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Deploy a global service
Deploy exactly one replica of a service on each machine in your cluster.
This is useful for cluster-wide infrastructure services like monitoring or security agents, log collectors, or reverse proxies.
Deploy to all machines
To deploy exactly one replica on each machine in your cluster for a specific service, set
mode: global under the deploy section in
your Compose file:
services:
monitoring:
image: quay.io/prometheus/node-exporter:latest
deploy:
# Run one container on each machine in the cluster
mode: global
Then deploy:
uc deploy
Before creating replicas on cluster machines, it will show you a deployment plan and ask for confirmation.
If you add more machines to the cluster later, you need to run uc deploy again to create replicas on the new machines.
Uncloud doesn't automatically scale global services to new machines.
Deploy to a subset of machines
You can combine the global mode with x-machines
to deploy one container to each specified machine:
services:
caddy:
image: caddy:2
deploy:
# Run one container on each of the three specified machines
mode: global
x-machines:
- ingress-1
- ingress-2
- ingress-3
This is useful when you want a service on a specific group of machines (for example, ingress or GPU machines) but still want the one-per-machine guarantee that global mode provides.
Global vs replicated mode
The default mode is replicated, where you specify the number of replicas.
| Mode | Replicas | Placement |
|---|---|---|
replicated (default) |
You specify with scale or deploy.replicas |
Uncloud evenly spreads replicas across all machines or x-machines |
global |
Always one per machine | One replica on each machine or each x-machines machine |
See also
- Deploy an app: Deploy from source code or prebuilt images
- Deploy to specific machines: Deploy services to specific machines in your cluster
- Compose Specification: deploy.mode: Compose specification for deployment modes