Mounting as a volume
- Docker & Kubernetes course
- Intermediate
- Lesson 46/82
- 4 min
Learn to mount a ConfigMap as a volume.
Mounting as a volume
When a ConfigMap is mounted as a volume, each key becomes a file in the mount directory. It's ideal for applications expecting a config file (nginx, Prometheus):
spec:
volumes:
- name: ayar
configMap:
name: nginx-ayar
containers:
- name: nginx
image: nginx:1.27
volumeMounts:
- name: ayar
mountPath: /etc/nginx/conf.d
readOnly: trueWhen a ConfigMap mounted as a volume is updated, the files refresh by themselves within a few minutes (unlike environment variables).
Mounting a single file
Mounting at a directory hides the existing files there. To place only a single file, subPath is used; however, a file mounted with subPath isn't refreshed when the ConfigMap is updated:
volumeMounts:
- name: ayar
mountPath: /etc/nginx/nginx.conf
subPath: nginx.confWith items, only specific keys of the ConfigMap can be mounted, under the wanted file names.
Practice Mount the config file
Write a pod's spec section (starting with spec:): an ayar volume from the nginx-ayar ConfigMap under volumes; container named nginx, image nginx:1.27; mount ayar at /etc/nginx/conf.d with readOnly: true.
Starter code
# buraya yazSample solution
spec:
volumes:
- name: ayar
configMap:
name: nginx-ayar
containers:
- name: nginx
image: nginx:1.27
volumeMounts:
- name: ayar
mountPath: /etc/nginx/conf.d
readOnly: trueExpected output
pod/web configured $ kubectl exec web -- ls /etc/nginx/conf.d default.conf
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 If the nginx-ayar ConfigMap has a default.conf key, which file appears in the container?
- /etc/nginx/conf.d/default.conf Correct answer
- /etc/nginx/nginx-ayar
- /configmap/default.conf
- None
Explanation: The key becomes the file name, the value its content.
2 Mount to a single file, not a directory.
- name: ayar
mountPath: /etc/nginx/nginx.conf
____: nginx.conf - name: ayar
mountPath: /etc/nginx/nginx.conf
subPath: nginx.confExplanation: subPath selects a single path inside the volume.
3 Match.
| Term | Meaning |
|---|---|
volumes.configMap |
ConfigMap source |
volumeMounts |
Mount location |
subPath |
Single file, not refreshed |
readOnly: true |
Read-only |