Start a Local Cluster (Insecure)

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Once you've installed CockroachDB, it's simple to run an insecure multi-node cluster locally.

Note:

Running multiple nodes on a single host is useful for testing CockroachDB, but it's not suitable for production. To run a physically distributed cluster, see Manual Deployment or Orchestrated Deployment, and review the Production Checklist.

Before you begin

Make sure you have already installed CockroachDB.
For quick SQL testing or app development, consider running a single-node cluster instead.

Step 1. Start the cluster

Use the cockroach start command to start the first node:

$ cockroach start \
--insecure \
--store=node1 \
--listen-addr=localhost:26257 \
--http-addr=localhost:8080 \
--join=localhost:26257,localhost:26258,localhost:26259 \
--background

You'll see a message like the following:

*
* WARNING: RUNNING IN INSECURE MODE!
*
* - Your cluster is open for any client that can access localhost.
* - Any user, even root, can log in without providing a password.
* - Any user, connecting as root, can read or write any data in your cluster.
* - There is no network encryption nor authentication, and thus no confidentiality.
*
* Check out how to secure your cluster: https://www.cockroachlabs.com/docs/v19.2/secure-a-cluster.html
*
*
* INFO: initial startup completed.
* Node will now attempt to join a running cluster, or wait for `cockroach init`.
* Client connections will be accepted after this completes successfully.
* Check the log file(s) for progress.
*

Take a moment to understand the flags you used:
- The --insecure flag makes communication unencrypted.
- Since this is a purely local cluster, --listen-addr=localhost:26257 and --http-addr=localhost:8080 tell the node to listen only on localhost, with port 26257 used for internal and client traffic and port 8080 used for HTTP requests from the Admin UI.
- The --store flag indicates the location where the node's data and logs are stored.
- The --join flag specifies the addresses and ports of the nodes that will initially comprise your cluster. You'll use this exact --join flag when starting other nodes as well.
  
  For a cluster in a single region, set 3-5 --join addresses. Each starting node will attempt to contact one of the join hosts. In case a join host cannot be reached, the node will try another address on the list until it can join the gossip network.
- The --background flag starts the cockroach process in the background so you can continue using the same terminal for other operations.

Start two more nodes:

$ cockroach start \
--insecure \
--store=node2 \
--listen-addr=localhost:26258 \
--http-addr=localhost:8081 \
--join=localhost:26257,localhost:26258,localhost:26259 \
--background

$ cockroach start \
--insecure \
--store=node3 \
--listen-addr=localhost:26259 \
--http-addr=localhost:8082 \
--join=localhost:26257,localhost:26258,localhost:26259 \
--background

These commands are the same as before but with unique --store, --listen-addr, and --http-addr flags.

Use the cockroach init command to perform a one-time initialization of the cluster, sending the request to any node:

$ cockroach init --insecure --host=localhost:26257

You'll see the following message:

Cluster successfully initialized

At this point, each node also prints helpful startup details to its log. For example, the following command retrieves node 1's startup details:

$ grep 'node starting' node1/logs/cockroach.log -A 11

The output will look something like this:

CockroachDB node starting at 
build:               CCL v19.2.12 @ 2021-01-19 00:00:00 (go1.12.6)
webui:               http://localhost:8080
sql:                 postgresql://root@localhost:26257?sslmode=disable
RPC client flags:    cockroach <client cmd> --host=localhost:26257 --insecure
logs:                /Users/<username>/node1/logs
temp dir:            /Users/<username>/node1/cockroach-temp242232154
external I/O path:   /Users/<username>/node1/extern
store[0]:            path=/Users/<username>/node1
status:              initialized new cluster
clusterID:           8a681a16-9623-4fc1-a537-77e9255daafd
nodeID:              1

Step 2. Use the built-in SQL client

Now that your cluster is live, you can use any node as a SQL gateway. To test this out, let's use CockroachDB's built-in SQL client.

Run the cockroach sql command against node 1:
```
$ cockroach sql --insecure --host=localhost:26257
```
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)
```
Now exit the SQL shell on node 1 and open a new shell on node 2:
```
> \q
```
```
$ cockroach sql --insecure --host=localhost:26258
```
Note:

In a real deployment, all nodes would likely use the default port 26257, and so you wouldn't need to set the port portion of --host.
Run the same SELECT query as before:
```
> SELECT * FROM bank.accounts;
```
```
  id | balance
+----+---------+
   1 | 1000.50
(1 row)
```
As you can see, node 1 and node 2 behaved identically as SQL gateways.
Exit the SQL shell on node 2:
```
> \q
```

Step 3. 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.

Load the initial dataset:

$ cockroach workload init movr \
'postgresql://root@localhost:26257?sslmode=disable'

I190926 16:50:35.663708 1 workload/workloadsql/dataload.go:135  imported users (0s, 50 rows)
I190926 16:50:35.682583 1 workload/workloadsql/dataload.go:135  imported vehicles (0s, 15 rows)
I190926 16:50:35.769572 1 workload/workloadsql/dataload.go:135  imported rides (0s, 500 rows)
I190926 16:50:35.836619 1 workload/workloadsql/dataload.go:135  imported vehicle_location_histories (0s, 1000 rows)
I190926 16:50:35.915498 1 workload/workloadsql/dataload.go:135  imported promo_codes (0s, 1000 rows)

Run the workload for 5 minutes:

$ cockroach workload run movr \
--duration=5m \
'postgresql://root@localhost:26257?sslmode=disable'

Step 4. Access the Admin UI

The CockroachDB Admin UI gives you insight into the overall health of your cluster as well as the performance of the client workload.

Go to http://localhost:8080.
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.
Click Metrics to access a variety of time series dashboards, including graphs of SQL queries and service latency over time:
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.

Step 5. Simulate node failure

In a new terminal, run the cockroach quit command against a node to simulate a node failure:
```
$ cockroach quit --insecure --host=localhost:26259
```
Back in the Admin UI, despite one node being "suspect", notice the continued SQL traffic:

This demonstrates CockroachDB's use of the Raft consensus protocol to maintain availability and consistency in the face of failure; as long as a majority of replicas remain online, the cluster and client traffic continue uninterrupted.

Restart node 3:

$ cockroach start \
--insecure \
--store=node3 \
--listen-addr=localhost:26259 \
--http-addr=localhost:8082 \
--join=localhost:26257,localhost:26258,localhost:26259 \
--background

Step 6. Scale the cluster

Adding capacity is as simple as starting more nodes with cockroach start.

Start 2 more nodes:

$ cockroach start \
--insecure \
--store=node4 \
--listen-addr=localhost:26260 \
--http-addr=localhost:8083 \
--join=localhost:26257,localhost:26258,localhost:26259 \
--background

$ cockroach start \
--insecure \
--store=node5 \
--listen-addr=localhost:26261 \
--http-addr=localhost:8084 \
--join=localhost:26257,localhost:26258,localhost:26259 \
--background

Again, these commands are the same as before but with unique --store, --listen-addr, and --http-addr flags.

Back on the Cluster Overview in the Admin UI, you'll now see 5 nodes listed:

At first, the replica count will be lower for nodes 4 and 5. Very soon, however, you'll see those numbers even out across all nodes, indicating that data is being automatically rebalanced to utilize the additional capacity of the new nodes.

Step 7. Stop the cluster

When you're done with your test cluster, use the cockroach quit command to gracefully shut down each node.
```
$ cockroach quit --insecure --host=localhost:26257
```
```
$ cockroach quit --insecure --host=localhost:26258
```
```
$ cockroach quit --insecure --host=localhost:26259
```
Note:

For the last 2 nodes, the shutdown process will take longer (about a minute each) and will eventually force the nodes to stop. This is because, with only 2 of 5 nodes left, a majority of replicas are not available, and so the cluster is no longer operational.
```
$ cockroach quit --insecure --host=localhost:26260
```
```
$ cockroach quit --insecure --host=localhost:26261
```
To restart the cluster at a later time, run the same cockroach start commands as earlier from the directory containing the nodes' data stores.

If you do not plan to restart the cluster, you may want to remove the nodes' data stores:
```
$ rm -rf node1 node2 node3 node4 node5
```

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, geo-partitioning, serializable transactions, and JSON support

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