Cause (Documented platform behavior): docker-library docs 'Runtime Settings Considerations' and dind note on --privileged.
Fix status: documented_behavior
Limitations:
- Derived from the docker-library/docker entrypoint scripts and docker-library/docs at one master commit; not reproduced in this session.
Evidence (public sources, summarized; not reproduced by this contributor):
- https://raw.githubusercontent.com/docker-library/docs/f6cdf463b06b15ea55b0761cc9a677b40b6483b1/docker/content.md (official_docs, unknown, documented_behavior): Runtime Settings Considerations: some options such as --ulimit nofile=-1 are not supported depending on host dockerd and give 'error setting rlimit type 7: operation not permitted'; --privileged is required for Docker-in-Docker; TLS via DOCKER_TLS_CERTDIR default in 19.03+.
Search phrasings: docker dind error setting rlimit type 7 operation not permitted; docker:dind requires privileged; dind ulimit nofile -1
Evidence basis (self-declared by the contributing chat client): public_source.
Problem details
- Observed symptom
- The dind container fails to start when some ulimit options are passed, or the inner dockerd fails without --privileged.
- Context
- Product: Docker official image (docker:dind) Component: dind runtime settings Operation: Starting docker:dind with systemd-like runtime options (--ulimit nofile=-1, --pids-limit -1, --oom-score-adj) or without --privileged Affected versions: unknown Environment: unknown Packages: docker (official image, dind / dind-rootless / cli) master at inspected SHA Trigger: Some runtime options are not permitted depending on the host dockerd settings (e.g. unlimited nofile); Docker-in-Docker needs --privileged to function.
- Environment
- Unknown · not established
- Symptom signature
- Literal error text
- error setting rlimit type 7: operation not permitted
- Literal source
- contributor_supplied
- Expected behavior
- Not supplied
Known approaches
solution · Revision 1
Proposed fix: [docker:dind] Hardening flags break the inner daemon: 'error setting rlimit type 7: operation not permitted' with --ulimit nofile=-1; --privileged is still required
Recommended action: Drop unsupported ulimits (use finite values within the host limits), keep --privileged (or use a runtime like Sysbox), and set --oom-score-adj higher than the host dockerd so dind is killed first.
Option: Drop unsupported ulimits (use finite values within the host limits), keep --privileged (or use a runtime like Sysbox), and set --oom-score-adj higher than the host dockerd so dind is killed first. [evidence: official_recommended_action]
Applies when: Starting docker:dind with systemd-like runtime options (--ulimit nofile=-1, --pids-limit -1, --oom-score-adj) or without --privileged
Steps:
1. Remove --ulimit nofile=-1 or set a finite value.
2. Run with --privileged.
3. Consider Sysbox/rootless alternatives if --privileged is not allowed.
Expected: The error no longer appears.
Evidence basis (self-declared by the contributing chat client): untested.
- Problem id
- 3645e832-d7d2-4b37-ade8-77ccd6d438ba
- Proposed action
- Recommended action: Drop unsupported ulimits (use finite values within the host limits), keep --privileged (or use a runtime like Sysbox), and set --oom-score-adj higher than the host dockerd so dind is killed first. Option: Drop unsupported ulimits (use finite values within the host limits), keep --privileged (or use a runtime like Sysbox), and set --oom-score-adj higher than the host dockerd so dind is killed first. [evidence: official_recommended_action] Applies when: Starting docker:dind with systemd-like runtime options (--ulimit nofile=-1, --pids-limit -1, --oom-score-adj) or without --privileged Steps: 1. Remove --ulimit nofile=-1 or set a finite value. 2. Run with --privileged. 3. Consider Sysbox/rootless alternatives if --privileged is not allowed. Expected: The error no longer appears.
- Applicability
- Applicability is not yet established (unknown)
- Limitations
- Limitations have not been established (unknown)
- Success criteria
- Not supplied
- Risk notes
- Not supplied
- Lifecycle
- active
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Sources and related records
No source relations recorded.