cluster.

Edit your StatefulSet configuration to add another pod for the new CockroachDB node:

$ helm upgrade \
my-release \
cockroachdb/cockroachdb \
--set statefulset.replicas=4 \
--reuse-values

Release "my-release" has been upgraded. Happy Helming!
LAST DEPLOYED: Tue May 14 14:06:43 2019
NAMESPACE: default
STATUS: DEPLOYED

RESOURCES:
==> v1beta1/PodDisruptionBudget
NAME                           AGE
my-release-cockroachdb-budget  51m

==> v1/Pod(related)

NAME                               READY  STATUS     RESTARTS  AGE
my-release-cockroachdb-0           1/1    Running    0         38m
my-release-cockroachdb-1           1/1    Running    0         39m
my-release-cockroachdb-2           1/1    Running    0         39m
my-release-cockroachdb-3           0/1    Pending    0         0s
my-release-cockroachdb-init-nwjkh  0/1    Completed  0         39m

...

Get the name of the Pending CSR for the new pod:

$ kubectl get csr

NAME                                                   AGE       REQUESTOR                               CONDITION
default.client.root                                    1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-0                  1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-1                  1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-2                  1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-3                  2m        system:serviceaccount:default:default   Pending
node-csr-0Xmb4UTVAWMEnUeGbW4KX1oL4XV_LADpkwjrPtQjlZ4   1h        kubelet                                 Approved,Issued
node-csr-NiN8oDsLhxn0uwLTWa0RWpMUgJYnwcFxB984mwjjYsY   1h        kubelet                                 Approved,Issued
node-csr-aU78SxyU69pDK57aj6txnevr7X-8M3XgX9mTK0Hso6o   1h        kubelet                                 Approved,Issued
...

If you do not see a Pending CSR, wait a minute and try again.

Examine the CSR for the new pod:

$ kubectl describe csr default.node.my-release-cockroachdb-3

Name:               default.node.my-release-cockroachdb-3
Labels:             <none>
Annotations:        <none>
CreationTimestamp:  Thu, 09 Nov 2017 13:39:37 -0500
Requesting User:    system:serviceaccount:default:default
Status:             Pending
Subject:
  Common Name:    node
  Serial Number:
  Organization:   Cockroach
Subject Alternative Names:
         DNS Names:     localhost
                        my-release-cockroachdb-1.my-release-cockroachdb.default.svc.cluster.local
                        my-release-cockroachdb-1.my-release-cockroachdb
                        my-release-cockroachdb-public
                        my-release-cockroachdb-public.default.svc.cluster.local
         IP Addresses:  127.0.0.1
                        10.48.1.6
Events:  <none>

If everything looks correct, approve the CSR for the new pod:

$ kubectl certificate approve default.node.my-release-cockroachdb-3

certificatesigningrequest.certificates.k8s.io/default.node.my-release-cockroachdb-3 approved

Verify that the new pod started successfully:

$ kubectl get pods

NAME                        READY     STATUS    RESTARTS   AGE
my-release-cockroachdb-0    1/1       Running   0          51m
my-release-cockroachdb-1    1/1       Running   0          47m
my-release-cockroachdb-2    1/1       Running   0          3m
my-release-cockroachdb-3    1/1       Running   0          1m
cockroachdb-client-secure   1/1       Running   0          15m
...

Back in the Admin UI, view the Node List to ensure that the fourth node successfully joined the cluster.

Remove nodes

To safely remove a node from your cluster, you must first decommission the node and only then adjust the spec.replicas value of your StatefulSet configuration to permanently remove it. This sequence is important because the decommissioning process lets a node finish in-flight requests, rejects any new requests, and transfers all range replicas and range leases off the node.

Warning:

If you remove nodes without first telling CockroachDB to decommission them, you may cause data or even cluster unavailability. For more details about how this works and what to consider before removing nodes, see Decommission Nodes.

Get a shell into the cockroachdb-client-secure pod you created earlier and use the cockroach node status command to get the internal IDs of nodes:

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach node status \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public

  id |               address                                     | build  |            started_at            |            updated_at            | is_available | is_live
+----+---------------------------------------------------------------------------------+--------+----------------------------------+----------------------------------+--------------+---------+
   1 | cockroachdb-0.cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 16:04:36.486082+00:00 | 2018-11-29 18:24:24.587454+00:00 | true         | true
   2 | cockroachdb-2.cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 16:55:03.880406+00:00 | 2018-11-29 18:24:23.469302+00:00 | true         | true
   3 | cockroachdb-1.cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 16:04:41.383588+00:00 | 2018-11-29 18:24:25.030175+00:00 | true         | true
   4 | cockroachdb-3.cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 17:31:19.990784+00:00 | 2018-11-29 18:24:26.041686+00:00 | true         | true
(4 rows)

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach node status \
--certs-dir=/cockroach-certs \
--host=my-release-cockroachdb-public

  id |                                     address                                     | build  |            started_at            |            updated_at            | is_available | is_live
+----+---------------------------------------------------------------------------------+--------+----------------------------------+----------------------------------+--------------+---------+
   1 | my-release-cockroachdb-0.my-release-cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 16:04:36.486082+00:00 | 2018-11-29 18:24:24.587454+00:00 | true         | true
   2 | my-release-cockroachdb-2.my-release-cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 16:55:03.880406+00:00 | 2018-11-29 18:24:23.469302+00:00 | true         | true
   3 | my-release-cockroachdb-1.my-release-cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 16:04:41.383588+00:00 | 2018-11-29 18:24:25.030175+00:00 | true         | true
   4 | my-release-cockroachdb-3.my-release-cockroachdb.default.svc.cluster.local:26257 | v20.1.17 | 2018-11-29 17:31:19.990784+00:00 | 2018-11-29 18:24:26.041686+00:00 | true         | true
(4 rows)

The pod uses the root client certificate created earlier to initialize the cluster, so there's no CSR approval required.

Note the ID of the node with the highest number in its address (in this case, the address including cockroachdb-3) and use the cockroach node decommission command to decommission it:

Note:

It's important to decommission the node with the highest number in its address because, when you reduce the replica count, Kubernetes will remove the pod for that node.

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach node decommission <node ID> \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach node decommission <node ID> \
--certs-dir=/cockroach-certs \
--host=my-release-cockroachdb-public

You'll then see the decommissioning status print to stderr as it changes:

 id | is_live | replicas | is_decommissioning | is_draining  
+---+---------+----------+--------------------+-------------+
  4 |  true   |       73 |        true        |    false     
(1 row)

Once the node has been fully decommissioned and stopped, you'll see a confirmation:

 id | is_live | replicas | is_decommissioning | is_draining  
+---+---------+----------+--------------------+-------------+
  4 |  true   |        0 |        true        |    false     
(1 row)

No more data reported on target nodes. Please verify cluster health before removing the nodes.

Once the node has been decommissioned, remove a pod from your StatefulSet:

$ kubectl scale statefulset cockroachdb --replicas=3

statefulset.apps/cockroachdb scaled

$ helm upgrade \
my-release \
cockroachdb/cockroachdb \
--set statefulset.replicas=3 \
--reuse-values

Expand disk size

You can expand certain types of persistent volumes (including GCE Persistent Disk and Amazon Elastic Block Store) by editing their persistent volume claims. Increasing disk size is often beneficial for CockroachDB performance. Read our Kubernetes performance guide for guidance on disks.

Get the persistent volume claims for the volumes:

$ kubectl get pvc

NAME                               STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-my-release-cockroachdb-0   Bound    pvc-75dadd4c-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       17m
datadir-my-release-cockroachdb-1   Bound    pvc-75e143ca-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       17m
datadir-my-release-cockroachdb-2   Bound    pvc-75ef409a-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       17m

NAME                    STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-cockroachdb-0   Bound    pvc-75dadd4c-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       17m
datadir-cockroachdb-1   Bound    pvc-75e143ca-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       17m
datadir-cockroachdb-2   Bound    pvc-75ef409a-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       17m

In order to expand a persistent volume claim, AllowVolumeExpansion in its storage class must be true. Examine the storage class:

$ kubectl describe storageclass standard

Name:                  standard
IsDefaultClass:        Yes
Annotations:           storageclass.kubernetes.io/is-default-class=true
Provisioner:           kubernetes.io/gce-pd
Parameters:            type=pd-standard
AllowVolumeExpansion:  False
MountOptions:          <none>
ReclaimPolicy:         Delete
VolumeBindingMode:     Immediate
Events:                <none>

If necessary, edit the storage class:

$ kubectl patch storageclass standard -p '{"allowVolumeExpansion": true}'

storageclass.storage.k8s.io/standard patched

Edit one of the persistent volume claims to request more space:

Note:

The requested storage value must be larger than the previous value. You cannot use this method to decrease the disk size.

$ kubectl patch pvc datadir-my-release-cockroachdb-0 -p '{"spec": {"resources": {"requests": {"storage": "200Gi"}}}}'

persistentvolumeclaim/datadir-my-release-cockroachdb-0 patched

$ kubectl patch pvc datadir-cockroachdb-0 -p '{"spec": {"resources": {"requests": {"storage": "200Gi"}}}}'

persistentvolumeclaim/datadir-cockroachdb-0 patched

Check the capacity of the persistent volume claim:

$ kubectl get pvc datadir-my-release-cockroachdb-0

NAME                               STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-my-release-cockroachdb-0   Bound    pvc-75dadd4c-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       18m

$ kubectl get pvc datadir-cockroachdb-0

NAME                    STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-cockroachdb-0   Bound    pvc-75dadd4c-01a1-11ea-b065-42010a8e00cb   100Gi      RWO            standard       18m

If the PVC capacity has not changed, this may be because AllowVolumeExpansion was initially set to false or because the volume has a file system that has to be expanded. You will need to start or restart a pod in order to have it reflect the new capacity.

Tip:

Running kubectl get pv will display the persistent volumes with their requested capacity and not their actual capacity. This can be misleading, so it's best to use kubectl get pvc.

Examine the persistent volume claim. If the volume has a file system, you will see a FileSystemResizePending condition with an accompanying message:
```
$ kubectl describe pvc datadir-my-release-cockroachdb-0
```
```
$ kubectl describe pvc datadir-cockroachdb-0
```
```
Waiting for user to (re-)start a pod to finish file system resize of volume on node.
```
Delete the corresponding pod to restart it:
```
$ kubectl delete pod my-release-cockroachdb-0
```
```
$ kubectl delete pod cockroachdb-0
```
The FileSystemResizePending condition and message will be removed.

View the updated persistent volume claim:

$ kubectl get pvc datadir-my-release-cockroachdb-0

NAME                               STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-my-release-cockroachdb-0   Bound    pvc-75dadd4c-01a1-11ea-b065-42010a8e00cb   200Gi      RWO            standard       20m

$ kubectl get pvc datadir-cockroachdb-0

NAME                    STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
datadir-cockroachdb-0   Bound    pvc-75dadd4c-01a1-11ea-b065-42010a8e00cb   200Gi      RWO            standard       20m

The CockroachDB cluster needs to be expanded one node at a time. Repeat steps 3 - 6 to increase the capacities of the remaining volumes by the same amount.

Upgrade the cluster

It is strongly recommended that you regularly upgrade your CockroachDB version in order to pick up bug fixes, performance improvements, and new features. The CockroachDB upgrade documentation describes how to perform a "rolling upgrade" of a CockroachDB cluster by stopping and restarting nodes one at a time. This is to ensure that the cluster remains available during the upgrade.

The corresponding process on Kubernetes is a staged update, in which the Docker image is updated in the CockroachDB StatefulSet and then applied to the pods one at a time.

Decide how the upgrade will be finalized.

Note:

This step is relevant only when upgrading from v19.2.x to v20.1. For upgrades within the v20.1.x series, skip this step.

By default, after all nodes are running the new version, the upgrade process will be auto-finalized. This will enable certain performance improvements and bug fixes introduced in v20.1. After finalization, however, it will no longer be possible to perform a downgrade to v19.2. In the event of a catastrophic failure or corruption, the only option will be to start a new cluster using the old binary and then restore from one of the backups created prior to performing the upgrade.

We recommend disabling auto-finalization so you can monitor the stability and performance of the upgraded cluster before finalizing the upgrade:
1. Get a shell into the pod with the cockroach binary created earlier and start the CockroachDB built-in SQL client:
```
$ kubectl exec -it cockroachdb-client-secure \-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public
```
```
$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=my-release-cockroachdb-public
```
2. Set the cluster.preserve_downgrade_option cluster setting to the version you are upgrading from:
```
> SET CLUSTER SETTING cluster.preserve_downgrade_option = '19.2';
```
3. Exit the SQL shell and delete the temporary pod:
```
> \q
```
Add a partition to the update strategy defined in the StatefulSet. Only the pods numbered greater than or equal to the partition value will be updated. For a cluster with 3 pods (e.g., cockroachdb-0, cockroachdb-1, cockroachdb-2) the partition value should be 2:
```
$ kubectl patch statefulset cockroachdb \
-p='{"spec":{"updateStrategy":{"type":"RollingUpdate","rollingUpdate":{"partition":2}}}}'
```
```
statefulset.apps/cockroachdb patched
```
```
$ helm upgrade \
my-release \
cockroachdb/cockroachdb \
--set statefulset.updateStrategy.rollingUpdate.partition=2
```
Kick off the upgrade process by changing the Docker image used in the CockroachDB StatefulSet:
```
$ kubectl patch statefulset cockroachdb \
--type='json' \
-p='[{"op": "replace", "path": "/spec/template/spec/containers/0/image", "value":"cockroachdb/cockroach:v20.1.17"}]'
```
```
statefulset.apps/cockroachdb patched
```
Note:

For Helm, you must remove the cluster initialization job from when the cluster was created before the cluster version can be changed.
```
$ kubectl delete job my-release-cockroachdb-init
```
```
$ helm upgrade \
my-release \
cockroachdb/cockroachdb \
--set image.tag=v20.1.17 \
--reuse-values
```

Check the status of your cluster's pods. You should see one of them being restarted:

$ kubectl get pods

NAME            READY     STATUS        RESTARTS   AGE
cockroachdb-0   1/1       Running       0          2m
cockroachdb-1   1/1       Running       0          2m
cockroachdb-2   0/1       Terminating   0          1m
...

NAME                                READY     STATUS              RESTARTS   AGE
my-release-cockroachdb-0            1/1       Running             0          2m
my-release-cockroachdb-1            1/1       Running             0          3m
my-release-cockroachdb-2            0/1       ContainerCreating   0          25s
my-release-cockroachdb-init-nwjkh   0/1       ContainerCreating   0          6s
...

Note:

Ignore the pod for cluster initialization. It is re-created as a byproduct of the StatefulSet configuration but does not impact your existing cluster.

After the pod has been restarted with the new image, get a shell into the pod and start the CockroachDB built-in SQL client:

$ kubectl exec -it cockroachdb-client-secure \-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public

$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=my-release-cockroachdb-public

Run the following SQL query to verify that the number of underreplicated ranges is zero:

SELECT sum((metrics->>'ranges.underreplicated')::DECIMAL)::INT AS ranges_underreplicated FROM crdb_internal.kv_store_status;

  ranges_underreplicated
--------------------------
                       0
(1 row)

This indicates that it is safe to proceed to the next pod.

Exit the SQL shell:
```
> \q
```

Decrement the partition value by 1 to allow the next pod in the cluster to update:

$ kubectl patch statefulset cockroachdb \
-p='{"spec":{"updateStrategy":{"type":"RollingUpdate","rollingUpdate":{"partition":1}}}}'

statefulset.apps/cockroachdb patched

$ helm upgrade \
my-release \
cockroachdb/cockroachdb \
--set statefulset.updateStrategy.rollingUpdate.partition=1 \

Repeat steps 4-8 until all pods have been restarted and are running the new image (the final partition value should be 0).

Check the image of each pod to confirm that all have been upgraded:

$ kubectl get pods \
-o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.containers[0].image}{"\n"}'

cockroachdb-0   cockroachdb/cockroach:v20.1.17
cockroachdb-1   cockroachdb/cockroach:v20.1.17
cockroachdb-2   cockroachdb/cockroach:v20.1.17
...

my-release-cockroachdb-0    cockroachdb/cockroach:v20.1.17
my-release-cockroachdb-1    cockroachdb/cockroach:v20.1.17
my-release-cockroachdb-2    cockroachdb/cockroach:v20.1.17
...

You can also check the CockroachDB version of each node in the Admin UI.

Finish the upgrade.

Note:

This step is relevant only when upgrading from v19.2.x to v20.1. For upgrades within the v20.1.x series, skip this step.

If you disabled auto-finalization in step 1 above, monitor the stability and performance of your cluster for as long as you require to feel comfortable with the upgrade (generally at least a day). If during this time you decide to roll back the upgrade, repeat the rolling restart procedure with the old binary.

Once you are satisfied with the new version, re-enable auto-finalization:
1. Get a shell into the pod with the cockroach binary created earlier and start the CockroachDB built-in SQL client:
```
$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=cockroachdb-public
```
```
$ kubectl exec -it cockroachdb-client-secure \
-- ./cockroach sql \
--certs-dir=/cockroach-certs \
--host=my-release-cockroachdb-public
```
2. Re-enable auto-finalization:
```
> RESET CLUSTER SETTING cluster.preserve_downgrade_option;
```
3. Exit the SQL shell and delete the temporary pod:
```
> \q
```

Stop the cluster

To shut down the CockroachDB cluster:

Delete the resources associated with the cockroachdb label, including the logs and Prometheus and Alertmanager resources:

Warning:

This does not include deleting the persistent volumes that were attached to the pods. If you want to delete the persistent volumes and free up the storage used by CockroachDB, be sure you have a backup copy of your data. Data cannot be recovered once the persistent volumes are deleted. For more information, see the Kubernetes documentation.

$ kubectl delete pods,statefulsets,services,poddisruptionbudget,jobs,rolebinding,clusterrolebinding,role,clusterrole,serviceaccount,alertmanager,prometheus,prometheusrule,serviceMonitor -l app=cockroachdb

pod "cockroachdb-0" deleted
pod "cockroachdb-1" deleted
pod "cockroachdb-2" deleted
statefulset.apps "alertmanager-cockroachdb" deleted
statefulset.apps "prometheus-cockroachdb" deleted
service "alertmanager-cockroachdb" deleted
service "cockroachdb" deleted
service "cockroachdb-public" deleted
poddisruptionbudget.policy "cockroachdb-budget" deleted
job.batch "cluster-init-secure" deleted
rolebinding.rbac.authorization.k8s.io "cockroachdb" deleted
clusterrolebinding.rbac.authorization.k8s.io "cockroachdb" deleted
clusterrolebinding.rbac.authorization.k8s.io "prometheus" deleted
role.rbac.authorization.k8s.io "cockroachdb" deleted
clusterrole.rbac.authorization.k8s.io "cockroachdb" deleted
clusterrole.rbac.authorization.k8s.io "prometheus" deleted
serviceaccount "cockroachdb" deleted
serviceaccount "prometheus" deleted
alertmanager.monitoring.coreos.com "cockroachdb" deleted
prometheus.monitoring.coreos.com "cockroachdb" deleted
prometheusrule.monitoring.coreos.com "prometheus-cockroachdb-rules" deleted
servicemonitor.monitoring.coreos.com "cockroachdb" deleted

Delete the pod created for cockroach client commands, if you didn't do so earlier:
```
$ kubectl delete pod cockroachdb-client-secure
```
```
pod "cockroachdb-client-secure" deleted
```

Note:

This does not delete the secrets you created. For more information on managing secrets, see the Kubernetes documentation.

Uninstall the release:
```
$ helm uninstall my-release
```
```
release "my-release" deleted
```
Delete the pod created for cockroach client commands, if you didn't do so earlier:
```
$ kubectl delete pod cockroachdb-client-secure
```
```
pod "cockroachdb-client-secure" deleted
```

Get the names of any CSRs for the cluster:

$ kubectl get csr

NAME                                                   AGE       REQUESTOR                               CONDITION
default.client.root                                    1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-0                  1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-1                  1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-2                  1h        system:serviceaccount:default:default   Approved,Issued
default.node.my-release-cockroachdb-3                  12m       system:serviceaccount:default:default   Approved,Issued
node-csr-0Xmb4UTVAWMEnUeGbW4KX1oL4XV_LADpkwjrPtQjlZ4   1h        kubelet                                 Approved,Issued
node-csr-NiN8oDsLhxn0uwLTWa0RWpMUgJYnwcFxB984mwjjYsY   1h        kubelet                                 Approved,Issued
node-csr-aU78SxyU69pDK57aj6txnevr7X-8M3XgX9mTK0Hso6o   1h        kubelet                                 Approved,Issued
...

Delete any CSRs that you created:

$ kubectl delete csr default.client.root default.node.my-release-cockroachdb-0 default.node.my-release-cockroachdb-1 default.node.my-release-cockroachdb-2 default.node.my-release-cockroachdb-3

certificatesigningrequest "default.client.root" deleted
certificatesigningrequest "default.node.my-release-cockroachdb-0" deleted
certificatesigningrequest "default.node.my-release-cockroachdb-1" deleted
certificatesigningrequest "default.node.my-release-cockroachdb-2" deleted
certificatesigningrequest "default.node.my-release-cockroachdb-3" deleted

Note:

This does not delete the secrets you created. For more information on managing secrets, see the Kubernetes documentation.

Stop Kubernetes:
- Hosted GKE:
```
$ gcloud container clusters delete cockroachdb --region {region-name}
```
- Hosted EKS:
```
$ eksctl delete cluster --name cockroachdb
```
Warning:

If you stop Kubernetes without first deleting the persistent volumes, they will still exist in your cloud project.

Cockroach
University

Docs Hub

Orchestrate CockroachDB in a Single Kubernetes Cluster

Before you begin

Kubernetes terminology

Limitations

Kubernetes version

Helm version

Resources

Storage

CSR names

Step 1. Start Kubernetes

Hosted GKE

Hosted EKS

Step 2. Start CockroachDB

Set up configuration file

Initialize the cluster

Step 3. Use the built-in SQL client

Step 4. Access the Admin UI

Step 5. Simulate node failure

Step 6. Monitor the cluster

Configure Prometheus

Configure Alertmanager

Step 7. Maintain the cluster

Add nodes

Remove nodes

Expand disk size

Upgrade the cluster

Stop the cluster

See also

Cockroach University

Docs Hub

Cockroach University

Docs Hub

Orchestrate CockroachDB in a Single Kubernetes Cluster

Before you begin

Kubernetes terminology

Limitations

Kubernetes version

Helm version

Resources

Storage

CSR names

Step 1. Start Kubernetes

Hosted GKE

Hosted EKS

Step 2. Start CockroachDB

Set up configuration file

Initialize the cluster

Step 3. Use the built-in SQL client

Step 4. Access the Admin UI

Step 5. Simulate node failure

Step 6. Monitor the cluster

Configure Prometheus

Configure Alertmanager

Step 7. Maintain the cluster

Add nodes

Remove nodes

Expand disk size

Upgrade the cluster

Stop the cluster

See also

Cockroach
University

Cockroach
University