depends_on points to a missing service
depends_on: - databse
Compose refuses to start the project. YAMLTools marks the exact line and tells you which services do exist.
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Docker Compose validator
Paste your docker-compose.yml and get more than "the YAML is valid": broken references between services, undeclared networks and volumes, port clashes and the security risks your team should know about, with a one-click fix when there is one.
Docker Compose
YAML
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What YAMLTools checks in your Docker Compose file
- The whole file against the official Compose Specification JSON Schema, including typos in keys such as imgae or enviroment, with a suggested fix.
- depends_on, links and network_mode pointing to services that do not exist, services that depend on themselves and circular dependencies.
- Networks, named volumes, secrets and configs used by a service but not declared at the top level.
- Two services publishing the same host port, duplicated container_name and service_healthy conditions on services without a healthcheck.
- Variables like ${API_KEY} without a default, env_file and extends that point outside the file, and the obsolete version key.
Risks it flags
- Privileged containers, dangerous capabilities (ALL, SYS_ADMIN, NET_ADMIN) and the Docker socket mounted inside a container.
- Passwords, tokens and connection strings written in plain text in environment.
- Images without a tag or on :latest, which change under your feet on every pull.
- Databases published on every network interface of the host (0.0.0.0).
- Services without healthcheck, restart policy or memory and CPU limits.
Common Docker Compose errors
The ones that break a deploy most often, and how YAMLTools reports them.
service_healthy without a healthcheck
depends_on:
db:
condition: service_healthyIf db does not define a healthcheck (and its image does not either), startup fails. The report explains which service needs one.
Network or volume not declared
networks: - backend # not in networks:
The service uses a network or named volume that is missing from the top-level section, so docker compose up stops.
Your file stays on your computer
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Docker Compose validator FAQ
What it checks, how it checks it and what happens with your file.