Couchbase 4.0 provides lots of features that allows you to develop with agility and operate at any scale. Some of the features that allow you to operate at any scale are:

• Elastic Scalability
• Consistent High Performance
• Always-On Availability
• Multi-Data Center Deployment
• Simple and Powerful Administration
• Enterprise-grade Security

Learn more about these enterprise features at couchbase.com/operate-at-any-scale.

A complete overview is available in Couchbase Server 4.0 datasheet.

This blog will explain how you can easily setup a 3-node Couchbase Cluster using Docker Compose.

👁 docker-couchbase-cluster

The source code and latest instructions are available at github.com/arun-gupta/docker-images/tree/master/couchbase-cluster.

Create Couchbase Nodes

Couchbase cluster can be easily created using the following Docker Compose file:

couchbase1:
 image: couchbase/server
 volumes:
 - ~/couchbase/node1:/opt/couchbase/var
couchbase2:
 image: couchbase/server
 volumes:
 - ~/couchbase/node2:/opt/couchbase/var
couchbase3:
 image: couchbase/server
 volumes:
 - ~/couchbase/node3:/opt/couchbase/var
 ports:
 - 8091:8091
 - 8092:8092 
 - 8093:8093 
 - 11210:11210

This file has service definition for three Couchbase nodes. Admin ports are exposed for only one node as other nodes will talk to each other use Docker-internally assigned IP addresses.

1. Create three directories ~couchbase/node1, ~couchbase/node2, ~couchbase/node3 – one for each node.
2. Start three Couchbase nodes as using the docker-compose.yml shown earlier:

   > docker-compose up -d
   Pulling couchbase1 (couchbase/server:latest)...
   latest: Pulling from couchbase/server
   70618b6e8070: Pull complete
   05820377a11a: Pull complete
   8de88a91bde5: Pull complete
   61994089e28e: Pull complete
   bc191c81777b: Pull complete
   939d0c2514c9: Pull complete
   fa75256f7885: Pull complete
   7bc9fb79dd30: Pull complete
   e4c99c5f6106: Pull complete
   307ac999aa30: Pull complete
   24eeb78ce9ab: Pull complete
   c4180973b487: Pull complete
   6e0c54ca80e7: Pull complete
   c6d69cc874d9: Pull complete
   31485a5bae7a: Pull complete
   31c8df734d6b: Pull complete
   Digest: sha256:0e983929897ae9bd396533ff7875f30027290c6acf164a66c967ca8884507381
   Status: Downloaded newer image for couchbase/server:latest
   Creating couchbasecluster_couchbase1_1
   Creating couchbasecluster_couchbase3_1
   Creating couchbasecluster_couchbase2_1

   This command is given on a Docker Machine.

3. Check status of the nodes:

   > docker ps
   CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
   07ff4f1823a4 couchbase/server "/entrypoint.sh couch" 5 minutes ago Up 5 minutes 8091-8093/tcp, 11207/tcp, 11210-11211/tcp, 18091-18092/tcp couchbasecluster_couchbase2_1
   18f7bf07134a couchbase/server "/entrypoint.sh couch" 5 minutes ago Up 5 minutes 0.0.0.0:8091-8093->8091-8093/tcp, 11207/tcp, 11211/tcp, 0.0.0.0:11210->11210/tcp, 18091-18092/tcp couchbasecluster_couchbase3_1
   4db3e1280776 couchbase/server "/entrypoint.sh couch" 5 minutes ago Up 5 minutes 8091-8093/tcp, 11207/tcp, 11210-11211/tcp, 18091-18092/tcp couchbasecluster_couchbase1_1
   

   Docker Compose can also show the status:

   > docker-compose ps
    Name Command State Ports 
   -----------------------------------------------------------------------------------------------------------------------------------------------------------------
   couchbasecluster_couchbase1_1 /entrypoint.sh couchbase-s ... Up 11207/tcp, 11210/tcp, 11211/tcp, 
    18091/tcp, 18092/tcp, 8091/tcp, 
    8092/tcp, 8093/tcp 
   couchbasecluster_couchbase2_1 /entrypoint.sh couchbase-s ... Up 11207/tcp, 11210/tcp, 11211/tcp, 
    18091/tcp, 18092/tcp, 8091/tcp, 
    8092/tcp, 8093/tcp 
   couchbasecluster_couchbase3_1 /entrypoint.sh couchbase-s ... Up 11207/tcp, 0.0.0.0:11210->11210/tcp, 
    11211/tcp, 18091/tcp, 18092/tcp, 
    0.0.0.0:8091->8091/tcp, 
    0.0.0.0:8092->8092/tcp, 
    0.0.0.0:8093->8093/tcp
   

4. Check logs of the nodes:

   > docker-compose logs
   Attaching to couchbasecluster_couchbase2_1, couchbasecluster_couchbase3_1, couchbasecluster_couchbase1_1
   couchbase2_1 | Starting Couchbase Server -- Web UI available at http://<ip>:8091
   couchbase3_1 | Starting Couchbase Server -- Web UI available at http://<ip>:8091
   couchbase1_1 | Starting Couchbase Server -- Web UI available at http://<ip>:8091
   

Configure Couchbase Cluster

Lets configure these nodes to be part of a cluster now.

1. Find IP address of the Docker Machine:

   >> docker-machine ip default
   192.168.99.104

2. Access Couchbase Admin Console at http://<DOCKER_MACHINE_IP:8091. This is http://192.168.99.104:8091 in our case. It will show the output as:
    
   👁 docker-couchbase-cluster-setup-1024x717
   
   Click on “Setup”.
3. Each container is given an internal IP address by Docker, and each of these IPs is visible to all other containers running on the same host. We need to use these internal IP address when adding a new node to the cluster.Find IP address of the first container:

   > docker inspect --format '{{ .NetworkSettings.IPAddress }}' couchbasecluster_couchbase3_1
   172.17.0.2

   Use this IP address to change the Hostname field:

   👁 docker-couchbase-cluster-node1-e1445384614211-1024x952
   

4. Click on “Next”. Adjust the RAM if necessary. Read more about Couchbase Cluster Settings.
5. Pick a sample bucket that you’d like to get installed, and click on Next.
6. Change Per Node RAM Quota from 400 to 100. This is required as we’ll add other nodes later.
    
   👁 docker-couchbase-cluster-node-ram-quota-1024x594
   
7. Click on Next, accept T&C, and click on Next.
8. Enter a password that you can remember as we’ll need this later to add more nodes.

Default view of the cluster looks like as shown:

👁 docker-couchbase-cluster-default-view-1024x409

Add More Couchbase Nodes

Now, lets add the other two nodes that were created earlier by Docker Compose.

1. Click on “Server Nodes” to see the default view as:
    
   👁 docker-couchbase-cluster-server-nodes-default-view-1024x316
   
2. Find IP address of one of the remaining nodes:

   docker inspect --format '{{ .NetworkSettings.IPAddress }}' couchbasecluster_couchbase1_1
   172.17.0.1

3. Click on “Add Server”, specify the IP address:
    
   👁 docker-couchbase-cluster-add-server-node1-1024x910
   
   and click on “Add Server”.
4. Repeat the previous two steps with the server name couchbasecluster_couchbase2_1.

Couchbase Cluster Rebalance

A cluster needs to be rebalanced to ensured that the data is well distributed amongst the newly added or removed nodes. Read more about Couchbase Cluster Rebalance.

Clicking on “Pending Rebalance” tab shows the nodes that have been added to the cluster but are not rebalanced yet:

👁 docker-couchbase-cluster-pending-rebalance-1024x367

Click on “Rebalance” and this will automatically rebalance the cluster:

👁 docker-couchbase-cluster-rebalanced-1024x409

You just deployed a Couchbase cluster using Docker Compose, enjoy!

Some more references:

• Couchbase 4 Administration Guide
• Couchbase 4 Server Architecture
• Couchbase 4 Cluster Setup