Hands-on Lab·Certified Kubernetes Administrator
Volume subPath and Mounted File Permissions
The two things that go wrong when configuration reaches a container as a file: a mount that hides the directory it landed on, and a permissions field that is decimal when everyone reads it as octal.
Storage Guide 66 of 103 Intermediate
- Kubernetes1.36.4
- Runtimecontainerd 2.2.6
- CNICalico v3.32.1
- TimeAbout 16 min
- Reviewed26 August 2026
Written against the versions above. The `..data` timestamp directory name is generated per mount. Everything else here is the same on any cluster.
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| CKA1001 | 192.168.0.175 | Ubuntu 26.04 LTS | Control Plane Node | 2 Core | 4 GB | 50 GB |
| CKA1001-NODE01 | 192.168.0.176 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
| CKA1001-NODE02 | 192.168.0.177 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
| CKA1001-NODE03 | 192.168.0.178 | Ubuntu 26.04 LTS | Worker Node | 2 Core | 4 GB | 50 GB |
Before you start
- guide 34 - the four ways configuration reaches a Pod, before this covers what the file mount does to the filesystem.
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What the image ships in that directory
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Mounting a ConfigMap over it
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The same ConfigMap, mounted with subPath
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The cost of subPath, which is the part that bites
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File permissions on a mounted Secret