Orchestrate a Local Cluster with Kubernetes

On this page

On top of CockroachDB's built-in automation, you can use a third-party orchestration system to simplify and automate even more of your operations, from deployment to scaling to overall cluster management.

This page walks you through a simple demonstration, using the open-source Kubernetes orchestration system. Using either the CockroachDB Helm chart or a few configuration files, you'll quickly create a 3-node local cluster. You'll run some SQL commands against the cluster and then simulate node failure, watching how Kubernetes auto-restarts without the need for any manual intervention. You'll then scale the cluster with a single command before shutting the cluster down, again with a single command.

Note:

To orchestrate a physically distributed cluster in production, see Orchestrated Deployments.

Before you begin

Before getting started, it's helpful to review some Kubernetes-specific terminology:

Feature	Description
minikube	This is the tool you'll use to run a Kubernetes cluster inside a VM on your local workstation.
pod	A pod is a group of one of more Docker containers. In this tutorial, all pods will run on your local workstation, each containing 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 storage 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. When using `minikube`, persistent volumes are external temporary directories that endure until they are manually deleted or until the entire Kubernetes cluster is deleted.
persistent volume claim	When pods are created (one per CockroachDB node), each pod will request a persistent volume claim to “claim” durable storage for its node.

Step 1. Start Kubernetes

Follow Kubernetes' documentation to install minikube, the tool used to run Kubernetes locally, for your OS. This includes installing a hypervisor and kubectl, the command-line tool used to manage Kubernetes from your local workstation.

Note:
Make sure you install minikube version 0.21.0 or later. Earlier versions do not include a Kubernetes server that supports the maxUnavailability field and PodDisruptionBudget resource type used in the CockroachDB StatefulSet configuration.
Start a local Kubernetes cluster:
```
$ minikube start
```

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.

From your local workstation, use our cockroachdb-statefulset-secure.yaml file to create the StatefulSet that automatically creates 3 pods, each with a CockroachDB node running inside it.

Download cockroachdb-statefulset-secure.yaml:
```
$ curl -O https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/cockroachdb-statefulset-secure.yaml
```
Warning:

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. Specify this amount by adjusting resources.requests.memory and resources.limits.memory in cockroachdb-statefulset-secure.yaml. Their values should be identical.

We recommend setting cache and max-sql-memory each to 1/4 of your memory allocation. For example, if you are allocating 8Gi of memory to each CockroachDB node, substitute the following values in this line:
```
--cache 2Gi --max-sql-memory 2Gi
```
Use the file to create the StatefulSet and start the cluster:
```
$ kubectl create -f cockroachdb-statefulset-secure.yaml
```
```
serviceaccount/cockroachdb created
role.rbac.authorization.k8s.io/cockroachdb created
clusterrole.rbac.authorization.k8s.io/cockroachdb created
rolebinding.rbac.authorization.k8s.io/cockroachdb created
clusterrolebinding.rbac.authorization.k8s.io/cockroachdb created
service/cockroachdb-public created
service/cockroachdb created
poddisruptionbudget.policy/cockroachdb-budget created
statefulset.apps/cockroachdb created
```
Alternatively, if you'd rather start with a configuration file that has been customized for performance:
1. Download our performance version of cockroachdb-statefulset-secure.yaml:
```
$ curl -O https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/performance/cockroachdb-statefulset-secure.yaml
```
2. Modify the file wherever there is a TODO comment.
3. Use the file to create the StatefulSet and start the cluster:
```
$ kubectl create -f cockroachdb-statefulset-secure.yaml
```
Tip:

If you change the StatefulSet name from the default cockroachdb, be sure to start and end with an alphanumeric character and otherwise use lowercase alphanumeric characters, -, or . so as to comply with CSR naming requirements.

As each pod is created, it issues a Certificate Signing Request, or CSR, to have the node's certificate signed by the Kubernetes CA. You must manually check and approve each node's certificates, 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.node.cockroachdb-0   1m    system:serviceaccount:default:cockroachdb   Pending
default.node.cockroachdb-1   1m    system:serviceaccount:default:cockroachdb   Pending
default.node.cockroachdb-2   1m    system:serviceaccount:default: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.cockroachdb-0

Name:               default.node.cockroachdb-0
Labels:             <none>
Annotations:        <none>
CreationTimestamp:  Thu, 09 Nov 2017 13:39:37 -0500
Requesting User:    system:serviceaccount:default:cockroachdb
Status:             Pending
Subject:
  Common Name:    node
  Serial Number:
  Organization:   Cockroach
Subject Alternative Names:
         DNS Names:     localhost
                        cockroachdb-0.cockroachdb.default.svc.cluster.local
                        cockroachdb-0.cockroachdb
                        cockroachdb-public
                        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 first pod:

$ kubectl certificate approve default.node.cockroachdb-0

certificatesigningrequest "default.node.cockroachdb-0" approved

Repeat steps 2 and 3 for the other 2 pods.

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 persistentvolumes

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

Use our cluster-init-secure.yaml file to perform a one-time initialization that joins the CockroachDB nodes into a single cluster:
```
$ kubectl create \
-f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/cluster-init-secure.yaml
```
```
job.batch/cluster-init-secure created
```
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 cluster initialization has completed successfully. The job should be considered successful and the Kubernetes pods should soon be considered Ready:

$ kubectl get job cluster-init-secure

NAME                  COMPLETIONS   DURATION   AGE
cluster-init-secure   1/1           23s        35s

$ kubectl get pods

NAME                        READY     STATUS      RESTARTS   AGE
cluster-init-secure-q8s7v   0/1       Completed   0          55s
cockroachdb-0               1/1       Running     0          3m
cockroachdb-1               1/1       Running     0          3m
cockroachdb-2               1/1       Running     0          3m

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.

Install the Helm client.

Install the Helm server, known as Tiller.

In the likely case that your Kubernetes cluster uses RBAC (e.g., if you are using GKE), you first need to create RBAC resources to grant Tiller access to the Kubernetes API:

Create a rbac-config.yaml file to define a role and service account:

apiVersion: v1
kind: ServiceAccount
metadata:
  name: tiller
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: tiller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
  - kind: ServiceAccount
    name: tiller
    namespace: kube-system

Create the service account:

$ kubectl create -f rbac-config.yaml

serviceaccount/tiller created
clusterrolebinding.rbac.authorization.k8s.io/tiller created

Start the Helm server and install Tiller:

Note:

Tiller does not currently support Kubernetes 1.16.0. The following command includes a workaround to install Tiller for use with 1.16.0.

$ helm init --service-account tiller --override spec.selector.matchLabels.'name'='tiller',spec.selector.matchLabels.'app'='helm' --output yaml | sed 's@apiVersion: extensions/v1beta1@apiVersion: apps/v1@' | kubectl apply -f -

deployment.apps/tiller-deploy created
service/tiller-deploy created

Install the CockroachDB Helm chart, providing a "release" name to identify and track this particular deployment of the chart and setting the Secure.Enabled parameter to true:

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 --name my-release --set Secure.Enabled=true,Resources.requests.memory="<your memory allocation>",CacheSize="<your cache size>",MaxSQLMemory="<your SQL memory size>" 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.

Warning:

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 CacheSize and MaxSQLMemory each to 1/4 of the memory allocation specified in your Resources.requests.memory parameter. For example, if you are allocating 8GiB of memory to each CockroachDB node, use the following values with the --set flag in the helm install command:
```
Requests.resources.memory="8GiB",CacheSize="2GiB",MaxSQLMemory="2GiB"
```
Note:

You can customize your deployment by passing additional configuration parameters to helm install using the --set key=value[,key=value] flag. For a production cluster, you should consider modifying the Storage and StorageClass parameters. This chart defaults to 100 GiB of disk space per pod, but you may want more or less depending on your use case, and the default persistent volume StorageClass in your environment may not be what you want for a database (e.g., on GCE and Azure the default is not SSD).

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 persistentvolumes

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:

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.

From your local workstation, use our client-secure.yaml file to launch a pod and keep it running indefinitely:
```
$ kubectl create \
-f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/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=cockroachdb-public

# Welcome to the cockroach SQL interface.
# All statements must be terminated by a semicolon.
# To exit: CTRL + D.
#
# Client version: CockroachDB CCL v19.1.0 (x86_64-unknown-linux-gnu, built 2019/04/29 18:36:40, go1.11.6)
# Server version: CockroachDB CCL v19.1.0 (x86_64-unknown-linux-gnu, built 2019/04/29 18:36:40, go1.11.6)

# Cluster ID: 256a8705-e348-4e3a-ab12-e1aba96857e4
#
# Enter \? for a brief introduction.
#
root@cockroachdb-public: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 cockroach SQL interface.
# All statements must be terminated by a semicolon.
# To exit: CTRL + D.
#
# Client version: CockroachDB CCL v19.1.0 (x86_64-unknown-linux-gnu, built 2019/04/29 18:36:40, go1.11.6)
# Server version: CockroachDB CCL v19.1.0 (x86_64-unknown-linux-gnu, built 2019/04/29 18:36:40, go1.11.6)

# Cluster ID: 256a8705-e348-4e3a-ab12-e1aba96857e4
#
# Enter \? for a brief introduction.
#
root@my-release-cockroachdb-public: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 one of the pods:
```
$ kubectl port-forward cockroachdb-0 8080
```
```
$ kubectl port-forward my-release-cockroachdb-0 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. Add nodes

Add a pod for another CockroachDB node:

$ kubectl scale statefulset cockroachdb --replicas=4

statefulset.apps/cockroachdb scaled

$ helm upgrade \
my-release \
cockroachdb/cockroachdb \
--set Replicas=4 \
--reuse-values

statefulset "my-release-cockroachdb" scaled

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

$ kubectl get csr

NAME                         AGE       REQUESTOR                                   CONDITION
default.client.root          8m        system:serviceaccount:default:cockroachdb   Approved,Issued
default.node.cockroachdb-0   22m       system:serviceaccount:default:cockroachdb   Approved,Issued
default.node.cockroachdb-1   22m       system:serviceaccount:default:cockroachdb   Approved,Issued
default.node.cockroachdb-2   22m       system:serviceaccount:default:cockroachdb   Approved,Issued
default.node.cockroachdb-3   2m        system:serviceaccount:default:cockroachdb   Pending

NAME                                    AGE   REQUESTOR                                              CONDITION
default.client.root                     8m    system:serviceaccount:default:my-release-cockroachdb   Approved,Issued
default.node.my-release-cockroachdb-0   22m   system:serviceaccount:default:my-release-cockroachdb   Approved,Issued
default.node.my-release-cockroachdb-1   22m   system:serviceaccount:default:my-release-cockroachdb   Approved,Issued
default.node.my-release-cockroachdb-2   22m   system:serviceaccount:default:my-release-cockroachdb   Approved,Issued
default.node.my-release-cockroachdb-3   2m    system:serviceaccount:default:my-release-cockroachdb   Pending

Approve the CSR for the new pod:

$ kubectl certificate approve default.node.cockroachdb-3

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

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

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

Confirm that pod for the fourth node, cockroachdb-3, is Running successfully:

$ kubectl get pods

NAME                         READY     STATUS    RESTARTS   AGE
cockroachdb-0                1/1       Running   0          28m
cockroachdb-1                1/1       Running   0          27m
cockroachdb-2                1/1       Running   0          10m
cockroachdb-3                1/1       Running   0          5s
cockroachdb-client-secure    1/1       Running   0          25m

NAME                                 READY     STATUS    RESTARTS   AGE
my-release-cockroachdb-0             1/1       Running   0          28m
my-release-cockroachdb-1             1/1       Running   0          27m
my-release-cockroachdb-2             1/1       Running   0          10m
my-release-cockroachdb-3             1/1       Running   0          5s
example-545f866f5-2gsrs              1/1       Running   0          25m

Step 7. Remove nodes

To safely remove a node from your cluster, you must first decommission the node and only then adjust the 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 | v19.1.11 | 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 | v19.1.11 | 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 | v19.1.11 | 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 | v19.1.11 | 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 | v19.1.11 | 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 | v19.1.11 | 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 | v19.1.11 | 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 | v19.1.11 | 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 Replicas=3 \
--reuse-values

Step 8. Stop the cluster

If you plan to restart the cluster, use the minikube stop command. This shuts down the minikube virtual machine but preserves all the resources you created:
```
$ minikube stop
```
```
Stopping local Kubernetes cluster...
Machine stopped.
```
You can restore the cluster to its previous state with minikube start.
If you do not plan to restart the cluster, use the minikube delete command. This shuts down and deletes the minikube virtual machine and all the resources you created, including persistent volumes:
```
$ minikube delete
```
```
Deleting local Kubernetes cluster...
Machine deleted.
```
Tip:
To retain logs, copy them from each pod's stderr before deleting the cluster and all its resources. To access a pod's standard error stream, run kubectl logs <podname>.

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Orchestrate a Local Cluster with Kubernetes

Before you begin

Step 1. Start Kubernetes

Step 2. Start CockroachDB

Step 3. Use the built-in SQL client

Step 4. Access the Admin UI

Step 5. Simulate node failure

Step 6. Add nodes

Step 7. Remove nodes

Step 8. Stop the cluster

See also