Swarm curl Client/Server Over Nextmini

This example adds external client/server services on top of a running swarm dataplane deployment (typically from examples/multi-dc).

For base swarm dataplane deployment, use Multi-DC Swarm Dataplane.

The flow is:

1. Deploy curl-server and curl-client services in the same overlay network as dataplane (nextmini_nextmini-net).
2. Insert explicit routes with route/insert_route.py.
3. Read service logs to confirm curl reaches the server through Nextmini.

Prerequisites

Before running this page, ensure:

• Multi-DC controller + dataplane are already running (see examples/multi-dc).
• You can run commands on the swarm manager.
• curl-server and curl-client images are built on the nodes where they will be scheduled.

Deployment order

1. Build server/client images

On the host that will run the server service:

cd /path/to/nextmini/examples/swarm-curl
docker build -t curl-server -f src/Dockerfile.server .

On the host that will run the client service:

cd /path/to/nextmini/examples/swarm-curl
docker build -t curl-client -f src/Dockerfile.client .

2. Manager: create server then client services

From the swarm manager, deploy server first:

docker service create \
  --name curl-server \
  --replicas 1 \
  --network nextmini_nextmini-net \
  --publish 8080:8080 \
  --constraint 'node.hostname==<SERVER_HOSTNAME>' \
  --restart-condition on-failure \
  --restart-delay 5s \
  --restart-max-attempts 3 \
  curl-server:latest

Then deploy client:

docker service create \
  --name curl-client \
  --replicas 1 \
  --network nextmini_nextmini-net \
  --constraint 'node.hostname==<CLIENT_HOSTNAME>' \
  --restart-condition on-failure \
  --restart-delay 10s \
  --restart-max-attempts 5 \
  curl-client:latest

3. Insert routes

route/insert_route.py does two important things:

• Reads service VIPs for curl-client and curl-server from Docker.
• Inserts two DB routes using INTERMEDIATE_HOPS = [1, 2, 3]:
  • client -> 1,2,3 -> server
  • server -> 3,2,1 -> client

Before running it, update database host in route/insert_route.py if needed:

cd /path/to/nextmini/examples/swarm-curl
rg 'host=' route/insert_route.py

Then insert routes:

cd route
uv run insert_route.py

Verify

From swarm manager:

docker service ls
docker service logs --tail 100 curl-server
docker service logs --tail 100 curl-client

Successful client logs include a completed curl run and HTTP output from the server (Hello World).

Optional DB verification from the controller host:

cd /path/to/nextmini/examples/multi-dc
docker compose -f controller-standalone.yml exec postgres \
  psql -U pgusr -d nextmini -c "SELECT src_node_id, dst_node_id, route FROM routes LIMIT 10;"

Tear down

Remove client/server services from the manager:

docker service rm curl-client curl-server

If this environment was created only for this test, also remove dataplane and control-plane services:

# swarm manager
docker stack rm nextmini

# controller host
cd /path/to/nextmini/examples/multi-dc
docker compose -f controller-standalone.yml down