These are the Compose file features supported on Kubernetes

Feature	docker stack deploy	Compose on Kubernetes
build
- context
- dockerfile
- args
- cache_from
- labels
cap_add		Yes
cap_drop		Yes
command	Yes	Yes
configs	Yes	Yes
- external	Yes	Yes
- file	Yes	Yes
- mode	Yes	Yes
cgroup_parent
container_name
credential_spec	Yes
deploy	Yes
- endpoint_mode: vip	Yes	Yes
- endpoint_mode: dnsrr	Yes
- labels	Yes	Yes
- mode	Yes	Yes
- placement	Yes	Partial
- replicas	Yes	Yes
- resources	Yes	Yes
-- limits	Yes	Yes
-- reservations	Yes	Yes
- restart_policy	Yes	Yes
-- condition: none	Yes	Yes
-- condition: on-failure	Yes	Yes
-- condition: any	Yes	Yes
-- delay	Yes
-- max_attempts	Yes
-- window	Yes
- update_config	Yes
-- parallelism	Yes	Yes
-- delay	Yes
-- failure_action	Yes
-- monitor	Yes
-- max_failure_ratio	Yes
- devices
- depends_on
- dns
- dns_search
- tmpfs		Yes
- entrypoint	Yes	Yes
- env_file	Yes	Yes
- environment	Yes	Yes
-- key=value	Yes	Yes
-- key	Yes
- expose	Yes	Yes
- external_links
- extra_hosts	Yes	Yes
- healthcheck	Yes	Yes
-- test	Yes	Yes
-- test: NONE	Yes	Yes
-- interval	Yes	Yes
-- timeout	Yes	Yes
-- retries	Yes	Yes
-- disable	Yes	Yes
- image	Yes	Yes
- isolation	Yes
- labels	Yes	Yes
- links
- logging	Yes
-- driver	Yes
-- options	Yes
- network_mode
- networks	Yes
-- aliases	Yes
-- ipv4_address	Yes
-- ipv6_address	Yes
- pid: host	Yes	Yes
- ports	Yes	Yes
-- target	Yes	Yes
-- published	Yes	Yes
-- protocol	Yes	Yes
-- mode: host	Yes	Not sure
-- mode: ingress	Yes	Not sure
- secrets	Yes	Yes
-- source	Yes	Yes
-- target	Yes	Yes
-- uid	Yes
-- gid	Yes
-- mode	Yes	Yes
- security_opt
- stop_grace_period	Yes	Yes
- stop_signal
- sysctls
- ulimits
- userns_mode
- volumes	Yes	Yes
-- type: volume	Yes	Yes
-- type: bind	Yes	Yes
-- source	Yes	Yes
-- target	Yes	Yes
-- read_only	Yes	Yes
-- bind/propagation	Yes
-- volume/nocopy	Yes
- restart
- domainname
- hostname	Yes	Yes
- ipc		Yes
- mac_address
- privileged		Yes
- read_only	Yes	Yes
- shm_size
- stdin_open	Yes	Yes
- tty	Yes	Yes
- user: numerical	Yes	Yes
- user: name	Yes
- working_dir	Yes	Yes

Not supported by k8s

• mac_address (https://github.com/kubernetes/kubernetes/issues/2289)
• shm_size (https://github.com/kubernetes/kubernetes/issues/28272)
• ulimits (https://github.com/kubernetes/kubernetes/issues/3595)
• non numerical user

Placeholders interpolation

Before a yaml file is sent to Kubernenetes, its ${...} placeholders are replaced with actual values.

• A first attempt is made at reading the variable from a .env file is current working directory.
• If no value is found, an environment variable are used.