Shardman docker compose.

• Shardman documentation: http://repo.postgrespro.ru/doc/pgprosm/14beta2.1/en/html
• Clone repo: git clone [email protected]:pkonotopov/shardman-docker.git shardman
• Limitations: Linux systems only. No MacosX and WSL supported.
• Inital cluster config in spec.json file: one node, no replication, no monitor.

After cloning shardman-docker repo please execute these steps.

1. Launch Shardman in containers via docker-compose

1.1 Up

docker-compose up -d

This command bring up two containers: etcd and shardman in simple configuration without additional nodes, replicas and monitor.

1.2 Initialization of cluster configuration

docker exec shardman_shard_1 shardman-ladle init -f /etc/shardman/spec.json

This command uploads initial configuraion into the etcd storage.

1.3 Get name of the first shardman node

docker ps --filter "label=com.shardman.role=shard" -aq

The expected output should be like this: 2ca4e1984120

1.4 Add first node to the cluster

docker exec shardman_shard_1 shardman-ladle addnodes -n 2ca4e1984120

2. Cluster scale up

2.1 Add new containers

docker-compose up --scale shard=4 --no-recreate -d

2.2 Get hostnames

docker ps --filter "label=com.shardman.role=shard" -a --format "table {{.ID}} {{.Names}}"

Expected output:

CONTAINER ID NAMES
ba2e956b5095 shardman_shard_4
d500d2c70b3e shardman_shard_3
5c42f00bca5a shardman_shard_2
2ca4e1984120 shardman_shard_1

Containers ID's are the hostnames of new containers, so add new hosts to the cluster:

2.3 Add nodes to cluster

docker exec shardman_shard_1 shardman-ladle addnodes -n 5c42f00bca5a,d500d2c70b3e,ba2e956b5095

3. Cluster scale down

3.1 Remove nodes from the cluster configuration:

docker exec shardman_shard_1 shardman-ladle rmnodes -n 5c42f00bca5a,d500d2c70b3e,ba2e956b5095

3.2 Remove containers

docker-compose up --scale shard=1 --no-recreate -d

4. Create cluster with shard replicas

If you want to create cluster with replicas and monitors you should change some parameters in the specification file spec.json:

"Repfactor": 1
"MonitorsNum": 1

Then at the Up step (1.1) run cluster with minimal nodes count 2: docker-compose up --scale shard=2 -d.

At the Initialization step (1.2) upload configuration file into etcd k/v store.

Finally, add two created nodes to the cluster.

Get nodes names: docker ps --filter "label=com.shardman.role=shard" -aq

The expected output should be:

2ca4e1984120
5c42f00bca5a

Add nodes: docker exec shardman_shard_1 shardman-ladle addnodes -n 2ca4e1984120,5c42f00bca5a.