uncloud/website/docs/3-concepts/5-compose/1-support-matrix.md

Compose support matrix

Uncloud supports a subset of the Compose specification with some extensions and limitations. The following table shows the support status for main Compose features:

Feature	Support Status	Notes
Services
build	✅ Supported	Build context and Dockerfile
command	✅ Supported	Override container command
configs	✅ Supported	File-based and inline configs
cpus	✅ Supported	CPU limit
depends_on	❌ Not supported	Services start independently
dns	❌ Not supported	Built-in service discovery
dns_search	❌ Not supported	Built-in service discovery
entrypoint	✅ Supported	Override container entrypoint
env_file	✅ Supported	Environment file
environment	✅ Supported	Environment variables
image	✅ Supported	Container image specification
init	✅ Supported	Run init process in container
labels	❌ Not supported	Not currently needed
links	❌ Not supported	Use service names for communication
logging	✅ Supported	Uses Docker daemon logging
mem_limit	✅ Supported	Memory limit
mem_reservation	✅ Supported	Memory reservation
mem_swappiness	❌ Not supported
memswap_limit	❌ Not supported
networks	❌ Not supported	All containers share cluster network
ports	⚠️ Limited	Basic port publishing. Use x-ports for HTTP/HTTPS
privileged	✅ Supported	Run containers in privileged mode
pull_policy	✅ Supported	always, missing, never
secrets	❌ Not supported	Use configs or environment variables
security_opt	❌ Not supported
storage_opt	❌ Not supported
user	✅ Supported	Set container user
volumes	✅ Supported	Named volumes, bind mounts, tmpfs
Deploy
labels	❌ Not supported	Not needed
mode	⚠️ Limited	Only replicated supported
placement	❌ Not supported	Use x-machines extension
replicas	✅ Supported	Number of container replicas
resources	⚠️ Limited	CPU and memory limits only
restart_policy	❌ Not supported	Services auto-restart
Volumes
Named volumes	✅ Supported	Docker volumes
Bind mounts	✅ Supported	Host path binding
Tmpfs mounts	✅ Supported	In-memory filesystems
Volume labels	✅ Supported	Custom labels
External volumes	⚠️ Limited	Must exist before deployment
Volume drivers	⚠️ Limited	Local driver only
Configs
File-based configs	✅ Supported	Read from file
Inline configs	✅ Supported	Defined in compose file
External configs	❌ Not supported	Not supported
Short syntax	❌ Not supported	Use long syntax only
Extensions
x-caddy	✅ Uncloud-specific	Custom Caddy configuration
x-machines	✅ Uncloud-specific	Machine placement constraints
x-ports	✅ Uncloud-specific	HTTP/HTTPS port publishing

Legend

• ✅ Supported: Feature works as documented
• ⚠️ Limited: Partial support or with restrictions
• ❌ Not supported: Feature is not (yet) available

Uncloud Extensions

Uncloud provides several custom extensions to enhance the Compose experience:

x-ports

Define HTTP/HTTPS endpoints for services:

services:
  web:
    image: nginx
    x-ports:
      - 80/https
      - example.com:80/https

x-caddy

Custom Caddy reverse proxy configuration:

services:
  web:
    image: nginx
    x-caddy: |
      example.com {
        reverse_proxy {{ upstreams 80 }}
      }

x-machines

Specify on what machines the service should run:

services:
  web:
    image: nginx
    x-machines: ["web-1", "web-2"]