SNOMED CT TERMINOLOGY SERVER - SNOWSTORM (PRODUCTION READY DEPLOYMENT FOR DOCKER SWARM)

• Snowstorm repository here https://github.com/IHTSDO/snowstorm
• This production ready deployment is tailor made for docker swarm, if you're not familiar with docker swarm please give a read here https://docs.docker.com/engine/swarm/
• Step by step for production ready deployment are given below
• The final setup of this SNOMED CT Terminology Server cluster will consist of the following containers
  • 3 node clusters Elasticsearch containers with high availability
  • 2 containers Snowstorm terminology servers with read only config connected to all 3 node cluster Elasticsearch
  • 1 container Snowstorm terminology server with read & write config connected to all 3 node cluster Elasticsearch (for maintenance, not for production use)
  • 1 container SNOMED CT browser connected to Snowstorm terminology server with read & write config (for maintenance, not for production use)

DEPLOYMENT STEPS

1. Make sure to set vm.max_map_count as Elasticsearch will require it to be set for it to run in docker container. Docs can be followed here https://github.com/IHTSDO/snowstorm/blob/master/docs/using-docker.md#docker-virtual-memory-limits

2. Create overlay network with --attachable flag so all the containers can connect to it later

docker network create --driver=overlay --attachable snowstorm-network

3. Deploy 3 node Elasticsearch clusters one by one in each VM if you have many of them

• Make sure your Elasticsearch container status health is in (healthy) state before you spawn another Elasticsearch container

docker ps -a
897eeb01f01f   docker.elastic.co/elasticsearch/elasticsearch:8.11.1   "/bin/tini -- /usr/l…"   27 minutes ago   Up 27 minutes (healthy)   9200/tcp, 9300/tcp                          snowstorm-es01

docker compose -f snowstorm-es01/docker-compose.yml up -d

docker compose -f snowstorm-es02/docker-compose.yml up -d

docker compose -f snowstorm-es03/docker-compose.yml up -d

4. Deploy read & write Snowstorm terminology server & SNOMED CT browser

docker compose -f snowstorm-write-browser/docker-compose.yml up -d

• Browse to http://your-server-ip:5000 for Snowstorm Swagger API and upload your RF2 file following this docs https://github.com/IHTSDO/snowstorm/blob/master/docs/loading-snomed.md#via-rest

• Your can check the logs of your upload progress

docker logs -fn 10 snowstorm-server-write

• SNOMED CT browser will be on http://your-server-ip:9090

5. Deploy read only Snowstorm terminology server

cat snowstorm-docker-service
# copy, paste and run the content

• Be sure to update your docker service snowstorm-server to connect to your application network so your application can interact with snowstorm-server

docker service update --network-add <your-application-network> snowstorm-server

6. Remove read & write Snowstorm terminology server & SNOMED CT browser

docker compose -f snowstorm-write-browser/docker-compose.yml down -v

• -v flag here is to remove anonymous volume that snowstorm-server-write create

• If you ever need to do maintenance eg: upload new RF2 specification, deploy again read & write Snowstorm terminology server & SNOMED CT browser following step no 4

7. Test for Elasticsearch resiliency

• You can test your cluster resiliency by trying to take down one of the Elasticsearch container and still having your Snowstorm Terminology server & SNOMED CT browser works in their API & query respectively

8. Scaling up or down Snowstorm Terminology Server

• To scale up or down your Snowstorm Terminology Server, you can run this

docker service scale snowstorm-server=<number-of-containers>

HAPPY HACKING !