Hey folks, I'm having a frustrating issue I hope you can help me with. I've migrated a project from Docker Compose to Kubernetes, and while the transition was mostly smooth, I'm stuck on getting my MongoDB container to initialize the user and password correctly. In Docker, using the same environment variables worked perfectly.
When the MongoDB container starts with a clean data directory, it's supposed to read the environment variables: MONGO_INITDB_ROOT_USERNAME, MONGO_INITDB_ROOT_PASSWORD, and MONGO_INITDB_DATABASE to set up the user. I've got my Docker command set up like this:
```bash
docker run -d
--name mongo
-p 27017:27017
-e MONGO_INITDB_ROOT_USERNAME=mongo
-e MONGO_INITDB_ROOT_PASSWORD=bongo
-e MONGO_INITDB_DATABASE=admin
-v mongo:/data
mongo:4.2
--serviceExecutor adaptive --wiredTigerCacheSizeGB 2
```
Here's my Kubernetes manifest:
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: mongodb
spec:
replicas: 1
selector:
matchLabels:
app: mongodb
template:
metadata:
labels:
app: mongodb
spec:
containers:
- name: mongodb
image: mongo:4.2
command: ["mongod"]
args: ["--bind_ip_all", "--serviceExecutor", "adaptive", "--wiredTigerCacheSizeGB", "2"]
env:
- name: MONGO_INITDB_ROOT_USERNAME
value: mongo
- name: MONGO_INITDB_ROOT_PASSWORD
value: bongo
- name: MONGO_INITDB_DATABASE
value: admin
ports:
- containerPort: 27017
volumeMounts:
- name: mongo-data
mountPath: /data/db
volumes:
- name: mongo-data
hostPath:
path: /k3s_data/mongo/db
```
The Kubernetes pod starts fine, but it seems to ignore the env variables and doesn't initialize. I verified that the env variables are set inside the pod, but it still doesn't work. Am I missing something? Could it be that the env variables are slow to take effect? Any thoughts would be greatly appreciated!
3 Answers
Another thing to consider is that you're using a static hostPath for your volume. If that path was initialized once, MongoDB might not re-initialize because it already finds an existing database. Try changing it to `emptyDir: {}` for testing, or switch to a StatefulSet with a volume claim template for more reliable management.
Have you checked the logs for any specific errors? Sometimes Kubernetes events can give a clue about what's going on. You can view those by running a `kubectl describe pod ` to see if any issues pop up there.
It looks like you're overriding the default command that MongoDB uses to initialize. The `command: ["mongod"]` line is what's messing things up. This image has a default entry point which is crucial for those environment variables to get recognized. Try removing that line while keeping your args and env variables, and it should sort the issue out! Also, you might want to update your image; using a more recent version could help with any hidden issues.
Thank you so much, CodeWizard99! That worked perfectly. I appreciate your help!
Also, just a heads-up, it’s generally better to avoid using older images unless necessary, as they might have unresolved bugs.