Deploy a Local Cluster in Docker (Insecure)

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Once you've installed the official CockroachDB Docker image, it's simple to run an insecure multi-node cluster across multiple Docker containers on a single host, using Docker volumes to persist node data.

Before you begin

• Make sure you have already installed the official CockroachDB Docker image.
• For quick SQL testing or application development, consider running a single-node cluster. When you use Docker to run a single-node cluster, some additional features are available to assist you with testing and development. See Start a single-node cluster. Single-node clusters are not highly available or fault tolerant, and are not appropriate for production use.
• Running multiple nodes on a single host is useful for testing CockroachDB, but it's not highly available or fault tolerant, and is not suitable for production. To run a physically-distributed cluster in containers, use an orchestration tool like Kubernetes. See Orchestration for more details, and review the Production Checklist.

Start a multi-node cluster

Step 1. Create a bridge network

Since you'll be running multiple Docker containers on a single host, with one CockroachDB node per container, create a Docker bridge network. The network has configurable properties such as a pool of IP addresses, network gateway, and routing rules. All nodes will connect to this network and can communicate openly by default, but incoming traffic can reach a container only through the container's published port mappings, as described in Step 3: Start the cluster. Because the network is a bridge, from the point of view of the client, the Docker host seems to service the request directly.

docker network create -d bridge roachnet

In subsequent steps, replace roachnet with the name of your Docker network.

Step 2: Create Docker volumes for each cluster node

Cockroach Labs recommends that you store cluster data in Docker volumes rather than in the storage layer of the running container. Using a volume has the following advantages over using bind mounts or writing directly to the running container's filesystem.

• Volumes are managed entirely by Docker. A bind mount mounts an arbitrary directory on the Docker host into the container, and that directory could potentially be modified or deleted by any process with permission.
• Volumes persist even if the containers that were using it are deleted. A container's local storage is temporarily unavailable if the container is stopped, and is permanently removed if the container is deleted.
• When compared to a container's local storage, writing to either a local volume or a bind mount has considerably better performance because it uses fewer kernel system calls on the Docker host. For an explanation, refer to Manage Data in Docker.
• A volume can be backed up, restored, or migrated to a different container or Docker host. Refer to Back Up, Restore, or Migrate Data Volumes.
• A volume can be pre-populated before connecting it to a container. Refer to Populate a Volume Using a Container.
• A volume can be backed by local storage, a cloud storage resource, SSH, NFS, Samba, or raw block storage, among others. For details, refer to Use a Volume Driver.

Create a Docker volume for each container. You can create only one volume at a time.

docker volume create roach1

docker volume create roach2

docker volume create roach3

Step 3. Start the cluster

This section shows how to start a three-node cluster where:

• Each node will store its data in a unique Docker volume.
• Each node will listen for SQL and HTTP connections at a unique port each on the roachnet network, and these ports are published. Client requests to the Docker host at a given port are forwarded to the container that is publishing that port. Nodes do not listen on localhost.
• Each node will listen and advertise for inter-node cluster traffic at port 26357 on the roachnet network. This port is not published, so inter-node traffic does not leave this network.

1. New in v23.1: Optionally, on each node, set the COCKROACH_ARGS environment variable to the string of arguments to use when starting CockroachDB. If COCKROACH_ARGS is set, its value is automatically passed to the cockroach command, and any additional arguments to the cockroach command are ignored.

2. Start the first node and configure it to listen on roach1:26257 for SQL clients and roach1:8080 for the DB Console and to publish these ports, and to use roach1:26357for inter-node traffic. The Docker host will forward traffic to a published port to the publishing container. CockroachDB starts in insecure mode and a certs directory is not created.

   docker run -d \
   --name=roach1 \
   --hostname=roach1 \
   --net=roachnet \
   -p 26257:26257 \
   -p 8080:8080 \
   -v "roach1:/cockroach/cockroach-data" \
   cockroachdb/cockroach:v23.1.30 start \
     --advertise-addr=roach1:26357 \
     --http-addr=roach1:8080 \
     --listen-addr=roach1:26357 \
     --sql-addr=roach1:26257 \
     --insecure \
     --join=roach1:26357,roach2:26357,roach3:26357
   

   This command creates a container and starts the first CockroachDB node inside it. Take a moment to understand each part:

   • docker run: The Docker command to start a new container.
   • -d: This flag runs the container in the background so you can continue the next steps in the same shell.
   • --name: The name for the container. This is optional, but a custom name makes it significantly easier to reference the container in other commands, for example, when opening a Bash session in the container or stopping the container.
   • --hostname: The hostname for the container. You will use this to join other containers/nodes to the cluster.
   • --net: The bridge network for the container to join. See step 1 for more details.
   • -p 26257:26257 -p 8080:8080: These flags cause the Docker host to publish ports 26257 and 8080 and to forward requests to a published port to the same port on the container.
   • -v "roach1:/cockroach/cockroach-data": This flag mounts the roach1 Docker volume into the container's filesystem at /cockroach/cockroach-data/. This volume will contain data and logs for the container, and the volume will persist after the container is stopped or deleted. For more details, see Docker's volumes documentation.
   • cockroachdb/cockroach:v23.1.30 start (...) --join: The CockroachDB command to start a node in the container. The --advertise-addr, --http-addr, --listen-addr, and --sql-addr flags cause CockroachDB to listen on separate ports for inter-node traffic, DB Console traffic, and SQL traffic. The --join flag contains each node's hostname or IP address and the port where it listens for inter-node traffic from other nodes.

3. Start the second node and configure it to listen on roach2:26258 for SQL clients and roach2:8081 for the DB Console and to publish these ports, and to use roach2:26357for inter-node traffic. The offsets for the published ports avoid conflicts with roach1's published ports. The named volume roach2 is mounted in the container at /cockroach/cockroach-data.

   CockroachDB starts in insecure mode and a certs directory is not created.

   docker run -d \
     --name=roach2 \
     --hostname=roach2 \
     --net=roachnet \
     -p 26258:26258 \
     -p 8081:8081 \
     -v "roach2:/cockroach/cockroach-data" \
     cockroachdb/cockroach:v23.1.30 start \
       --advertise-addr=roach2:26357 \
       --http-addr=roach2:8081 \
       --listen-addr=roach2:26357 \
       --sql-addr=roach2:26258 \
       --insecure \
       --join=roach1:26357,roach2:26357,roach3:26357
   

4. Start the third node and configure it to listen on roach3:26259 for SQL clients and roach2:8082 for the DB Console and to publish these ports, and to use roach3:26357for inter-node traffic. The offsets for the published ports avoid conflicts with roach1's and roach2's published ports. The named volume roach3 is mounted in the container at /cockroach/cockroach-data.

   docker run -d \
     --name=roach3 \
     --hostname=roach3 \
     --net=roachnet \
     -p 26259:26259 \
     -p 8082:8082 \
     -v "roach3:/cockroach/cockroach-data" \
     cockroachdb/cockroach:v23.1.30 start \
       --advertise-addr=roach3:26357 \
       --http-addr=roach3:8082 \
       --listen-addr=roach3:26357 \
       --sql-addr=roach3:26259 \
       --insecure \
       --join=roach1:26357,roach2:26357,roach3:26357
   

5. Perform a one-time initialization of the cluster. This example runs the cockroach init command from within the roach1 container, but you can run it from any container or from an external system that can reach the Docker host.

   cockroach init connects to the node's --advertise-addr, rather than the node's --sql-addr. Replace roach1:26357 with the node's --advertise-addr value (not the node's --sql-addr). This example runs the cockroach command directly on a cluster node, but you can run it from any system that can connect to the Docker host.

   docker exec -it roach1 ./cockroach --host=roach1:26357 init --insecure
   

   The following message displays:

   Cluster successfully initialized
   

   Each node also prints helpful startup details to its log. For example, the following command runs the grep command from within the roach1 container to display lines in its /cockroach-data/logs/cockroach.log log file that contain the string node starting and the next 11 lines.

   docker exec -it roach1 grep 'node starting' /cockroach/cockroach-data/logs/cockroach.log -A 11
   

   The output will look something like this:

   CockroachDB node starting at 
   build:               CCL v23.1.30 @ 2024-12-12 00:00:00 (go1.19.6)
   webui:               http://roach1:8080
   sql:                 postgresql://root@roach1:26357?sslmode=disable
   client flags:        /cockroach/cockroach <client cmd> --host=roach1:26357
   logs:                /cockroach/cockroach-data/logs
   temp dir:            /cockroach/cockroach-data/cockroach-temp273641911
   external I/O path:   /cockroach/cockroach-data/extern
   store[0]:            path=/cockroach/cockroach-data
   status:              initialized new cluster
   clusterID:           1a705c26-e337-4b09-95a6-6e5a819f9eec
   nodeID:              1
   

Step 4. Connect to the cluster

Now that your cluster is live, you can use any node as a SQL gateway. To test this out, let's use the docker exec command to start the built-in SQL shell in the roach1 container.

1. Start the SQL shell in a container or from an external system that can reach the Docker host. Set --host to the Docker host's IP address and use any of the ports where nodes are listening for SQL connections, 26257, 26258, or 26259. This example connects the SQL shell within the roach1 container to roach2:26258. You could also connect to roach3:26259.

   docker exec -it roach1 ./cockroach sql --host=roach2:26258 --insecure
   

2. 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)
   

3. Exit the SQL shell on roach1 and open a new shell on roach2:

   > \q
   

   docker exec -it roach2 ./cockroach --host=roach2:26258 sql --insecure
   

4. Run the same SELECT query as before:

   > SELECT * FROM bank.accounts;
   

     id | balance
   +----+---------+
      1 | 1000.50
   (1 row)
   

   As you can see, roach1 and roach2 perform identically as SQL gateways.

5. Exit the SQL shell on roach2:

   > \q
   

Step 5. Run a sample workload

CockroachDB also comes with a number of built-in workloads for simulating client traffic. Let's run the workload based on CockroachDB's sample vehicle-sharing application, MovR.

1. Load the initial dataset on roach1:26257

   docker exec -it roach1 ./cockroach workload init movr 'postgresql://root@roach1:26257?sslmode=disable'
   

2. Run the workload for five minutes:

   docker exec -it roach1 ./cockroach workload run movr --duration=5m 'postgresql://root@roach1:26257?sslmode=disable'
   

Step 6. Access the DB Console

The DB Console gives you insight into the overall health of your cluster as well as the performance of the client workload.

1. When you started the first node's container, you mapped the node's default HTTP port 8080 to port 8080 on the Docker host, so go to http://localhost:8080. If necessary, replace localhost with the hostname or IP address of the Docker host.

2. On the Cluster Overview, notice that three nodes are live, with an identical replica count on each node:

   

   This demonstrates CockroachDB's automated replication of data via the Raft consensus protocol.

   Note:

   Capacity metrics can be incorrect when running multiple nodes on a single machine. For more details, see this limitation.

3. Click Metrics to access a variety of time series dashboards, including graphs of SQL queries and service latency over time:

   

4. Use the Databases, Statements, and Jobs pages to view details about your databases and tables, to assess the performance of specific queries, and to monitor the status of long-running operations like schema changes, respectively.

5. Optionally verify that DB Console instances for roach2 and roach3 are reachable on ports 8081 and 8082 and show the same information as port 8080.

Step 7. Stop the cluster

1. Use the docker stop and docker rm commands to stop and remove the containers (and therefore the cluster). By default, docker stop sends a SIGTERM signal, waits for 10 seconds, and then sends a SIGKILL signal. Cockroach Labs recommends that you allow between 5 and 10 minutes before forcibly stopping the cockroach process, so this example sets the grace period to 5 minutes. If you do not plan to restart the cluster, you can omit -t.

   docker stop -t 300 roach1 roach2 roach3
   

   docker rm roach1 roach2 roach3
   

2. If you do not plan to restart the cluster, you can also remove the Docker volumes and the Docker network:

   docker volume rm roach1 roach2 roach3
   

   docker network rm roachnet
   

Start a single-node cluster

When you use the cockroach start-single-node command to start a single-node cluster with Docker, additional features are available to help with testing and development.

• You can optionally set the following Docker environment variables to create a database and user automatically and to set a password for the user.

  • COCKROACH_DATABASE
  • COCKROACH_USER
  • COCKROACH_PASSWORD

  To prevent loss of a cluster's existing data, the environment variables are used only if the /cockroach/cockroach-data directory within the container is empty.

• You can optionally mount a directory of initialization scripts into the docker-entrypoint-initdb.d directory within the container. These scripts are run after CockroachDB starts and after the database and user (if specified as environment variables) have been created. The scripts run in the alphanumeric sort order imposed by your locale. The init scripts are run only if the /cockroach/cockroach-data directory within the container is empty.

During local development and testing, you can re-initialize the default database, user, and password by deleting the contents of /cockroach/cockroach-data within the running container and then restarting the container.

This section shows how to start a single-node cluster that uses these features.

Step 1. Create a Docker volume for the node

Cockroach Labs recommends that you store cluster data in a Docker volume rather than in the storage layer of the running container. Otherwise, if a Docker container is inadvertently deleted, its data is inaccessible.

To create the Docker volume where the cluster will store its data, run the following:

docker volume create roach-single

Step 2. Start the cluster

This section shows how to start a single-node cluster that:

• Stores its data in the roach-single volume on the Docker host, which is mounted on the /cockroach/cockroach-data directory within the container.

• If the /cockroach/cockroach-data directory within the container is empty, creates the specified database, user, and password automatically.

  Tip:

  Instead of specifying each value directly by using the -e or --env flag, you can store them in a file on the Docker host. Use one key-value pair per line and set the --env-file flag to the file's path.

• Bind-mounts the ~/init-scripts directory on the Docker host onto the /docker-entrypoint-initdb.d directory within the container. Initialization scripts stored in this directory are run after CockroachDB starts and the default database, user, and password are initialized.

• Accepts database client connections on hostname roach-single on port 26257.

• Accepts connections to the DB Console on hostname roach-single on port 8080.

The cockroach process listens on 127.0.0.1:26257 and localhost:26257, and this cannot be changed for single-node cluster running in a container. The --listen-address option is ignored.

1. Start the cluster node and configure it to listen on port 26257 for SQL clients and run DB Console on port 8080.

   docker run -d \
     --env COCKROACH_DATABASE={DATABASE_NAME} \
     --env COCKROACH_USER={USER_NAME} \
     --env COCKROACH_PASSWORD={PASSWORD} \
     --name=roach-single \
     --hostname=roach-single \
     -p 26257:26257 \
     -p 8080:8080 \
     -v "roach-single:/cockroach/cockroach-data"  \
     cockroachdb/cockroach:v23.1.30 start-single-node \
     --http-addr=roach-single:8080
   

   By default, a certs directory is created and CockroachDB starts in secure mode.

   Note:

   The COCKROACH_DATABASE, COCKROACH_USER, and COCKROACH_PASSWORD environment variables and the contents of the /docker-entrypoint-initdb.d directory are ignored if you use cockroach start rather than cockroach start-single-node. They are also ignored if data exists in the /cockroach/cockroach-data directory within the container.

   Docker adds a DNS entry that resolves the hostname roach-single to the container's IP address in Docker's default network. The following examples use this hostname.

2. After the cluster is initialized, the cluster node prints helpful startup details to its log, including the DB Console URL and the SQL connection string. To retrieve roach-single's startup details:

   docker exec -it roach-single grep 'node starting' /cockroach/cockroach-data/logs/cockroach.log -A 11
   

   CockroachDB node starting at 2023-11-07 20:26:36.11359443 +0000 UTC m=+1.297365572 (took 1.0s)
   build:               CCL  @ 2023/09/27 02:36:23 (go1.19.10)
   webui:               https://127.0.0.1:8080
   sql:                 postgresql://root@127.0.0.1:26257/defaultdb?sslcert=certs%2Fclient.root.crt&sslkey=certs%2Fclient.root.key&sslmode=verify-full&sslrootcert=certs%2Fca.crt
   sql (JDBC):          jdbc:postgresql://127.0.0.1:26257/defaultdb?sslcert=certs%2Fclient.root.crt&sslkey=certs%2Fclient.root.key&sslmode=verify-full&sslrootcert=certs%2Fca.crt&user=root
   RPC client flags:    /cockroach/cockroach <client cmd> --host=127.0.0.1:26257 --certs-dir=certs
   logs:                /cockroach/cockroach-data/logs
   temp dir:            /cockroach/cockroach-data/cockroach-temp2611102055
   external I/O path:   /cockroach/cockroach-data/extern
   store[0]:            path=/cockroach/cockroach-data
   storage engine:      pebble
   clusterID:           60f29a4e-1c87-4b0c-805d-eb73460766b1
   status:              initialized new cluster
   nodeID:              1
   

Step 3. Connect to the cluster

1. After the cluster is initialized, you can connect to it, run tests on it, and stop it using the same instructions as a multi-node cluster. To monitor the cluster node's logs interactively:

   docker logs --follow roach-single
   

   To stop monitoring the logs, press Ctrl+C to exit the docker logs command.

2. To connect to the cluster interactively using the cockroach sql command-line interface, set --url cluster's SQL connection string, which is printed next to sql: in the cluster's startup details. Connect to the roach-single cluster:

   docker exec -it roach-single ./cockroach sql --url="postgresql://root@127.0.0.1:26257/defaultdb?sslcert=certs%2Fclient.root.crt&sslkey=certs%2Fclient.root.key&sslmode=verify-full&sslrootcert=certs%2Fca.crt"
   

Step 4. Access the DB Console

The DB Console gives you insight into the overall health of your cluster as well as the performance of the client workload.

When you started the cluster container, you published the container's DB Console port 8080 to port 8080 on the Docker host so that DB Console can be accessed from outside the cluster container. To connect to DB Console, go to http://localhost:8080. If necessary, replace localhost with the hostname or IP address of the Docker host.

Step 5. Stop the cluster

1. Use the docker stop and docker rm commands to stop and remove the container (and therefore the single-node cluster). By default, docker stop sends a SIGTERM signal, waits for 10 seconds, and then sends a SIGKILL signal. Cockroach Labs recommends that you allow between 5 and 10 minutes before forcibly stopping the cockroach process, so this example sets the grace period to 5 minutes. If you do not plan to restart the cluster, you can omit -t.

   docker stop -t 300 roach-single
   

   docker rm roach-single
   

2. If you do not plan to restart the cluster, you can also remove the Docker volume that contains the cluster's data:

   docker volume rm roach-single
   

What's next?

• Learn more about CockroachDB SQL and the built-in SQL client
• Install the client driver for your preferred language
• Build an app with CockroachDB
• Further explore CockroachDB capabilities like fault tolerance and automated repair, multi-region performance, serializable transactions, and JSON support