# Orchestration with Kubernetes (Insecure)

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. To deploy a 30-day free CockroachCloud cluster instead of running CockroachDB yourself, see the Quickstart.

## 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

1. 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.

2. 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.

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

       $ kubectl create -f https://raw.githubusercontent.com/cockroachdb/cockroach/master/cloud/kubernetes/cockroachdb-statefulset.yaml

       service/cockroachdb-public created
       service/cockroachdb created
       poddisruptionbudget.policy/cockroachdb-budget created
       statefulset.apps/cockroachdb created

2. 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

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

       $ kubectl get pv

       NAME                                       CAPACITY   ACCESSMODES   RECLAIMPOLICY   STATUS    CLAIM                           REASON    AGE
       pvc-52f51ecf-8bd5-11e6-a4f4-42010a800002   1Gi        RWO           Delete          Bound     default/datadir-cockroachdb-0             26s
       pvc-52fd3a39-8bd5-11e6-a4f4-42010a800002   1Gi        RWO           Delete          Bound     default/datadir-cockroachdb-1             27s
       pvc-5315efda-8bd5-11e6-a4f4-42010a800002   1Gi        RWO           Delete          Bound     default/datadir-cockroachdb-2             27s

4. Use our `cluster-init.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.yaml

       job.batch/cluster-init created

5. 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

       NAME           COMPLETIONS   DURATION   AGE
       cluster-init   1/1           7s         27s

       $ kubectl get pods

       NAME                 READY   STATUS      RESTARTS   AGE
       cluster-init-cqf8l   0/1     Completed   0          56s
       cockroachdb-0        1/1     Running     0          7m51s
       cockroachdb-1        1/1     Running     0          7m51s
       cockroachdb-2        1/1     Running     0          7m51s

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.

1. 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

2. Update your Helm chart repositories to ensure that you're using the latest CockroachDB chart:

       $ helm repo update

3. Install the CockroachDB Helm chart.

   Provide a "release" name to identify and track this particular deployment of the chart.

   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 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.

4. 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

5. 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

1. Launch a temporary interactive pod and start the built-in SQL client inside it:

       $ kubectl run cockroachdb -it \
       --image=cockroachdb/cockroach:v20.1.17 \
       --rm \
       --restart=Never \
       -- sql \
       --insecure \
       --host=cockroachdb-public

       $ kubectl run cockroachdb -it \
       --image=cockroachdb/cockroach:v20.1.17 \
       --rm \
       --restart=Never \
       -- sql \
       --insecure \
       --host=my-release-cockroachdb-public

2. Run some basic CockroachDB SQL statements:

       > CREATE DATABASE bank;

       > CREATE TABLE bank.accounts (
           id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
             balance DECIMAL
         );

       > INSERT INTO bank.accounts (balance)
         VALUES
             (1000.50), (20000), (380), (500), (55000);

       > SELECT * FROM bank.accounts;

                          id                  | balance
       +--------------------------------------+---------+
         6f123370-c48c-41ff-b384-2c185590af2b |     380
         990c9148-1ea0-4861-9da7-fd0e65b0a7da | 1000.50
         ac31c671-40bf-4a7b-8bee-452cff8a4026 |     500
         d58afd93-5be9-42ba-b2e2-dc00dcedf409 |   20000
         e6d8f696-87f5-4d3c-a377-8e152fdc27f7 |   55000
       (5 rows)

3. Exit the SQL shell and delete the temporary pod:

       > \q

## Step 4. Access the Admin UI

To access the cluster's Admin UI:

1. 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.

2. Go to http://localhost:8080.

3. 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. Add nodes

1. Use the `kubectl scale` command to add a pod for another CockroachDB node:

       $ kubectl scale statefulset cockroachdb --replicas=4

       statefulset "cockroachdb" scaled

       $ kubectl scale statefulset my-release-cockroachdb --replicas=4

       statefulset "my-release-cockroachdb" scaled

2. Verify that the pod for a fourth node, `cockroachdb-3`, was added 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
       example-545f866f5-2gsrs   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 `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.

1. Launch a temporary interactive pod and use the `cockroach node status` command to get the internal IDs of nodes:

       $ kubectl run cockroachdb -it \
       --image=cockroachdb/cockroach:v20.1.17 \
       --rm \
       --restart=Never \
       -- node status \
       --insecure \
       --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 run cockroachdb -it \
       --image=cockroachdb/cockroach:v20.1.17 \
       --rm \
       --restart=Never \
       -- node status \
       --insecure \
       --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)

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 run cockroachdb -it \
       --image=cockroachdb/cockroach:v20.1.17 \
       --rm \
       --restart=Never \
       -- node decommission <node ID> \
       --insecure \
       --host=cockroachdb-public

       $ kubectl run cockroachdb -it \
       --image=cockroachdb/cockroach:v20.1.17 \
       --rm \
       --restart=Never \
       -- node decommission <node ID> \
       --insecure \
       --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 "cockroachdb" scaled

       $ helm upgrade \
       my-release \
       cockroachdb/cockroachdb \
       --set statefulset.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>`.

## See also

Explore other core CockroachDB benefits and features:

- Replication & Rebalancing
- Fault Tolerance & Recovery
- Low Latency Multi-Region Deployment
- Serializable Transactions
- Cross-Cloud Migration
- Orchestration
- JSON Support

You might also want to learn how to orchestrate a production deployment of CockroachDB with Kubernetes.