Orchestrate CockroachDB in a Single Kubernetes Cluster

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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.

Before you begin

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

• Kubernetes terminology
• Limitations

Kubernetes terminology

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

Hosted GKE

1. 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.

2. 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.

3. 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.

4. 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

1. 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.

2. 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.

3. 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.

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.

Step 4. Access the Admin UI

To access the cluster's Admin UI:

1. 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
   

2. Assign roach to the admin role (you only need to do this once):

   > GRANT admin TO roach;
   

3. Exit the SQL shell and pod:

   > \q
   

4. 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.

5. 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.

6. 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:

1. 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
   

2. 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.

3. 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.

1. 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.

2. 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
   

3. 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
   

4. 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
   

5. 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.

1. Download our alertmanager-config.yaml configuration file:

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

2. Edit the alertmanager-config.yaml file to specify the desired receivers for notifications. Initially, the file contains a placeholder web hook.

3. 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.

4. 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
   

5. 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:

      

6. Ensure that the Alertmanagers are visible to Prometheus by opening http://localhost:9090/status. The screen should look like this:

   

7. 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
   

8. Ensure that the rules are visible to Prometheus by opening http://localhost:9090/rules. The screen should look like this:

   

9. Verify that the TestAlertManager example alert is firing by opening http://localhost:9090/alerts. The screen should look like this:

   

10. 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)
       

Step 7. Maintain the cluster

• Add nodes
• Remove nodes
• Expand disk size
• Upgrade the cluster
• Stop the cluster

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.

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.

1. 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.

2. 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.
   

3. 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.

1. 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
   

2. 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
   

3. 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
   

4. 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.

5. 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.
   

6. 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.

7. 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
   

8. 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.

1. 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
      

2. 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
   

3. 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
   

4. 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.

5. 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
   

6. 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.

7. Exit the SQL shell:

   > \q
   

8. 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 \
   

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

10. 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.

11. 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:

1. 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.

See also

• Kubernetes Multi-Cluster Deployment
• Kubernetes Performance Guide
• Production Checklist
• Manual Deployment
• Orchestrated Deployment
• Monitoring and Alerting
• Performance Benchmarking
• Performance Tuning
• Local Deployment